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2001 "REV4" - Build Thread

101381 Views 144 Replies 27 Participants Last post by  tylerwatts
Formally introducing myself - I am an Electrical Engineer working in power
systems (wind farms, HVDC links, machines etc...) and specializing in
computer simulation. I also have a bit of auto-mechanic experience (I
have owned a 1975 F250 4x4 Highboy since 1983).

I have been a long time lurker here - thank you all for the phenomenal
support/information - this is a great site!

I am also fortunate to have my nephew (Derek) helping me on this - he is
18 and will graduate from high school this year. He has an aptitude for
taking stuff apart and fixing things, so this is a win-win situation. I enjoy
working with him, and his help will be appreciated. We hope to work every
Saturday and maybe one evening during the week. I have 2 boys (6 and 8)
who play hockey etc... so I am already pushing the limits of my spare
time - this will be a very slow build...

I recently saw Rob's (RKM) Red Miata - this lit a bit of a fire, so here we go...

My overall plan is to convert a relatively new vehicle (>2000) and to make
an EV that works just like its ICE counterpart in all ways - it will have
power everything, heated leather seats, full trunk space, air conditioning,
AWD etc... The plan is to demonstrate that you do not have to give up
anything to drive an EV (in fact it will be faster and better). Of course this
will not be a cheap build, nor will it be a super-efficient low kWH/kM build,
but it will be a very driveable car I will use as a daily driver in all seasons
(also more on this later).

I really only need about 50kM of range per day, but given winter
conditions in Winnipeg, and my desire to not push any equipment close to
its ratings, I will try to squeeze in more batteries/range than what is
really needed.

I finally bought my donor and started work:
2001 Toyota RAV4, 135,000 kM, AWD

I choose the RAV as it is a family car (would love a light 2 seater
convertible but with a family of 4 it is a no go), has some height/weight,
plus it has a history/reputation for EV'ers (stock RAV4 Ev etc...). also
considered a Ford Escape or Honda CR-V...

Everyone loves pics (although this is only the stock car so far):

Yeah - I know - the big sticker on the hood has to go. You should have
seen the car before - it had "all available Canadian Tire options". I bought
an OEM leather interior kit, as well as some carbon seat heaters for driver
and passenger with 5 position dial (I can hear the groans from all the EV
purists who have scrimped on weight/features etc... to get max range!)

My "REV4" EV Conversion Plan (please - all comments/suggestions/feedback welcome!):
- Warp 11 (or maybe even Warp 11 HV?) motor
- Zilla HV 1K or Soliton1 (not decided yet)
- SE or TS LFP batteries, probably 65*100AH (more if there is room - more on this later)
- keeping the 5 spd manual transmission, have bought a new clutch

Note that the motor and controller are likely more than the stock
clutch/transmission/AWD system can handle - I figure that equipment that
is rated for higher duty conditions but driven "soft" will last longer, not
heat up etc... (definitely an engineer talking - over design it). I love the
power however, so will start with the max controller amps limited, then
increase it until everything feels shakey, then back it down a bit...

If the Warp 11 HV motor receives good tests reports, then it seems like a
no-brainer for the cost - I will use a high voltage and as many batteries
as I can fit.

I plan to put the majority of batteries under the hood (on top of the DC
motor, manual transverse transmission and AWD transfer case). There
also is room under the rear of the car where the gas tank used to be (2
smaller boxes) - keeping the 4x4 definitely adds a penalty here as the
rear drive shaft cuts everything into 2. I do not want to fill up the
trunk/back seat with batteries though.

The batteries are a big pain (a low-height LFP battery that can stick under
the floor pans would be killer) - in reality I only have about 11" to work
with (which means TS or SE 100AH batteries, which are 8.66" high - once
you add the BMS, enclosure, insulation and heating pads, this doesn't
leave too many options. There are also the new SE 240Ah batteries (6.73"
high, 17.72" long, 2.8" thick) but that massive 18" length just won't match
up with the room I have in the car.

Horizontal placement of the batteries would also work, but I have been
told by SE that this is not recommended and would void warranty.

I think I can fit about 20kWH of batteries into the 3 boxes - I will pull out
all the junk in the way before ordering batteries though (maybe a
reasonable priced A123 deal will come along between now and then?)...

One non-logical aspect to my choices are using a 1000Amp controller with
100AH batteries - 5C would be a huge draw (perhaps too much?) so higher
AH batteries would be a better fit - they are too darn tall however (or too
wide for the 240AH) so I am somewhat torn/stuck. All suggestions
appreciated here - what would you do?

