# Advice on new Performance/daily conversion



## Kevin Sharpe (Jul 4, 2011)

24Seven said:


> The car is about 1300kg/2850lbs (curb weight) and has 260hp from an inline 5 cyl 2.0 litre turbo Engine and FWD.


Take a look at the Tesla based projects using the 'small' front drive unit (here) and 'small' rear drive unit (here). These typically weigh ~90kg including the transmission and inverter (so you can dump the ICE clutch, transmission, diff, etc). Peak input power is ~220 kW (294 HP).

An open source inverter controller (here) is currently being tested in several cars with a range of different Tesla 'large' and 'small' motors;

Tesla Powered BMW E31 8 Series - 'large' rear motor with Tesla battery modules

Tesla Powered Nissan 350Z - 'large' rear motor with Tesla battery modules

1967 VW Split Screen Van - "ICE Breaker" - 'small' rear motor with Tesla battery modules

1978 VW Beetle 1303 Convertible - "ICE Breaker 2" - 'small' rear motor with Leaf battery modules

The open source controller supports a wide range of battery types ranging from ~250V to ~400V. Depending on your range and top end requirements a battery containing 10 Tesla Modules might be a suitable choice.

Open source solutions are also in development for the Tesla charger (here), BMS (here), DCDC, Air Compressor, etc., etc. 

If you add your location to your profile it might be possible for you to visit one of the developers and discuss your project if that's helpful.


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## 24Seven (Nov 19, 2017)

Thank's Kevin!

That was just the kind of answer I was looking for  

With a hacked Inverter this would (almost) drop staight in and solve alot of issues with gearbox and clutch mating to a motor.

I guess the only downside is that batteries will be expensive at 250V+ but that might be the price you have to pay for simplicity.

I live in Sweden and unfortunately the is not really a plenthora of used Tesla parts available here, but there is always Ebay I guess... Is there any other good reputable source selling Tesla parts? 

With this simple drivetrain I might even consider converting to RWD at the same time


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## Kevin Sharpe (Jul 4, 2011)

24Seven said:


> I guess the only downside is that batteries will be expensive at 250V+ but that might be the price you have to pay for simplicity.


If you're looking for performance you'll need to invest in some decent batteries... Leaf modules are pretty cheap but probably don't have the performance you need... Volt modules might be a better fit... What's your budget?



24Seven said:


> Is there any other good reputable source selling Tesla parts?


Here is a good place to start


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## 24Seven (Nov 19, 2017)

Kevin Sharpe said:


> If you're looking for performance you'll need to invest in some decent batteries... Leaf modules are pretty cheap but probably don't have the performance you need... Volt modules might be a better fit... What's your budget?


Thank's again Kevin, I will look more into Leaf and Volt modules, but I´m shure youre right about the lower performance of Leaf batteries

The initial budget is always about a third of what the build is ending up costing  I was hoping to be able to do the conversion for about 15000 Euro. This does not include AC, Heater etc. just to get the car running.




Kevin Sharpe said:


> Here is a good place to start


Thanks for pointing me in the right direction.


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## Boxster-warp (Jun 22, 2014)

Hello
I am selling the older technic Netgain dc Controller on eBay.
https://www.ebay.de/itm/Netgain-1400-ampere-360v-Controller/152794114854

The Tesla drivetrain is Not so easy to install, i think.

In an other selling on eBay i have a new Netgain warp11 Motor.
But Not with shipping.

I am from Germany, and the TÜV whant no Motors without CE Plate.
Bad fore me.

Greetings Boxster-Warp


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## 24Seven (Nov 19, 2017)

Boxster-warp said:


> Hello
> I am selling the older technic Netgain dc Controller on eBay.
> https://www.ebay.de/itm/Netgain-1400-ampere-360v-Controller/152794114854
> 
> ...


Hi Boxter Warp,

Thank's for bringing up CE-approval, I'll have to check with the Swedish equivalent of TÜV, that might actually be a problem here as well.

I also want to do a bit more reseach on OEM drive units from Tesla and Leaf before i buy any parts, thank's anyway!

Regards 
Martin


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## brian_ (Feb 7, 2017)

24Seven said:


> With this simple drivetrain I might even consider converting to RWD at the same time


It would be a lot easier and perhaps cheaper to scrap the Fiat Coupé (assuming that you mean the 1990's Type 175) and start with something that has rear wheel drive... although the Coupé does have an interesting style.


