# Suzuki Cappuccino Conversion



## MalcolmB (Jun 10, 2008)

Hi Tom,

The Cappuccino is a neat choice. I considered one of those as a conversion candidate myself, but there weren't many around at the time.

Those batteries look good as well, based on the specs and the test done on Endless Sphere. Building the pack will obviously be more time-consuming than using something like Leaf modules, but the advantage is you can package them to fit your available space.

I've been looking at BMS options as well and I like the look of the Zeva BMS. You can combine it with a dash display and it's easily integrated with an Elcon charger. The Thunderstruck TSM2500 charger package also looks to be good value. 

It's good to know there's someone else in the north east working on a conversion. I'm in Newcastle myself. Good luck with your build!

Malcolm


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## tom3141 (Jul 2, 2016)

Hi Malcolm.

Thanks for the charger/BMS suggestions - I will have a look into those.

The cells I have bought are actually already assembled into packs of 8 cells in parallel so the assembly shouldn't be too bad. I'm planning on pairing these up to get 16 cells in parallel and then connecting around 80 of these in series. This will give me around 300V and 70aH.

Cheers,

Tom


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## tylerwatts (Feb 9, 2012)

Hello Tom
This sounds like an exciting build. Don you have any pictures of your car and parts please? I follow with interest.
Cheers


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## tom3141 (Jul 2, 2016)

Thanks for your interest. 

Progress has been slow over the winter, hence the lack of updates. The rust was worse than I first thought but I'm now about ready to weld in the repair patches. The floor had practically detached itself from the sill along the driver's side of the car.

I've removed quite a lot of the engine ancillaries so once the rust is sorted I'm hoping that I can progress a bit quicker and get the engine and fuel tank out.

Unfortunately, I don't have many photos at the moment. Mainly because they would just be photos of rust! I have attached a couple. Hopefully I'll have some more interesting photos soon.

Tom


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## tom3141 (Jul 2, 2016)

This is the motor and inverter that I have:

https://evpartssale.co.uk/ev_motors_and_controllers.html


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## tylerwatts (Feb 9, 2012)

That looks like a great setup and powerful with that reduction direct to the rear diff. In such a light donor you could possibly run it without the reduction. Any idea how much torque it produces continuously?
And how much the battery will weigh roughly?
You'll be much better off packaging without the reduction and tucking the motor right into the transmission tunnel.

Apologies if I'm raining on your parade or teaching you to suck eggs etc etc.


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## tylerwatts (Feb 9, 2012)

Here's a picture from the web. Helps see where bits could go.


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## tom3141 (Jul 2, 2016)

Yeah, I’m going to run it without the reduction gearbox. Just direct drive to the prop shaft. With the 5.25:1 reduction in the rear diff it should still have enough torque.

I don’t know how much torque the motor produces. The stock engine only produces 64lbft and feels quick. I’m expecting double if not triple that from the motor.


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## tylerwatts (Feb 9, 2012)

And a view of what's to come. Not the biggest space but with that motor in the tunnel it should be ok. I wonder how much space is available in the fuel tank area to locate chargers or other electronisa. You might struggle with the size of the controller housing but no point speculating yet.


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## tom3141 (Jul 2, 2016)

No problem, nice to know that you’re thinking along exactly the same lines that I am.

Unfortunately I don’t think the motor will tuck very far up into the transmission tunnel as it is so narrow. The stock gearbox is very long and thin.

The full battery pack weighs around 150kg (bare with no connections/cables/casing). I think I might struggle to fit the whole pack in as it’s such a small car. Once I have the engine and fuel tank out I will have a better idea. The fuel tank area looks quite big (relatively!) but it is difficult to access as the entire rear subframe must be removed to get to it.

Weight wise I think the car will end up heavier than stock but hopefully not by much. It’s 725kg as standard so I’m hoping to stay under 850kg at a guess.


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## tylerwatts (Feb 9, 2012)

Well assuming peak power is at 7000 for guestimates sake, nm = 9.5488 x 90kw x 1000 / 7000rpm = 120nm so x 5.25 = 640nm at the wheels and with stock tyre size is alot! Likely more than the tyres will hold so plenty acceleration.


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## tylerwatts (Feb 9, 2012)

That sounds reasonable.

I was thinking the fuel tank space must be hidden and good for locating larger items, similar to an mx5. It would be good to put the controller up there to give Mac space for battery and keep good weight distribution. And the fuel tank location is a good place to be able to trim/modify the structure to make space for the controller say. It is not too highly stressed as the subframe and chassis structure wrap round there. Well notionally looking at it. I didn't design the car so take my comments with a pinch of salt until you've stripped the car down properly.

I've seen alot of conversions where builders put some battery in the fuel tank area which is ok but it's a compromise with the longer power cables. If you can split the capacity but keep the same voltage in 2 separate packs that would be ideal and it sounds like that might be possible with your setup.

I look forward to any updates you have, don't let me rush you though. Anyway I need to get off my rear and building my conversion.

Cheers


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## Duncan (Dec 8, 2008)

Hi
If you are going direct drive then you won't need a clutch pedal - with only two pedals you don't need as much space in the footwell - and the passenger never needed that much anyway

I would cut out the transmission tunnel and make a lightweight removable tunnel that the motor would live in

Then you have the whole engine bay for your batteries


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## brian_ (Feb 7, 2017)

Duncan said:


> If you are going direct drive then you won't need a clutch pedal - with only two pedals you don't need as much space in the footwell - and the passenger never needed that much anyway
> 
> I would cut out the transmission tunnel and make a lightweight removable tunnel that the motor would live in


I understand the logic of enlarging the tunnel and forcing the occupants' feet outboard... but the tunnel is probably significant to the unibody structure, so I'm not sure some non-structural piece would be a suitable replacement.



Duncan said:


> Then you have the whole engine bay for your batteries


It certainly would be good to get the motor out of the engine compartment.


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## Duncan (Dec 8, 2008)

Hi Brian - valid point
The easiest way would be to make a new tunnel out of something like 20 mm square tubing to take any loads and to have a bolt on lightweight cover so that you can get to the motor when you want

On my car I closed in the bottom completely - helps the strength and you don't need to let the drips escape - but that does mean that you have to get at the motor from inside the car


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## brian_ (Feb 7, 2017)

Duncan said:


> On my car I closed in the bottom completely - helps the strength and you don't need to let the drips escape - but that does mean that you have to get at the motor from inside the car


In an open-top car and with the access panel, that wouldn't be unreasonable at all.


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## tom3141 (Jul 2, 2016)

Thanks for all the input guys. It's getting me motivated to get this rust sorted and get cracking on the conversion!

My current plan is to split the battery pack between the fuel tank area and the engine bay. With the charger and some other electrical gizmos in the boot and the inverter above the motor at the rear of the engine bay. 

What are the disadvantages to splitting the battery pack? Power losses in the long cables? It seems that whichever way it is done (split the battery or put the inverter at the back) the same problem is going to be present. 

I could split the battery into two equal voltage packs but I seem to remember reading that it is best to put the cells together in parallel to get the amp hours that are needed and then connect these all in one series string. 

I would also rather keep the inverter near the motor as it has a nice 1m cable with connectors that I would rather not mess around with. I have thought about trying to put the motor directly onto the rear diff but there is just not enough room.

The discussion on the transmission tunnel is interesting. I hadn't really considered this, mainly because I'm not sure if there are extra legal hoops that have to be jumped through in the UK if you start cutting into structural parts. Also, the footwell is already extremely small. I'm 6'3" and, although I find it very comfortable to drive (once I'm in!), there isn't much room for manouvre. I will have a look next time I'm working on the car.

I'm hoping to get the rust work finished over Easter and from there it shouldn't take too long to get the engine out. I think I'll need to get the cardboard out after that to make some models for test fitting! It's definitely going to be a puzzle.


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## tom3141 (Jul 2, 2016)

Attached are some photos of the batteries. Each of these contains 48 cells.


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## tylerwatts (Feb 9, 2012)

Wow those are nice blocks. Shame to break them up.

Regarding batteries, I'd recommend splitting in parallel with same amperage and voltage. So you wire both halves in parallel directly to the inverter or preferably through a junction box with separate pack fuses and even contactors. So you could run off 1 pack at a time in an emergency etc, or if one pack fuse blows you can run off the second etc.

I agree also if it is similar challenge that you split the pack and keep the inverter with the motor rather than move the inverter further away.

