# *Another* Mazda MX5/Miata conversion



## mjb (Mar 17, 2013)

Hi all,

Long time peruser, first time poster.

As the title suggests, I'm converting an MX5/Miata. My dad had a couple of conversions under his belt (a Mitsubishi Triton and a Daihatsu Charade), so I thought I'd carry on the tradition.

I'm documenting the process on my blog - http://electricmx5.wordpress.com/

I'm planning on using 62 CALB CA100 cells (198.4V) to power a WARP 9 through a Soliton 1. I'm retaining the gearbox (with clutch) to get the most torque out of the motor. I'm hoping for 0-100km/h in just shy of 6 seconds, and a range of around 100-110km (@80%DOD).










So far, the ICE/exhaust etc. has been removed, and plans for the motor mount and battery boxes have been completed. The next few weeks will consist of removing ECU wiring, installing coilovers and bushings, and replacing the front and rear bearings. 

I'm hoping to get started on the EV components in mid-December, with a view to having it on the road in January/February.


----------



## dougingraham (Jul 26, 2011)

mjb said:


> Hi all,
> 
> Long time peruser, first time poster.


Welcome. I will be watching your build with interest.


----------



## pumpdatbass420 (Dec 3, 2013)

You have my interest as well. I too have long perused this site just reading from the shadows. Practicing my ninja stuff lol


----------



## dtbaker (Jan 5, 2008)

mjb said:


> I'm planning on using 62 CALB CA100 cells (198.4V) to power a WARP 9 through a Soliton 1. I'm retaining the gearbox (with clutch) to get the most torque out of the motor. I'm hoping for 0-100km/h in just shy of 6 seconds, and a range of around 100-110km (@80%DOD).



wow.... I'm dying to see how you squeeze 62 cells into a Miata! I can see a little more room available than used by my 48 cells, but not much unless you plan to put a double layer in the trunk and have NO cargo space?

also curious about your plan for tranny.... how heavy a clutch are you planning? I have a stage 1, and it seems to hold, but I think I may be near the edge of what it and the rear diff can handle.

and..... and 200v, what are you planning to use for a charger? will you be limiting voltage to the motor, or just let it cook occasionally when you really hammer it? How about dc-dc and other HV components; anything else special you are planning to handle 160+v rating?


----------



## mjb (Mar 17, 2013)

dtbaker said:


> wow.... I'm dying to see how you squeeze 62 cells into a Miata! I can see a little more room available than used by my 48 cells, but not much unless you plan to put a double layer in the trunk and have NO cargo space?


It's tight, but I'm putting 27 (box measuring 442x612x245mm) in the engine bay, 27 in the fuel tank cavity (with very little room to spare!), and another 8 recessed into the boot floor. This arrangement should let me keep a good weight distribution (50/50 would be great, but we'll see). 

I've just finished hacking apart the boot and parcel shelf, and I'm hoping that the battery boxes will be finished next week. 



dtbaker said:


> also curious about your plan for tranny.... how heavy a clutch are you planning? I have a stage 1, and it seems to hold, but I think I may be near the edge of what it and the rear diff can handle.


I'll be using an Xtreme HD clutch - which I believe is a stage 1. I've never been too sure what sort of power the stock drivetrain would be happy to cope with, but at least there's a huge range of aftermarket parts available if anything does fail!

What sort of power/performance figures have you got from your setup? I imagine ours would be very similar. 



dtbaker said:


> and..... and 200v, what are you planning to use for a charger? will you be limiting voltage to the motor, or just let it cook occasionally when you really hammer it? How about dc-dc and other HV components; anything else special you are planning to handle 160+v rating?


I've got a Zivan NG3 set to 219V for charging. I would've liked to get a dual 1 phase and 3 phase charger (Dad spec'd a three phase outlet for our house for his Triton), but I couldn't stomach the extra cost.

I'll be limiting the voltage to the Warp9 to 192V, and the power to 150kW. If it's not quite quick enough I may up it a tad, and just show some restraint - I'm also fairly keen to set up an 'eco' mode through one of the Soliton's inputs to limit the power for test drives and the like, so that may just be left on for the daily drive.

DC/DC will be an IOTA DLS-55HV (which is happy up to 360VDC) - providing 13.4V @ 55A output. I'm planning on installing an aftermarket stereo/amp - though it's only 150watt/25A, so it should do fine.

As for HV wiring, I'll be running 52mm2 cable to the controller, and 70mm2 to the motor. I won't be using any contactors between the three battery packs (instead, I'm relying on the Soliton's internal contactor). I've also only got plans to use one fuse, between the battery pack on the controller, but I may add another between the front and rear packs for extra safety (I also have to have another look of the Gov regulations to check out requirements in this regard). There will also be a big red button to physically disconnect the pack from the controller.

I'm using one of the earlier ZEVA BMS systems, which uses a series of modules connected to a control unit with outputs for drive enable and charge enable relays (as well as a warning buzzer for HV/LV). I went for this system because of its simplicity, and it seems like it will work quite well as a stand-alone system (meaning that I can use it in addition to the inputs/outputs on the Soliton in lieu of an EVMS).

I've also brought a TBS E-Xpert pro to monitor pack voltage/discharge currents. It's a reasonably expensive bit of kit, but I'll able to monitor average discharge rates and make sure that the pack stays in good health (I'm worried I'm going to be too-much of a lead-foot once I don't have fuel bills to worry about!).

