# VX220 with Tesla SDU



## Tomdb (Jan 28, 2013)

Which LG 16S modules are you planning on using? Have you looked at the price of these batteries vs something like modules from Zero-EV? (to be clear I work at Zero-EV and have used certain LG 16S modules in the past)
Zero-EV 6S Module


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## catphish (Jul 30, 2017)

Tomdb said:


> Which LG 16S modules are you planning on using? Have you looked at the price of these batteries vs something like modules from Zero-EV? (to be clear I work at Zero-EV and have used certain LG 16S modules in the past)
> Zero-EV 6S Module


Thanks, your modules are marginally higher capacity (2.2 vs 1.8kWh, at the same weight 12kg) and do look like they'd be a good option for me. I'll compare prices wen I can as I haven't had firm information about the price / availability yet. I was hoping I might be able to use the OEM BMS slave boards included on the LG modules, but if not, then those CALB modules may be the better choice, so thanks for the pointer. Are the connectors to plug into the cell taps readily available? If so, I'll look at BMS options.

Edit: I ignored your first question. Please see this post too: Unknown LG 16S pack with water cooling


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## catphish (Jul 30, 2017)

PS. I'd need a minimum of 16 of these modules, to achieve 96s, vs only 6 (but realistically 12) of the 16s modules, so this will be a factor too, but will of course also depending on my current draw requirements and available space. I think I want 600A peak for the Tesla SDU, so 16 of your 6s modules might be spot on!


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## Mango Animal (Oct 1, 2021)

Hi, I'm new.
Does SDU mean single drive unit?


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## catphish (Jul 30, 2017)

Mango Animal said:


> Hi, I'm new.
> Does SDU mean single drive unit?


It means "Small Drive Unit". Tesla Model S comes in various configurations, using some combination of "Smal Drive Unit" (approx 200kW) and "Large Drive Unit" (approx 400kW). I believe 4-wheel-drive versions use one of each.


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## brian_ (Feb 7, 2017)

catphish said:


> It means "Small Drive Unit". Tesla Model S comes in various configurations, using some combination of "Smal Drive Unit" (approx 200kW) and "Large Drive Unit" (approx 400kW). I believe 4-wheel-drive versions use one of each.


Yes, but...

2WD Model S had one large drive unit in the rear (the large unit was used only in the rear)
the first AWD Model S had small drive units at front and rear, while Performance AWD versions had a small unit in the front and the large unit in the rear (the small units were used only in AWD vehicles)
These are all the original Model S/X induction motor drive units; they are no longer used in current Tesla vehicles, but they are what can be found in salvage and they're what most people mean when they talk about conversions using "Tesla motors" or "Tesla drive units". They are what all of the aftermarket controller modifications are for. There are now different drive units first introduced in the Model 3 and Model Y, with variations of them now used in the Model S (and presumably Model X) as well.


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## brian_ (Feb 7, 2017)

For those (mostly in North America) who are unfamiliar with the Speedster and VX220, these are the GM versions of the Lotus Elise. It's an aluminum-framed mid-engine car.


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## brian_ (Feb 7, 2017)

If I understand this correctly, the LG Chem 16S modules that are being considered are not the ones used in the Chrysler Pacifica Hybrid and widely sold by conversion suppliers such as EV West. Those appear to now be unavailable from those sources (allegedly due to legal action by LG Chem).

The appeal of a low Ah capacity - and so a lot of cell groups in series for the size of the module - is to keep the total size of a ~360 V pack down. By the same logic, any plug-in hybrid is a potential source of a suitable small high-voltage battery pack; this is one reason that Chevrolet Volt packs were popular. The LG Chem 16S modules in the linked thread were apparently from a Volvo XC90 T8, an example of a plug-in hybrid.

The problem if you go too small in cell group capacity is that - as in this case - there isn't enough capacity and you need to parallel strings of modules, increasing the complexity of battery management.


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## brian_ (Feb 7, 2017)

Tomdb said:


> Zero-EV 6S Module


These appear to be in the VDA 355 format, sometimes called the "shoebox" size. There are a few choices of manufacturers and sources of modules in this format; an example is the OX Drive series from Electric GT. The relatively small size is good for flexibility in arrangement, and in the 6S version the total pack size is moderate so a high-voltage pack might fit in a small car like the VX220.


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## brian_ (Feb 7, 2017)

With a Tesla SDU sitting mostly behind the rear axle, and most of the battery presumably in the original engine compartment, the result is going to be even more rear-biased in mass (weight) distribution than the original car. That's not necessarily a problem (and it has been done before in similar vehicles), but needs to be considered when making selections such as tire sizes and spring stiffnesses.


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## catphish (Jul 30, 2017)

brian_ said:


> With a Tesla SDU sitting mostly behind the rear axle, and most of the battery presumably in the original engine compartment, the result is going to be even more rear-biased in mass (weight) distribution than the original car. That's not necessarily a problem (and it has been done before in similar vehicles), but needs to be considered when making selections such as tire sizes and spring stiffnesses.


Thank you very much for your replies. With regard to the SDU, I had hoped it might be possible to run the SDU either upside down, or in reverse, so that it could sit where the original engine did. I'm told both of these may have implications for lubrication / cooling. Do you know if either is feasible, or whether I'll definitely have to place the motor behind the axle? In either case, I hope to put at least some of the batteries in the front compartment (in place of the radiator) to partially rebalance the weight, though I won't know for sure what is possible until I choose battery modules and pull the car apart.


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## catphish (Jul 30, 2017)

brian_ said:


> These appear to be in the VDA 355 format, sometimes called the "shoebox" size. There are a few choices of manufacturers and sources of modules in this format; an example is the OX Drive series from Electric GT. The relatively small size is good for flexibility in arrangement, and in the 6S version the total pack size is moderate so a high-voltage pack might fit in a small car like the VX220.


Thanks for the additional battery module suggestion. Looking at the OX-Drive datasheet, they appear to have plenty of options, but in order to get the 600A peak current, I'd need 24 x 4s modules. I'll definitely need to give some serious thought to how many modules I can fit, and how much current I actually need. If I reduce peak current to 410A, I could use 16 x 6S modules, which may be a little saner. I'll look at the available space and see what makes sense.


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## catphish (Jul 30, 2017)

brian_ said:


> The problem if you go too small in cell group capacity is that - as in this case - there isn't enough capacity and you need to parallel strings of modules, increasing the complexity of battery management.


I agree entirely. I think a potentially cheap source of a small number of the 16S packs may be a false economy. I'd need a minimum of 2 strings in parallel, and future maintenance could well be painful. I'll look more at the 6S options, and measure space to see how much capacity I can realistically fit.


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## brian_ (Feb 7, 2017)

catphish said:


> With regard to the SDU, I had hoped it might be possible to run the SDU either upside down, or in reverse, so that it could sit where the original engine did. I'm told both of these may have implications for lubrication / cooling. Do you know if either is feasible, or whether I'll definitely have to place the motor behind the axle? In either case, I hope to put at least some of the batteries in the front compartment (in place of the radiator) to partially rebalance the weight, though I won't know for sure what is possible until I choose battery modules and pull the car apart.


The usual approach is to keep the drive unit the same side up, and turn it around so it rotates in opposite to the usual direction, but perhaps turning it over is also possible with suitable lubrication modification. A Model 3 drive unit has a better motor, and places the motor ahead of the axle line, but it's not as well supported by aftermarket controllers.

To me, the problem with putting the motor ahead of the axle line is the loss of space for battery modules... and there isn't enough of that to start with. 

You can't entirely eliminate the radiator if you are using any modern drive unit (they're all liquid-cooled) or liquid-cooled battery... although you could use a much smaller radiator, and could place it differently.


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## catphish (Jul 30, 2017)

brian_ said:


> You can't entirely eliminate the radiator if you are using any modern drive unit (they're all liquid-cooled) or liquid-cooled battery... although you could use a much smaller radiator, and could place it differently.


That's a good point. This is why I come here for sanity checking! Your approach is probably the correct one then, putting the batteries as far forward as possible in the engine bay.


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## catphish (Jul 30, 2017)

It occurs to me that I _really_ don't actually need to draw 600A at 360V unless I want to reach the moon, so I can definitely sacrifice either some voltage in the battery, or sacrifice some peak current capacity in the battery.

If I understand correctly, both options will essentially have the same effect, limiting the amount of current I can draw at high RPM, the only difference being the programming of the inverter.

In both cases, there will be less peak power available and hence a reduced top speed. If I use 6S cells, which seems like the leading option right now, I could fit as many as I can, which may end up with a reduced voltage, but performance should still be quite impressive. Is there a power vs weight vs top speed calculator for such decisions?


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## brian_ (Feb 7, 2017)

catphish said:


> It occurs to me that I _really_ don't actually need to draw 600A at 360V unless I want to reach the moon, so I can definitely sacrifice either some voltage in the battery, or sacrifice some peak current capacity in the battery.


True, 180 kW is more than the VX220 should need to match the original performance.



catphish said:


> If I understand correctly, both options will essentially have the same effect, limiting the amount of current I can draw at high RPM, the only difference being the programming of the inverter.


Close, and valid at lower speeds. Since the controller can only reduce voltage from the battery to the motor (with a corresponding increase in motor current versus battery current), the battery voltage is a limitation on how much voltage can be delivered to the motor. Higher motor speed requires more voltage (due to back-EMF... good to look up, if not familiar with this), so reduced battery voltage is a limitation on high-speed performance.

Certainly something less than the normal battery voltage for a production EV motor is still usable.


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## brian_ (Feb 7, 2017)

catphish said:


> Is there a power vs weight vs top speed calculator for such decisions?


Not really, in part because the power required to keep moving at any speed depends more on aerodynamics than on weight.

In most modern EVs, 

top speed higher than any normal highway speed so it doesn't matter, and
top speed is limited by the motor's top speed and gearing, not by power.


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## TeZla (Feb 18, 2021)

This should be a good build.

A suggestion for one of your points - 6.6kW 400V+ charger with CAN (brand undecided)


https://www.ovartech.com/product/6-6kw-obc1-5kw-dc-dc-liquid-cooled-on-board-charger/










Stealth EV 6.6KW 400V Liquid Cooled Charger+1.5KW DC/DC Converter


Shop the Stealth EV 6.6KW 400V Liquid Cooled Charger+1.5 % KW DC/DC Converter and other products by Stealth EV. Click here to learn more...




stealthev.com





Its the same as the unit from StealthEV but direct from the manufacturer in china. I bought mine from them, but if your in the US, the StealthEV unit is probably better suited to you as the supplier and support is 'local'. Cost wise, its about the same. It combines the charger and DC-DC converter into one compact unit, which is a bonus when space is a premium.


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## AusS2000 (Jul 9, 2021)

Thought I'd join in on this discussion as I am doing a similar project. Have a Honda S2000 and installing an SDU reversed in the subframe.

All the fabrication is done. Now I need to modify the oil pump (swap hoses, change pressure limiter) and install OpenInverter board.

Batteries are my next issue. I bought a wrecked Hyundai Ioniq but then found out it was on the battery safety recall list. No way I'm taking that chance so got rid of it. Looking for a new source of battery modules available in Australia.