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## Kevin Sharpe (Jul 4, 2011)

24Seven said:


> Thank's for bringing up CE-approval, I'll have to check with the Swedish equivalent of TÜV, that might actually be a problem here as well.


If you do need a CE certificated drivetrain then afaik New Electric are the only company that have invested in the testing of Siemens and HPEVS in Europe.

Going forward a number of people have expressed an interest in testing and certifying the Tesla components for use in countries that require it.


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## 24Seven (Nov 19, 2017)

brian_ said:


> It would be a lot easier and perhaps cheaper to scrap the Fiat Coupé (assuming that you mean the 1990's Type 175) and start with something that has rear wheel drive... although the Coupé does have an interesting style.


Hi Brian, 

You are absolutely right, would be MUCH easier to start with an e36 or simular. Unfortunately I am one of the few that really love the Chris Bangle/Pininfarina design of the Coupé, and have a real weakness for Italian cars. I have actually been playing with the idea of RWD-converting my Coupé with the ICE motor before, but this might be "Stage 2" of a conversion.


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## 24Seven (Nov 19, 2017)

Kevin Sharpe said:


> If you do need a CE certificated drivetrain then afaik New Electric are the only company that have invested in the testing of Siemens and HPEVS in Europe.
> 
> Going forward a number of people have expressed an interest in testing and certifying the Tesla components for use in countries that require it.


That is interesting, I just assumed that (almost) all modern technology was CE-certified. 

I built a Super Seven replica about ten years ago and then there were no rules (in Sweden) that stated parts had to be CE-approved. An electric converison follows the same approval process as my Super Seven, so I hope that this will not be an issue. I will be shure to double check this before getting to deep into the build though.


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## Kevin Sharpe (Jul 4, 2011)

24Seven said:


> I built a Super Seven replica about ten years ago and then there were no rules (in Sweden) that stated parts had to be CE-approved. An electric converison follows the same approval process as my Super Seven, so I hope that this will not be an issue. I will be shure to double check this before getting to deep into the build though.


New rules were introduced across Europe in the last couple of years... some countries decided to implement more stringent requirements including EMC certification (The Netherlands). Here's a thread that discusses some of the issues;

http://www.diyelectriccar.com/forums/showthread.php/uk-iva-october-2016-update-now-177961.html

I would suggest trying to find someone in Sweden who has registered an electric conversion recently


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## Duncan (Dec 8, 2008)

If you don't need your electronics to be "approved" then a DC setup is much much cheaper and can be more powerful

This is my "Device"

http://www.diyelectriccar.com/forum...dubious-device-44370p15.html?highlight=duncan


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## 24Seven (Nov 19, 2017)

Kevin Sharpe said:


> New rules were introduced across Europe in the last couple of years... some countries decided to implement more stringent requirements including EMC certification (The Netherlands). Here's a thread that discusses some of the issues;
> 
> http://www.diyelectriccar.com/forums/showthread.php/uk-iva-october-2016-update-now-177961.html
> 
> I would suggest trying to find someone in Sweden who has registered an electric conversion recently


I have emailed an inspector from SFRO, which is the organisation that inspects and approves home built or modified vehicles in Sweden. Should be interesting to hear what he has to say.


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## 24Seven (Nov 19, 2017)

Duncan said:


> If you don't need your electronics to be "approved" then a DC setup is much much cheaper and can be more powerful
> 
> This is my "Device"
> 
> http://www.diyelectriccar.com/forum...dubious-device-44370p15.html?highlight=duncan


Hi Duncan,

I bet your home grown Seven is super quick of the line. If I could do my Super Seven build again it would definitly have an electric motor.

Without really knowing what conversion parts are availiable or what's possible, The initial plan was roughly: 


No need for gears 
Regen Braking 
150-200kw Power 
50 miles+ range
 Like any other EV to drive (Wife-proof)

Allthough compromises are inevitable with a limited budget.

I now know that regen is a no go and gears are hard to avoid with most DC-motors. If there is a good DC alternative where price/power/availability/weight is better than an AC setup I'd be willing to compromise.

