# The Mazda RXVolt



## madderscience (Jun 28, 2008)

Hi-

Sounds like you have the mechanical/technical acumen to do this. that's a good start.

The RX8 should be a decent conversion candidate.

As for budget, 100 miles means you are going to need a pretty good sized battery. Chevy volt packs are 16kwh IIRC so you'll need 2 at minimum. That should give you approximately 100 mile range if driven fairly conservatively. If you want to drive less conservatively, or you really want "100+" mile range you'll need a third pack or some fraction thereof.

I'd try to keep battery voltages as high as the controller you pick allows. I believe the Zillas will allow 300-ish volts and I'd try to keep to that. It allows more consistent performance and less stress on individual cells, and reduces complications associated with massive series/parallel combinations.

As for sundry parts (cables, connectors, tools, plexiglass etc) try ebay. Welding cable can be bought in bulk online or at your local welding or industrial supply place. There are also places like onlinemetals.com, metalsupermarkets.com, etc. which can cut and ship a wide variety of raw materials.

I can't speak to repurposing OEM chargers and other components, but I know others are hard at work doing this. hopefully they will chime in.

Overall even with the better pricing available for batterise these days, I'd be guessing your budget might be more like $15-20K minimum. If you were to stick with a more typical for conversions 50 mile range, then you could probably do something for around $10k.

Good luck


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## skeyes (Dec 3, 2016)

Good call on the welding cable. Thanks for the support! I'll post pics as I start getting into the build. Looking to probably start in the next couple months.


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## Duncan (Dec 8, 2008)

Hi skeyes
I put most of a Chevy volt pack in the Device
http://www.diyelectriccar.com/forum...dubious-device-44370p11.html?highlight=duncan

Very impressive technology


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## skeyes (Dec 3, 2016)

Duncan, I read your whole build. Nice work!


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## skeyes (Dec 3, 2016)

So I've been looking into chargers a bit. Having never owned an electric vehicle I may be asking some dumb questions here so bear with me 

1. If I build the car with a charger installed, such as an Elcon PFC, do I still need to install an "evse" charging station in the garage? Or is it possible to just plug in to a 120v or 240v standard AC outlet?
2. Is the only purpose of the EVSE to convert the cable to the J1772 plug? Or does it do something else?
3. It seems from what I'm reading that all the "smart charging" functions are managed by the charger in the vehicle... So couldn't I in theory supply the raw power to the charger and be good to go? Ideally I would want a charger that can hook up to standard 120v and 240v, and I would make an extension cable that could adapt to both sockets....

Any advice would be great! Thanks.

Just in the research phase at the moment, as I am in the middle of moving. But probably 1 month out from starting the project in earnest.


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## Moltenmetal (Mar 20, 2014)

The EVSE is a safety device only. You can, as I do, use a regular (outdoor, ground fault interrupted) 120 or 240 single phase AC outlet for charging. If you do a good job of isolation and waterproofing and use a charger like an ElCon, the EVSE's ground fault protection isn't really all that essential. 

It is handy to have a J1772 port to connect to level 2 charging ports which are becoming plentiful at shopping malls and underground parking lots these days. A simple little AVC2 board can be used to fake the signal needed to turn in an EVSE. Mine is basically used rather like an adapter plug on the end of my charger's input plug.

All the brainwork is done by the charger and, hopefully if you're using Li-ion chemistry, the battery management system too. In fact my charger's several steps (constant current, then constant voltage, then constant low current) are of little practical use- my BMS terminates my charge every time, and squeezing a few extra Wh into the pack at the top end is of little practical value.


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## skeyes (Dec 3, 2016)

Awesome. So I am not completely off base it sounds like.

I'm thinking of making a cable reel would spool out of the former gas cap location and have maybe 30ft length, with either a 240v/120v adapter on the end, or a y-type split with a plug cover on the cable not in use. 
This would run to the charger and basically allow me to plug in anywhere.

I do like the idea of having a J1172 socket as well in case I come across them in the world. Maybe I could run that in parallel close to the charger. Can you tell me a bit more about the AVC2 board? How on your system does it fit in? Or what is the purpose of the AVC2 board? Really appreciate the info Moltenmetal!

Thanks


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## Moltenmetal (Mar 20, 2014)

http://modularevpower.com/Active_Vehicle_Side_Control_development.htm

The j1772 has five pins- line and neutral, ground, and two signal pins which must receive a 2 kHz square wave signal before the EVSE will turn on. That signal is what the AVC2 provides, to fool the EVSE into thinking an OEM EV is plugged in and ready to receive charge. That the EVSE contactor does the heavy lifting means the line pins need not be sized to withstand current during connection and disconnection, so they can be quite a bit smaller than a NEMA plug's pins.