Regarding UK law, there are new rules I've not checked but the rule has always been any major changes to structure of the vehicle requires an IVA test same as building a vehicle from scratch. What constitutes major changes is subject to the investigator's opinion but you'll need a basic VOSA inspection to verify the conversion to electric so speak to the centre about any mod to the chassis ref mounting the motor in the tunnel and you should know what's achievable and how far to go. An MOT is always required first but that is easier with an EV.

Regarding mounting the motor in the tunnel and space, if you build a frame into the floor pan with strong box/tube section and load the motor from above your structure should be fine if my stronger. I'd tie it to the side rails of the chassis for added torsional stiffness. And mount the motor slightly offset to passenger side to have good driver leg room as a passenger only needs somewhere to rest their feet.

Any pics of the underside of the chassis would help also, perhaps with a tape measure in view for scale and reference and we can brainstorm a robust design for locating the motor. That is the biggest blocker to begin with because of six and shape in the small car.


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## tom3141 (Jul 2, 2016)

I'm hoping to keep them in the original blocks. The busbars can be swapped around within it to change the cell configuration to whatever I need.

I'm not convinced splitting into two equal packs is worth it. Other than the extra redundancy in case of failure, what are the advantages? It seems to me that it would introduce issues with the two packs charging and discharging unevenly. I was planning to connect 16 cells togther in parallel and then 80 of these batteries together in series. If I do what you are suggesting I will need to monitor twice as many cell voltages. I would have to connect 8 cells together in parallel and then 80 of these batteries in series for each pack. I'm open to doing this if it's the best way but I can't see what the advantage is at the moment.


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## tom3141 (Jul 2, 2016)

Made some progress today. 

I'm now ready to weld the floor repair patches in. Hopefully this will be done next weekend if everything goes well. The engine is also now ready to remove. Everything is disconnected apart from the mounts. I may need to remove some more of the exhaust downpipe but I will wait and see if I can lift it out as it is first.

I also got some photos of the transmission tunnel. They are not the best as the car is on axle stands so I was a bit close to get a decent photo. 

The main body of the motor is around 280mm diameter by 330mm long. It is around the same diameter as the gearbox bell housing at its largest. Without any modifciation to the structure I should be able to tuck the motor in so that the front face is around 5-6 inches further back than the engine/gearbox interface.

One nice feature of the transmission tunnel is that it is pretty tall. Originally the exhaust ran down the transmission tunnel underneath the propshaft and was completley hidden as it was above the floor line of the car. It will be tight but I think that I may be able to squeeze some of the battery blocks in underneath the propshaft. If they fit in the width and height then I guess I could probably fit 5 or 6 along the length of the tunnel.

When I'm looking at battery packaging how much thought needs to go into cooling/heating? I believe most OEM EVs have the ability to cool their batteries. Is this generally done amongst DIYers as well? I'm just thinking about whether I need insulation and space for cooling around the batteries. I'm not planning to use the car in sub zero temperatures (celsius) as my commute is quite rural and I'm going to keep my 4x4 for icy/snowy days. The Cappuccino was also pretty tailhappy with the stock engine so I think it would be terryfying in slippery conditions with twice the power! Summer temperatures very occasionally reach 25C but are generally high teens. My current plan is not to worry about heating or cooling but obviously just to make sure they are protected from water and dirt.


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## brian_ (Feb 7, 2017)

tom3141 said:


> The main body of the motor is around 280mm diameter by 330mm long. It is around the same diameter as the gearbox bell housing at its largest. Without any modifciation to the structure I should be able to tuck the motor in so that the front face is around 5-6 inches further back than the engine/gearbox interface.


If I understand this correctly, the output face of the motor, which is the motor's "front" face but is at the end of the motor toward the rear of the car, will be at about the current rear of the transmission bellhousing. That puts about 127 to 152 mm of the 330 mm length of the motor behind the original engine/gearbox interface, and the rest ahead of it. That sounds reasonable.

It would be really nice to put the motor entirely in the transmission tunnel, but without tunnel modification (or a custom car build) this rarely turns out to be viable.


That is one impressively short engine. I wish I could find something that short to swap into my Spitfire, but I don't think I would be happy with a Kei-class engine for that car. Thus, the consideration of other options, including EV conversion.


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## brian_ (Feb 7, 2017)

tom3141 said:


> When I'm looking at battery packaging how much thought needs to go into cooling/heating? I believe most OEM EVs have the ability to cool their batteries. Is this generally done amongst DIYers as well? I'm just thinking about whether I need insulation and space for cooling around the batteries. I'm not planning to use the car in sub zero temperatures (celsius)...
> My current plan is not to worry about heating or cooling but obviously just to make sure they are protected from water and dirt.


If you really don't want to worry about cooling the battery, use one which is designed for use without active cooling in the original vehicle - the common example would be the Nissan Leaf. Heat for a Leaf battery is electric, and optional.

I think batteries which are designed with integrated liquid thermal management - such as Chev Volt and Tesla - are usually hooked up to a radiator even in DIY installation, but the sophistication of the installations varies.

There's a forum thread on Working with Tesla Packs which started in November 2016 and is still active at 215 posts (and counting), with many side-tracks. The subjects of thermal management and housing are not trivial... happy reading!


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## tom3141 (Jul 2, 2016)

Yes, you've understood correctly about the motor position. I think I will be happy with that, especially if I can get some of the batteries in the tunnel.

It's a lovely little engine but would need to be put in a car with a similar diff ratio (5.25:1) otherwise it would be really sluggish. Feels genuinely quick in a car this light but a lot of that is due to the ridiculous gearing. You sit at something like 4500rpm at 70mph in 5th. Redline is at 8500rpm! 

The battery I have is made up of Boston Power Swing 4400 cells. They did come from a prototype EV but I'm not sure whether they had any heating or cooling. Just checked the data sheet for them (http://liionbms.com/pdf/bostonpower/swing4400.pdf) and the discharge operating temperature is -40C to +70C, charge is -10C to +60C. From the temperature performance graph it looks as though ideally they want to be kept between 30C and 60C. What I don't know is how much heat they will generate themselves under charging/discharging.


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## Duncan (Dec 8, 2008)

Hi Tom
Re-battery heat
Probably very little!
You are most unlikely to want to cool your battery - for max performance you probably want to heat it

I'm using most of a Volt pack - which is water cooled/heated - I'm actually using it as the heat sink for my controller
I circulate water from the controller to the battery - keeps the controller nice and cool - provides a tiny amount of heating for the battery


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## tylerwatts (Feb 9, 2012)

Tom
I agree with the guys. Given your chemistry all I'd worry about is heating for winter and I'd suggest having air cooling like fans for hot weather. But save that for a future possibility. Ie design your battery boxes so you have space for airflow and fitting a fan but have some insulation in the walls. I'd suggest using angle iron or small 18mm square tube to frame the box and aluminium skin outside. And possibly thin rubber mat to insulate the bricks from vibration. And possibly clamp the bricks top to bottom in the box to keep them together and stable.


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## tom3141 (Jul 2, 2016)

I've managed to get hold of a Brusa charger. It arrived yesterday so I now have nearly all the parts I need. The only big thing left is to decide on the BMS options. I'm still thinking of going down the route of a simple overvoltage and undervoltage cut off (no balancing). I'm looking at something like the CellLogs or Zeva 8-cell battery monitor module.

I also noticed something on the motor spec plate yesterday. It has the base frequency listed as 121Hz (3630 rpm). From my research online it appears that this is the frequency at which peak power is available. So, correct me if I'm wrong, I have a peak torque at the motor of (9.5488*90000W)/3630rpm = 237Nm. This gives a wheel torque of 237Nm*5.125 = 1214 Nm. I think I'm right in saying that this is constant between 0 and 3630rpm. 3630rpm equates to around 45mph with the 5.125 diff ratio.

The original engine makes a peak torque of 85Nm at the engine (at 4000rpm), which is 1515Nm at the wheels in 1st gear (3.478 gear ratio x 5.125 diff ratio) or 880Nm at the wheels in 2nd gear (2.021 gear ratio x 5.125 diff ratio).

Looks like I will have plenty of grunt . I'm hoping for a 0-62mph time of around 6 seconds which seems reasonable.

I've borrowed an engine hoist for the weekend so I'm hoping to get the engine out in the next few days. I'll keep you posted.


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## tylerwatts (Feb 9, 2012)

You'll have loads of torque for sure!


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## tom3141 (Jul 2, 2016)

The Cappuccino has been de-ICEd! Got the engine and gearbox out this morning. That leaves the fuel tank as the only part left that needs removing. 

I also began the process of welding the sills. Not the most fun job but it's got to be done!