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## AusS2000 (Jul 9, 2021)

TeZla said:


> A suggestion for one of your points - 6.6kW 400V+ charger with CAN (brand undecided)
> 
> 
> https://www.ovartech.com/product/6-6kw-obc1-5kw-dc-dc-liquid-cooled-on-board-charger/


I'm also speaking to Ovartech.


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## TeZla (Feb 18, 2021)

I saved myself around $400 or so dealing direct with Ovartech instead of StealthEV, once currency conversion and freight costs were worked out



AusS2000 said:


> Looking for a new source of battery modules available in Australia.


I've made inquiries with EV Power Australia, looking at their NCM cells. the NCM120A cell looks like it'll work for my needs while only ever needing to discharge at around 3C max, so within its specs. I think ive got it worked out properly, but im still learning a lot here. works out to around $19k worth of battery, but they are brand new, compared to around $23k for used model S batteries from Leon at lithium power.


https://www.ev-power.com.au/westart-ncm-cells/



but, this is probably hijacking his thread a bit.


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## catphish (Jul 30, 2017)

TeZla said:


> I've made inquiries with EV Power Australia, looking at their NCM cells. the NCM120A cell looks like it'll work for my needs while only ever needing to discharge at around 3C max, so within its specs. I think ive got it worked out properly, but im still learning a lot here. works out to around $19k worth of battery,


Is that based on 96 x 120AH cells? That would meet my needs (ideally 120AH x 96s with a 5C peak discharge), but like the other options, I'll need to spend some serious time measuring available space, and seeing what will fit. Most likely I'll have to sacrifice a little of this ideal capacity. I see these cells for sale in Europe too at a similar cost for example https://eveurope.eu/en/product/westart-ncm-120-ah-lithium-battery-cell/

I suspect I'll be on the hunt for something a little lower cost too, but right now not decided on anything in particular.


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## TeZla (Feb 18, 2021)

88 cells, It packages a little nicer for me and the slight drop in voltage isnt an issue for me, But yes, all 120AH cells.


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## junkcar (Oct 8, 2021)

AusS2000 said:


> Thought I'd join in on this discussion as I am doing a similar project. Have a Honda S2000 and installing an SDU reversed in the subframe.
> 
> All the fabrication is done. Now I need to modify the oil pump (swap hoses, change pressure limiter) and install OpenInverter board.
> 
> Batteries are my next issue. I bought a wrecked Hyundai Ioniq but then found out it was on the battery safety recall list. No way I'm taking that chance so got rid of it. Looking for a new source of battery modules available in Australia.


Yes! Your explenation is valid


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## catphish (Jul 30, 2017)

AusS2000 said:


> Batteries are my next issue. I bought a wrecked Hyundai Ioniq but then found out it was on the battery safety recall list.


I'm disappointed that this doesn't mean you get a new battery pack for free! Isn't that how recalls work?


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## remy_martian (Feb 4, 2019)

Stealth EV charger sems pretty useless if the CAN documentation is not provided. Where do you find this?


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## catphish (Jul 30, 2017)

remy_martian said:


> Stealth EV charger sems pretty useless if the CAN documentation is not provided. Where do you find this?


I can't find it published, but I'm sure ovartech will provide it if you ask. As you say, the product would be useless without it.


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## AusS2000 (Jul 9, 2021)

catphish said:


> I'm disappointed that this doesn't mean you get a new battery pack for free! Isn't that how recalls work?


Yep, but when you show up at Hyundai with a battery pack on the back of a trailer they laugh at you.

Car was written off. The motor was actually hanging out the front, only held in by wiring looms.


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## AusS2000 (Jul 9, 2021)

TeZla said:


> I saved myself around $400 or so dealing direct with Ovartech


I found it even cheaper on Alibaba. Anyone know the deal with these?






Integration-2-in-1-1-5KW


Integration-2-in-1-1-5KW



www.alibaba.com


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## TeZla (Feb 18, 2021)

its the same company, thats just Ovartech's Alibaba page.


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## SuperV8 (Jan 22, 2020)

brian_ said:


> For those (mostly in North America) who are unfamiliar with the Speedster and VX220, these are the GM versions of the Lotus Elise. It's an aluminum-framed mid-engine car.


Which was also what the Tesla Roadster was based on!


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## catphish (Jul 30, 2017)

SuperV8 said:


> Which was also what the Tesla Roadster was based on!


I finally found a photo of the layout of the Tesla Roadster. I will certainly use it for inspiration when it comes to my setup. I'll have to get the car apart before I can figure out what orientation of the motor will work, which is looking like it might not be for a few more weeks, but it definitely seems like the correct place for the battery is directly behind the seats.


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## brian_ (Feb 7, 2017)

catphish said:


> I finally found a photo of the layout of the Tesla Roadster. I will certainly use it for inspiration when it comes to my setup. I'll have to get the car apart before I can figure out what orientation of the motor will work, which is looking like it might not be for a few more weeks, but it definitely seems like the correct place for the battery is directly behind the seats.
> View attachment 124030


That Power Electronics Module over the motor is impressively large. 

In that photo the motor appears to be over the axle line, rather than behind it (other Tesla models before Model 3, including the Model S SDU), ahead of it (Model 3 rear and most other EVs), or coaxial with it (Chevrolet Bolt and various recent models from other manufacturers). That keeps the motor from interfering with the crossmember of the subframe, or with the battery ahead of it. The battery extends further rearward on bottom than at the top.

These images confirm the motor location:








(from a for sale post in another forum)
and








(from Tesla promotional material via an Inside EVs article)

... and this one shows the battery shape:








(from Tesla Motors SEC filing)


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## brian_ (Feb 7, 2017)

catphish said:


> I finally found a photo of the layout of the Tesla Roadster...
> View attachment 124030


That appears to have come from a caradvice.com.au (now drive.com.au) article (possibly via a Reddit contributor):
Tesla Roadster Sport – Electric Supercar
There are 72 images in that article's gallery; this is the only useful one.


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## SuperV8 (Jan 22, 2020)

catphish said:


> I finally found a photo of the layout of the Tesla Roadster. I will certainly use it for inspiration when it comes to my setup. I'll have to get the car apart before I can figure out what orientation of the motor will work, which is looking like it might not be for a few more weeks, but it definitely seems like the correct place for the battery is directly behind the seats.
> View attachment 124030


The Roadster is listed in the Tesla EPC - might find some of the images useful.






Parts Catalog







epc.tesla.com


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## catphish (Jul 30, 2017)

I don't have workshop space to begin taking the VX220 apart yet, but started work on the Tesla SDU today, installing openinverter board...


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## catphish (Jul 30, 2017)

I have also designed an interface board to bridge between my battery modules and CAN bus. These should be arriving from China in a couple of weeks 

Looking forward to getting started with the mechanical work soon!


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## 57Chevy (Jan 31, 2020)

catphish said:


> I have also designed an interface board to bridge between the LG battery modules and CAN bus. These should be arriving from China in a couple of weeks:


I'm looking for a programmable can bridge, is yours Arduino based/programmable/available for sale?

Also, not sure if you are aware but the openinverter board is quite limited in its protections, it is therefore very easy to destroy the power stage with incorrect settings


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## catphish (Jul 30, 2017)

57Chevy said:


> I'm looking for a programmable can bridge, is yours Arduino based/programmable/available for sale?


This device is very specifically to allow communication between the LG batteries I'm using, and the CAN bus (for master devices like SimpBMS). It may be available for people who have the same batteries.


57Chevy said:


> I'm looking for a programmable can bridge, is yours Arduino based/programmable/available for sale?
> 
> Also, not sure if you are aware but the openinverter board is quite limited in its protections, it is therefore very easy to destroy the power stage with incorrect settings


With that said, what kind of mistakes are likely to cause damage? I'm familiar with inverter programming, but since I didn't write openinverter I need to be mindful of what might cause damage. I'd hope iacmax would be able to prevent any damage by limiting the max current through the inverter and motor.


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## 57Chevy (Jan 31, 2020)

catphish said:


> what kind of mistakes are likely to cause damage? I'm familiar with inverter programming, but since I didn't write openinverter I need to be mindful of what might cause damage. I'd hope iacmax would be able to prevent any damage by limiting the max current through the inverter and motor.


There is no hardware interlock, i.e. it is entirely reliant on the program sending out the correct on/off sequence to the bridge to prevent it blowing up. If at any point an upper and its lower are activated together, even for a microsecond, infinite current tries to flow from + to - via the pair. Boom. From the wiki, this is just one of a wide variety of things that could end up with bridge destruction. I'd even go as far as saying plan on it blowing up several times before you get it dialled in completely, particularly as you get more adventurous. At least do all your testing on low voltage and then start your HV testing on capacitors that don't have sufficient energy to blow the bridge.









Industry standard is to have interlocks so that any issue with the code cannot propagate to the bridge


https://e2e.ti.com/blogs_/b/industrial_strength/posts/interlocking-gate-drivers-for-improving-the-robustness-of-three-phase-inverters


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## TeZla (Feb 18, 2021)

57Chevy said:


> Also, not sure if you are aware but the openinverter board is quite limited in its protections, it is therefore very easy to destroy the power stage with incorrect settings


This worries me and is the main thing stopping me from using the openiverter board. Its not like you can just buy a new power stage, So if I killed the inverter, That's another $6500 straight up for a whole new motor. Unfortunately the alternatives seem to be very limited. Either its a control unit that the vendor will only sell complete with a motor, Or its an expensive unit on its own. The EVControls T2C unit seems to be the pick of them all, It interfaces directly with the Tesla control board and is a simple plug and play setup, but its quite expensive.
Does the stock Tesla control board have interlocks to protect the IGBT's? Surely it would.

Catphish, In regards to the openinverter board, They mention that there is some assembly required. What is it? Just soldering some plugs on? I guess if its that simple then once its installed its just a matter of following the same parameters as another 'known' running setup. I've seen some people post their parameters on the openinverter forum.


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## catphish (Jul 30, 2017)

TeZla said:


> Catphish, In regards to the openinverter board, They mention that there is some assembly required. What is it? Just soldering some plugs on? I guess if its that simple then once its installed its just a matter of following the same parameters as another 'known' running setup. I've seen some people post their parameters on the openinverter forum.


The assembly is quite challenging for the small drive unit because some sensors need to be de-soldered from the board as it is removed. Watch this video for details: 



It is very much my hope that copying the known good settings from https://openinverter.org/parameters/view.html?id=15 will give me a working (and not exploding) drive!


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## 57Chevy (Jan 31, 2020)

TeZla said:


> So if I killed the inverter, That's another $6500 straight up for a whole new motor. Unfortunately the alternatives seem to be very limited.


That is entirely the reason I rejected the openinverter board. It is a pretty amazing bit of kit in that it is done mostly by two guys in their spare time, however HVDC is merciless and it will find the weaknesses, it is only a matter of time. Even with interlocks, there are still plenty of other ways to kill the bridge

It is entirely possible to run successfully with this hardware, you just have to be very, very clinical in your approach. Any change you make could end in boom. Scope any signal wires for noise that could send incorrect information, sneak up on any changes with low voltage and then high voltage capacitors first before battery. Ground, shield, isolate everything that could put noise on a signal line. Fit a fuse that is a lower rating than full power for initial battery testing- it won't protect the bridge but it will limit the damage inside, bridge failure can be quite violent. Have a plan on how to replace the bridge so you aren't stuck when it happens.

