2008 Mini Cooper clubman s conversion

I finally got some batteries. I bought 6 just in case I want to upgrade to an ac-51 or hyper 9.
now I need to find a bms, charger, dc/dc converter and a cooling system. I’m thinking of going with the Orion bms but only because if it’s compatibility with the Curtis controller.

I was thinking of putting 3 modules on top of the motor and 2 where the gas tank was. Not sure if that’s a bad idea. I heard that splitting the pack uneven can cause problems but I’ve seen it done before. I’ll do some more research on that. If it’s true I’ll have to find a way to stuff 5 modules up front.

Too bad my controller can’t handle all 6.
3 up front and 3 in the back would be nice.

What's the max voltage on your controller?

130v max
It’s a Curtis ac-50 system from HPEV

You could run 6 modules and set charging to a max of 3.6V per cell group (130V pack) 😬

If it was me, I'd sell the old controller and get one that handles the full SoC 6-module stack voltage.

Yes I would like to upgrade the controller but it’s really starting to add up in cost.
i think I’m going togo with the 5 modules and use the spare for my travel trailer.
would it be a bad idea to split the pack uneven?
3 in the front and 2 where the tank was.
I could fit them all in the front if I make a battery box to stand them on edge.

Yeah, but you're offsetting it with the sale of the old controller, so not horrible. More range, more speed (maybe) might be worth it, despite an extra 55lb.

I don't see the big deal in unevenly splitting the modules. Maybe someone else has a strong opinion for not doing it.

FXSmith said:

I finally got some batteries. I bought 6 just in case I want to upgrade to an ac-51 or hyper 9.
now I need to find a bms, charger, dc/dc converter and a cooling system. I’m thinking of going with the Orion bms but only because if it’s compatibility with the Curtis controller.

I was thinking of putting 3 modules on top of the motor and 2 where the gas tank was. Not sure if that’s a bad idea. I heard that splitting the pack uneven can cause problems but I’ve seen it done before. I’ll do some more research on that. If it’s true I’ll have to find a way to stuff 5 modules up front.

Too bad my controller can’t handle all 6.
3 up front and 3 in the back would be nice.

Click to expand...

If you are running any number packs in parallel with each other, they need to be matched in voltage (is using all identical modules, that means matching the number of modules). If running any number of packs in series with each other, it doesn't matter if they have different numbers of modules or cells in series, as long as they have the same number in parallel.

If I understand your plan correctly, you are using all identical modules, and placing all modules in series. In that case how many packs you split them into and how many modules are in each pack are irrelevant - put them where they fit and where you can tolerate the mass.

It could matter for the BMS...it might interpret the connecting cable drops between two boxes as a high/low top or bottom cell during highway operations and consistently screw up cell balance to where a module will fail out early relative to its sisters, since some BMS may only take one wiring tap for each cell level in the battery stack.

Cell balancing voltage measurements can't be made correctly where there's a long power cable in a cell voltage measurement loop and during power draw from the pack.

This may not be a problem if the Tesla BMS boards are used to make measurements within its own Tesla module.

I doubt many people give much thought to this.