Photos of the empty engine bay are attached. I'm going to make some mock-ups of the motor and batteries so that I can play around with the layout without having to lug the motor around. I'd love to create a Solidworks model of the engine bay to make this easier but without a 3D scanner it would probably take far more time than it's worth and not be very accurate. I think I'll have to resort to Cardboard Aided Design!


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## brian_ (Feb 7, 2017)

tom3141 said:


> Attached are some photos of the batteries. Each of these contains 48 cells.


So that a 4x12 array of the Swing cells, each of which is probably a pair of 18650 cells wrapped together and connected in parallel, so essentially an 8x12 array of 18650's... that means something greater than
65 mm tall
8 x 18 mm = 144 mm wide
12 x 18 mm = 216 mm wide
and 48 x 90 g = 4.3 kg
occupying about 2 litres​... per module

Capacity is 4400 mAh per Swing unit, so 781 Wh per module (nominal).



tom3141 said:


> I was planning to connect 16 cells togther in parallel and then 80 of these batteries together in series.


So 80s16p Swing units, or 80s32p 18650 cells, for 296 volts (nominal). That's 1280 units (or 2560 18650 cells) in 27 modules each configured as 3s16p, totalling 115 kg of bare cells plus module overhead, plus enclosures.

It's actually 26 2/3 modules, so perhaps 81s16p Swing units (or 81s32p 18650 cells) for 300 volts (nominal). That's 1296 units (or 2592 18650 cells) in 27 full modules.

Total volume would be about 60 litres, which doesn't seem unreasonable at all. The challenge is that it is a lot more difficult to pack a couple dozen rigid bricks than the same volume of liquid in a tank which can be shaped to conform to the available space.

I wouldn't expect all of that to fit in the front with the motor and controller, and the space used by the fuel tank is not going to conveniently fit the modules. I'm looking forward to seeing the pack design.


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## tom3141 (Jul 2, 2016)

They’re actually in a 6 x 8 array currently connected 6s8p so I just need to reconfigure to get 3s16p within each module. Although they are almost identical in size to two 18650 cells apparently they are actually one oval shaped cell. Someone on a forum (I can’t remember which one) took a cell apart to find this out.

The external dimensions of each module with the plastic casing included is 285mm x 180mm x 80mm.

I have 28 modules in total but I’m just going to have to see how many I can fit in. I only need a range of 40 miles but I want to put as many in as I can so that I can use as little of the capacity as possible in normal use.

The motor is rated at 208V AC which would be a 293V DC battery pack voltage. That’s why I thought 27 modules giving 300V nominal would be the maximum I would want. A slightly lower pack voltage wouldn’t be the end of the world. I think even 24 modules would be ok at 266V nominal (and around 18.5 kWh) if space is an issue.


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## tom3141 (Jul 2, 2016)

I had a lot of trouble trying to weld up the sills and floor at the weekend. It may just be my lack of skill with a welder but the steel is so thin on the Cappuccino that I'm finding it impossible to weld. I'm going to reassess it at the weekend but I have even started to conisder whether this is the right car. I don't want to patch it up badly now and put all the work into a conversion only for it to rust to bits in a couple of years. Cappuccinos are terrible for it, mine isn't too bad compared to some but it's not as good as it first seemed. I'm going to try to take the rear subframe out at the weekend so that I can double check for rust on the bodyshell above it. If there is any serious rust there that I haven't already spotted it might be game over for the shell.

Before purchasing the Cappuccino I had considered a kit car or scratch built. I'm half considering this again using everything out the Cappuccino other than the bodyshell. However, reading through the IVA (Individual Vehicle Approval) manual has scared me off a bit. The section on EVs is worrying. Have any of you UK based builders got an EV through the IVA? It seems that it has to be tested against the ECE R100.01 standard which sounds pricey. Also, on this note, for a normal EV conversion in the UK, is it still the case that you just have to send the V5 off with a change of fuel/engine and then get it MOT'd? Or is there an EV test/inspection that it must pass?

I'll probably end up sticking with the Cappuccino, I think it was just an overeaction to laying under the car all day attempting to weld and not getting anywhere! The other option is getting a professional in to do the welding. However, I think it would need to go to a proper car restorers rather than a local garage/bodyshop. They are going to want to strip it right down to a shell to dip or blast it before repairing properly. I don't think replacement floor or sills are available so it would need repair panels making from scratch. I don't know if it's going to be worth the cost.


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## Duncan (Dec 8, 2008)

Hi Tom

It's a small car and you are stripping it down - have you thought about making a "rotisserie" for the shell so that you can weld across and down rather than up

as far as future rust is concerned paints are incredibly good these days - but the most important coat is the first one 

Sills/floor panels

Back in the day the process was not to buy a new sill but to bend a bit of welding wire to the required shape and the sheet metal man would then bend the sheet to match your template - I can remember mini "sills" that were so wide we welded them to the centre tunnel


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## brian_ (Feb 7, 2017)

tom3141 said:


> Before purchasing the Cappuccino I had considered a kit car or scratch built. I'm half considering this again using everything out the Cappuccino other than the bodyshell.


Since it's unlikely there's a kit in existence designed to use Cappuccino components, this would presumably be a scratch-built (although potentially following an existing general frame and body design, or a general pattern such as the "LoCost" style). Are the Cappuccino components really what you want in a scratch-built (maybe they are, as they would be light, have a sophisticated design, and use modern parts), and is that the best way to get value out of the car you have?


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## MalcolmB (Jun 10, 2008)

Hi Tom,

I spent many hours last summer repairing the sills, inner arches and floor rails on my son's MX5, so I know how frustrating a task it can be. It does give you a sense of achievement though when it's finally done.

You probably already know this, but here a couple of things I found useful, assuming you're using a gas MIG welder.

It's essential to cut back to clean metal, or at least metal that can be ground back to a clean surface without becoming too thin. Grind back paint or rust at least a centimetre from the edges to be welded.

Don't try to make continuous seam welds. Make a series of overlapping "spot" welds.

If the existing metal is so thin that it still keeps burning back, it helps to use lap joints where possible. Make patches that lap underneath the existing metal. That way the new metal will draw some of the heat away and prevent burning through. The easiest way to make these patches is with a joggling tool – you can find them for as little as £20 on ebay.


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## tom3141 (Jul 2, 2016)

> It's a small car and you are stripping it down - have you thought about making a "rotisserie" for the shell so that you can weld across and down rather than up


Yes, I've considered that - it might be the way to go if I decide to stick with the Cappuccino.



> Since it's unlikely there's a kit in existence designed to use Cappuccino components, this would presumably be a scratch-built


Yes. I've always fancied designing a car from scratch. I do a lot of design using Solidworks for my job so have the tools to do it. I might even have a go at a design just for fun even if I don't proceed with it. Another reason I'm tempted by the scratch built route is that I can design it around my components. I wouldn't have all the issues trying to cram the motor and batteries into spaces where they don't fit. 



> Are the Cappuccino components really what you want in a scratch-built (maybe they are, as they would be light, have a sophisticated design, and use modern parts), and is that the best way to get value out of the car you have?


This is bascially what I'm weighing up at the moment. As I said I want to have a proper check over the entire bodyshell once the subframes are out. Then I'll have to decide how I get the most value out of the car. If the rust I have already found is all there is, then it would probably be silly to scrap the shell. However, the components would be really nice for a scratch built car. All the important bits are bolted to the subframes so it would be relatively easy to build.



> It's essential to cut back to clean metal, or at least metal that can be ground back to a clean surface without becoming too thin. Grind back paint or rust at least a centimetre from the edges to be welded.
> 
> Don't try to make continuous seam welds. Make a series of overlapping "spot" welds.
> 
> If the existing metal is so thin that it still keeps burning back, it helps to use lap joints where possible. Make patches that lap underneath the existing metal. That way the new metal will draw some of the heat away and prevent burning through. The easiest way to make these patches is with a joggling tool – you can find them for as little as £20 on ebay.


Thanks for your tips Malcolm. I think one of the problems I've had is that I haven't cut enough metal out. I cut out all the actual rust but the edge of the floor I'm trying to weld to is too thin. It's ridiculously thin metal from the factory so any rust at all makes it paper thin.

I have made up the patches already. I'm doing lap joints as well but still burning through the floor on my MIG's lowest setting. I've also had trouble getting the two overlapping pieces of metal clamped up nicely, any little gaps and it is impossible to weld. 