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## skeyes (Dec 3, 2016)

Bookmarked. Great info. These are exactly the kind of little details which will be really helpful when I start building this thing.


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## skeyes (Dec 3, 2016)

Well I started doing more research and I think I have some new ideas of how this thing might go together

I found a sketchup model of an RX8, scaled it to true dimensions (or 98% close), and started dropping in several white boxes of 23.5x24.5x28cm (the approx size of a 2kwh volt battery module) Again this is super rough. 










On paper at least I think I will be able to fit them... I want to do a 12kwh + 12kwh + 12kwh (3P) configuration of volt modules. This means I will have to buy 2 complete volt packs, as well as 4kwh from a 3rd pack. If salvage prices stay the same for the next few months this should not be a problem. I'd then look to fit 12kwh in the hood, and 24kwh in the back somewhere between the old fuel tank location, under the rear seats, and trunk space. I will probably need to do some cutting and welding to make it work. I also plan on retaining the liquid cooling system, so i'll need to route hoses between everything. 

As far as voltages, this puts me around 288V nominal in 3p. I think actual max voltage when charged to 4.09V top end (feel free to chime in here if this voltage is too high, too low, just right, etc) will be around 294V for the pack. 

As far as motor and controller, I am now leaning towards the Netgain Warp11HV paired with a Soliton 1. I want to push 800 to 1000 amps at 288v to the motor, and from what I am reading this combo should be able to handle it. 

Anyone have good experience with the Warp11HV? I watched the EVTV episode on it and the guy seemed to think it could handle some serious power. Any recommendations on how to seat the brushes properly or break in procedures?

Also any recommendations on an emergency shutoff? I am not sure if the one that comes on the Volt pack will be up to the challenge? I am guessing the cabling isn't either... Let me know what yall went with for your build!! I have been reading a lot but still hard to find all the info. 

Thanks for your support. Really excited to start this build.


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## Yabert (Feb 7, 2010)

skeyes said:


> Anyone have good experience with the Warp11HV?.


Not me, but RWaudio and Matt Rimac yes. Both had output serious power from this DC motor, but both run AC motor now for the same raison: Reliability.
http://electricporsche.rwaudio.com/electric-porsche/
http://www.topspeed.com/cars/bmw/1984-bmw-e-m3-by-rimac-ar136364.html

With your planned set up you will have great fun with access to high power, but you will probably end with some problems with the motor. Brushes dust and high voltage is a destructive combo!


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## skeyes (Dec 3, 2016)

Unfortunately I don't think an AC build is going to be in the budget for this project... 

I am planning on doing everything possible to keep the DC motor alive. Here is what I have learned so far from research on how to do that:
1. Proper break-in of the motor to make sure the brushes are seated nicely and there's a good surface on the comm (still looking for an exact procedure, but I'll find it eventually).
2. Forced air cooling to keep the temperature down. I saw some 12v fans built off of old turbo housings, but having a hard time finding where to buy them.
3. Regular inspection of brushes, and blowing out dust with oil-free compressed air.
4. Proper alignment. I'm hoping to achieve this with a professionally made transmission adapter plate setup, machined with good tolerances, rather than jerry-rigging something myself.
5. Not driving it like the fast and the furious all the time. Ideally I'd like to setup a toggle switch or something with the soliton for two different driving modes: one mode for normal driving with reduced power, and one mode for track or race driving with full power (within reason that doesn't pose serious reliability risks).

I'd definitely welcome more feedback and additions to this list! 

Probably still a few weeks away from starting the build physically. Fail to plan is plan to fail right? 

I'd be really interested to hear what settings other people are running on their Soliton 1 / DC motor in their vehicle! And what forced air cooling setup!


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## Duncan (Dec 8, 2008)

skeyes said:


> Ideally I'd like to setup a toggle switch or something with the soliton for two different driving modes: one mode for normal driving with reduced power, and one mode for track or race driving with full power (within reason that doesn't pose serious reliability risks).


I am using some toggle switches and resistors across across the throttle pot

With all three switches OFF - I have just the throttle pot and 1200 amps

With all three ON - I have about 40% - 500amps


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## skeyes (Dec 3, 2016)

Duncan, toggles at the pot box makes perfect sense! Thanks! I was thinking it had to be way more complicated than that.

How often do you end up using the 1200 amp setting? How many miles do you have on The Device now, and is your motor still doing well? Your build is super awesome by the way.


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## Yabert (Feb 7, 2010)

skeyes said:


> Unfortunately I don't think an AC build is going to be in the budget for this project...