The other thing is that if you are running a single accel pedal sensor then it only takes a glitch in the signal or a break in the 0V line and you have lost control of the rig. Redundant accel input is mandatory here, for a very good reason.

This gap in the market will be filled at some point by commercial operators. AEM are just now releasing the LDU control board and VCU, presumably at some point they will release an SDU one. Yes it is expensive but it is cheaper in the long run if it significantly reduces the chances of destroying the power stage.

I have spent several years developing/testing/blowing up inverters in a commercial application, the sound is burned into my brain


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## catphish (Jul 30, 2017)

Today I got my Tesla SDU powered up on the bench for the first time (at 36v). Initial indications are good!


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## catphish (Jul 30, 2017)

TeZla said:


> https://www.ovartech.com/product/6-6kw-obc1-5kw-dc-dc-liquid-cooled-on-board-charger/


I'm starting to look more seriously at buying parts, and have a couple of questions about this charger.
1) Do you have the documentation, particularly the wiring diagrams and CAN command set? It doesn't seem to be published.
2) How much hassle is the water cooling? I'm thinking I likely already need to run 2 water cooling loops, one for batteries, and one for motor. I'll also have to think about running the cooling loop during charging, though this doesn't seem insurmountable.

This alternative part was also recommended to me, I'm somewhat unsure how to choose between these Chinese devices: Dilong New Energy Technology Official Website EV OBC DCDC On-board Charger Power Supply Manufacturer
Interestingly, they also do an air cooled version, but I'm unclear on the pros and cons of air cooling, apart from seemingly simpler installation: Dilong New Energy Technology Official Website EV OBC DCDC On-board Charger Power Supply Manufacturer

I assume (since they're rare) that 6.6kW probably isn't a good match for air cooling. I could also go with a 3.3kW charger instead. Less impressive, but potentially simpler, and still capable of fully charging my (approx 27kwh) pack over night.

Any advice welcome!


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## TeZla (Feb 18, 2021)

catphish said:


> I'm starting to look more seriously at buying parts, and have a couple of questions about this charger.
> 1) Do you have the documentation, particularly the wiring diagrams and CAN command set? It doesn't seem to be published.


No, It didn't come with much documentation at all, but im not at that stage in my build where ive even installed it yet. Maggie and Frank at Ovartech are very prompt and helpful in their responses, I have no doubt that when I request the documentation on the CAN messaging, it'll be no issues. The wiring is pretty straight forwards. It's listed along with a whole bunch of specs in the datasheet, available on their website. It comes pre configured with either 250k or 500k baud rate, you need to know which one your using before you order it. The Orion BMS I was planning on using is 500k, as is the Tesla motor to my understanding, It seems simple enough to just make any other CAN parts match those critical components.


https://www.ovartech.com/wp-content/uploads/2017/12/Ovartech-Liquid-cooled-6.6KW-OBC-CAD662DF-400A-Data-Sheet.pdf





catphish said:


> 2) How much hassle is the water cooling? I'm thinking I likely already need to run 2 water cooling loops, one for batteries, and one for motor. I'll also have to think about running the cooling loop during charging, though this doesn't seem insurmountable.


It's not a high heat load item. Yes, it needs to be water cooled but my understanding is that the peak heat load will be during charging, so its simple enough just to add the inverter loop inline with the battery loop, which would ideally be running circulation when charging anyways. Setting it up to do that is easy enough, you just used a switched output to activate the cooling loop when the system is registering a charging state, Basically the same switched output to activate the OBC when its connected to the wall supply. Id say that if you have the capacity to use a liquid cooled unit, you should, especially if your in a hot part of the world. That's between you and your build though.

The only thing I didn't like about the unit is that the DC-DC output is not adjustable, Its fixed at 14.4v. Its not a big thing at all and for user simplicity this is best and not something ive ever really seen as an adjustable setting in any other model, But if I was able to adjust that output up to around 18v, I could have replaced my 12v battery with a Li-ion pack. Pretty much everything electrically on the 12 side is voltage regulated at each unit, and all the lights are LED so it would have been nice to use a better battery, more compact, better tech, sits idle for longer without issue etc, I can probably still figure out a way to manage it though, but that's specific to my build, its by no means a show stopper.

6.6kw is essentially level 2 charging, Here in Aus, 240v is standard at the wall, so it makes no sense for me to use a smaller derated charger. It also gives me the ability to charge at a faster rate elsewhere away from home, where time may be more of a concern. For my situation, it was a no brainer. I would like to add DC fast charging ability to the build, but im not there yet and that'll be its own charging system anyways.


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## catphish (Jul 30, 2017)

TeZla said:


> It's not a high heat load item. Yes, it needs to be water cooled but my understanding is that the peak heat load will be during charging, so its simple enough just to add the inverter loop inline with the battery loop, which would ideally be running circulation when charging anyways.
> 
> 6.6kw is essentially level 2 charging, Here in Aus, 240v is standard at the wall, so it makes no sense for me to use a smaller derated charger. It also gives me the ability to charge at a faster rate elsewhere away from home, where time may be more of a concern. For my situation, it was a no brainer. I would like to add DC fast charging ability to the build, but im not there yet and that'll be its own charging system anyways.


Thanks, I think I'll give the water cooled 6.6kW a try. As you say, it makes sense to cool the batteries during charging anyway, so putting the charger in the battery cooling loop is no trouble at all.
Mains power in the UK is also 240V. A normal socket is 13A (3KW), but there are lots of 30A (officially 7KW) chargers around, and it's easy to install one at home too, so it's probably worth it.

I think there are 2 competing chargers I need to look at, the ovartech version, and a similar "dilong" version:


https://www.ovartech.com/product/6-6kw-obc1-5kw-dc-dc-liquid-cooled-on-board-charger/







Dilong New Energy Technology Official Website EV OBC DCDC On-board Charger Power Supply Manufacturer


Dilong is Professional manufacturer in R&D, production and sales of EV power supply, on-board charge




www.powerdilong.com





Ovartech seems to be more widely known, but I've had recommendations for both. I'll try to get documentation for both.


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## AusS2000 (Jul 9, 2021)

catphish said:


> I don't have workshop space to begin taking the VX220 apart yet, but started work on the Tesla SDU today, installing openinverter board...


Do you know of a step by step on disassembly of the SDU inverter side like you have just done? Youtube or blog?

I'm sure I could muddle through but would be nice to know where I am going.


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## catphish (Jul 30, 2017)

AusS2000 said:


> Do you know of a step by step on disassembly of the SDU inverter side like you have just done? Youtube or blog?
> 
> I'm sure I could muddle through but would be nice to know where I am going.


Basically, it's very easy apart from one part (desoldering the current sensors) which is quite difficult and delicate. I'd suggest you don't attempt to remove the board without watching and understanding this video:






The only other thing to mention is that you need to remove the bolts from the motor cables (though a small plastic access panel) before removing the inverter itself.


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## AusS2000 (Jul 9, 2021)

Yeah, I've watched that video a few times and even managed to stay awake once. But I was more interested in the disassembly of the motor/inverter assembly (such as disconnecting 3 phase and whatever that blue wire is).


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## catphish (Jul 30, 2017)

I don't have a video, but there are 4 steps:
1) Remove the small orange plastic cover that probably says VOID all over it.
2) Deep behind that cover are 3 bolts. Reach in with a long enough tool, unscrew and remove all 3 bolts.
3) Unscrew the 10 bolts that hold the motor on. Support the inverter when you remove the final bolt. It will probably take a couple of taps with a hammer to actually come away, but you don't want it to fall and damage the blue wire.
4) As you pull the inverter away, you will see the blue wire is quite tight. There are 2 connectors to unplug. You ideally need 3 or 4 hands to hold the inverter body while unclipping the cables.

Once you've done that, you will have the detached inverter as below (plus a bracket that holds the motor wires).

5) Remove the plastic bracket that holds the motor wires. This is fiddly but you'll figure it out.
6) Unclip the remaning wires.
7) Unscrew the metal tray from the inverter, and remove the tray and board together. Do not unscrew the board from the tray until you are sure you know what you're doing.

Sorry I don't have more photos or video.


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## catphish (Jul 30, 2017)

Bonus photo showing the motor cable bracket. The following explanation may or may not make sense, but I'll try: To slide the cables out of the bracket, you need to slide them further in, so that the insulation is between the clip. This is easy if you unscrew the bracket and rotate it so that its screw mounts are out to the left.


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## AusS2000 (Jul 9, 2021)

Ah, I remember mention of sliding the cables further in. Sure there is a video somewhere of this process. Cheers.


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## catphish (Jul 30, 2017)

Small update: I now have basic BMS functionality ((cell voltage reporting and balancing) working on my LG cells using their built-in slave modules, yay.

I am now trying to decide between purchasing an Ovartech 6.6kW charger, or attempting to hack an OEM tesla charger. The Ovartech option is certainly easier!

Still waiting for workshop space before beginning serious mechanical work.


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## catphish (Jul 30, 2017)

This week I've bought a 10kw Tesla on board charger. I'm waiting for an open source logic board to get this up and running. I'll hopefully get a Tesla DC-DC converter to complete my set!


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## catphish (Jul 30, 2017)

I have now received 18 x 1.5kWh 16S LG battery modules, which I intend to run in a 6S 3P configuration, if space allows. These came with a big stack of 250A and 150A relays and fuses, and a couple of smaller 40A fuses from the original battery pack.

I have also tested the Tesla charger, which is faulty (I got it for next to nothing). 2 of the 3 modules work so it can achieve my desired 6.6kW, but I've decided it's too bulky for my build. Instead I've ordered the Ovartech 6.6kW charger and DC-DC converter.

I have also tested my new BMS which is able to automatically and accurately balance strings of these LG modules.

So I now have the following ready to go:

Vauxhall VX220 - currently unmolested
Tesla Small Drive Unit - Openinverter board installed and tested, HV cable
Tesla driveshafts
18 x LG 16S battery modules
3 x DIY BMS controller for LG modules
Ovartech 6.6kW charger + 1.5kW DC-DC converter
150A and 250A relays for general use
175A, 225A, and 40A fuses for general use
I anticipate still requiring the following:

Type 2 charge socket
Main contactor
2 x radiators + 2 x coolant pumps
Lots of cable, connectors and custom fabricated parts
Current sensor / charge counter

I hope to have my VX220 in the workshop by newyear!

Batteries and charger testing:









Relays and fuses from a mystery OEM battery pack:









GEN2 charger openinverter board ready to go:









My custom BMS for my LG battery strings, balancing and CAN bus monitoring


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## catphish (Jul 30, 2017)

Small update. I've now developed a charge controller to connect to the EVSE and Ovartech charger.

I've decided that I will use the 3 x 175A fuses independently on each of my 3 parallel battery strings, and the 250A relays will be sufficient as main contactors, as they can handle 500A for longer periods than the Tesla SDU can.

I've had word that my workshop space is available, so the real work can begin soon!

I've ordered a 100A CAN isa current sensor, so the only major parts still to source are the charging socket, heating + cooling, and everything I've forgotten. I hope to follow up with a complete wiring diagram, and in the new year, photos of the beginnings of disassembling the VX220.


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## mistrycomposites1 (Dec 9, 2021)

HI, I've been reading your post and was wondering how you have been getting on?
I have been considering an conversion on my VX for a while.
Do you have any advice?