I am undecided on many other parts - will be deciding soon though. I will need:

- electric vacuum pump for power brake booster (Rob/RKM showed me a
pump that was enclosed inside of the vacuum tank - that made sense to
- electric power steering pump (no-one in Canada has a 2000-2005 MR2
Spyder pump - trying hard to find one in US for a decent cost - let me
know if you find one!)
- hydraulic pump/heater for interior heat (will keep stock heater core and
fan/controls - I don't like the idea of electric heaters inside the interior
heater core)
- 1000 Amp contactors/breakers/fuses?
- battery heating pads (it gets to -40 deg in Winnipeg for a few weeks
every year and I have to get to work!).
- charger (I want a dual voltage 120/240 charger - 30 Amps would be lots)

I plan to pull the motor etc... soon (1 or 2 weekends from now) - I will
take careful measurements for the motor and batteries and make some
decisions then...

I have never done this (and definitely respect the people who have) so
please - all comments/suggestions appreciated!

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41 - 60 of 145 Posts
Another thing that may affect how you add a motor that won't otherwise fit is whether or not you are planning on keeping the flywheel and clutch.

If no flywheel/clutch then you can use the space in the bell housing for the gears, pulleys, cv joints or what ever you feel is the best option for you.
Good point Wood - are you planning on clutch? :eek:
My thought was that you mounted a bearing in the adapter plate to take the side torque off the shaft - come out there and have the CV joint as close to the plate (and bearing) as you can and ANGLE UP and to the front with the motor.

Mounting is not too hard from there. the CV shaft could be machined to fit the spline... Would be an unusual motor mount but maybe not impossible. make a mock up of cardboard and see what ya got ..... :)
I was planning on keeping the clutch - I like the idea of a mechanical safety/off switch (in addition to an electrical breaker) for DC runaway scenarios, plus easier gear changes...

I gave up on the direct drive idea - would consider this with an AC motor only (higher usable rpm range) - I don't think DC motors like operating at low speeds in the city. It is a 4.562:1 rear diff ratio though (unusually high)... I would loose AWD with this too (there is snow on the ground 5-6 months of the year around here).

I like the twin motor and CV ideas - there is not much room below as there is a frame member (which probably could be moved/lowered). I had the 36x24 area above the motor/transmission pegged for batteries.

I will pull the diff cover plate and see what it looks like - it looks quite thick from the outside, so will see how much grinding I get away with. Also good idea to shave the motor itself (although my warranty would be toasted likely).

On the bright side, sure glad I waited until the motor was pulled before ordering batteries, motor and controller - they are all linked together. Definitely recommended for transverse AWD builds...
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Mock up two 8" motors using manufacturers specs and see if you can fit them both flat at the bottom of the engine bay.
One would line up with the transmission and the other will be to the front to just clear the crossmember.
Being only 8" will leave you the space above for the battery pack.

I am exerting a vested interest as I have been thinking of this for the MR2. Plenty of space below for a cheap twin motor set up if I can't get a cheap 11".;)
Thanks Dave - I see you have been there - done that. I will plan to keep the ECM and tach as-is - hopefully I can add the stock crank sensor and toothed wheel to the rear shaft, and it will all work...
gdirwin, your new controller (at least zilla) will want to know the RPM of the electric motor. Just like the gas ECU did excpet in the case of zilla it wants a 4 pulls per rev. The zilla can feed tach output. So unless this vehicle has a can bus and it doesn't sound like it does since you talk of OBDII the ECU is just going to get in the way. Zilla controllers also integrate into the check engine light and Battery light. Having 2 controllers (the ICE ECU and new controller) just will be a headache in my opinion.

Oh on your clearance issue with the diff. I'd go with dimple/shave the diff cover and a warp9. The complexity of the dual motors I do not believe worth it. I know you want a quick car but unless you are building a dragster I think the single warp9 will be enough. And yes the drawing on the warp9 states 9.25" for diameter. One thing to consider is how much torque can your clutch even hold. no use hooking up a huge electric motor to a clutch that can only hold 200-300 ft lbs of torque. Besides if you dump to much torque into this car you're likely to start breaking differentials and transmissions.....What's the factory peak torque for the ICE?

Edit: went to measure my warp9 but my calipers only go to 6". Oh and if your vehicle is Can bus then everything I have said is meaning less :)
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Thanks Thaniel, Dave, Jim, Rob and all - great ideas and advice. It is great to get help on these issues from people who have been through this.