Part of the problem is that I was not expecting to have to do this welding when I bought the car and I'm desperate to get cracking with the conversion. If I decide to stick with it and do the repair then I'm going to have to accept that it's going to take a while to do properly.


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## brian_ (Feb 7, 2017)

tom3141 said:


> I've always fancied designing a car from scratch.
> ...
> Another reason I'm tempted by the scratch built route is that I can design it around my components. I wouldn't have all the issues trying to cram the motor and batteries into spaces where they don't fit.
> 
> ...


While I hope the body repair works out, this sounds like a great scratch build. 

I did a quick web search to see the Cappuccino chassis components, and they do look nice for integration with a custom tube frame, at least at the rear.









If building your own body and tubular steel frame, you might even be able to fit a small complete drive unit (motor with transaxle) into the rear.


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## tom3141 (Jul 2, 2016)

So I've decided to stick with the Cappuccino. It seems currently the regulations are fairly straightforward for a scratch built EV but they are expected to change in the near future. If I started a scratch built and didn't finish before any new regs come in it would cost a fortune to make road legal.

I've found someone who can do the welding for me so I'm going to pay him to do it. It will mean that I can get cracking on the conversion which I'm desperate to do. He can't fit me in for a few weeks so in the meantime I'm planning to confirm the mounting points for the motor and battery boxes.

I did some measuring up at the weekend and I think I can fit 12 battery modules in the engine bay in front of the motor, 10 modules in the boot, and 3 modules in the fuel tank area. This will give me 25 modules which should be enough. I'm going to design some battery boxes and double check these fit in the space available.


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## brian_ (Feb 7, 2017)

tom3141 said:


> They’re actually in a 6 x 8 array currently connected 6s8p so I just need to reconfigure to get 3s16p within each module. Although they are almost identical in size to two 18650 cells apparently they are actually one oval shaped cell.





tom3141 said:


> I did some measuring up at the weekend and I think I can fit 12 battery modules in the engine bay in front of the motor, 10 modules in the boot, and 3 modules in the fuel tank area. This will give me 25 modules which should be enough.


So 25(3s16p) Swing cells, for 75s16p overall, for 278 V (nominal) at 70.4 Ah and 19.6 kWh (nominal). Sounds promising.


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## itchyback (May 28, 2014)

i've got an old jaguar and i can completely understand the frustration of having to weld up rust. it seems whenever i finish some i find more and small jobs turn into big ones. I'm an amateur welder as well so my skills never meets the requirements. like you i wondered if i should find another car and then decided to stick with it but persist with the conversion as is, leaving the remaining rust bits. that way i dont feel like i'm never going to complete it. I'll keep an eye out for a better example and may reshell the conversion in the future. That or wait until i win lotto and pay someone else to fix it for me.


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## tom3141 (Jul 2, 2016)

I did a test fit of the motor and inverter at the weekend. Unfortunately I wasn't able to get the motor fully into position as it wouldn't slide underneath on a jack and is too heavy to lift in from above. I'll need to borrow an engine hoist again to do this. It looks like it will fit and will mount quite easily on the subframe though. 

The inverter is a really snug fit - I didn't realise how big it was until I put it in the car! A photo is attached. I had forgotten about the water cooling pipe outlets which mean that it sticks further out into the space that I was planning to use for batteries. With the inverter in place I think I'm only going to be able to fit 8 batteries in the front and even that is going to be quite a squeeze. This will bring the number down to 21 (233V nominal, 16.4kWh). I'm not sure that I'm going to be happy with this so I'm considering a few different options. 

I could try to reduce the size of the inverter. There is a fair amount of empty space inside but I'm not sure that I will be able to reduce the size enough to gain much/any more space for batteries. It would mean machining a new water cooled base plate so I don't think the slight gain in space would be worth the effort.

Another option I'm considering is removing the passenger seat. I could fit the entire battery pack (28 units, 310V, 21.8kWh) in the passenger space and it would simplify the conversion quite a lot. The main purpose of this car is a fun and cheap car for me to commute in (40 mile round trip) so not having a passsenger seat wouldn't be the end of the world.

The issues with the plan to split the pack between the engine bay, boot, and fuel tank are:


smaller than ideal pack size
lots of batteries just behind the front bumper and just in front of the rear bumper worries me from a safety point of view
weight distribution probably isn't ideal (batteries in front of front axle and behind rear axle)
radiator would need to be relocated
no room for spare wheel or roof panels in the boot
quite a lot of design work needed for three seperate battery boxes
complex wiring and long cables between different parts of the pack
not much room left for things like vacuum pump, water pump, contactors and charger
Putting the batteries in the passenger space would solve all of this. The only downside is the loneliness! 


I'm still weighing it up at the moment. I don't really need to make a final decision until I've had the welding done so I will see if there is any other way around it over the next few weeks.


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## brian_ (Feb 7, 2017)

tom3141 said:


> Putting the batteries in the passenger space would solve all of this. The only downside is the loneliness!


Quite a few racing cars have been built with a side-mounted engine, and it works well, for the same reasons (central mass position, large volume available) and others.

Only you can decide how important passengers are. Do you want to let people experience your car without letting them drive? If you do want to let them drive, do you want to ride along?

Here's an out-of-the-box idea: build it with the battery in the passenger seat area, get the EV system sorted out, then as a follow-up project do a scratch-built structure and body with more room for the battery and transfer all of the components (possibly including the Cappuccino chassis bits) so it can have two seats.


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## tom3141 (Jul 2, 2016)

So I test fitted the motor today. Thankfully there were no suprises - it actually fits quite nicely! I should be able to use one of the mounts that came with the motor along with a simple bar to support the back of the motor. 

What is the general consensus on rubber motor mounts? It will be easier and simpler for me to just bolt/weld the solid mounts directly to the subframe. I've read a few threads giving pros and cons but personally I don't really see the need for rubber mounts. 

The attached photo shows the front motor mount roughly in position.


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## EKit (Dec 17, 2016)

Hi Tom. thanks for the link from the Enova 12v discussion we are having. You certainly have/had your hands full with the rust bug. Invest in a TIG welder, you can control the weld a bit better in my humble opinion for thin sheet.
Looks so much easier with front motor and rear wheel drive, my transverse rear drive set up in the Smart has been a challenge so yours should be done a lot quicker.
You could trim the Enova heatsink quite a lot if necessary. Attached pic of initial cut down plate. It did have one of the attached pipe fittings (I broke off later to use plate as a welding heatsink) the cut section of the cooling channel I was going to make a stub to fit a new connection. Makes the whole heatsink half the size  Let me know if thats an option for you. Plenty of machining time spare and welder at the ready. Speak soon. Peter P.S. Dont forget the splines on the motor, I used a cheap clutch plate from Ebay which fit nicely. Alternatively if you strip the gearbox the primary gear will fit (obviously) but you will have to machine it down and its been hardened so that may prove a grinding job if not careful. I will ask my buddy to see if he can machine it on the lathe.


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## EKit (Dec 17, 2016)

Hi Tom. Sorry for the confusion, I am having two conversations at once and got mixed up thinking we were talking about the Enova 12v converter. Engage brain this time  Peter


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## tom3141 (Jul 2, 2016)

No problem Peter 

I've arranged for a guy to do the welding for me as I didn't want to get bogged down with all the rust. It should be getting fixed at some point in the next couple of weeks. I do have access to a TIG welder at work - I've had a few attempts using it but I find it very difficult to have a steady enough hand. The guys on Youtube make it look so easy! 

I think I'm going to stick with the inverter at its original size (at least for the time being) but thanks for your offer. I do have acces to a machine shop at work but I'm trying to keep things as simple as possible so that I can get on the road quicker.

The plan for connecting the motor to the propshaft is to use the primary gear from the gearbox as you suggest. I have already stripped the gearbox down but I haven't tried machining the gear yet. I'm hoping to give it a go on the lathe at work this week.

I've ordered a second hand propshaft (from a Bentley!) that should be turning up on Tuesday. The original propshaft is obviously too short and it seemed easier to find a new propshaft the correct legth rather than extending the old one. The first one I found on eBay that was roughly the right length was from a Bentley Turbo R! It was cheap so I thought I may as well give it a go . The plan is to machine an adapter plate for each end so that I can bolt the prop flanges to the diff at one end and to the primary gear at the other.

I put the motor in position today ready for test fitting the propshaft when it arrives. Once I'm happy that the propshaft, adaptor plates, and motor all fit together nicely I will get the motor mounted permanently.