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## catphish (Jul 30, 2017)

mistrycomposites1 said:


> HI, I've been reading your post and was wondering how you have been getting on?
> I have been considering an conversion on my VX for a while.
> Do you have any advice?


The short answer is that I can't offer any advice specific to the VX220 yet. All the work I've done so far has been on the electronics while I wait for workshop space. That workshop should be available to be in about a week, so after that I will begin disassembling the car and will definitely be posting updates here.


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## catphish (Jul 30, 2017)

Update 15th Jan:

I now have all major components in hand, and the VX220 is in the workshop! Substantial time has been spent developing the new BMS electronics, but hopefully I can now begin full speed on the mechanical work.

Tesla Small Drive Unit - Openinverter board installed and tested, HV cable, OEM driveshafts
18 x LG 16S battery modules
DIY BMS supporting 3 x LG module strings (CAN)
DIY Charge controller to manage EVSE / charger (CAN)
Ovartech 6.6kW charger + 1.5kW DC-DC converter (CAN)
ISA shunt current sensor (CAN)
150A and 250A relays for general use
175A, 225A, and 40A fuses for general use
Generic type 2 charge port
Generic rotary gear selector (may use an OEM device instead, TBD)
10A inline (granny) charge cable for testing
I have begun disassembly of the vehicle. So far just the seats and rear liner has been removed I but will update once the bodyshell is removed and I have more interesting details.


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## TeZla (Feb 18, 2021)

good luck, here comes the madness.

This will be awesome to watch


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## catphish (Jul 30, 2017)

Disassembly has commenced! Undertrays, rear clamshell, and exhaust have been removed. Engine and gearbox next!


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## VintageVolts (Jul 7, 2020)

wow nice! I think the boot needs to be hoisted a bit higher up in the air though, lol


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## TeZla (Feb 18, 2021)

> wow nice! I think the boot needs to be hoisted a bit higher up in the air though, lol



Good way to store it out of the way though...


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## catphish (Jul 30, 2017)

In the next few days I hope to finish removing the engine, gearbox, and radiator in order to start measuring up for EV parts. In the meantime, I have put together an initial draft of the wiring for my HV, ignition, and BMS systems.


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## catphish (Jul 30, 2017)

Engine and gearbox have now been removed!



















Couldn't resist offering up the Tesla drive unit. It looks like it will fit very well, but it is rotated 180 degrees from its original configuration, which means that some modifications will need to be made to its oil pump.










Next I will remove the fuel tank and measure up for the battery box. It's looking promising!

On the electronics side, I have now received and tested version 3 of my BMS and charge control circuit boards. All working very well.


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## TeZla (Feb 18, 2021)

Does the motor bolt up to factory mounting points? You lucky bastard...

Nice 'Artwork' on that strip of metal too, lol


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## catphish (Jul 30, 2017)

TeZla said:


> Does the motor bolt up to factory mounting points? You lucky bastard...
> 
> Nice 'Artwork' on that strip of metal too, lol


Amazingly yes it does!

but... it's a couple of degrees off from being correctly aligned, and a little low at the front, so I will look to fabricate a new mounting point at the front, a little higher and to one side. I couldn't believe it though when it dropped straight in!

The artwork goes to show I need more mature friends


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## catphish (Jul 30, 2017)

Front clamshell removed. There's not really much room in the front, though I intend to replace the radiator with one or two more sensibly sized ones.









Fuel tank also removed, not a huge amount or room under there, but a convenient place for wiring.


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## catphish (Jul 30, 2017)

Next step (and the last major stage of disassembly) will be to remove the radiator, interior heater, and gearstick. The radiator will be replaced with a much smaller unit, and the heater will be converted to an electric (PTC heater). The entire original cooling system will be removed and I'll use the space to engineer a new cooling loop with a smaller radiator.

I am not certain yet whether it will be worth running two cooling loops, with the drive unit having its own loop, or just keep it simple with a single loop.

The braking system (ABS) I hope to leave alone.


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## catphish (Jul 30, 2017)

Today (with a lot of help from Jack at Silent Classics) I created the first engine mount.


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## catphish (Jul 30, 2017)

I'm spending a lot more time on this project, and things are still moving slowly! I attempted to fit an iBooster in place of the master brake cylinder, but it doesn't fit properly, header tank is too high, and control electronics block the heater pipe, so I've decided to keep the original brake booster, and add a vacuum pump and container. Any advice on vacuum pumps, reservoirs, sensors etc appreciated!










I've also removed the pedal assembly, the clutch will be removed and the brake re-installed. The accelerator is hanging by its cable for now. I'll get that out shortly to work out how to wire it to the Tesla SDU.










I've also started work on designing the mounts for the battery box. This turns out to be fairly simple, using angle. I also need to fabricate the final engine mount, currently hanging by a strap!

This week has involved a LOT of measuring, offering things up, and design, so progress seems slow. One key decision that has been made is the layout of the batteries. I will be be using only 15 of my 18 modules, giving me a 80S3P configuration. This allows the whole battery pack to sit above and in front of the drive unit in a single block, 5 modules across, 3 front to back. They will be pressed up against the partition to improve weight distribution as much as possible. Putting battery modules in the front, or fuel tank space is not practical.


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## brian_ (Feb 7, 2017)

catphish said:


> I attempted to fit an iBooster in place of the master brake cylinder, but it doesn't fit properly, header tank is too high, and control electronics block the heater pipe, so I've decided to keep the original brake booster, and add a vacuum pump and container...
> 
> View attachment 127505


If the only issue were the reservoir, that could certainly be fixed with a remote reservoir mounted at a similar height but further back and flatter if necessary.


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## TeZla (Feb 18, 2021)

The iBooster was used in the 2017 honda CRV, amongst other cars. In that particular car, it has a remote mounted reservoir. The header reservoir on the master cylinder is quite small and low profile. Im using the reservoir from a 2014 Honda Jazz with my iBooster, Its compact and will only need a simple bracket made up to mount it.

You can also turn the whole unit over so the electronics are on the other side, the master cylinder can be unbolted from the booster part and flipped 180 degrees, so that could help clear the heater pipe. If it were me, I'd figure out how move the heater pipe to a different location. The iBooster will be 100 times better than a noisy vacuum pump. Infact, I'd probably ditch the coolant heater completely and use an electric heater, seeing as you'll have a HV battery to run it. Basically instant heat and less overall parts/complexity


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## catphish (Jul 30, 2017)

Thank you for the pointers on the brake boosters. While I still think an iBooster is the superior option, I have decided to stick with the OEM booster, and have now bought an MES 70/6E2 vacuum pump. Engine bay is progressing gradually - I am currently building a frame on which my battery box will be mounted above the drive unit. This will also support the final mounting point of the SDU.


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## catphish (Jul 30, 2017)

I've now finished fabricating the battery box mounting frame. This is secured to the chassis above the motor and will provides a base on which I can start designing the battery box.

Next steps:
1) Secure the third and final motor mount. It will likely need to be suspended from the battery box mounting frame.
2) Begin battery box design, and replace rear clamshell to double check clearance for this. Fingers crossed my 15 planned battery modules will fit!

I have now received two small radiators (VW Golf auxiliary radiators), which I will likely mount in the front, there the original VX220 radiator was located. The front of the car will be only minimally modified.


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## brian_ (Feb 7, 2017)

It's unfortunate that the way the structure is designed, the substantial volume of the fuel tank space is effectively not usable for battery modules, due to the shape and separation from the rest of the rear volume. That forces all of the battery to sit very high, but at least it looks like it will be a tidy setup.


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## catphish (Jul 30, 2017)

brian_ said:


> It's unfortunate that the way the structure is designed, the substantial volume of the fuel tank space is effectively not usable for battery modules, due to the shape and separation from the rest of the rear volume. That forces all of the battery to sit very high, but at least it looks like it will be a tidy setup.


That's absolutely the conclusion I've come to. The weight will be much higher and further back than I'd originally hoped, but at least it will be forward of the rear axle. With the disapointingly shaped fuel tank space (not large enough for the battery modules I'm using at all), I don't feel that there was ultimately much choice in the setup, so I'm rolling with it and hoping the result is fun anyway  I'm putting my effort into ensuring it's tidy, secure, and safe.


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## 4Foxtrot (Apr 1, 2019)

Awsome build 👍 I was very tempted to do the same. But a bit to close to my ‘pop-up electric Toaster’ 🤣 … By comparison, my imaginary vx220 build would trade some range to be nearer the ice weight (sub 1000kg) vs toasters 1200+Kg.
Colin Chapman’s ‘add lightness’ for benefits on the straights AND the bends still holds. So I hope your search for an ideal battery pack goes well.
I’m 20 miles south of Silent Classics, and would love to see how you are getting on - I’m sure Elon would love to see it too (LotusElon 😎),
Cheers
Mark


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## catphish (Jul 30, 2017)

4Foxtrot said:


> Awsome build 👍 I was very tempted to do the same. But a bit to close to my ‘pop-up electric Toaster’ 🤣 … By comparison, my imaginary vx220 build would trade some range to be nearer the ice weight (sub 1000kg) vs toasters 1200+Kg.
> Colin Chapman’s ‘add lightness’ for benefits on the straights AND the bends still holds. So I hope your search for an ideal battery pack goes well.
> I’m 20 miles south of Silent Classics, and would love to see how you are getting on - I’m sure Elon would love to see it too (LotusElon 😎),
> Cheers
> Mark


Thanks! Hopepfully my build won't actually end up much heavier than the OEM ICE. The motor is 90kg, and battery back 180kg. I only went with 22.5kWh in the end. I didn't weigh the removed engine, gearbox and fuel tank so I'm not certain.

I live in Blandford, so we can't be far away at all!


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## brian_ (Feb 7, 2017)

catphish said:


> Hopepfully my build won't actually end up much heavier than the OEM ICE. The motor is 90kg, and battery back 180kg. I only went with 22.5kWh in the end. I didn't weigh the removed engine, gearbox and fuel tank so I'm not certain.


One source says that an Ecotec engine (like the one in an VX220) weighs 139 to 150 kg dry. The electric motor with transaxle and battery will certainly weigh more than the engine plus transaxle and fuel tank, but with this small battery it won't be as much of a weight penalty as a typical conversion.


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## 4Foxtrot (Apr 1, 2019)

catphish said:


> Thanks! Hopepfully my build won't actually end up much heavier than the OEM ICE. The motor is 90kg, and battery back 180kg. I only went with 22.5kWh in the end. I didn't weigh the removed engine, gearbox and fuel tank so I'm not certain.
> 
> I live in Blandford, so we can't be far away at all!


Excellent  Colin would be pleased and with a decent 'C' rating from the cells - it will fly (along the straights _and_ around the bends).
We are almost neighbours - I live in Poole. Silent classics and I are connected on Social media (but I've not yet visited), even though they are on one of my favourite 'Elon' and 'Toaster' - err 'test loops' (A350 - ZigZag hill - B3081 - B3078).

This SW area is an amazing hive of EV activity: with Zero EV , Tom-De Bree, Castleman Motors (E-DeLorean & E-Etype), Second life ev batteries, and 'Tesla Powered speed Boats' (in same Christchurch industrial estate), R Symonds EV specialists, Dorset EV's, to name a few. Plus Electric Classic Cars up the road in Wales !!!