From my short research the biggest cost by far seems be the batteries on both AC and DC setups. A new Warp 11 motor costs roughly the same as a used Tesla front drive unit, which includes an inverter and diff.


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## Boxster-warp (Jun 22, 2014)

Hello
My used Netgain Controller and my new warp11 on eBay cost 3900€, without shipping.
Controller shipping is ok but Motor Not.
I paid fore Both 5700€ 

Tesla Drive Unit Are a good Choice too.
Here in Germany cost a Tesla drivetrain 5000-7000€ without new Axels.

The Most conversions in Germany was with Curtis Controllern.(with low power).
But One Factory whant sell in Summer the scottdrive Controller with an TÜV Option.
The Controller cost alone 6000€, many Money.
It is Not easy to Build an ev conversion in Germany 
Greetings Boxster-Warp.


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## Duncan (Dec 8, 2008)

Hi 24seven

My motor cost me $100NZ
The controller was about $800NZ
Batteries $3300NZ all up (Volt pack)

No gearbox
1200 amps and 340 v

I built it a bit too heavy - 805 Kg - 900 kg with me in it

55% of the weight on the rear wheels, Subaru diff with LSD

It will smoke the rear tyres! - I have ordered some super sticky only just road legal tyres for next year

I normally drive it at 45% power - 100% is a bit too exciting


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## 24Seven (Nov 19, 2017)

Boxster-warp said:


> Hello
> My used Netgain Controller and my new warp11 on eBay cost 3900€, without shipping.
> Controller shipping is ok but Motor Not.
> I paid fore Both 5700€
> ...



Sorry for the late answer, been down with the flu and a nasty cough.

Yeah, shipping and customs/tax really add alot to the price. 

If going with the Tesla drive train I would much rather buy it from somewhere in EU to minimize shipping and avoid customs. However, I´m affraid it will be hard to find parts as cheap here. Found this on Ebay, not within EU though.

I really hope we don´t have as strict rules here as you do in germany, still waiting for reply from the Swedish Car inspectors.


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## 24Seven (Nov 19, 2017)

Duncan said:


> Hi 24seven
> 
> My motor cost me $100NZ
> The controller was about $800NZ
> ...


That is really impressive! I now have to read your build thread again from start to finish 

My super Seven had a Curb weight of about 500kg and 200hk/250N. I can only imagine how it would be with almost twice the Power


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## Smatt (Jun 25, 2019)

Hi, I know this is an old thread, but was just wondering if you got anywhere with the coupe? I am really keen to convert one, but am just at initial planning stages
Regards, Matt


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## 24Seven (Nov 19, 2017)

Smatt said:


> Hi, I know this is an old thread, but was just wondering if you got anywhere with the coupe? I am really keen to convert one, but am just at initial planning stages
> Regards, Matt


Hi Matt,

This project is still active, but progress is slow. Since last time I posted here I've done alot more research, spoken with SFRO (the local inspection/registration agency for altered vehicles), built an electric Cafe racer motorbike and cleaned the garage 

As of now my recipe looks like this:


Tesla front motor
Aftermarket control board for Tesla inverter
350-400V, 20-30kWh, 600A+ battery
Steering column with electric servo
Electric water pump
Electric vacum pump for the brakes
.....

Most of the components are relatively easy to get hold of here in Sweden, apart from the battery. The Kia Soul EV battery would be a good match, but seems really hard to find. 

I don't really want to raise the weight of the car, hence going for low weight/short range. 

Would really appreciate suggestions on other batteries that might be a good fit for what I'm doing.


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## Smatt (Jun 25, 2019)

24Seven said:


> Smatt said:
> 
> 
> > Hi, I know this is an old thread, but was just wondering if you got anywhere with the coupe? I am really keen to convert one, but am just at initial planning stages
> ...


Hi there,
Thanks for the update! 

You have a lovely looking coupe - looks like a 'LE' - much too nice to scrap as suggested above!!
I am stalling at the moment as I am not sure the car I have in mind is in good enough condition to start on without loads of work
Once I've resolved this, I was planning on looking into Tesla front motors as some say they will not fit, but if they do, I feel they would be perfect level of performance vs the original car...


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## 24Seven (Nov 19, 2017)

Smatt said:


> Hi there,
> Thanks for the update!
> 
> You have a lovely looking coupe - looks like a 'LE' - much too nice to scrap as suggested above!!
> ...