Why? There is some Leaf motor available for 500$ and you plan a 6k$ drive system... that seem to give you some buffer to find proper controller.
The Leaf motor is rated 80 Kw continuous but can output way more... in comparison, the Warp 11HV is probably rated around 50-60 Kw continuous.

Understand me well, your plan will work and you will have a lot of torque / power / fun, but your plan is so.... 2010.
Few years ago we haven't access to high quality part from OEM and it's why many of us gone with the less reliable Warp motor and Soliton controller, but now the game has changed.

Availability of OEM parts at scrapyard change everything. Here a good example: http://www.diyelectriccar.com/forums/showthread.php/1988-crx-diy-controller-and-nissan-178169.html


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## favguy (May 2, 2008)

OEM salvage is the way to go today, why not buy a complete salvage nissan leaf. You'll have a complete conversion kit in a "Leaf tin". This and the donor should come in within your budget


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## skeyes (Dec 3, 2016)

Haha 2010 doesn't seem that long ago to me, but I guess it is in the EV world!

Ok guys, say I do find a salvage Leaf and get the motor. Here are my initial questions-
1. Where can I find a controller that will be essentially plug and play for the leaf motor? I am assuming it will need an inverter and all kinds of CAN communication to get it to work. Much of which may be over my head...
2. How much power can the leaf motor really handle? It needs to be fast!! I have never driven a leaf but they do not look fast! (I am shooting for the 350hp mark)
3. I have not heard good things about the leaf battery packs... Do you think they are worth the risk?
4. Does anyone have an adapter plate template for the leaf motor? I still would need to somehow attach the rx8 transmission

I saw some threads on the lexus hybrid motor/trans as well, and while it definitely seems awesome, I am not sure I could pull it off. DC motor seems much easier at a glance.


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## skeyes (Dec 3, 2016)

So Yabert & favguy, (and anyone else who wants to weigh in)

Say for instance I go the OEM salvage route. (obviously I am not opposed to this since I'm planning Volt cells from the beginning).

What motor and other AC build components should I pick up? Is the Leaf motor the best available or is there anything more powerful?

Are there any 'off-the-shelf' AC motor controllers/inverters out there which don't cost an arm and a leg, that will still meet high performance? The Rinehart pm250 controller looks awesome but 7K+ is pretty steep. I have seen some pretty cool DIY controllers now from doing some reading, but let's face it I am not going to be able to build my own. I am a gearhead, not an electrical engineer. I am looking for components that are already tried and tested that I can just swap in to this application. 

What is the 2017 equivalent of doing the Warp 11 / Soliton 1 combo that was popular in the 2010 days?

Thanks


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## Yabert (Feb 7, 2010)

skeyes said:


> The Rinehart pm250 controller looks awesome but 7K+ is pretty steep. I have seen some pretty cool DIY controllers now from doing some reading, but let's face it I am not going to be able to build my own. I am a gearhead, not an electrical engineer.


I fully understand what you mean. It's a little bit frustrating to see some other guys playing with a Tesla drivetrain or pimp a nissan Leaf motor and you don't know how they do...

I suggest you to look at MPaul Holmes thread about his AC motor controller.
Maybe give it a call and ask him how much for a 250 Kw controller.
https://pandspowerelectronics.ecwid.com/#!/Fully-Assembled-Tested/c/22093524/offset=0&sort=normal


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## skeyes (Dec 3, 2016)

Ok after emailing back and forth with Paul, the Leaf motor and a custom AC controller is looking like a better and better option...

However it does throw off my plans for running the accessories such as air conditioning compressor and alternator off of the 2nd motor shaft (leaf motor only has one output shaft)

Questions for the DIY experts:

1. Are there any high voltage DC-DC converters which would convert 400V to 12V (or 13.8V)? I'm looking at a pack voltage around 400V to work with the motor optimally.

2. How hard is it to get a standalone electric A/C compressor to work at the press of a button? I'm talking like the Prius or Leaf A/C compressors. I'm assuming they need all kinds of CAN communication and voodoo magic to work. 

Thanks


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## Yabert (Feb 7, 2010)

skeyes said:


> 1. Are there any high voltage DC-DC converters which would convert 400V to 12V (or 13.8V)?


I use a meanwell power supply in my smart since few years now. It's a SP-320-12 adjusted at 13,4v.
It work from 124v to 370v DC. Perfect for my 180v pack.

Now there is some really nice led power supply available. they are super efficient and seal for harsh environment.
By exemple, a HEP-320-12 is rated for 127-431v DC. They come in power from few watts up to 600w.
There is also HLG series who seem good and probably other led power supply can do a great job.
HLG have constant current limiting during over current event (an advantage).


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