BTW did you see ECC's latest 'Vintage Voltage' with the Mini Mk1 Plus 'Your' SDU motor reversed ? (on Quest TV)
And Petrol Peds subsequent test at Bentwaters > 




I only just twigged that ECC's 'Pedro' is actually 'Petrol Pod' 
Hope to meet you and see the VX soon.
all the best
Mark


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## catphish (Jul 30, 2017)

That reminds me, once I've finished sorting out the mounts for the motor and battery back, I will remove the motor to embark on reversing the oil pump!


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## catphish (Jul 30, 2017)

Very slow progress this week, after installing the support frame for the battery pack I've spend a long time working out details of the battery box itself. This is my design so far, but some more work will be needed (clamping down the modules, side walls, and lid). Hopefully I will finalize this next week. 5 modules shown (of 15 total).








I've taken a little time out to start building an open source CCS charge module, but no guarantees this comes to anything 
Next week I really hope to finish the motor mount so that the motor can be removed for oil pump modification.


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## catphish (Jul 30, 2017)

Design of the battery box continues. This is an abandoned design I started using 3mm aluminium sheet construction.


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## catphish (Jul 30, 2017)

I successfully modified the VX220 cabin heater to replace the matrix with a ZeroEV high voltage PTC heater.


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## catphish (Jul 30, 2017)

I have also modified the OEM radiator to replace the huge 32mm pipes with 16mm pipes to match the rest of the hardware. This is my first time using a lathe!


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## TeZla (Feb 18, 2021)

catphish said:


> I successfully modified the VX220 cabin heater to replace the matrix with a ZeroEV high voltage PTC heater.


Nicely done!

So now the heater hoses aren't getting in the way of the iBooster, is that being reconsidered?


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## catphish (Jul 30, 2017)

TeZla said:


> Nicely done!
> 
> So now the heater hoses aren't getting in the way of the iBooster, is that being reconsidered?


Sadly not, it's that huge 80mm air hose that gets in the way. I've got a vacuum pump (MES 70/6E2) up and running, and perhaps down the line, I'll look again at e-brake-boosters.


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## catphish (Jul 30, 2017)

After a lot of stressing about how to design the battery box, I finally got around to putting the clamshell back on the car. This allowed me to really get a feel for the space, and I took the opportunity to do some 3D scanning to help the process. As a consequence, I discovered that height is going to be extremely tight, which really constrains the design and focuses my mind.

The battery box will essentially have to be a minimal sheet metal box with external reinforcement (to avoid adding any extra height) so that's fairly simple.

I also finally did something about the final motor mount (big chunky box section). It's not pretty, but it works.


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## catphish (Jul 30, 2017)

Final concept for my battery box, hopefully going to order this tomorrow. It's a very basic steel box with no dividers, to keep the depth and height to an absolute minimum. There's a little room at the sides for electronics, and it will be reinforced externally rather than internally.
























I'm hoping I can design a 3d-printed insert for each side to pack out the space, and sandwich the contactors, fuses and bus bars securely.

Fingers crossed it actually fits in the car. Space is very tight at the top-rear of the space because of the shape of the clamshell, though there's plenty of room at the sides for HVJB etc.


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## catphish (Jul 30, 2017)

Today I started disassembly of the small drive unit. The goal is to reverse the oil pump so the drive unit can run at full speed in reverse.

The disassembly of the SDU is a bit tricky. After removing the inverter, it is necessary to remove the toothed encoder wheel. After removing the hall effect sensor, and the encoder wheel cover, the wheel itself needs to be removed with a (likely modified) puller.









After the encoder wheel is removed, there are two very strong circlips. The inner clip must be removed before the main case can be prized open.










I have not yet been able to remove the clip, but have ordered an appropriate tool to do so. Once the case is apart, my intention is to rotate the oil pump 180 degrees so that it can be driven in the same way, but pumps oil forward when the drive runs in reverse. I believe this will need an adapter plate. I will post more photos of the inside of the unit once I get it open.


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## catphish (Jul 30, 2017)

I've continued the oil pump modification today. I followed the guide found at Tesla SDU oil pump modification for reverse operation - openinverter forum

I've not finished yet, as I need to test with a pressure gauge and adjust things, but fingers crossed it works. I also need to modify the oil pickup (as per the above post) too.


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## catphish (Jul 30, 2017)

SDU oil pump reversal now complete. As per the linked instructions, I modified it as follows:

1) Tap the original piston actuation port and insert M10 grub screw. Allow 5mm protrusion so that the piston doesn't return to the bottom. This allows the original outlet to become the new inlet as per the above design.
2) Tap the original pressure relief port and insert a grub screw (M4).
4) Drill new outlet and pressure relief holes. I have drilled the outlet hole rather conservatively to begin with.








5) Machine a new inlet pipe. This is designed to fit the OEM oil filter inside one end, and a short section of pipe inside the other end, which then mounts over the pump. Also a press fit end cap.

Full assembly:









6) Remove any plastic from the black cover that prevents it from reattaching.

Video of test, showing pump running at approx 1.2 bar: Oil Pump


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## catphish (Jul 30, 2017)

Battery box arrived from fabrication company yesterday. Went with a very simple box. It fits nicely, now working on installing the wiring and plumbing.




























One mistake here - mounted the contactors much too high, so the busbar between the bottom of the fuse, and the contactor is going to be a very tight bend!


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## catphish (Jul 30, 2017)

On a side note, I have spent a couple of days writing my own firmware for my small drive unit.

I don't know if I'll use this, or if it'll come to anything, but it's a good exercise, and helped me to understand openinverter much better. Hopefully I'll get the motor spinning with it, even if I don't ultimately use it in my build. GitHub - catphish/sdu-basic: A basic alternative firmware for the OpenInverter Tesla SDU board


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## catphish (Jul 30, 2017)

General progress post. Battery box pipework now finished.














Battery box mounting tray has cross pieces to support battery weight.








Gearstick removed from centre console.














Next step will be to 3D print some holders for the precharge resistor and BMS inside the battery box.


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## catphish (Jul 30, 2017)

More work assembling the battery box today. This box has a number of connectors on it:

ELR4A03 / ELP4A03 - 4 pin connector, 70A, 6mm^2 - 2 pins are used for the charger output and 2 pins go to the DC-DC converter

DT04-12PA-L012 / DT06-12SA - 12 pin connector - this provides all low voltage connections to the battery box such as 12V power, contactor drivers, and CAN for the BMS.

SLPRBBPSO / SLPPB35BSO - 1 pin 150A 35mm^2 connector - these allow connection of the 35mm cables from the Tesla SDU.

I still need to find a good -pin 2.5mm^2 connector for the HV heater connection to the battery box.


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## catphish (Jul 30, 2017)

This battery box design and build has REALLY dragged on, but almost finished now!


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## catphish (Jul 30, 2017)

Spent the entire today making up the low voltage loom for the battery box interior. This connects:

12-pin external connector DT04-12PA-L012 - this connector is an absolute joy to work with as long as you can find an appropriate crimp tool
4 x contactors with common +12v
BMS with +12V, GND, CAN, and two wakeup signals (ignition and charge)
ISAScale IVT current sensor with +12V, GND, and CAN
Half way through making this cable, I realised I have an annoying problem. The ISAScale IVT draws 30mA from the 12V supply. This means that connecting it to permanent live is a bad idea as it'll drain the lead acid battery pretty fast. On the other hand, connecting it to a switched power source like the ignition or charger, or both, means that it will not be able to persistently and accurately store coulomb count.

As a consequence, I have decided to expose its +12v directly to the external connector, and decide later how to deal with this. My battery box low voltage therefore has the following pinout:

GND
CANL
CANH
Precharge contactor (-)
Heater contactor (-)
Negative main contactor (-)
Positive main contactor (-)
Relay supply for contactors (probably +12v when key is turned)
Charging supply (+12V when charging, wakes the BMS)
Ignition supply (+12V when key is turned, wakes the BMS)
ISAScale IVT supply (+12v, not sure when!)
+12v permanent live for BMS
A mildly interesting aspect of this design is that I will not have a HV junction box. The inverter, DC-DC converter, and cabin heater PTC each plug directly into the battery box, The Cabin heater is controlled by a relay inside the battery box, meaning that it can be switched safely and independently of the inverter, and doesn't get in the way of precharge.


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## catphish (Jul 30, 2017)

After a lot of phone calls, I have now got this car insured from 1st June 2022. This gives me motivation to get moving in the next 4 weeks. Once the battery box is finished. I still have a substantial TODO list:

Mount charger, likely in the space previously occupied by the exhaust system
Mount Type 2 charge socket
High voltage wiring, this should just be charger, drive unit, and heater, all of which plug directly into battery box
Low voltage wiring, I have no idea how much work will be involved here, but I have the OEM wiring diagrams, so hopefully I can figure it out and avoid touching OEM systems like lights and ABS.
Mount water pump and run all coolant pipes
Re-install brake pedal, brake master cylinder
Re-install accelerator pedal
Mount vacuum pump and connect up brake vacuum line
Join drive axles!!
Battery box lid
Powder coat all steel parts
Rebuild suspension and brakes, bleed, etc. I did a fair bit of damage to the ball joints and brake disks getting it all apart.
Get the gauges working! At least the speedo ideally also repurpose the tacho as a current gauge
Finish programming the BMS, charge controller, and Inverter
MOT!
More stuff, probably!


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## catphish (Jul 30, 2017)

Annotated pictures of my battery box high voltage wiring.


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## remy_martian (Feb 4, 2019)

Don't forget a condensate drain at the bottom of the box...


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## alexbeatle (Jul 28, 2020)

catphish said:


> Annotated pictures of my battery box high voltage wiring.


Excellent build. 
What do you use to insulate the bus bars? Look like some kind of insulation sleeves.


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## remy_martian (Feb 4, 2019)

I believe it's called "heat shrink tubing"


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## catphish (Jul 30, 2017)

alexbeatle said:


> Excellent build.
> What do you use to insulate the bus bars? Look like some kind of insulation sleeves.


As Remy says, this is orange heat shrink sleeve / heat shrink tube.


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## catphish (Jul 30, 2017)

As I now believe I've bought just about everything needed to finish the conversion, I wanted to write a short piece about the cost. Due to the small battery pack size, I believe this project was quite reasonably priced. This is a rough account of what I've spent so far and *actually used*. It does not include money I've wasted on unused / incorrect parts. I've included all VAT and delivery charged where possible.

Car - 2001 VX220 - £9,000. eBay. An additional £300 was paid to transport it to me
Tesla SDU, including Tesla driveshafts - £2,500 - eBay
Tesla SDU HV power cables - £105 - eBay
SDU Oil £65 - eBay
Openinverter SDU board - 350€. This was actually gifted to me, but makes sense to include it here.
Batteries - 18 x 1.5kWh - £3,600 - Seller found through forum contacts
6.6kW charger and DC-DC converter - £2,000, Ovartech
BMS and Charge controller boards, DIY, £200, JLCPCB
ISAScale IVT shunt - £120, forum contact
Gear Selector (DNR) Knob - £10, aliexpress
Water pump - £44 - eBay
Brake vacuum pump - £116 - eBay
3KW PTC Cabin Heater High Voltage - £140 - ZeroEV
Battery box and lid laser cut from 1.5mm steel - £150, local engineering company
Powder coating - £120
Steel and aluminium for battery box, tray, and motor mount, including box section tubing and angle - approx £100 if properly planned and ordered together, metals4U
Copper bus bar - £77, RS
Amphenol connectors for Battery box - £169, combination of RS, Mouser, eBay
Rubber hose - £67 - eBay
Hose joiners, grub screws, nuts, bolts, jubilee clips - maybe £200, hard to keep track
Wire, 0.5mm, 1mm, 4mm, 6mm, various colours, maybe £100, hard to keep track
Dymo printable heatshrink tubing - £13
Insurance - £500, Adrian Flux
Cabin heater hose - £24 - eBay
Coolant header tank - £18 - eBay
EV Number Plates - £17 - eBay
Brake Fluid - £30 - eBay
G48 Coolant - £25 - eBay
Other plugs, connectors, crimps, £50
Toe link ball joints - £80, only necessary because I damaged the ball joints while removing the driveshafts
Wheel alignment - £60,only necessary because I replaced the toe links
I'm sure there are lots of small parts, consumables, etc I have neglected to list here, but I think this is a good overview of the bulk of the costs. This also notably excludes all tools, workshop space, and man hours used!