Tom


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## EKit (Dec 17, 2016)

Hi Tom. A step closer with motor in temporary position, all fits nicely. Dont forget your cooling pipes, I had to buy some elbows to allow pipes to fit on my install, elbows in stainless of course  You struggled a bit with TIG, so did I at first, especially as mine has HF start which is a wake up call if I forget to attach the earth/ground lead. Not managed to zap myself yet but give it time. Let me know how you get on with turning the gear, my colleague is a toolmaker by trade and has all the equipment and turning tips if you are struggling, fingers crossed. All the best. Peter


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## tom3141 (Jul 2, 2016)

I've made some progress over the last few weeks, some photos are attached. The adaptor plates for the propshaft have been made and the motor mount has been tacked in place. The Bentley propshaft is the perfect length and fits really nicely in the transmission tunnel, if a little snug! It's nearly twice the diameter of the original one! The only snag that I have hit with the drivetrain is that the gear that I was planning to use to go from the motor splines to the propshaft flange is proving impossible to drill. Everything else is ready to be bolted together.

The options I have for the gear are

-try to anneal the gear and then reharden after drilling. Someone also suggested trying to 'soften' the spots where I need to drill using a welder or similar. Might be worth a try before I give up on it.
- find some special tooling that will drill the hardened steel
- get a new part machined from scratch that has the correct spline
- find another off the shelf (wheel hub, clutch plate etc) part with the same spline
- check the Enova gearbox output flange to see if that has the same splines 9for some reason I haven't done this yet!)

I also bought a electronic throttle pedal from a Rover 75 to give me the 0-5V input I need for the inverter. It was an early electronic throttle that had a seperate pot connected to the pedal with a linkage. I'm planning to use the Cappuccino's original pedal and mount the pot from the Rover pedal in the engine bay and actuate it with the original cable from the Cappuccino.

The car should be going off to the welders this week to have the floor and sills sorted. Once it is back hopefully I will be able to get the motor connected to the wheels .

On another note, I have been looking into the BMS options for the battery pack. I'm planning (at least initially) to use the passenger seat space for the battery pack. This means that I can fit the full pack in fairly easily (28 blocks of 3s16p giving a total pack of 84s16p 310V 21.8 kWh nominal). I don't really want to spend a fortune on an all singing all dancing BMS and I'm not sure that I need it. I should have more than enough capacity for my needs so my plan is to limit the charge voltage to something like 4.15V per cell. I will then monitor individual cell voltages with a HV (4.2V) and LV (2.75V?) cutoff. I'm looking at the Zeva 8 cell battery monitors to do this (http://www.zeva.com.au/index.php?product=125). In addition to this I will have an Ah meter such as the JLD404 to use as a 'fuel' gauge. Any thoughts on this approach? I know there are a lot of different opinions on this topic! As far as I can tell as long as I balance the cells before they are assembled and stop any cell from going over 4.2V whilst charging and under 2.75V whilst discharging then I should be good. I may loose a bit of range as cells become slightly unbalanced but I should have enough extra capacity to cope.


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## tylerwatts (Feb 9, 2012)

Looking very good. You'll need a carbide cutter to drill that sprocket and a very large pillar drill or ideally a mill. Should be a simple job for a tool maker however so try locally for someone to machine it for you. Not worth annealing it then hardening and too thick to anneal locally... Can't risk softening the splines!


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## EKit (Dec 17, 2016)

Hi Tom. Would you like me to try machining the primary gear ? If so send me a drawing of what the final splined unit is to be and I will let you know the progress. If all goes well we can swap gears so I have an original  Thanks for the link to the BMS too, I am investigating and my credit card is twitching ! Peter


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## tom3141 (Jul 2, 2016)

Thanks for the offer Peter. I'm going away for a couple of weeks tomorrow so I will have a look at the primary gear again when I return and let you know what I decide.

In other news, the car has been to the welders this week and has returned today with no more holes in the floor .

Tom


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## tom3141 (Jul 2, 2016)

I finally managed to machine the hardened gear last week. I did it by machining through the top few mm with a carbide end mill before drilling the rest of the way with a cobalt drill. It was an absolute nightmare but I got through it eventually! 
I've got a bit more painting to do on the parts that have been welded but I'm not far off being able to mount the motor. I'm having a few problems with the inverter though which I need to sort with the motor on the bench before I go ahead and put it in the car for good.


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## hiura (Jul 25, 2018)




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## EKit (Dec 17, 2016)

Hi Tom. I am also working on my inverter parameters at present. What I expect to happen doesnt seem to be however. One thing I will say is be careful with Boost, dont set that too high or the instant torque will be detrimental to whatever else the motor is driving. I have asked Damien Maguire if he will give me some insight into fslipmin, I asked that because the Enova motor states two frequencies on the name plate... 121Hz & 305Hz. If we use Johannes equation for the 121Hz we get a negative value for fslipmin... that cant be right, but I need a definitive answer to be sure. The equation works for the 305Hz and gives a positive value but I am not sure if thats the one we should use ? I do have the motor rotating with gearbox connected and one wheel jacked up but its definitely not right yet. Maybe we could collaborate on settings and see if we can get a good result. Peter
P.S. For those who know Damien in one way or another... he is in hospital at the moment, lets wish him luck and a speedy recovery.


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## tom3141 (Jul 2, 2016)

Hi Peter.
As far as I can tell the parameters that I am using work well (at least with a 30V PSU, I suspect they will need to change for 300V). I don't think the intermittent problem that I'm having is parameter related as it spins really nicely when it occassionaly decides to work!
My parameters are based on what Damien sent over to me but I did tweak them a bit. I haven't got the kit all powered up at the moment so I can't download the parameters I'm currently using. I've attached the last set of parameters that I saved which I'm pretty sure are very close to what I'm using now. I've also attached the parameters that Damien sent me.
Sad to hear that Damien is in hospital. Let's hope he has a speedy recovery.
If you haven't already, make sure that you put the latest firmware on the board from the Huebner website as there is a fairly recent fix to ensure the PWM pins are actively pulled down at start up.
Tom


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## tom3141 (Jul 2, 2016)

Forgot to attach the files!


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## EKit (Dec 17, 2016)

Hi Tom. Thanks for the parameter lists. Somehow I think my micro or pcb may have a bug ! No matter what I do with the parameters the motor jumps around like mad, some settings its not too bad others it tries to rip itself apart. Also it doesnt save the last set of parameters properly. Next power up it has saved some of them and reverted to ones from a session before ! I am using a wifi link which could be the issue as its a bit hit and miss somtimes and I have to keep refreshing the link as well as the page. Are you talking to your system direct via USB ? If its anything other than wifif please would you tell me how you are doing parameter changes please, thanks. Frustration has gripped me big time today !! All the best. Peter
P.S. Its thrown so many ERROR signals which shut down the main Kilovac style contactor each time that the contactor is now knackered, wave goodbye to £130.


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## tom3141 (Jul 2, 2016)

I'm using a USB cable, it's just a printer cable. I've been using this web interface to change/view parameters - https://github.com/poofik/Huebner-Inverter. I struggled with the standard Huebner web interface. If you download the one in the link and double-click Hueber Inverter.bat (Windows Batch file) with the inverter plugged into a USB port it will automatically connect and open your web browser.

Are you using a power supply or batteries? I've been using a 30V 20A power supply without a contactor. Also, are you using a 0-5V signal for the throttle (automatic mode) or setting the frequency in the software (manual mode)? I've had trouble getting it to work properly in manual mode. It runs better in automatic mode.

I'm also a bit frustrated at the moment with my inverter problem. Not sure if you've seen my posts in the Huebner inverter thread but I have an intermittent issue where the inverter shorts as soon as I put it in forward or reverse. I believe both the transistors in one of the IGBTs are being turned on at the same time but I'm a bit stumped as to how to troubleshoot or fix this. The electronics side of the conversion is what I know least about! It's frustrating because I've almost finished all the restoration work on the car and I have all the parts to mount the motor and connect it to the wheels but I want to get the inverter problem solved before I do that (it's awkward to test the inverter in the garage where the car is located). It's also worrying because if this problem occurs when the battery is connected it will immediately destroy the IGBT.

Seems very odd that the errors would have killed the contactor. They are rated to many thousands of cycles aren't they?


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## tom3141 (Jul 2, 2016)

Just noticed that I've had a helpful reply in the Huebner inverter thread that somehow I'd missed.