Thanks! yes it is an LE. It has been garage kept most of its life so it is 99% rust free. Sorry to hear about the condition of your Coupe, but it might be for the better. I am hesitant to put the angle grinder and welder to the original metal of my car, allthough this would make it much easier to get parts to fit good. In your case maby this is not an issue and you could make batteries etc. fit perfect by cutting and altering your coupe.

I have not yet meassured the engine bay but was almost certain that the Tesla front motor would just drop in, Have you heard of any specific reason to why it would not fit? Is it the centered gearcase/diff that would hit the steering pherhaps?


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## brian_ (Feb 7, 2017)

24Seven said:


> Tesla front motor
> .....


Why the front motor, rather than the small rear motor? Does it provide better clearance for the tires when steering, or is the motor intended to sit over the steering rack? The small front and rear units have the same motor and gearing, but are just packaged differently, and the rear unit places the motor lower (handy for lower centre of mass and more room above it).


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## brian_ (Feb 7, 2017)

24Seven said:


> ...
> 350-400V, 20-30kWh, 600A+ battery
> .....
> 
> ...


Most current EVs have a much larger battery, and cannot be readily configured to half size while maintaining voltage. Plug-in hybrids generally have half of that battery capacity and it is awkward to combine two of them while maintaining the same pack voltage.

The other obvious battery of the desired size is from the Nissan Leaf. 

There are other current or recent EVs which are adapted from gas engine models, and have battery capacity at about the target:

Volkswagen eGolf
Ford Focus Electric
Fiat 500e
Chevrolet Spark EV (on the small side; came in two entirely different types in the same package size)
What is available locally depends more on the manufacturer's marketing strategy than any technical factor.

If you really like Tesla bits, you could also risk internally converting Model S/X modules to 12S (from the stock 6S configuration) and using six or seven of them in series for roughly the desired combination of pack voltage and capacity.


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## 24Seven (Nov 19, 2017)

brian_ said:


> Why the front motor, rather than the small rear motor? Does it provide better clearance for the tires when steering, or is the motor intended to sit over the steering rack? The small front and rear units have the same motor and gearing, but are just packaged differently, and the rear unit places the motor lower (handy for lower centre of mass and more room above it).


Hi Brian,

Really good feedback, and the answer is: I'm not really shure anymore... 

The initial reson for choosing the front motor was to have better clearence for the steering rack keeping the drive shafts level. I have relized now though that this might not be necessery as my car is lowered about 40mm and the drive shafts are pointing slightly upwards as it sits.

The other reason for choosing the front drive unit was that I liked the OEM mounts better on that one compared to the small rear motor.

I will need to mount some of the batteries in the engine bay so It would be nice with a lower drive unit to keep the CG as low as possible in the car.

Rear drive unit is looking better and better, just need to get the ICE motor out and take some meassurements. 


Thank's!


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## 24Seven (Nov 19, 2017)

brian_ said:


> Most current EVs have a much larger battery, and cannot be readily configured to half size while maintaining voltage. Plug-in hybrids generally have half of that battery capacity and it is awkward to combine two of them while maintaining the same pack voltage.
> 
> The other obvious battery of the desired size is from the Nissan Leaf.
> 
> ...


Again, excellent suggestions Brian, thank's!

I have tried doing some quick research but it is often hard to find battery specs on newer cars. If the e-Golf or Focus has voltage and amps the might be good donor candidates as they are available in our market.

The problem is usually that the smaller battery packs don't deliver enough of a punch (amps), although they might have close to optimal voltage. That seems to be the case for the Leaf, and might also be true for the Tesla modules if you make them 12S. 

Ideally I would like to be able to make around 200kW peak, that would mean 500A @400V. From what I've found tesla modules are rated at about 750A peak, which I guess would be divided in two when changing to a 12S configuration? If not this would be the perfect solution.

Regards
Martin


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## brian_ (Feb 7, 2017)

24Seven said:


> I have tried doing some quick research but it is often hard to find battery specs on newer cars.


Almost all current and recent production EVs use a 96S pack, so they nominally run 360 V with almost 400 V peak (which is why fast DC chargers are designed to deliver up to 400 V).