The stock 2.0L engine has 148 HP, 142 ft-lbs at 6000 rpm.

I also think it is better to keep it simple. The diff cover of concern has some thickness which can be shaved - also worst case there is some clearance behind the cover so a custom/thin metal cover could also be whipped together as Plan B. The Warp9 should fit (perhaps with some "persuasion"/grinding). It will not be a rocket, but I am sure I will not be disappointed.

Thaniel - you are bang-on that the Zilla will also need a speed input (for over-speed control) and can drive the tach - I have not considered this yet - it does not make sense to have 2 tach sensors/circuits...

I will add a pulley onto the end shaft (for the A/C) and hopefully can add the tach sensor for the Zilla onto the end too (and use the Zilla output to drive the tach)... If the ABS brakes, A/C, or airbags do not work (hopefully the ECU wires for these signals are only for diagnostics) then I can weld the 36 tooth wheel, stock CPS sensor and re-enable the ECU to work in parallel. I am still waiting for the factory wiring diagram/manual to arrive (so far relying on Haynes manual - not so good) so maybe can learn more shortly.

So, Warp9 it is. Also a Zilla 1K is the most likely contender (although hoping to avoid liquid cooling).

I will post plans for the motor, batteries, controller etc... shortly... Now that a "low" voltage for the Warp9 is enforced, this will also input into the battery decision.

All other inputs appreciated - thanks all!
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So, Warp9 it is. Also a Zilla 1K is the most likely contender (although hoping to avoid liquid cooling).

I will post plans for the motor, batteries, controller etc... shortly... Now that a "low" voltage for the Warp9 is enforced, this will also input into the battery decision.
The question of voltage brings up a question to my mind. Does the battery max voltage HAVE to match the motor max voltage? I believe the zilla (and maybe others) can limit the max current to the motor and looking at the manual maybe even the max voltage? No expert here. Just talking out loud. I'll have to do some research. If that's the case it may change some of my plans on batteries slightly.

I wasn't a big fan of liquid cooling either. However after reading about so many people having controler overheating problems water cooling may work out for the best. Currently I'm looking at using a water cooling system that people use to liquid cool home PC's. People liquid cool their home PC (for high performance) and we want to air cool our computer/controller for our EV....:confused: Just a thought.
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THE PLAN - Overview

Now that the ICE is out and I know how big of a motor will fit, this guides everything else...

So, here's "THE PLAN":
- Motor: Netgain Warp 9
- Controller: Zilla Z1K HV
- Batteries: 50 TS200AH LFP batteries
- DC/DC converter: IOTA DLS-90
- Charger: Manzanita PFC20
- Interior Heat: 2x1500W Ceramic heaters
- Power Steering: MR2 electric power steering pump
- Brakes: 12V power brake vacuum booster

More details on each of these (and some factors of each decision) is in separate thread/posts below.
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Overall Front Layout

THE PLAN - Overall Front Layout:
- PS pump in bottom middle (near to the PS rack) attached to the belly pan
- Controller and charger mounted in the very front (where the original radiator and fans are)
- Brake booster at front driver side (far away from the cab)
- A/C pump in original location (passenger front, low) and mounted to motor
- DC/DC converter (not sure yet - hopefully room in bottom passenger side close to the 12V battery)
- Batteries on top of everything else (hopefully room to access the controller and DC/DC).
- Other wiring (relays, etc..) - not sure yet, probably hanging off front
- full belly pan (plastic of some sort?) to keep water out
- air handling/routing (to get air flow across batteries in summer).
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THE PLAN - Motor

THE PLAN - Motor:
Netgain Warp 9
- this will be tight (9.25" diameter)
- no room for anything bigger (probably have to shave 1/16" from somewhere
- backup plan is for a Kostov 9 (8.66" diameter)

I will keep the clutch, so a taper-lock bush and hub will have to be machined (not my expertise - I will find a machinist to do this). The inside of the hub also has to be drilled for a end-bushing (for the transmission shaft to ride in).

The "critical distance" (flywheel face to engine-transmission joint) is 1.30".
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THE PLAN - Controller:

THE PLAN - Controller:
Zilla Z1K HV

I also would consider Soliton1, but Zilla seems to have more software/protection features and has been around longer.

I am not super keen on liquid cooling, but it seems to be recommended. I haven't thought about the pump/mini-radiator yet, but will look around to see what others are using...