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## EKit (Dec 17, 2016)

Hi Tom. Some news.... more by luck than judgement I increased fslipmin to 5 and fslipmax to 10 (default parameters say 1 and 3) hey presto the motor now responds in a much more controlled manner. I have had the wheels spinning (car jacked up) and so far its looking ok but max RPM is not being acheived as yet, need to play again tomorrow. However a new issue has appeared... if I plug in my encoder the inverter just sits there doing nothing !! Checked 5v, thats not being pulled down and the encoder channel is switching between 0.2v and 2.2v so that seems ok (ish). Need to check if encoder channel gives a higher voltage when not connected to inverter next. Contactor has definitely stopped working, its popped a control fuse so maybe the wiring/coil has had an issue, about half a days work to take battery box out and get to the contactor itself... another reason I shouldnt have done a Smart car as the box is under the car floor. Now why wasnt there a Suzuki Jimny or Pinin Junior when I was prowling around Ebay at the time :-(
As to your dilemma, thinking about that, will check schematic. What does the direction switch look like physically, is it new, check its resistance and try it with a couple of leds to see if it is working 100%. Separate the direction wires to fwd and rev, check the resistance to gnd on each wire with control power switched off. Are the wires pulled down to gnd with a resistor? If not try adding a 1K resistor to each wire so its definitely pulled down to gnd, that makes sure it is either high or low when its meant to be. Let me know what you find. Good luck. Peter


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## hiura (Jul 25, 2018)

Just curious....is this but another of legion projects online that generate a lot of hype and interest and respect only to stall near the finish line and never be completed? 

As someone who would want to make a Hayabusa V8 Cappuccino but never will, seeing an EV Cappuccino generates much respect and interest.


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## tom3141 (Jul 2, 2016)

I hope not! I’m still slowly progressing with the project but I’ve not been very good at updating this thread.

The motor is now mounted and connected to the wheels. The inverter is also in place. The interior has also been refitted now that the rust has been sorted and the floor repainted and waxoiled. 

I have been trying to decide where to put the batteries. I was considering spreading them throughout the car (possibly under the floor) so that I can keep the passenger seat. However, I think that I’m going to stick with the original plan of filling the passenger seat area. It will be much easier and hopefully allow me to get the car on the road quicker.

Next jobs are to design and make the battery box as well as getting the pumps and other ancillaries mounted.

I’ve attached a few photos of the progress.

PS. A Hayabusa V8 Cappuccino sounds interesting! Two hayabusas side by side?


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## brian_ (Feb 7, 2017)

hiura said:


> As someone who would want to make a Hayabusa V8 Cappuccino...





tom3141 said:


> A Hayabusa V8 Cappuccino sounds interesting! Two hayabusas side by side?


Not likely two engines; it would be too wide and combining the outputs is awkward. There have been V8's built by welding together two blocks (and of course the original heads, etc), and some built with a custom V8 block (using two original heads, etc). Radical offers one of their cars with their production Hayabusa-based V8 from Powertec.

Motorcycle engines typically don't suit cars well anyway, due to the integrated and inappropriate transmission, so it makes a lot more sense to make an automotive block to use the motorcycle heads, pistons, and maybe connecting rods... and one transmission.


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## hiura (Jul 25, 2018)

tom3141 said:


> I hope not! I’m still slowly progressing with the project but I’ve not been very good at updating this thread.
> 
> The motor is now mounted and connected to the wheels. The inverter is also in place. The interior has also been refitted now that the rust has been sorted and the floor repainted and waxoiled.
> 
> ...


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## EKit (Dec 17, 2016)

Hi Tom. Forget Hayabusas, two Enovas would be better  Been a while since I have been on the forum too. Update from me being my inverter/motor parameter issues were down to my encoder signal. I had extended the cabling from the inverter via an interface box to my encoder wiring. The penalty for doing that being I induced a lot of noise onto the 5v bus supply to the encoder. Add to that I also made a stupid mistake in linking the motor frame to the gnd of the 5v supply. The encoder signal instead of being a square wave was just a mass of noise and spikes. Disconnect the cable to the motor frame and the signal is almost perfect. So, as things are looking better I decided to take the plunge and send off my covering letter and pictures of the build (on local garage headed notepaper, with their permission and approval of work done) to the DVLA in hope they will accept the change from ICE to EV this time. Previously I just sent in the reg docs with a simple 'change of fuel' but got a letter back saying they need proof. Fingers crossed I get an 'ok' this time. Keep in touch. Peter


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## tom3141 (Jul 2, 2016)

I reckon the performance of a single enova should be similar to a single hayabusa. I think a standard hayabusa is around 170hp but only 100lbft torque. 

Glad your nearing the finish line, hopefully the DVLA are fine with it. I’ll try to keep this thread updated as I progress. I’m really busy with work at the moment but hoping to get it finished over the winter ready for spring.


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## EKit (Dec 17, 2016)

Hi Tom. Well here I am again, sadly no further on with my inverter !! Cant get it to spin up my motor without it shutting down. It spins up to about 500rpm then becomes as rough as anything finally tripping the inverter. I have been checking all sorts and trying various things to reduce the encoder/5v bus noise but the spikes are still there, frustration has kicked in big time now and have asked Damien Maguire to check my Combi board when he gets back in a few days from his Tesla venture. DVLA have not replied yet either, they do like me to keep worrying and my fingers have turned blue as I dare not un-cross them for fear of getting another 'NOT until' .... So, need to find out whats going on and why my inverter system/setup isnt working, so annoying as I am ready to test drive ! Keep in touch. Peter


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## tom3141 (Jul 2, 2016)

Sorry to hear of your troubles. I still haven’t fixed the issue that I had with my inverter either. I wonder if it could be the same/related problem? Mine usually works fine but occasionally it will keep tripping the power supply as if the IGBT is shorting. I haven’t had chance to look into this again. I saw Damien has recently designed a new control board to use the original Enova driver board. I guess this could be an option if the worst comes to the worst. 

Seems like it might be worth me contacting the DVLA as soon as I can make it look finished then. I was going to wait until it was all ready to drive but if it’s going to take a while I’ll look at doing it sooner. What exactly did they ask for?

On the Cappuccino, I now have my throttle cable connected up to the Rover 75 electronic throttle pot (photo attached). The 3D printer at work has come in handy!

I’m in the process of making brackets for the water pump and vacuum pump and I’m also nearly done designing the battery box. I’ve settled on situating the batteries in the passenger seat space as I can’t get the pack size I want anywhere else. I’m planning to use Palight which is a rigid PVC foam for the box. It’s very light but surprisingly rigid and is also pretty fire retardant (hopefully this will never be tested!). The box will be split into 5 layers, with 16 batteries in each layer. Each battery will be made of 16 cells in parallel. The 80 batteries across the 5 layers will be connected in series. I’ve decided to take the cells out of the cases that they came with as I think I’ve come up with a nicer, more compact way of housing them and connecting them together. I’ll upload a screenshot of the CAD once I’m happy with it.


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## tom3141 (Jul 2, 2016)

I’ve also been looking again at the BMS options. I think I’ve setttled on the Zeva 8 cell monitoring modules. These basically just trigger an output when any cell goes above or below the preset HV and LV cutoff values. What I’m currently trying to decide is what these HV and LV values need to be. If anyone could give any advice on this it would be much appreciated. The Zeva units usually come setup for LiFePO4 but they can configure them to whatever I need. The data sheet for my batteries is here: http://liionbms.com/pdf/bostonpower/swing4400.pdf . 

I’m thinking the LV cutoff probably wants to be at 2.75V. It seems they will be happy down to 2.5V but I’d rather have a bit of margin as I shouldn’t need to use the full capacity of the pack. I had considered slightly undercharging the batteries as a way of prolonging their lifespan. The data sheet states to charge them to 4.2V and mentions a 10s pulse charge cutoff voltage of 4.3V. I’m not entirely sure what that means but I guess if I were to charge to 4.2V then I’d want the HV cutoff at something like 4.25V. Or is it a good idea to only charge to 4.15V and have a cutoff at 4.2V to prolong their life at the expense of some range?