24Seven said:


> If the e-Golf or Focus has voltage and amps the might be good donor candidates as they are available in our market.
> 
> The problem is usually that the smaller battery packs don't deliver enough of a punch (amps), although they might have close to optimal voltage. That seems to be the case for the Leaf, and might also be true for the Tesla modules if you make them 12S.
> 
> Ideally I would like to be able to make around 200kW peak, that would mean 500A @400V.


All of these similar basic EVs have roughly the same motor power, so their battery packs must be able to deliver about the same power, so with the same voltage they must be capable of about the same current.

You're looking for roughly double the power output of these cars in stock production form, so you have some options:

use a bigger battery, 
use a battery optimized for power rather than energy (such as from a plug-in hybrid, but then you would need two of them for enough energy capacity), or
just keep peak demand short in duration, counting on the cells withstanding the discharge rate at the expense of reduced life, and assuming that you change any protective device limiting current to a level which is too low.



24Seven said:


> From what I've found tesla modules are rated at about 750A peak, which I guess would be divided in two when changing to a 12S configuration? If not this would be the perfect solution.


Right - double the voltage and half the current. You can think of this as

the series or parallel configuration doesn't change the power capacity, so the voltage and current must change in inverse proportion, or
twice as many cells in series means half as many in parallel, and half as many of the same cells means half as much current capability.
There is no magic in batteries, even if you fall for the cult of Elon Musk. Two EV modules of the same mass will have similar capabilities. They improve with time, of course, and there is a power density versus energy density trade-off to some extent.


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## dtbaker (Jan 5, 2008)

Looking at recent threads in the forum, it looks like everybody is stuck on using OEM AC motors and high voltage OEM battery packs. This seems to be a bit much for the typical DIY-er as you have to cobble together many cells that may not be matched, and hack your way into a complex BMS to manage the charge and balancing.

What has happened to the simple, less expensive, but really fun 'performance build' with something like:
Warp9 DC motor
Zilla 1000amp controller
144v or 156v pack of 130, 160, or 200ah CALB LiFePO4 cells?


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## MattsAwesomeStuff (Aug 10, 2017)

dtbaker said:


> What has happened to the simple, less expensive, but really fun 'performance build' with something like:
> Warp9 DC motor
> Zilla 1000amp controller
> 144v or 156v pack of 130, 160, or 200ah CALB LiFePO4 cells?


Warp9 - https://www.go-ev.com/End_User_Pricing.html , $2400. Versus a forklift motor for $200 and the same performance.

Zilla 1000amp controller - https://www.evwest.com/catalog/prod...ucts_id=419&osCsid=5uom2bcrt4im12b7ti33s4h8i4 , $2600. Versus, many DIY options.

144v pack of CALB LifePO4 cells - https://www.evwest.com/catalog/prod...ucts_id=211&osCsid=5uom2bcrt4im12b7ti33s4h8i4 - 40 x $259 = $10,000. And they are famously bad, and suck, and still need a BMS as much as any other DIY options does.

Conversion cost for those 3 components: $15,000.

...

Why aren't people doing things that way?

... Because you can buy a used Nissan Leaf for $5,000, that comes with motor, controller, transaxle, and batteries.

... Because you can spend $200 on a junkyard motor, $1000 on a P&S controller, and $2000 on Volt batteries and get more power and range for $3200 than your suggestion for $15,000?

... Because you can buy a Prius transaxle and controller for $500, and it's looking like you can get 500hp out of the controller, from Damien's Prius hack board?

I honestly haven't even heard of anyone using LiFe batteries on an active project, other than for repair/replacement in years.


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## brian_ (Feb 7, 2017)

MattsAwesomeStuff said:


> I honestly haven't even heard of anyone using LiFe batteries on an active project, other than for repair/replacement in years.


Although LiFePO4 (LFP) chemistry was available in various formats and used in many applications including a wide variety of EVs, I think it has now been basically relegated to recreational vehicle house batteries (usually packaged with BMS as drop-in replacements for common "12 V" deep-cycle batteries). They work reasonably well in an RV, in part because the voltage range of a 4S configuration is moderately compatible with systems intended for nominally 12 V lead-acid batteries.

When I first joined this forum, a couple of years ago, CALB cells were still a current solution, but the transition to salvaged EV modules was underway.


