openinverter forum

Hello

I'm thinking about converting one of my two Midas Gold Mk3 kit cars to EV. Its been stored up for a while so seen better days. Currently runs on Austin A series engined metro running gear front and rear with the hydrogas spheres removed and replaced with coil spring suspension and rear subframe cut down to make a beam axle.

The car is a hatchback with quite a bit of space in the back to put in batteries (plus longtitudinal underslung tank inside the rear subframe area).

I noted a few recent mini conversions using the mitsubishi outlander phev rear drive train and rear inverter so Im going to attempt to go down that route and accumulated/ordered a few outlander parts.

rear differential unit
rear inverter
inverter converter/charger
pair of refurbed driveshafts to tube mock up for
type 1 charger port (for now)
zombieverter fully built to save errors. I'm fine with having built ECUs such as megasquirt in the past but my eyesight is getting poor so going the lazy route on that.
VAG throttle pedal off a SEAT

Someone has suggested the BMW sp41 battery so looking at that as an option over the mitsubishi battery pack.

Looking to keep it as front wheel drive. Interestingly the existing A series power output is around 94 bhp/70kw so a good balanced like for like power output from the mitsubishi outlander I think,

I have a spare metro subframe so will have a look at the initial diff unit mounting as a sandbox and work from there. Things will get a bit more difficult after that as the engine bay isnt massive, probably similar to a classic mini.

Will be a slow burner but will try and pop some stuff on here.

Mitsubishi Outlander PHEV rear drivetrain came today so I offered it up to a spare NOS metro A series engined subframe I had in stock to see if it fits. I think thats a yes, looking at these images. Even the driveshaft angle is the same (or maybe even better actually as the offset is less than the OEM ICE motor):











And a comparison to swindons ev mini kit

Pondering with the battery pack probably an IBM sp41 set - which I havent bought yet. Looking to get some at the right price when the opportunity arises. It might be some time before I get round to drop the batteries in though. What are the strategies people have to keep them in a safe state to get the max life, best condition, out of them while they are standing idle while the project proceeds.

Keep the pack closed as long as possible and store the battery modules in a warm location to prevent condensation issues.

Thanks Tom.

Still gathering bits and pieces. What I am not sure about is BMS. Anyone know what the favoured BMS solution is to match up with Zombieverter and outlander inverter and drivetrain, give the official simpBMS is unobtanium due to teensy v3.x becoming a thing of the past.

BMS depends on battery used. So choose a battery and then you can review options.

im thinking bmw sp41 for battery pack

A SimpBMS spin-off is fine then, some others have ported the code to run on ESP32 hardware.

tom91 wrote: ↑Sat Oct 11, 2025 9:53 pm A SimpBMS spin-off is fine then, some others have ported the code to run on ESP32 hardware.

Tom, I think I’m right in saying Simp was yours? So do you have any good or bad recommendations for variations on your original? Or do you know of a good thread where they were discussed or compared? Thanks.

ianlighting wrote: ↑Sun Oct 12, 2025 10:40 am Simp was yours?

Yes SimpBMS is my work. I have no direct experience with any spin offs so cannot comment on that.

tom91 wrote: ↑Sun Oct 12, 2025 10:42 am Yes SimpBMS is my work. I have no direct experience with any spin offs so cannot comment on that.

Do you know if its possible to use the bmw bms, has anyone hacked it yet?

manifold wrote: ↑Sat Oct 11, 2025 9:39 pm im thinking bmw sp41 for battery pack

I looked at this as a relatively cheap and easy option as it pairs up nicely with the zombie and was used in petes opto mini successfully. I don’t doubt there will be better options but as a proven concept i’m happy for now. Gregski runs them in that big old truck of his so they should drag a little mini or midas around for a mile or two

PEDR0 wrote: ↑Mon Oct 13, 2025 5:39 pm Do you know if its possible to use the bmw bms, has anyone hacked it yet?

No-one has hacked it and shared the info publicly. A SimpBMS derived monitoring solution plus ZombieVerter would be the recommended approach.

managed to source a newer type BMW SP51 battery. seems these are coming in around 22kW/h 8878976 2022-2025. hoping to get a decent bit of range with it.

No idea what kind of BMS is in the SP51. Please take plenty of pictures for us.

Absolutely will do Tom. Looks slightly different. Seems to have a steel top lid.

Heres a starter for ten of outside appearance before I get at it. Came from an g21 330e estate touring I think.

I think looking at the spec the safety box is same as earlier ones when I checked out the spec on some bmw parts suppliers. Wont know till I dig into it.

https://www.sytnerstevenagebmwparts.co. ... 44217.html

heres one on youtube stripped down:

https://www.youtube.com/watch?v=4m67B1P0Glg&t=237s

battery terminal connectors look a lot different in that video.

While I had some spare moments today I built up the spare subframe I had around putting all the upper and lower arms in, along with steering hubs and outer cv joints and metro drive shafts offered up to the outer cvs to get a feel for how its going to fit and align.

Bought a second set of outlander inner cvs and dry fitted in the outlander gearbox without the clips on, Then mock lined up the whole assembly up with some white marker (tippex in my case). Obviously I need to cut and sleeve the metro drive shafts on the outside to the outlander ones on the inside same as others have done with the minis. (already bought some cheapo 3.25mm walled tube x 25.4mm OD as a mock up. Will need cut and drop the diameters of both slightly on the lathe. Interesting the inner cvs on the outlander look a lot more feeble than the metro ones.

Need to chock everything up with some wooden blocks to get a feel for full top and bottom suspension travel but looking good, when sighted on sideways, compared to my other ICE engined Midas. (I have 2, the other is convertible but sadly has no room to convert to EV like the Coupe can).

Once happy with alignment I can start to make some mounting plates off existing bolt holes around the subframe. I am thinking 6-8mm plate with some gussetting probably on my plasma cutter after making cardboard templates.

Picked up my BMW SP51 battery today (from a march sometime onwards 2025 33e touring).

Lifted the lid to take a look inside and it looks like a different setup to the earlier ones. Note the different type of connectors now. Similar to some other BMW ev models. eg iX

Looks like its still a 5 battery setup with 2 packs on one side with the sme underneath and 3 packs on the other side, with one pack laid on its side. Not sure where the contactors and precharge circuits (what was in an s-box) are at the moment as not unpicked all the wiring. Have a suspicion the contactors/precharge/sme are all contained in a single tin box underneath the 2 batteries. Thats where the HV power outlet is.

I would need to see all of these modules To determine what sort of interface they are using. Likely the the large one on the other side of the saddle bags means they moved away from CAN based comms.
It be interesting to get some more info on the wiring and such to figure out how best to approach a BMS for this pack.

Yes its looking like quite a step change from the previous iterations. The battery ally housings look different too. One of the batteries (the one on its side) has terminals at the ends, whilst the others have terminals on the same side. In the YT vid above there are 3 csc modules referred to. 1 has 6 plugs, 2 has 2 plugs and 3 has 6 plugs.

a link here refers to the SME module. Quite a few of these components in this box appear to be from this company:
https://www.vitesco-technologies.com/en ... stem-(bms)

CSC module:
https://www.vitesco-technologies.com/en ... cuit-(csc)

Sure but that does not give me much to tell you if a solution exists, or can be adapted or that it needs full reverse engineering.

Looking at the connectors used on the HV cell taps you might be into the impossible to find connectors too.

Same goes for the HV cable connectors, this was the the same in the past but likely not changed. There connectors are not available to the general public and likely are ultra sonically welded.