[WIP] Unimog 404S EV conversion

[powercontrol]

Hello,

I am slowly starting my first EV-project, and I am looking into converting a ex-Belgian Military Unimog 404S into an EV.
My aim is to also use the truck as V2H solution, as it makes no sense to use a truck 10 times a year without using the battery to power the house the rest of the time.


I happen to have a complete 2019 Kia e-Niro 68kWh battery pack, as well as the all the electronics of another battery pack without the cells.
I have just managed to connect to the battery and record my first PCAN messages. The rest of the project is undecided yet, I first want to master the BMS for static use before moving forward.

Thanks for having this forum! I hope to one day be able to contribute to the community.

[fuzzy]

This sounds fun. I haven't seen a ev unimog yet. I've seen a few ev Pinzgauers.

Look forward to hearing about progress on this.

[powercontrol]

2 years later.. and I will finally start. the Bat-Emu unlocked my situation with the battery pack, so I can start the next phase

I stripped it down to the frame, cleaned it enough to not be greasy every time I am getting close to it, and got my Nissan Leaf EM61 engine pack 2 weeks ago.

Space for mechanical components is not an issue in the truck, but the original design is pushing the engine forward because of the frame crossmember, which explains the length of the gearbox input axle. I am looking at potentially installing the motor on the side of the gearbox, shortening and rewelding the input axle, and build a plate mating the front of the gearbox to the front of the engine (side by side). The side of the gearbox has also plenty of attach points to solidely anchor the motor with the gearbox. Keeping a ratio of 1:1 should be fine (the truck gets to 107kph at 5500rpm with the original petrol engine). The next mechanical problem is how to transfer the rotation from one axle to the other axle. I do not plan to run a clutch, the 280Nm of the EM61 in stock form will easily surpass the 158Nm at 3200 rpm of the original engine.

I have dropped the motor next to the gearbox with the cabin on the frame, just to confirm there is enough room to get it there.

I have ordered my Zombieverter VCU and processing as much info as I can find the time for these last weeks.

[Bratitude]

Cool!

I would not rear the motor beside like that, belt or chain drive is just adding more unnecessary losses.

I’d look into what gearbox it is and if you can get alternatives input shafts

[powercontrol]

Hello,
That would be the easiest indeed - and I got the same feedback elsewhere. Packaging is nice but it will complicate the conversion. I think I have been biaised by looking at the TH425 transmission when considering that option.

Well, it seems I also have a good starting point for mating the engine to the transmission. Thanks to you the measurement of the EM61 bolt pattern is available, and the Mercedes engine is factory delivered with an adapter plate which mate the engine to the transmission.Found quite some good info in the benz forum, and a link to another topic with DXF file (have not tested yet).

Next step is axles alignment and depth, as well as mean to mate the 2 axles.
I am still not confident on the overhang of the gearbox input shaft, certainly when it will spin at 10K rpm :-/

More to come...

[Jacobsmess]

Will you need to spin it at 10k? Surely the original ICE paired with the same gearbox maxed out at 4000rpm or so. You have a gearbox, so you can use this to keep the lead rpm low and speeds adequate. But regardless of that, I get you want things well aligned.

[HlektrikosVasilis]

I think Unimog's gearbox is weak and unnecessary. Through it away and install the leaf motor direct to the transfer case!

[powercontrol]

alas, the gearbox an transfer case are a single unit, at least on a 404.