As for progress....
The subframes and control arms have all been repainted (surface rust treated where needed), and the bushings changed (except for the Diff, where the bushings are housed in a metal sleeve that's pressed in with 2t of pressure - so I've made that someone else's problem), and the BC coilovers have been installed. I've also hacked at the ECU wiring, with a little bit of tidying still to go.

There was a mad rush on Christmas Eve to get the car back together and out from under my Patio, so except for a couple of bits and pieces, it's ready for all of the electric gear!

I'm hoping to get another blog entry, or two, completed shortly. The past few weeks have just been a matter of doing a million little things, and I'm hoping things will move quickly from now-on (it will have to to meet my self-imposed deadline of having it 'on the road' this month!).


----------



## dtbaker (Jan 5, 2008)

mjb said:


> It's tight, but I'm putting 27 (box measuring 442x612x245mm) in the engine bay, 27 in the fuel tank cavity (with very little room to spare!), and another 8 recessed into the boot floor. This arrangement should let me keep a good weight distribution (50/50 would be great, but we'll see).


i have 24 under hood, 12 at fuel cell, 12 in spare tire well.... and balance is only slightly front heavy. I think you are going to need to move more cells further back.



mjb said:


> I'll be using an Xtreme HD clutch - which I believe is a stage 1. I've never been too sure what sort of power the stock drivetrain would be happy to cope with,


if you limit output to around 150kW you may be fine. mine seems to be holding together at that level with the occasional full out accellerations, but not race use....



mjb said:


> What sort of power/performance figures have you got from your setup? I imagine ours would be very similar.


torque off the line is incredible. have to be careful with throttle starting in 2nd. starting in third is at the traction limit on most surfaces. you start running out of torque at the higher rpm though, so while the 0-40 times are great, the shifting and rpm tail off the acceleration and the 0-60 time is a little slower than it feels like it should be at about 9 seconds. but, maybe thats because I am not speedshifting and being cruel to the clutch on the shifts. I have found peak torque band is pretty much 2500-3500rpm, but that's just how it feels, not on a dyno.



mjb said:


> I'm also fairly keen to set up an 'eco' mode through one of the Soliton's inputs to limit the power for test drives and the like, so that may just be left on for the daily drive.


it is very hard to resist punching it..... I have 'valet mode' on zilla with a button I can hit from driver's seat, but never use it.  I figure the few seconds it takes to get the car up to speed at 1000 amps really isn't too hard on the batteries.... I hope.



mjb said:


> There will also be a big red button to physically disconnect the pack from the controller.


you will not find a button capable of interupting 192v at 1000amps. best bet is a big airpax circuit breaker with a manual choke cable on the switch pull just in case.


----------



## tylerwatts (Feb 9, 2012)

mjb when might your blog be updated? Keen to see pics of your battery boxes. I'll be impressed by your cramming in that many cells.


----------



## dtbaker (Jan 5, 2008)

mjb said:


> It's tight, but I'm putting 27 (box measuring 442x612x245mm) in the engine bay, 27 in the fuel tank cavity (with very little room to spare!), and another 8 recessed into the boot floor. This arrangement should let me keep a good weight distribution (50/50 would be great, but we'll see).


i have 24 under hood, 12 at fuel cell, 12 in spare tire well.... and balance is only slightly front heavy. I think you are going to need to move more cells further back. I did just notice you are using 100ah cells; I am using 130ah cells, which explains my space limitation, and PROBABLY will give your car a performance edge over mine just because of a little less weight, and higher voltage.



mjb said:


> I'll be using an Xtreme HD clutch - which I believe is a stage 1. I've never been too sure what sort of power the stock drivetrain would be happy to cope with,


if you limit output to around 150kW you may be fine. mine seems to be holding together at that level with the occasional full out accellerations, but not race use....



mjb said:


> What sort of power/performance figures have you got from your setup? I imagine ours would be very similar.


torque off the line is incredible. have the be careful with throttle starting in 2nd. starting in third is at the traction limit on most surfaces. you start running out of torque at the higher rpm though, so while the 0-40 times are great, the shifting and rpm tail off the acceleration and the 0-60 time is a little slower than it feels like it should be at about 9 seconds. but, maybe thats because I am not speedshifting and being cruel to the clutch on the shifts.



mjb said:


> I'm also fairly keen to set up an 'eco' mode through one of the Soliton's inputs to limit the power for test drives and the like, so that may just be left on for the daily drive.


it is very hard to resist punching it..... I have 'valet mode' with a button, but never use it. 



mjb said:


> There will also be a big red button to physically disconnect the pack from the controller.


you will not find a button capable of interupting 192v at 1000amps. best bet is a big airpax circuit breaker with a manual choke cable on the switch pull just in case.


----------



## mjb (Mar 17, 2013)

I've (finally!) posted an update to my blog!

http://electricmx5.wordpress.com/2014/05/26/03-motor-install/










This installment covers the motor mount, adaptor plate, and install.

As I write this, the car is not too far from its first drive. I'm just finalising the 12v wiring. 

I've been slow to update the blog because progress has been a bit non-linear. I've been jumping from one thing to another while I wait for parts, or think up a solution for whatever issue has popped up. 

I'm planning to update the blog more frequently now, seeing as the odds and ends associated with some of the bigger tasks have now been sorted.

The next installment will cover the installation of the battery boxes, and should hopefully be up in the next week or two!


----------