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## dtbaker (Jan 5, 2008)

MattsAwesomeStuff said:


> Warp9 - https://www.go-ev.com/End_User_Pricing.html , $2400. Versus a forklift motor for $200 and the same performance.
> 
> Zilla 1000amp controller - https://www.evwest.com/catalog/prod...ucts_id=419&osCsid=5uom2bcrt4im12b7ti33s4h8i4 , $2600. Versus, many DIY options.
> 
> ...


hhhmmmmm,
well, I've noticed a number of COMPLETE conversions come up, just lacking batteries for a song. And, I'm still pretty convinced that with 38-48 cells you really don't need a BMS at all if you are willing to top-balance and re-balance manually every 6 months.

each to their own.

I just love to see experimentation and people getting it DONE with DIY rather than paralysis by analysis. I guess its the rat-rod DIY keep-it-simple approach in me....


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## MattsAwesomeStuff (Aug 10, 2017)

dtbaker said:


> And, I'm still pretty convinced that with 38-48 cells you really don't need a BMS at all if you are willing to top-balance and re-balance manually every 6 months.


I'm kinda with you there. Though, having some ability to check is important.

However, that's not a unique argument for LiFe batteries.

I presume you're saying that 38-48 cells doesn't need a BMS, but the typical 96 cells in an OEM EV does? 

It's linearly, 2-3x the risk. Not that much, not an order of magnitude. And, considering the failure rate of CALB or other LiFe cells (almost always) versus OEM cells (almost never?), I think the balance actually goes the other direction.



> I just love to see experimentation and people getting it DONE with DIY rather than paralysis by analysis. I guess its the rat-rod DIY keep-it-simple approach in me....


That's where I don't follow you...

If you want to spend less, and have a simpler approach, then buying a Warp9, Zilla, and CALB cells is the opposite direction I'd expect you to take. I would've figured spending 20% as much and getting a forklift motor, P&S controller, and bulletproof, idiot-proof, Chevy Volt cells would've been your way to go.

Sure there's lots of project stuck deep into gutting OEM vehicles and trying to keep all the subsystems and brains, but, I dunno that there's any more there than on cheap DC projects that people abandon or sell because they're not as useful or desireable for whatever reasons.


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## dtbaker (Jan 5, 2008)

MattsAwesomeStuff said:


> I'm kinda with you there. Though, having some ability to check is important.


thats the basis of my (current) preference for fewer large format cells.... less to check. fewer connections to go wrong, and no time or expense trying to hack into a Volt, Leaf, or Tesla BMS to set parameters to a 'partial pack' at 120-160v for a DC motor. 

The second issue is that the wiring in most of the OEM battery packs is designed to handle twice the voltage, but half the current I'd expect to pull with a DC motor. Pulling 1000amps out of a pack with multiple series and parallel connections designed for 500amps seems risky.




MattsAwesomeStuff said:


> I presume you're saying that 38-48 cells doesn't need a BMS, but the typical 96 cells in an OEM EV does?


I'm saying it's just easier to 'get by' without a BMS when you have fewer cells to check. When I built my eSwift, and eMiata, there were no OEM packs available and the BMS systems were either unreliable and/or very expensive.


I haven't kept up in this forum for a while.... and wanted to ask if there is a new 'cookbook' with the kinks worked out to effectively use OEM packs for DC voltages. 

What I am seeing in the build threads I'd scanned thru is that if a person wants to use OEM packs, it is probably best to stick with the factory AC motor, charger, BMS transplanting the WHOLE thing to your project whatever that may be. Leading me to the conclusion that for projects with DC motors, it's still best to use the large format cells for simplicity sake.


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## MattsAwesomeStuff (Aug 10, 2017)

dtbaker said:


> I'm saying it's just easier to 'get by' without a BMS when you have fewer cells to check.


Makes sense, but, your safety margin isn't that big. Like, if not having a BMS is 'dangerous', you're only avoiding said danger by 50% by using a pack with half as many cells.

And, with how unreliable LiFe batteries are (IIRC you've had multiple failures, not your fault), versus the nearly perfect track record of OEM packs, I think it more than makes up for it.



> I haven't kept up in this forum for a while.... and wanted to ask if there is a new 'cookbook' with the kinks worked out to effectively use OEM packs for DC voltages.