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## EKit (Dec 17, 2016)

Hi Tom. I asked Damien for the new board but he is up to his neck in Tesla at the moment so waiting for his return, hopefully next week. In the meantime I am going to feed my encoder supply totally separate from the car 12v and run the signals back through an optocoupler into the Combi board to see if that helps, if I have any fingers left that are not crossed then they will be used ! As to DVLA.... Take as many pics as you can, engine out, fuel tank out... whatever to show empty engine bay firstly. Then show motor and associated control gear in various states of installation and finally what the installed engine bay looks like. I sent all the pics and a write up on my local garage headed notepaper (a good friend of mine who looks after my car) he supervised somewhat and participated in the work to a small degree, I returned the favour with elec help. He gave a lot of help with certain parts of it but left the grunting and sweating to me, typical  The actual requirement options (if thats what they meant as to give all of them would be ridiculous) where... 
1. Notification from vehicle manufacturer of modification (ask Mercedes to check it.. no chance).
2. Written report from RAC or AA, rang AA and didnt really get a final answer... "dunno if we can do that ?". To be fair I should have pursued that option harder which if I get another 'we need more proof' then thats my next option to try.
3. Written confirmation of change from a garage on their headed notepaper detailing the change, that was my best choice.
4. Hmm.. cant remember that one, will check and update you tomorrow but it was another long shot.
My garage friend told me however that a recently built ICE kit car had to be taken to a DVLA inspection garage for registration to prove its been done, not sure if for tax reasons or just to prove it exists, maybe I will have to do that too ?
As to your tripping problem, do you mean the main contactor drops out on an error? Mine did that so much initially trying to get the motor to run I ruined a Kilovac contactor, somehwat my fault as I had not fitted a bemf diode and had stupidly removed the economiser to site it in the control box instead but not connected it... doh!
Anyway fingers crossed for the postman tomorrow, I am now panicking when the letter box rattles in case its a NO from DVLA, not the end of the world but still a pain. I did a caclualtion the other day too.. How much have I spent so far £6000 ish, thats £500 more than a low mileage Renault Zoe and absolutely zero hassle, makes you wonder why I guess. Never mind, its been fun  All the best. Peter


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## tom3141 (Jul 2, 2016)

Thanks. I’ve been taking plenty of photos so that should help. I can’t believe they suggested the 1st option!

On the inverter problem, no it’s not the contactor. I’m running it on a power supply so not using contactors yet. It’s as if the both of the IGBTs in one of the bricks are being turned on at the same time causing the main positive and negative terminals to be connected together. I believe it’s known as shoot through. I’ve been asking about it on Johannes “AC Motor controller” thread but I’ve not had chance to try their suggestions yet.

I seriously considered an OEM EV before I started this but there just aren’t any in my budget that I would want to drive. I am expecting to spend a similar amount to you so was looking at the very oldest Leafs, iMievs, or Zoe’s. I’m more interested in EVs from an engineering and car enthusiasts point of view than for the ‘green’ benefits so none of these really appeal to me. I decided I could make a much more fun vehicle for the same money and have fun building it along the way. I’m sure you will enjoy a 90kw Smart that you have built yourself much more than a Zoe!

On this note, it baffles me that car manufacturers still haven’t produced a simple cheap EV (or an electric sports car for that matter). They’re all focusing on electric SUVs that cost the earth and have every gadget imaginable. I’m sure there would be a market for a basic small electric hatchback (in the UK at least) with a decent range at a sensible price (£15k not £30k+). Something like an electric kei car! I’m convinced it must be possible.

Anyway, I’ve laser cut and folded all the pieces so that I can assemble my water pump and vacuum pump mounting brackets at the weekend. I’m also going to make up some prototype brackets that replicate the passenger seat rails tomorrow. Hopefully these will give me a solid base to mount the battery box onto.


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## Duncan (Dec 8, 2008)

Hi Tom
_On this note, it baffles me that car manufacturers still haven’t produced a simple cheap EV (or an electric sports car for that matter). They’re all focusing on electric SUVs that cost the earth and have every gadget imaginable. I’m sure there would be a market for a basic small electric hatchback (in the UK at least) with a decent range at a sensible price (£15k not £30k+). Something like an electric kei car! I’m convinced it must be possible.
_

The car manufacturers dirty secret is that the fully loaded car with all mod cons COSTS about 10% more than the basic model - but they can charge 100% more

So the incentive is always to sell the top models FIRST - and the base models only after you have satisfied the demand for the expensive ones


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## brian_ (Feb 7, 2017)

tom3141 said:


> On this note, it baffles me that car manufacturers still haven’t produced a simple cheap EV (or an electric sports car for that matter). They’re all focusing on electric SUVs that cost the earth and have every gadget imaginable. I’m sure there would be a market for a basic small electric hatchback (in the UK at least) with a decent range at a sensible price (£15k not £30k+). Something like an electric kei car! I’m convinced it must be possible.


A low-performance low-speed car is possible, where it is legally allowed. The Euro "heavy quadricycles", such as the Renault Twizzy, are a good examples.

A basic car of conventional size and performance is much more expensive in battery-electric than engine-driven, so the £15k is just not possible, unless it is heavily subsidized. The vehicles which physically meet this description are much more expensive, and are generally purchased only where they are subsidized by government programs. Even a Kei-class vehicle (such as the Cappucino) is requires a substantial powertrain and so isn't cheap.

So to make any money - or even come close to covering costs - manufacturers target the high-feature market. I don't blame them. Ideally, the moderate volume of production of these vehicles (the fancy ones and the subsidized ones, and even the fancy subsidized ones) will bring costs down to the point that more reasonable EVs become economically viable.


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## EKit (Dec 17, 2016)

Hi Tom. Been looking at Eric Tischers website where he uses an industry standard control board from a branded inverter drive coupled to his own power stage, sounds VERY interesting indeed. As an option to see if that would work with the car as a test unit for control I can see the benefits of having something already tried. I am only looking at this idea to gain back some incentive with my build, if I can just drive around the car park once it will lift my spirits  The first pitfall however is my pack voltage 230v! The 1ph to 3ph inverters use 220vAC rectified up to 310vDC ish. Need to see if lower input voltage units are available or can be fooled to see my pack volts and work ok. I do have another 50v DC pack if I need to increase that but still only 280v DC. Thats tonights challenge, what minimum inverter input voltages are available ? Speak soon. Peter


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## EKit (Dec 17, 2016)

Hi Tom. Check my new post subject... DVLA registration


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## tom3141 (Jul 2, 2016)

Thanks Peter. Any luck with your inverter?

I mounted the vacuum pump and water pump at the weekend. They sit on each side of the car behind the radiator and below the inverter.

The next jobs are the vacuum reservoir and battery box and that should be most of the mechanical work done. The BMS units are now on order from Zeva as well.

Making progress! 🙂


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## EKit (Dec 17, 2016)

Hi Tom. Good to see you are progressing, a good feeling when each part is completed. Keep your head down with the work and you should be ready for Spring. Did you read my write up 'DVLA change to electrickery'  What a relief to get that sorted, the rest is engineering thankfully before MOT. Inverter is still on the bench sadly, it developed a new fault which after investigation turned out to be a duff LEM HTFS400-P current sensor, output 2.5v was ok out of circuit but as soon as it saw 10K resistance to gnd the output fell to 0.2v ish ! New one purchased £16 so not the end of the world. So reassemble and see what happens, if still no joy then all will be shipped back to Damien Maguire for him to test. Have also been looking at Damiens videos on branded inverters, Leaf, Prius, etc. If Damien can hack one of those and if it can handle 90Kw then that could be my choice to run my next car challenge. All the best and keep in touch. Peter


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## tom3141 (Jul 2, 2016)

Yes, I read your DVLA write up. Good news, nice to know what is required even if it is a bit of a faff on. 

Hope you get the inverter sorted soon. I’ve put my inverter problems on the back burner for now. I’m trying to get the majority of the work done before I tackle that again as I don’t won’t to get bogged down with that and not make any progress.

I’ve sourced a vacuum reservoir today so I’ve got to design some brackets for mounting it. I’ll then be onto finalising the battery box design and making that.


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## EKit (Dec 17, 2016)

Hi Tom. Have asked Damien to supply a new STM microprocessor board with latest software, its the only thing I cannot check, the rest of the board checks out ok. Not sure if it will make a difference but I wont to be able to eliminate any unknowns... if that makes sense ! Encoder is the next thing to test as that didnt want to play, but again I cannot be 100% that the encoder is my problem. Will be bench testing that this weekend. Dont frorget to find your friendly neighborhood garage before Xmas and ply him/her with many alcoholic beverages over the next few months for the write up needed in Spring  All the best. Peter


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## hiura (Jul 25, 2018)

Any chance that Santa is bringing an update soon?


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## tom3141 (Jul 2, 2016)

Not in time for Christmas I'm afraid but a Happy New Year to you all!

I have been making progress but not much of it has been visible so it's not a very exciting update. I've been working out the plan for wiring and ordering relays, switches, cables etc over the last few weeks.

I've made a prototype of the bottom battery box layer which seems like it will work. However, I want to concentrate on getting everything wired first so that I can test the whole system on a power supply before I start on the battery pack.