Defintely want over-speed control, so will probably use a sensor on the motor shaft into the Zilla, then use the Zilla to directly feed the tach (bypassing the ECU - thanks Thaniel). A bit of experimenting required here.
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THE PLAN - Batteries and boxes:

THE PLAN - Batteries and boxes:
It turns out I have oodles of room for batteries - the vertical height under the hood is good for the 200Ah batteries (11" high) with room for insulation - I will have to fabricate a new driver side transmission mount (as the stock one sits up very high).

There is room under the hood, behind the rear axle, and even 2 more small boxes in front of the rear axle where the gas tank used to be (on either side of the rear drive shaft) - I will use only the under-hood and rear boxes.

Front box (above motor): 36"x27" - 30 cells will use up only 28"x21.6"
Back box (behind rear axle): 36"x18" - 20 cells will use up only 28"x14.4"

50*3.2=160V (nominal), 200Ah each = 32kWH (way more range then I need, means low DOD and long life).

- lots of room for ventilation/insulation
- will try and make "insulation inserts" which can be removed in summer time (for airflow for a ventilator/fan).
- will imbed Gro-quick wire into the bottom insulation (for heating when plugged into AC)
- aluminum angle with aluminum enclosures (this way I get to figure out how to weld Alum!)
- batteries are multiples of 5 (the cells come strapped this way - easier)

I will also use 4/0 orange cable (for HV) and black welding cable - these will run from front to back in metal conduit strung under the frame (and grounded to the frame). Near the controller, I also will have some sort of metal-sheath flexible cable (also grounded) to minimize EMI - Rob (RKM) has already dealt with this I believe...
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The plan - bms

Not 100% sure yet:
- Elithion distributed BMS (
- Hardy BMS ( )

I wanted a system which adds cell voltage monitoring as well - this will ultimately connect to a CAR-PC which will have all media, GPS/Navigation, engine diagnostics etc... This would avoid yet another set of spaghetti wiring. I do not think the Hardy BMS is isolated, so a wireless USB or some other sort of interface would have to be used...

The BMS should detect high voltage across any cell and signal the charger to slow down, and should detect low voltage and signal the controller to back off while driving (or turn on a light or something).

Is is true that with some controllers the BMS can dynamically reduce the maximum current? This would be a nice addition as it would basically limit your acceleration when the batteries are run down (ie not an on/off switch limp mode, but progressively more stringent limits).
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THE PLAN - Interior Heat and A/C:

THE PLAN - Interior Heat and A/C:
2x1500 W ceramic heater elements in the heater core - will connect to DC pack voltage
- each element has 2 or 3 stages of elements
- individual wires from each element will be brought through the firewall
- temperature dial on the dash will be a rotary switch to choose the required # of elements
- use DC SSR (solid state relays - Mosfet type) to switch each stage based on pack DC volts
- air flow flapper (normally attached to the temperature dial) will be wide open all the time
- stock fan switch used as-is
- stock A/C compressor driven from front pulley on the dual shaft motor
- A/C controls used as-is

SSR (solid state relays) should last longer then relays (and not be affected by bumps etc...) but can get hotter (so small heat sinks are required) - the Mosfet ones have lower heat loss - for example, see:

The SSR relays have a low on voltage (3.5V I think) - I will take the DC outputs from the fan switch (through diodes so there is 1 signal which will be high whenever the fan is on at least 1 position) - this will be the input to the rotary switch.

I also will have an AC interlock, so when the car is plugged in, a few of the heating elements can be turned on with a timer (say 1 hour before I get in the car in the morning) - this means you never have to scrape the windshield (plus I am a suck). A bit in-efficient (AC power, to DC from the charger into the pack volts, then re-converted to 12V through the DC-DC) but should be okay as it uses cheap AC power (not valuable DC power).