Basically, forklift motor + OEM packs. I can't recall the last time someone actually bought a Warp9 or whatnot. If you're going DC, you might as well go cheap.



> What I am seeing in the build threads I'd scanned thru is that if a person wants to use OEM packs, it is probably best to stick with the factory AC motor, charger, BMS transplanting the WHOLE thing to your project whatever that may be. Leading me to the conclusion that for projects with DC motors, it's still best to use the large format cells for simplicity sake.


I'd say there's still just as much interest in DC builds, but, not a lot of people getting them finished. Maybe the people buying whole cars are a little more committed to their projects.

Large format cells aren't "simpler" than OEM cells I wouldn't say.

You can compartmentalize most OEM packs into smaller sizes if you want.

The Nissan Leaf cells for example are about the size of a hardcover book, and just stack together like LEGO (in pairs, 7.4v per book). Tesla packs area bit trickier, but you can easily cut each module chunk in half. If you want lower voltage, you can use fewer of them.

Also, if you want lower voltage because you think it's less risky to run without a BMS, then you can just parallel up an OEM pack cut in a half rather than using it fully in series.

But most battery packs come with the BMS onboard and it's not much extra work to use it, it seems.

OEM packs are *tempting* to use the extra features that are easily available, but if you want to dumb it down for simplicity, I don't see why you couldn't be back in the same boat as using CALBs if that was your thing. And they're 20% the cost. That's a big, big deal.


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## 24Seven (Nov 19, 2017)

So the car is now on jack stands and I have started the process of removing the Engine/gearbox/Intercooler..... It is really squeezed in there and will unfortunately not be easy to remove.

Also found a Kia Soul EV battery locally, so that part is finally solved.


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## 24Seven (Nov 19, 2017)

Tried documenting the Project:

https://www.youtube.com/watch?v=kQ2qaf_isfs


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## Smatt (Jun 25, 2019)

24Seven said:


> Tried documenting the Project:
> 
> https://www.youtube.com/watch?v=kQ2qaf_isfs


Nice one !


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## 24Seven (Nov 19, 2017)

Smatt said:


> Nice one !


Thank's!


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## 24Seven (Nov 19, 2017)

Here is part two:
https://www.youtube.com/watch?v=k8TKckYPrPg


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## 24Seven (Nov 19, 2017)

The ICE is almost out and I begin to see the space availiable for the tesla motor.










There does not seem to be enough room to mount the Tesla front drive unit at the same angle as it is mounted originally.

Would it be ok to tilt the drive unit forward without creating lubrication or cooling issues?


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## brian_ (Feb 7, 2017)

24Seven said:


> There does not seem to be enough room to mount the Tesla front drive unit at the same angle as it is mounted originally.
> 
> Would it be ok to tilt the drive unit forward without creating lubrication or cooling issues?


There is an oil pickup in the bottom of the gear case; if you rotate the unit significantly you would need to relocate that so it still picks up properly.


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## 24Seven (Nov 19, 2017)

Thank's Brian!

Might be easier to mod the firewall then.

I guess turning the drive unit 180 degrees and drive the motor in reverse direction is not a good idea either?


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## brian_ (Feb 7, 2017)

24Seven said:


> I guess turning the drive unit 180 degrees and drive the motor in reverse direction is not a good idea either?


It can be done, by replacing the internal oil pump with one that still pumps properly when the motor is turning the other way. Zero EV has a reverse rotation pump for the large drive unit, and apparently this works okay even though the gears will be slinging oil the opposite directions to normal; I don't know if anyone has a solution for the small drive units.


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## 24Seven (Nov 19, 2017)

brian_ said:


> It can be done, by replacing the internal oil pump with one that still pumps properly when the motor is turning the other way. Zero EV has a reverse rotation pump for the large drive unit, and apparently this works okay even though the gears will be slinging oil the opposite directions to normal; I don't know if anyone has a solution for the small drive units.


Once again, thank's Brian!

The knowledge on this forum is amazing!


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## Smatt (Jun 25, 2019)

24Seven said:


> The ICE is almost out and I begin to see the space availiable for the tesla motor.
> 
> 
> 
> ...


Does this mean that the small rear drive unit is no longer an option?