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## catphish (Jul 30, 2017)

Finally settled on a way to clamp the batteries into the battery box, so hoping to complete the final assembly of this next week (final-ish anyway, as it'll need to be disassembled and powder-coated once everything is tested).


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## catphish (Jul 30, 2017)

I only achieved one thing today, but it makes me happy. Car now has a charge port!









Battery box is now awaiting powder coating.


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## catphish (Jul 30, 2017)

Charger now installed. I'd hoped this might fit in the fuel tank, but it doesn't, so instead it occupies some of the space at the rear where the exhaust system was removed.


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## brian_ (Feb 7, 2017)

catphish said:


> Charger now installed. I'd hoped this might fit in the fuel tank, but it doesn't...


Too bad - it would be nice to make use of that tank space, especially for something as dense as the charger, since the location is low and central.


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## catphish (Jul 30, 2017)

Today I implemented the majority of the logic for the J1772 charge controller. It now detects EVSE connection, reads allowed AC current, combines this with the pack voltage from the BMS, and commands DC charge current. It also uses the data from the BMS to implement safety limits based on temperature and maximum cell voltage.



















A little bit more code needed to add low power sleep. Code and hardware available here: GitHub - catphish/ev-charge-controller: Charge controller for DIY EV project


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## catphish (Jul 30, 2017)

Today I removed the dash. I'd bee worried this would be a big job and had been avoiding it, but it turned out to be trivial, and has given me great access to wiring. It will allow me to run a high voltage cable from the battery box at the back to the PTC cabin heater at the front.

For now I won't be making any significant changes to the interior, switches, or gauges. I will replace the cable mechanism of the heat control dial with a magnetic reed switch that activates the PTC heater relay when the dial is on the hot side, but otherwise will be leaving this as is.


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## catphish (Jul 30, 2017)

Decided to keep it very simple with the heater and blower controls. I no longer have a blower resistor, so the fan switch is wired for single speed. I've added a microswitch to the hot/cold dial so that it can enable the heater relay when it's turned to "hot". Very primitive.








I've wired the fan switch as switched ground rather than the original switched 12V so I could potentially add PWM for the fan in the future, but for now single speed will be fine.

It will be another week before I have everything back from powder coating, so working on some smaller items (low voltage stuff, plumbing) while that's happening. Next step will be mount coolant pump and brake vacuum pump.


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## catphish (Jul 30, 2017)

Today I installed the vacuum pump. Plenty of space in the fuel tank bay so makes sense to use it.









Made up a simple bracket to allow me to use the nuts already present in the bay.


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## remy_martian (Feb 4, 2019)

Mounting it to the short wall of that bay should quieten it if it is too loud where you put it.

If you've ever played with a music box mechanism, you'd understand what I'm saying


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## catphish (Jul 30, 2017)

The next major challenge seems to be placement of a coolant header tank. The issue I have is that the rear of the car has plenty of space, but the battery box fully consumes the opening of the engine bay, so there's nowhere a header tank can be placed where it would be accessible with the clamshell installed. Conversely, the front of the car has a nice accessible bay, but no space! The options are either to install a miniature header tank in the front, or to replace the radiator with a smaller one and place the header tank alongside. The latter would require considerable work.


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## catphish (Jul 30, 2017)

remy_martian said:


> Mounting it to the short wall of that bay should quieten it if it is too loud where you put it.
> 
> If you've ever played with a music box mechanism, you'd understand what I'm saying


You could be right, that thing vibrates a lot, and if that wall resonates, it'll be unpleasant! I'd better turn it on and find out.


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## remy_martian (Feb 4, 2019)

Why not make the battery case lid the header tank?


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## catphish (Jul 30, 2017)

remy_martian said:


> Why not make the battery case lid the header tank?


Unfortunately I don't think it would allow the necessary vertical height. I think a small cylinder like this will fit somewhere in the front bay though: Car Water Coolant Expansion Tank Bottle Header Aluminium Alloy 350ml | eBay


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## remy_martian (Feb 4, 2019)

The front bay is lower than your battery cooling plate, isn't it? If not, carry on...


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## remy_martian (Feb 4, 2019)

Now you've made me do the math:

60cm*50cm*1.25cm (my 1/2") = 3750cc = 3,750mL.

Go with two pieces of sheet metal as the lid separated by a 1/4 inch bar, and you have a 1.8L coolant tank. Battery box length and width were guesses.

350mL seems pretty puny for a surge tank. A coke can???


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## catphish (Jul 30, 2017)

remy_martian said:


> The front bay is lower than your battery cooling plate, isn't it? If not, carry on...


I realised part way through writing my other post that I don't actually know which is higher, the radiator, or the battery cooling plate. However since the system forms a U shape, I wasn't sure if it matters, as air could rise both front and rear, and I also wasn't sure if it would simply be pumped out.
I will try to get a better idea of which point(s) in the system will actually be the highest. The original VX220 has a header tank at the rear, and also a (not very accessible) bleed valve at the front.


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## remy_martian (Feb 4, 2019)

Coolant pumps pump liquid, not air.


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## catphish (Jul 30, 2017)

After a couple of days of fretting about cooling, I've decided on a simple layout. I will use a small inline water tank adjacent to the radiator at the front, with the pump directly below it. This will provide a point for coolant to be added and air to leave. I will also add bleed valves at any other high points in the system.

I will also not put the batteries in the loop for now, but will leave the option of either adding them to loop, or giving them their own loop, depending on 1) whether the batteries actually get warm during my charge-discharge cycle and 2) the temperature the main coolant loop reaches.









I will build this and see how it performs. If necessary, I will use a vacuum pump to fill the system.


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## catphish (Jul 30, 2017)

Sketched out a plan for all my low voltage wiring today. I decided to place the charge controller under the dash for easier maintenance and better weather protection. This dramatically increases the number of wires required between the front and rear of the vehicle, but probably worth it. This means I will need to run 13 new wires from the rear to the dash.


CANH / CANL (communication between BMS, charger, and charge controller, hopefully I can expose these on the OBD2 port)
CP / PP (communication with EVSE)
SWD / SWCLK (for emergency programming of SDU, I probably won't expose these on OBD2 because they would be severely damaged by +12V)
DC-DC enable line (turns on converter and pump, wakes BMS)
ISA Shunt power (for now will turn on with DC-DC converter during charging and driving)
FORWARD / REVERSE
Start Button
Cruise Control
Heater relay control

Draft wiring diagram attached. One decision I need to make is whether to use the start button on the dash as the start button, or whether to instead use the key to start, and repurpose the start button to enable cruise control. Luckily the throttle and power wires can easily be appropriated from the OWM ECU loom at the rear and from the alarm loom under the dash.


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## catphish (Jul 30, 2017)

After another day of thinking about wiring, I've made some improvements. I realized I can use the cool button on the dash for start *and* cruise control with a bit of software magic, and doing so saves me some wires, as it will be done over CAN.


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## catphish (Jul 30, 2017)

My battery box came back from powder coating and is now almost assembled, yay! I also got started on installing the heating system.


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## catphish (Jul 30, 2017)

I now have the remaining parts (motor mount, charger mount, vacuum pump mount) back from powder coating. I have started the final assembly and re-installed the drive unit (hopefully for the final time!).

The next (and hopefully final) fabrication task is the driveshafts. I have OEM Tesla and Vauxhall shafts, and will need to cut and join these. The Tesla shafts are wider, so the current plan is to machine down the Vauxhall shafts into a peg, and drill out the Tesla shafts, then press the Vauxhall peg into the Tesla hole. I'm pretty scared of this step so will be getting a lot of help!








In addition to making my own wiring diagram, I've spent some time studying the OWM wiring diagrams, available here: https://jimdo-storage.global.ssl.fastly.net/file/9285eaf8-c751-41af-92f6-45c6db1d9070/shema electrique speedy.pdf and here: https://www.speedsterclub.nl/bibliotheek/technische documentatie/tis/Wiring Diagrams/index.html
This should allow me to easily break out the wires I need at the front and rear of the car and avoid having to run to many additional wires.

The battery box is finally finished, yay!


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## Joske (7 mo ago)

hello,
I am new to this topic and group as a friend of mine has a lotus Elise and we are investigating if we can do something similar. 
He asked me to review your work and see if we are able to do something similar. 
Great work by the way with the whole build and the oil pump solution. Great to see your progress and I look forward when you can update on the driving experience in the next weeks. 

As you have the drivetrain already in position, do you have me some information how high the drivetrain is from the floor level? Would it be possible to take a picture from the underside when the vehicle is on its wheels, purpose is to estimate if we could lower the SDU a bit more in the vehicle and have some more space on top for example for batteries. Also the driveshafts, from what I can see your shafts would run quite straight into the differential. It would be interesting to see the angle when the vehicle is on the ground and when it has the wheels off the ground. To check what is clearance to the wheel triangles. As the battery is not yet in place, the vehicle would still be quite high from the floor, but would already give us good idea. 

Thank you for the great documentation and I like the professionalism of this project.


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## catphish (Jul 30, 2017)

I've started the low voltage wiring by cutting off the ECU plugs and labeling every wire. I also labeled the wires on the SDU loom. This should make it fairly easy to match everything up once I'm ready to begin splicing. I bought a Dymo Rhino 4200 label printer, and printable 6mm heatshrink, which I strongly recommend!



























I spliced into the alarm loom under the dash in order to get power for my charge controller and the other bits at the front of the car.


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## catphish (Jul 30, 2017)

Joske said:


> As you have the drivetrain already in position, do you have me some information how high the drivetrain is from the floor level? Would it be possible to take a picture from the underside when the vehicle is on its wheels, purpose is to estimate if we could lower the SDU a bit more in the vehicle and have some more space on top for example for batteries. Also the driveshafts, from what I can see your shafts would run quite straight into the differential. It would be interesting to see the angle when the vehicle is on the ground and when it has the wheels off the ground. To check what is clearance to the wheel triangles. As the battery is not yet in place, the vehicle would still be quite high from the floor, but would already give us good idea.


The SDU is now fully installed so next time I'm with the car, I will measure the height from the floor for you (when loaded with the SDU but not the batteries). I will measure both the bottom of the sump and the centre of the driveshaft entry holes to the ground.