I'm waiting for some more parts to turn up and I've got a few mechanical bits to do but I should be able to start wiring pretty soon.

I'll try to keep you updated and include some photos next time!


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## hiura (Jul 25, 2018)

You know that we are all so very much looking forward to the progress. So many projects start but never find completion.


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## tom3141 (Jul 2, 2016)

I've been slowly working on a box to contain all the electrical components over the last few weeks. This will be mounted on top of the battery enclosure where the passenger seat used to be. This means that I can have the majority of the wiring in one place and should keep things fairly simple. The box will contain two main contactors, the precharge circuit, the BMS, some charger circuitry, a JLD404 Ah meter (and shunt), an emergency stop button, a battery enclosure temperature display and a low voltage alarm/beacon (triggered by the BMS LV output). I've built the box and checked the positioning of all the components so I will be wiring this up over the next couple of weeks. Then I've got a bit of wiring to do in the 'engine' bay in order to be able to test the whole system with a power supply.

I've also mounted a forward reverse switch where the gearstick used to be. This is an illuminated switch which I've made a custom 3D printed housing for.

Hopefully I will have some exciting new developments over the next few weeks!


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## hiura (Jul 25, 2018)

If you can have the AT lever in the stick location, that could create great fun to the unsuspecting with your sleeper. AT kei car....no power and then...wheeeeeeeeeeeeeeeeee you're gone!


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## tom3141 (Jul 2, 2016)

I've made some good progress over the last week. The majority of the low voltage wiring has been completed and I was able to power everything up today and spin the wheels! 

It's still only on a 30V power supply as I've got the battery pack to sort out. I was able to turn on via the key and the forward/reverse switch and throttle worked perfectly. The precharge and contactor circuits seemed to work fine too. 

The bad news is that I still have an intermittent problem with the inverter gate drivers/IGBTs. I had this before when testing on a bench but I decided to get it all wired in properly before investigating further in case it was a wiring problem with my test setup.

This is the process I went through today:

- I turned the ignition on, and then to the momentary start position after a couple of seconds. The power supply hit the current limit (20A). (no throttle input and neither forward or reverse selected)

- I knew the problem before had been related to the gate drivers/IGBTs so I unplugged the lead between the driver board and the first IGBT. The whole system then turns on fine and forward or reverse can be selected.

- I then plugged this lead back in. Everything turned on but the PSU hit the current limit as soon as I selected either forward or reverse. (no throttle input). If I then flick back to 'neutral' it stays at the current limit but if I turn it off and back on again it will be fine until I then select forward or reverse again.

- Unplugging the other driver-IGBT leads doesn't help at all so it seems related to the first IGBT lead that I unplugged.

- Eventually, after a few minutes of turning it on and off and fiddling with these leads I got it to the point where I could select forward or reverse without it hitting the current limit but upon applying some throttle the PSU would cut in and out and the motor would turn rather jerkily.

- It then started working perfectly, spun the wheel up fairly quickly without hitting the PSU current limit

- After taking some videos and enjoying seeing the wheels spinning for the first time it then stopped working again. This time there was no PSU current limit but the motor would only jerk back and forth however much throttle I applied (as if one phase was not working?).

- It then went back to hitting the current limit every time forward or reverse was selected

My feeling is that it is something to do with the gate driver or connections on the combi board. The intermittent nature makes me think it's not a parameter issue or a something broken in the power electronics. I had a few suggestions back when I was testing it on the bench that I still haven't tried but if anyone has any ideas let me know.

I have some videos of it working that I'll try to upload later.


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## tom3141 (Jul 2, 2016)

Videos should be here:

https://1drv.ms/f/s!Am-VyIvBzOs6g80VvC8oEZoAhPBGgw

The bleeping in the first video is the battery low voltage alarm which I had disabled before the second video as it was getting annoying! The JLD404 hasn't been setup properly yet hence the incorrect amp reading.


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## hiura (Jul 25, 2018)

tom3141 said:


> Videos should be here:
> 
> https://1drv.ms/f/s!Am-VyIvBzOs6g80VvC8oEZoAhPBGgw
> 
> The bleeping in the first video is the battery low voltage alarm which I had disabled before the second video as it was getting annoying! The JLD404 hasn't been setup properly yet hence the incorrect amp reading.


Something went wrong......

https://onedrive.live.com/?cid=3aebccc18bc8956f&id=3AEBCCC18BC8956F!59029&authkey=!ALwvKBGaAITwRoM


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## tom3141 (Jul 2, 2016)

I've been having issues with the inverter that I've been troubleshooting over the last few weeks with help from the guys on the Open Inverter forum. 

Progress with this is slow but I've been working on a few other things in the meantime. 

I've machined out all the components for the battery box. It's all made from a rigid PVC foam which I then fold and glue. Photos to come when I've glued all 5 layers. 

Once I've fixed the inverter problem, I shouldn't be too far away from testing with the full battery pack in


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## Casanova (May 9, 2019)

Fascinating thread - I love the Cappuccino and think it's an excellent choice for a base vehicle. Good luck getting it over the line; doesn't look like you're too far away!


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## tom3141 (Jul 2, 2016)

Cheers. It’s a great donor vehicle apart from the lack of space for batteries!

I think that I’ve sorted the inverter problem (thanks to the guys on the open inverter forum). I’m currently working my way through the batteries, charging them up individually and making the battery boxes too. Hopefully should have the battery pack ready in around a months time.

Also discovered that I have a vibration issue with the propshaft now that I can spin it up to full speed. I’m going to add a bearing plate to the front face of the motor in order to support that end of the propshaft. I think the problem lies with a bit of play that exists between the splined motor shaft and the gear that I have adapted to fit the propshaft. I’m going to use part of the gearbox housing that came with the motor to support the gear in a bearing.


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## ElectricCappa (Aug 23, 2019)

Hi I have a cappa in AUS and am thinking of going down this track with mine. Is there no chance of mounting any batteries in where the fuel tank was? So keen to see this finished


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## tom3141 (Jul 2, 2016)

Nice to hear from you. I'm keen to see it finished too! I've got some time off work over the next few days so I'm trying to make some progress. Currently working on BMS and charger wiring.

You could fit some batteries in the fuel tank space but I don't think you could fit a whole pack in, even if you only need a really low range. I've got a ~20kwh pack and could probably fit no more than a quarter of the pack in there. It's a really awkward shape (I'll try to get a photo of the shape of the fuel tank later) so it would also depend on what format your batteries are in. If they are small cells and you're willing to fabricate a crazy shaped box then you could pack quite a lot in but with any kind of larger format batteries you'll struggle to fit anything in. I've attached an image of the fuel tank space without the fuel tank in place (the subframe is not attached in this photo and has been lowered slightly on a jack so you'd actually have less space than this).

I think you could fit a full battery pack in a Cappuccino (without using the passenger space!) by spreading them around the car - some in the boot (trunk), some in the fuel tank space, and some under the bonnet (hood). I decided that I'd rather simplify the conversion and keep all the batteries in one place. It's a long and complicated project as it is! 

My motor and inverter are quite large as well so if you had a more modern and sensibly sized motor/inverter package then you'd have lots more room in the engine bay for batteries. I literally have no space in the engine bay at all. Ideally, you'd want a motor that fitted in the transmission tunnel or within the rear subframe.

Do you have any components yet or are you still at the dreaming stage?!

Edit: for some reason it's rotated the photo but you should be able to make it out. The fuel tank sits right up against the top (the only bit that's not rusty!)


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## ElectricCappa (Aug 23, 2019)

Hey mate yea a bit of dreaming and some serious thought. Mine is completely stripped and slowly fixing the rust on it. Considering the cost of all the parts from Japan its not too bad an idea. Some useful information if you are looking for a different diff is the auto cappa had a 4.556 ratio. Depending on motor size ill probably be mounting onto the gearbox.


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## jalovick (Sep 19, 2019)

I've wondered if a Lexus 450h Rear Drive Unit or similar would fit under there. It's around 53 kW and would get the Cappa going okay, or a Nissan Leaf drive unit.


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## tom3141 (Jul 2, 2016)

Well, it's been a while but the Cappuccino finally moved under battery power today. There are still some inverter parameter issues, a propshaft vibration, and a few odd jobs to sort but I should be very close to getting it on the road. I would add some photos and videos but it doesn't seem to be letting me.


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## tylerwatts (Feb 9, 2012)

Looking forward to those pics of progress Tom! Well done getting her moving too.

Cheers
Tyler


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