[EKit]

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

 

[hiura]

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.

 

[tom3141]

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?

 

[brian_]

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

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.

 

[hiura]

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?

 

[EKit]

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

 

[tom3141]

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.

 

[EKit]

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

 

[tom3141]

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.

 

[tom3141]

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?

 

[EKit]

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

 

[tom3141]

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.

 

[Duncan]

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

 

[brian_]

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.

 

[EKit]

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

 

[EKit]

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

 

[tom3141]

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! 🙂

 

[EKit]

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

 

[tom3141]

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.

 

[EKit]

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