I really didn't give much thought to the position of the SDU when I started the project. I was so glad it fitted so well into the original rear engine mount that I didn't really stop to consider if it was actually in the right place or not! I now realise that the differential is a little forward of the rear wheels. I roughly measured the angle of the shorter driveshaft at around 9 degrees. The CV should be able to handle this, but definitely something to consider.


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## catphish (Jul 30, 2017)

Continuing with wiring, I've started running a new main loom from behind the dash, through the cabin, to the engine bay. This includes 3 important bundles of wires:
1) Low volatge control, runs from behind dash to engine bay. Connects charge controller in dash to battery box, SDU and EVSE. Includes CAN, CP/PP, heater contactor control, BMS wakeup line.
2) Gear selector, breaks out from new loom where it passes the gearstick location, provides FWD, REV, and 12v illumination for the knob.
3) High voltage 2-core heater cable. Joins heater wired behind dash. Connects to HV at battery box.

The cable routing past the handbrake is quite bad, the cabling runs very close to the handbrake mechanism and i spent a couple of hours just trying to make sure it sits securely and doesn't interfere. This seems like a pretty poor design in the original car!


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## catphish (Jul 30, 2017)

After a few days off, I've finally started work on my driveshafts! So far I've disassembled them, cut them over-length, and started cleaning them up. Later in the week will be be the final length measurement and final cut! The plan is to bore out the larger tesla shaft and insert the smaller Vauxhall shaft inside, then finish with a v-cut and weld.


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## catphish (Jul 30, 2017)

Using a simple 3D printed plate, I've now mounted the gear selector into the centre console (the hole left by the original gearstick). Unfortunately I can't upload the CAD files here, but it's not too complex, 90mm x 72mm x 8mm, with a corner radius of 16mm and a rectangular hole (20.5mm x 30.5mm).


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## catphish (Jul 30, 2017)

Driveshafts have now been cut and bored, hopefully I will be able to shrink fit them together tightly before welding.


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## remy_martian (Feb 4, 2019)

Got a place where you can borrow a thermos of LN2? Do not cap the container if you do...

I'd assume the axles are heat treated. You might want to anneal those ends with a torch and bucket of sand before joining and welding to lessen the chance of cracking.


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## catphish (Jul 30, 2017)

remy_martian said:


> Got a place where you can borrow a thermos of LN2?


I'll definitely ask around and see if anyone has any LN2, combination of cold and heat seems like it would definitely be the best overall option. I don't think I'll have the patience or knowledge to anneal them, so will have to hope I don't overdo the shrinking and crack them! Depending how well it goes, I may send the prototypes off to be re-made into new shafts professionally.


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## catphish (Jul 30, 2017)

Had a god day on the car today. Did the final installation of the charger, coolant pump, header tank, and vacuum pump. Ran all the coolant lines, tested the pump and ran water through to test for leaks. All seems to be working well! I went with a simple loop: Radiator -> Pump -> Inverter -> Charger -> Motor -> Radiator. I also re-installed the brake master cylinder. Sadly sticking with the OEM vacuum brake boost for now.


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## remy_martian (Feb 4, 2019)

I doubt it's the shrink fit, but the welds that may crack...hundreds vs thousands of degrees. 

Which is why you heat it cherry and slow cool it (jab it into a sand bucket is a poor man's slow cooling annealing method)


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## catphish (Jul 30, 2017)

Today was a big day of low voltage wiring! I've made up and installed low voltage looms for each component and brought them all to a single location:

VCU (charge controller)
Gear Selector
Small Drive Unit
Charger / DC-DC Converter
The existing OEM engine loom (power, throttle, warning lights, etc)
Vacuum pump
With all that in one place, I am now ready to splice everything together as needed. The Dutch 12 pin plug for the battery box really is a joy to assemble. Highly recommended!

I made some last minute changes to my wiring plans to ensure that the CAN bus meets the standards. In particular, making sure that stubs are kept below 300mm. Because my battery box contains a "dead end" on the CAN bus, and because the SDU contains a termination resistor, I decided to start the bus in the battery box, run it all the way to the front of the car to the VCU under the dash, then all the way back to the rear, to the charger (there are 2 CAN pairs in the charger loom) and then finally into the SDU.

I also took the opportunity to give the car 12V for the first time in a while. I have an array of warning lights for the brakes, ABS, and airbags, but hopefully those will be happy once the brakes and seatbelts are reconnected. I've bought an OpCom OBD2 cable to reset those fault codes as needed. Apart from that, everything still seems to work as it should, and power is available where I need it to be. I've tested the vacuum pump, which is a little loud as expected, but only runs during braking to replenish the vacuum, so not too annoying.


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## catphish (Jul 30, 2017)

Done most of the splicing. it looks a little messy, but once I've shortened a couple of wires and wrapped it up, it should be nice and neat. So far so good. Everything appears to work so far including the OWM throttle.


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## catphish (Jul 30, 2017)

So today I've been reflecting in potential problems with my design. There are two things of mild concern:
1) The main contactor has an inrush current of 2.5A. The Openinverter SDU board is driving the contactors using NCV8402. These _should_ be able to supply about 3A but it's something I need to be careful of.
2) My battery box has a space on each side of the batteries where contactors etc are mounted. The batteries are clamped down from the top, but I suspect it would be a good idea to place some hard plastic spacers between the side of the bateries and the side of the box to ensure that the battery terminals are not taking any of the (sideways) weight of the batteries during cornering.

I've also realized with some embarrassment that I have no idea how to fill the SDU with oil!

On an entirely different note, I realised today with some irritation that there are two different standards for CAN on a DE-9 connector. CAN has one standard but OBD2 has its own. This means that I can't plug an OBD2 cable directly into a CAN debugging tool. I'll have to find (or make up) the correct cable.


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## Joske (7 mo ago)

catphish said:


> The SDU is now fully installed so next time I'm with the car, I will measure the height from the floor for you (when loaded with the SDU but not the batteries). I will measure both the bottom of the sump and the centre of the driveshaft entry holes to the ground.
> 
> I really didn't give much thought to the position of the SDU when I started the project. I was so glad it fitted so well into the original rear engine mount that I didn't really stop to consider if it was actually in the right place or not! I now realise that the differential is a little forward of the rear wheels. I roughly measured the angle of the shorter driveshaft at around 9 degrees. The CV should be able to handle this, but definitely something to consider.


Hello Brian, thanks for the update. Purpose of my question is that I would like to investigate if with a modified rear beam we can keep the original driving direction of the drive unit. If we know the amount of modification of this beam we could discuss with a certified engineer if this is allowed to be modified in a way it would allow to have the gearbox in the tesla orientation. Pitty you live the opposite of the world otherwise would like to pass by and check your nice work. thanks.


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## Ken S (8 mo ago)

catphish said:


> On an entirely different note, I realised today with some irritation that there are two different standards for CAN on a DB-9 connector


 _Isn't that a nuisance_?!? What a hack! _What were they thinking_?!? 

It's tempting to use a pair of screw terminals, but that is not recommended. I've seen control systems in heavy equipment that use a phoenix contact plug with built-in screw terminals. These are not as pretty as a DB-9, but they handle rough service. I may install a DB-9 port with the standard CiA 303 pinout (2&7) with clear labeling. I might include a second well-labelled port with the alternative goofy-foot wiring (5&3), just to simplify direct connection to popular cheap CAN/USB adapters. (The next owner will need remember to terminate only one of them!)


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## catphish (Jul 30, 2017)

Joske said:


> Hello Brian, thanks for the update. Purpose of my question is that I would like to investigate if with a modified rear beam we can keep the original driving direction of the drive unit. If we know the amount of modification of this beam we could discuss with a certified engineer if this is allowed to be modified in a way it would allow to have the gearbox in the tesla orientation. Pitty you live the opposite of the world otherwise would like to pass by and check your nice work. thanks.


I do apologise, I still haven't done this, I remembered a coupld of times but couldn't put my hands on a tape measure. The batteries are now in the car, so I will try to get this measurement for you when I can.


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## catphish (Jul 30, 2017)

Today I completed the low voltage wiring, and got the battery box lifted into the car. I've tested the contactors and made a good start on the HV wiring. Just the inverter wiring to do, and then I can think about powering it all up!

I also filled the oil. This drive unit is designed to take 2.25 litres of Mobil SHC 629. I'm using an equivalent called "Indisyn Mild 150".

I've written some basic code for the charge controller (which I've started calling the VCU because it it also controlling the heater contactor and pumps). Finished / updated wiring diagram also attached.


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## catphish (Jul 30, 2017)

Small update with good news. I connected up my HV today and everything works so far:

Small drive unit controls contactors correctly and spins!
DC-DC converter works
Heater works
VCU is correctly sending the start signal to the inverter (CAN) and correctly controlling the coolant pump, heater, and DC/DC converter.
The only big thing remaining to test is the charger. Hopefully next week I'll get the charge port wired up to test that.

To celebrate I removed some workshop dust and took some photos. This is with the battery box installed without its lid


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## catphish (Jul 30, 2017)

I have been quite alarmed by reports of random failures of SDU inverters. I've been working on an openinverter configuration, but I now think I will tune it a little more in line with a configuration from a car that I know has been running without issue for a year. boxster986ev/params.json at master · Zero-ev-conversion-ltd/boxster986ev


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## remy_martian (Feb 4, 2019)

^^ S3XY


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## catphish (Jul 30, 2017)

I've run into a fairly serious problem with my BMS. The charger creates high frequency electrical noise on the high voltage system which is interfering with the BMS communications. This means the BMS does not work during charging, not ideal! I am looking into options to mitigate this electrical noise. Hoping to avoid yet another redesign of the BMS!


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## Ken S (8 mo ago)

<hack>If hardware redesign is not an option, can you do something in software? Suppose you let the charger do it's noisy deed for 60~120 seconds, then stop sending target voltage&current and wait 5~7 seconds for it to stop charging. When that happens your BMS can check the status of the cells and compute a new target voltage and current. Lather, rinse, repeat. </hack>


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## catphish (Jul 30, 2017)

Ken S said:


> <hack>If hardware redesign is not an option, can you do something in software? Suppose you let the charger do it's noisy deed for 60~120 seconds, then stop sending target voltage&current and wait 5~7 seconds for it to stop charging. When that happens your BMS can check the status of the cells and compute a new target voltage and current. Lather, rinse, repeat. </hack>


You're right, this will certainly work, if my attempts to fix the hardware fail, I will absolutely do this


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## remy_martian (Feb 4, 2019)

Ferrite bead/balun on the charger leads might mitigate the conducted EMI.


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## catphish (Jul 30, 2017)

I had another small electrical noise problem, my design for reading the CP line wasn't particularly noise immune, and it received garbage in the rather specific case where both the charger and ignition (ie HV precharge) were on. Luckily this was easily fixed with a capacitor on the CP input.


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## catphish (Jul 30, 2017)

The front of the car is just about finished now. I got the brake lines reconnected and the new cabin blower hose installed. This means I can probably get on now and re-install the headlights and front clamshell!


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## catphish (Jul 30, 2017)

catphish said:


> I've run into a fairly serious problem with my BMS. The charger creates high frequency electrical noise on the high voltage system which is interfering with the BMS communications. This means the BMS does not work during charging, not ideal! I am looking into options to mitigate this electrical noise. Hoping to avoid yet another redesign of the BMS!