I am a little worried about using 50*3.2=160VDC (nominal) or 50*3.8=190VDC (max) DC voltage across a heating element which is expecting 120V rms. It is the rms voltage which should be used for heating calculations (not the peak of the sine wave), so 190V is a big increase. Anyone else used 190V max across a 120VAC ceramic heating element...
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THE PLAN - DC/DC Converter:

THE PLAN - DC/DC Converter:
90 amps sound huge, but remember this is Winnipeg (and I am a suck) - imagine it is -40 deg , 2 seat heaters are on full, the heater fan is cranked, the headlights are on, the rear window defrost is on, you are parallel parking using P/S pump and vacuum brake booster etc... These are all 12V loads, so a big converter is warranted. I have not measured the load in the stock vehicle. I also will keep the stock battery (Which is nicely situated out of the way on far passenger side, high near the firewall).
THE PLAN - Charger:

THE PLAN - Charger:
Manzanita PFC20 or PFC30
- defintely want 120 or 240V
- AC plug where the fuel filler is
- 2 cables will plug in (120 or 240V)

I also may consider Rob's (RKM) idea of a retractable cord reel with 120 or 240V fittings on the end - see

I am a bit concerned about the PFC charger and its connection to the battery negative connection - it is not isolated, so apparently if you touch a batttery connection you can get a bit of an AC shock...

The BMS should sense whenever any cell reaches its upper charging threshold, then signal the charger to slow down and charge slowly (ie balance mode).
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THE PLAN - Power Steering:

THE PLAN - Power Steering:
I found an electric power steering pump from a 2005 MR2 Spyder (this has a reservoir and controller built in). I will connect the VSS speed sensor signal to save power at high speeds.
THE PLAN - Power Brake Vacuum Booster:

THE PLAN - Power Brake Vacuum Booster:
- Quiet unit with oil-filled muffler (sold by EVSource or EVComponents)
- Brian (rctous)'s unit with pump inside the reservoir:

I also saw a post from Thaniel (see ) where he used a hydraulic vacuum booster - Vacuum pumps seem to be the noisiest things on the car, so this is a great alternative. I did not want to mess with this as I was not sure how it would integrate with my ABS brakes - looks like a good solution though...
Re: THE PLAN - Interior Heat and A/C:

Here's the interior ceramic heater wiring plan:

Note each SSR relay is about $20-25, so you could save some $$$ by grouping the elements together (say 4 stages instead of 8) - make sure to use DC SSR relays with the correct voltage and current capability... Also SSR relays generate heat, so should be used with heatsinks (Mosfet SSR relays generate less heat but cost a bit more).

Be sure to use a relay with a low turn on voltage (3V - determined by the lowest fan voltage)...

You could also generate the trigger signal (to allow heat only when the fan is on) by using diodes from all fan switch outputs, but be careful that the input trigger signal should be 12V (some fan wires may have only 3V) or else the diode voltage drop will be too high and you cannot turn on the heating elements (this is why the relay out front was used). I think using the motor wire directly is better/safer - if a fan motor fuse blew or the OEM fan controller conked out, this would also inhibit the heater operation (you do not want the ceramic heater to be cooking away without a fan on).

The fuse ratings should be bigger than the sum of all 8 SSR relay input current ratings (maybe 5 mA each?).
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So, I know that you are a small business owner, a family man and that you were up at 3:30 am posting your schematics for your heater control (very impressive). You've got it bad Garth! Forget H1N1, the EV bug has already claimed you.

Lots of updates, looks like most of the ducks are in a neat row. I'll make a few comments;

I'm pleased with Brian's vacuum kit, though I don't know how it would compare with the alternative you list. I chose Brian's for its compact size (like the pump inside the reservoir, till it fails of course), to support a fellow EVer and for its economical price. The kit offered by EVcomponents looks excellent and was the other system I considered. I like the sound (no pun) of the oil muffler. This kit was over twice the price.

The DC-DC is a monster, which is good. Mine is about 2/3rds that size, which I think will be more than adequate given the buffer of the 12V battery. I haven't added up the sum of the 12V loads, I expect you will though. The largest single load will likely be the PS pump and that will only be a very brief load. Better too large than too small.

I thought you'd have lots of room for cells! I'm wishing I'd had room for more thorough insulation and a heating system (the Miata is that tight). Some recent posts are suggesting the performance of LiFePO4 in cold weather is not as good as I had thought. If you can accomodate it insulate and heat the boxes. Good for you to opt for Al. That was my intention, then I changed my mind for economics and convenience. I don't regret the decision. I'd estimate the steel boxes are only about 30-40 pounds heavier than Al would have been. I should be able to make up for that differential personally!

Long live the Zilla. Green is beautiful. I agree that motor over speed protection is very important. Bryan (Beltronix) did a great job with his option. It also provides a tach signal. Works great, saves a motor.

The WarP 9 shaft is machined for a pilot bushing. I don't know if your tranny shaft and motor shaft will reach each other or not. You may just need a sintered bronze bushing to get the correct match for OD/ID.

Very well thought out conversion!

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