openinverter forum

Hi all,

we successfully transplanted a Leaf system into another car, taking all the periphery with us, largely leaving the system intact. That worked, but is a big faff really, you need to use the Leaf stalks at the steering wheel, their power steering, a lot of reverse engineering of undocumented parts, spare parts are expensive, etc.

Now we are looking to move away from that for those reasons and more, and OpenInverter seems an obvious and exciting choice.

What BMS do you guys combine OpenInverter with?
Does your choice support ChaDeMo?
What do you use for isolation resistance measurement?
How do you handle temperature management?
How do you handle pre-charging?

Pardon my ignorance if there is a handy sheet somewhere already explaining all this.

Suppliers I am aware of:
- Thunderstruck
- LithiumBalance
- OpenInverter BMS (very exciting the idea of going "full Huebner", is anyone using it in production yet?)
- Damien McGuire's BMS
- SimpBMS (haven't looked into it much)

My understanding is that the latest Leaf isn't yet supported by OI, is that correct? So if we want 40kWh it would have to be a Gen 2 donor?

VCU, pedals etc. can be used from the existing vehicle.

Goal of the project are range, reliability and future flexiblity, at inner city speeds, with only the odd trip at 100kmh and acceptable performance (40kw-80kw).

*Flexibility means we don't want to replace one proprietary system with another one and tie ourselves to one supplier by accident.

Why would you not use the stock BMS? It integrates well into openinverter style stuff.
https://openinverter.org/wiki/Nissan_Leaf_BMS
https://github.com/jsphuebner/stm32-car
viewtopic.php?f=13&t=370

That's great. I thought people were combining your motor controller board with a 3rd party BMS.

I didn't realise that it would also integrate well with the existing BMS/LBC.

I find the forum sections to be layed out well enough for all this to be covered.

I think the general theme of open inverter is reusing oem stuff as much as possible, but in a open fashion.

They are generally the cheaper option
And the safer one!
There’s many cases of people messing battery systems up because they installed a fancy
aftermarket bms.

The leaf bms works great “out of the box” and is well documented. with an obdii dongle + leaf spy pro you can see what’s going on.

SimpBMS is used to replace/emulate the master bms module for a variety of oem packs. Works well with lots of useful functions.

Yes, I am completely onboard with reusing the BMS, didn't realise it would work well.

Now, looking at my first questions:
ChaDeMo -> Yes, supported
Isolation Resistance measurement? -> How does this work, My understanding is that is usually handled in the PDM, which we would take off for this approach. That also opens the question of DC/DC converter to charge 12V battery.
Temperature management? -> 4 sensors come with the Leaf LBC
How do you handle pre-charging? -> My understanding is that thats done by OpenInverter if wired up correctly like described here: https://openinverter.org/wiki/Battery_Charging

So if we were to purchase "Brain Board Rev 3 with Nissan Leaf™ Gen 2 adapter - community edition/w. personal support" we don't need any other hardware? Apart from harvesting that plug from the Inverter and re-soldering it?

Yes the kit sorts the inverter but has nothing to do with the PDM or ChaDeMo.
The stock Leaf wire harness will only let you control the inverter via CAN since most pins are unpopulated. The main DC contactor is even populated on the stock harness in place of the former "enable" input.

If you want to use other traditional IO you will have to add wires to the plug. I think people have done it, I have no experience with that though.

Haven't seen automatic isolation resistance measurement in any conversion here so far. For a hobbyist, keeping it as a manual maintenance item should be fine. If one sells the vehicle, that might be something to think about.

An EVSE can detect some ground faults when charging, which is a good reason to use the standard type 1 or 2 connector on the vehicle and get a cheap EVSE adapter.

Johannes, would you recommend your daisy-chain system as the best way to implement BMS on a split Leaf pack? I guess no one would want to connect 48 wires between 2 packs that are mounted at opposite ends of the car?

Can you use the Leaf BMS with a reconfigured pack? Like, if you wanted to use half the pack or two packs?

DaveH wrote: ↑Sun Nov 01, 2020 10:25 pm Johannes, would you recommend your daisy-chain system as the best way to implement BMS on a split Leaf pack? I guess no one would want to connect 48 wires between 2 packs that are mounted at opposite ends of the car?

Sorry, totally missed that question.
Yes it would work, 12 cell boards for each half-pack and two master units. The two masters must be connected via CAN. One of them can handle an analog current sensor or an ISA CAN shunt.

Tremelune wrote: ↑Wed Nov 18, 2020 5:54 pm Can you use the Leaf BMS with a reconfigured pack? Like, if you wanted to use half the pack or two packs?

Apparently people have done that and the BMS adapts to the doubled capacity. For a half pack each cell is sensed by two inputs.

celeron55 wrote: ↑Sun Nov 01, 2020 8:41 pm Haven't seen automatic isolation resistance measurement in any conversion here so far. For a hobbyist, keeping it as a manual maintenance item should be fine. If one sells the vehicle, that might be something to think about.

An EVSE can detect some ground faults when charging, which is a good reason to use the standard type 1 or 2 connector on the vehicle and get a cheap EVSE adapter.

I have to look into it more, but I think an automatic solution would be quite neat. Will look into it early in '21 and report back if I have any good results/we came up with something simple.

celeron55 wrote: ↑Sun Nov 01, 2020 8:41 pm Haven't seen automatic isolation resistance measurement in any conversion here so far. For a hobbyist, keeping it as a manual maintenance item should be fine. If one sells the vehicle, that might be something to think about.

An EVSE can detect some ground faults when charging, which is a good reason to use the standard type 1 or 2 connector on the vehicle and get a cheap EVSE adapter.

Just stumbled on this again: Dala says he does pass the bits through in his CAN bridge. The corresponding DTC for it is described in the Leaf workshop manual EVB-33, EVB-156, not sure how exactly that maps to the CAN messages.

We have measured IR a few times now, maybe I should take a log next time and see what the BMS reports when you put the resistor between HV bus (one side only!!) and chassis, you can see the BMS reacting on the scope.