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## brian_ (Feb 7, 2017)

24Seven said:


> I guess turning the drive unit 180 degrees and drive the motor in reverse direction is not a good idea either?


If you're still seriously considering turning the drive unit around, an alternative to reversing the oil pump in a Tesla Model S/X unit might be to use the drive units which Tesla supplied for the Mercedes B250e or Toyota RAV4 EV, which place the motor ahead of the axle line in front-wheel-drive vehicles. You would need to check for compatibility with whatever you are planning to use for controller replacement or modification.


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## Evbeddy (Jan 5, 2020)

thats the basis of my (current) preference for fewer large format cells.... less to check. fewer connections to go wrong, and no time or expense trying to hack into a Volt, Leaf, or Tesla BMS to set parameters to a 'partial pack' at 120-160v for a DC motor. 

The second issue is that the wiring in most of the OEM battery packs is designed to handle twice the voltage, but half the current I'd expect to pull with a DC motor. Pulling 1000amps out of a pack with multiple series and parallel connections designed for 500amps seems risky.



I haven't kept up in this forum for a while.... and wanted to ask if there is a new 'cookbook' with the kinks worked out to effectively use OEM packs for DC voltages. 




Hi Everyone

For someone who is new to the diy ev scene this has been a very interesting build thread. Lots of info for someone trying to learn. 

Without trying to take over this tread Ive got a question which I think relates to what has already been talked about. What do people is the max voltage and current you can run with a dc motor (forklift or otherwise)?

Above on this thread people are talking about running 120 to 160v but Im sure Ive read on Duncan's build that he is running 400v and 1200A from volt batteries. What are peoples thoughts?

Thanks Brennan


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## Duncan (Dec 8, 2008)

Max voltage for a DC motor

You can't actually just "overvolt" a DC motor
You controller controls the motor voltage to achieve the commanded current

So it may need 10 v to get 1000 amps when stationary
But as the motor starts to spin it develops a back EMF and that adds to the voltage

When I had a 130 v battery and a controller set to 1000 amps it took off like a scalded rat - and then as the revs rose the required voltage increased

With 130 volts it topped out at 200 amps and 100 kph (3500 rpm) 
Which means that the controller was at 100% but the voltage was only driving 200 amps through the motor

To need a high voltage you need high current and high rpm

My current battery is 300v empty and 340v full - I'm still accelerating at 150 kph and 5300 rpm but I have passed 100% on the controller and the current is dropping as the rpm's increase

If using more sensible numbers I would say that 150v was enough 
Or you could use 400v and simply let the controller adjust it to what the motor wants


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## Evbeddy (Jan 5, 2020)

Hi Duncan 

Good to talk to you again.

Thanks for sharing your experiences. So just to make sure I have this straight in my head, current = torque and voltage = rpm. If you set your controller to your max current yoy have max acceleration. Then you will keep accelerating until you run out of rpm (voltage) which is like hitting the rev limiter in an ICE car.

So my next big question (and hopefully its not a stupid one), how do you decide on the best voltage for your car? I know it will depend on what you want your max rpm to be but is there a way to calculate what voltage is needed?

Just to be clear I know how to use tyre size and diff ratios to calculate speed and rpm I'm more interested in voltage. 

Thanks 
Brennan


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## Duncan (Dec 8, 2008)

Evbeddy said:


> Hi Duncan
> 
> Good to talk to you again.
> 
> ...


The back EMF is proportional to current and to rpm 

So you then need the RATIO! - and that is down to your motor!

Which is the rub

If you have a Warp9 or Warp11 you can use the graphs they give to make a very good estimate

I am using a Hitachi 11 inch - no graphs!

But when I used 130 v the effect was "noticeably"

With 130 v - my Device topped out at 100 kph and 200 amps 

So 130 v (probably sagged to 105 V) - allow 5 volts for the resistive load

100 volts of EMF = 3500 rpm and 200 amps

So to drive 1000 amps at 3500 rpm - would take 500 volts

At half of that rpm (1750 rpm) 1000 amps would take 250 volts

At the end of the 1/8th when I'm doing about 5250 rpm it would take 150 volts for 200 amps
My actual voltage of 300 volts would give me 400 amps


That is all approximations - but it gives you an idea of what is happening


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