I believe I now have a solution to this problem. I temporarily installed an isolating transformer between one battery string and the BMS. That battery string was able to maintain communication while charging at 10A (the most I can easily test). It's a shame I didn't build these transformers into the BMS PCB, but I'm not inclined to remake the board at this point, so I will simply put transformers in line with my data cables, at least for now.










As the front end of the car is now (I hope) complete, I've bolted the front clamshell back on! Just waiting on driveshafts now.

Not really related to the conversion, but I've some parts for general maintenance, new brake discs and pads for the rear that I disassembled, new toe links, I caused some damage to the old ones removing them to free the driveshafts, and a new bonnet catch release mechanism the original one really sucks.


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## remy_martian (Feb 4, 2019)

There's a pretty massive shortage of isolation actives right now, with nothing available until 2023 🤬, so it's great you found a workaround.


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## catphish (Jul 30, 2017)

Joske said:


> hello,
> I am new to this topic and group as a friend of mine has a lotus Elise and we are investigating if we can do something similar.
> He asked me to review your work and see if we are able to do something similar.
> Great work by the way with the whole build and the oil pump solution. Great to see your progress and I look forward when you can update on the driving experience in the next weeks.
> ...


Sorry it's taken quite so long for me to do this! Here's a photo of the underside of the car. This is with the car fully loaded (90kg SDU and 200kg battery box). The photo doesn't really help much, but the distance from the bottom of the drive unit to the ground is 85mm. I'd say you probably wouldn't want to go any lower than this!


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## catphish (Jul 30, 2017)

Driveshafts are now complete and installed!
















The wheels are now spinning. There's a slight knocking sound under acceleration, hopefully this will go away once everything is properly loaded.


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## catphish (Jul 30, 2017)

Big day today, the electric VX220 had its first test drive!

Mostly seems to work well. I need to do a better job of bleeding the brakes as they're very soft, and I definitely need to do some tuning on the drive unit as for some reason it's cutting power at full throttle.

Will post some driving videos soon I hope!


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## remy_martian (Feb 4, 2019)

Nicely done, great packaging, nothing fell out, & congrats on it runing under its own power.

They're so cute, I want one, but the steering wheel is on the wrong side 😭


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## SuperV8 (Jan 22, 2020)

catphish said:


> Big day today, the electric VX220 had its first test drive!
> 
> Mostly seems to work well. I need to do a better job of bleeding the brakes as they're very soft, and I definitely need to do some tuning on the drive unit as for some reason it's cutting power at full throttle.
> 
> Will post some driving videos soon I hope!


Nice work.
Was the knocking still evident with it on its wheels? or has it gone?
If you have new pads - they will feel a little soft until fully bedded in.
If you can pump your pedal a few times and it goes hard (oow ur..) they yes probably air.


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## catphish (Jul 30, 2017)

SuperV8 said:


> Nice work.
> Was the knocking still evident with it on its wheels? or has it gone?
> If you have new pads - they will feel a little soft until fully bedded in.
> If you can pump your pedal a few times and it goes hard (oow ur..) they yes probably air.


Fortunately yes, I think the knocking has gone now it's fully loaded. I need to spend a little more time carefully listening for any sounds to make sure everything is good though. I did put new pads on the rear, but I strongly suspect I did not bleed the brakes well enough anyway. The pedal travel is just excessive.


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## catphish (Jul 30, 2017)

Good news: everything is finished, the car has been for a proper drive and has passed its MOT! The only issue raised was that I should add more cable clips for my new wiring.

Bad news: one of the cells in my battery is showing a voltage dramatically lower than all the others (probably 25% or more SoC difference). This has to be either a bad cell or a BMS fault, but the only way to investigate (and fix) is to disassemble the rear of the car again  (remove seats, remove parcel shelf, remove wheel arch liners, remove clamshell, unbolt battery box, slide it back, remove its lid).

Once I have access to the batteries I can determine whether the problem is a bad cell, or a bad BMS slave module, or just a bad connection. I have spares, but the process is rather tedious, especially if I have to get the battery module out of the pack! Just wish I'd noticed this before I finished assembling everything!


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## catphish (Jul 30, 2017)

Today I replaced the bad battery module. There was some corrosion in the BMS slave module and cell tap connector. After cleaning it up, it still measured the exact same voltage. My theory is that some liquid got into the slave module, shorted the cell and drained it a bit while simultaneously corroding the contacts. I suspect there's no serious problem but decided to replace the whole module anyway as I had a spare. The new module is annoyingly not at the same SoC as the rest of the pack, and I had no easy way of quickly draining it, so I suspect I'll be balancing for a while, but at least I know the cells are good now!


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## catphish (Jul 30, 2017)

After fixing the battery and installing the charge port, I drove the car home, 17 miles. Everything seems good apart from the wheel alignment which I will get fixed professionally in the next couple of days. There will also be a bit of tuning needed on the openinverter SDU. I've resolved a couple of overcurrent warnings, and it's driving very smoothly, I'd just like a little extra torque off the line and I'll be happy.

Once the alignment is done and the undertrays are reinstalled, I will turn my attention to the gauges, as I only have MPH right now. I'm probably going to take a break from engineering and a long sleep first though!


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## Hairy (6 mo ago)

Great thread Catphish, I have just come across this by accident and read the whole story end-to-end. As an owner of an EV and a VX220 I found it absolutely fascinating.

I really don't have much experiemce of the electrical set up and wondered how I could learn a bit more on that - does anyone have any recommended basic reading or training courses? I recognise that I might have to follow this path one day so would like to start building up my knowledge.

Best regards, Hairy


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## catphish (Jul 30, 2017)

The car has had some love in the form of a wheel alignment and a clean!









After a couple of test drives, I noticed a sound during acceleration that sounded like the motor moving slightly in its mount. I checked it out and discovered that I hadn't fully torqued the motor mounting bolts and one was starting to come loose.  Very important lesson learned! After tightening all the bolts at home, followed by a brief trip the workshop to torque them properly, the car is now running silently.

I did some basic tuning of the motor by doing some 0-60 runs and monitoring the AC and DC current. The initial tuning runs the motor (AC current) at a consistent 400A, and the battery (DC current) at 400A maximum (at full throttle). This graph shows one such run, in this case the AC current was quite consistent at 400A, but DC current rose a little above 400A causing the throttle (bottom line) to be automatically limited by openinverter. This is a very conservative configuration, giving a 0-60 time of about 8 seconds, and smooth consistent throttle response.


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## catphish (Jul 30, 2017)

After a few more tuning runs, I've concluded that a somewhat lower amount of slip works well for the SDU. While constraining AC and DC current to around 400A, and avoiding hitting any limits, I'm now able to achieve a 0-60 time of about 7 seconds. I will be continuing to optimize, but this seems quite reasonable.

Here's a chart of a 0-60 run with my final parameters. It's not winning any drag races, but very consistent performance.


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## catphish (Jul 30, 2017)

I had an opportunity to make some videos today!


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## catphish (Jul 30, 2017)

After driving the car for a while and worrying about every little rattle (the worst of which turned out to be my keys that fell out of my pocket onto the aluminium floor), I've now started work on gauges.

For now I have decided not to touch the stock gauges, and instead just add a small (2 inch) OLED display elsewhere on the dash. For now this will display battery voltage information and temperatures. I can also add more visual bars, which I will probably use for (approximate) state of charge.


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## 4Foxtrot (Apr 1, 2019)

Brothers from the same mother ... EV's on Poole Quay, Dorset UK









3 in total ! .. with a Tesla Roadster down the line ( some might argue that was a DIY EV too  )


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## catphish (Jul 30, 2017)

This week I've been working on a simple OLED gauge to display battery data and temperatures. This uses a 2.4" OLED display, and a RP2040 based CAN adapter:









2.42" inch OLED Display RGB SSD1309 12864 SPI Serial Port for Arduino C51


Features:This is a 2.42 inch OLED display module of 128x64 resolution in which the emissive electroluminescent layer is a film of organic compound that emits light in response to an electric current.Working without backlight, the OLED display module could give out light by itself.In low ambient...




www.diymore.cc









CANBED RP2040 - Longan Docs


Docs of Longan Labs




docs.longan-labs.cc





These 2 boards can be sandwiched together to build a fully integrated CAN display with just +12V, GND, CANH, CANL. I 3D printed a simple casing to fix it onto my dash.

Source code is available at GitHub - catphish/vx220-oled: Source Code for EV VX220 OLED info display


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## catphish (Jul 30, 2017)

4Foxtrot said:


> Brothers from the same mother ... EV's on Poole Quay, Dorset UK
> View attachment 132119
> 
> 
> 3 in total ! .. with a Tesla Roadster down the line ( some might argue that was a DIY EV too  )


That's a nice looking car, where's the exhaust pipe?!

Great photo, and nice to meet you last week, thanks!


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## catphish (Jul 30, 2017)

Display is now finished and installed. Not the ideal location, but a convenient space to mount it. When driving it shows a complete set of data, and when charging is shows only what is received from the BMS. The state of charge is purely voltage based, so it's not very linear, but good enough to avoid accidentally running out of power!


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## catphish (Jul 30, 2017)

I've spent a fair bit of time tuning and testing in the last week. I now have the following performance:

0-60 in 5.1 seconds (based on a current limit of 500A)
75 miles confirmed range (using 90% to 10% SoC)
I currently have no regen braking set up, which is probably reducing my range a little, but haven't found regen settings I like yet.


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## remy_martian (Feb 4, 2019)

Nice. 

I'm not too thrilled with the way OI does regen, but I'm pretty far away in time from worrying about it.


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## catphish (Jul 30, 2017)

remy_martian said:


> I'm not too thrilled with the way OI does regen, but I'm pretty far away in time from worrying about it.


I actually wrote a patch to change the regen and make it work more like an ICE: Speed dependent throttle curve - openinverter forum
Unfortunately, apart from a brief test, I never used it because it's difficult to update the software in my car so I preferred to stick with something stable.
Edit: just realised you already commented on my other post


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## remy_martian (Feb 4, 2019)

Yep - an ally in crime I am. 

Regen is nice. If you're not in hill/mtn country you can get by without it. 

Maybe at least install a full regen paddle or pushbutton and decouple it from braking entirely? Don't forget to turn on the brakelights 😂


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## joekitch (Sep 13, 2013)

AusS2000 said:


> I found it even cheaper on Alibaba. Anyone know the deal with these?
> 
> 
> 
> ...


this link is dead (makes sense as this comment is a year old) but what's a good search term to relocate it on alibaba? i cant seem to locate it on there anymore, even with the CAD662DF400-14152 model name


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## remy_martian (Feb 4, 2019)

Ask: https://www.ovartech.com/product-category/ev-on-board-charger/


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## dlud (Jul 19, 2021)

Just reviewed your videos posted above. Nice job! I like the charge port cover. Is this original fabrication and if not, where did you source it?


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## catphish (Jul 30, 2017)

joekitch said:


> this link is dead (makes sense as this comment is a year old) but what's a good search term to relocate it on alibaba? i cant seem to locate it on there anymore, even with the CAD662DF400-14152 model name


The best thing to do is just to contact the manufacturer directly. They're very helpful and you should be able to get a good price.


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## catphish (Jul 30, 2017)

dlud said:


> Just reviewed your videos posted above. Nice job! I like the charge port cover. Is this original fabrication and if not, where did you source it?


The charge port cover comes with the charge port. Lots of people on aliexpress sell these, just search "type 2 socket" there.


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