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My Power Controller

6882 Views 23 Replies 5 Participants Last post by  kennybobby
Finished Soldering 6 Power Controller boards last night. :)

In my Solectria E10, I am planning on having 4 parallel groups of 20 Leaf modules in series (150V @ 65Ah per group), and thus I need a way to pre-charge, connect, and disconnect them to/from the main vehicle power bus.

That is the main function of my Power Controller board:
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The main problem with paralleling large battery packs together, is when one cell fails shorted. You now have lots of available power from the other good packs, attempting to charge the (now lower voltage) pack with the short in it.

This can cause thermal runaway (fire). :eek:

So the power controller monitors the stack and pack voltage (individual cell voltages, via the BMS), and current into and out of the pack.

If it detects an anomaly* it will disconnect that pack from the main bus.

Pack over/under volt
Pack over/under temperature
Pack over/under charge (Amp Hours)
Cell over/under volt
Current over/imbalance (compared to other power controllers)

It can also send a CAN message and/or +12V signal to force a controller into limp home mode, and/or stop a battery charger.

Designed to bolt directly* on to the Nissan Leaf Contactor.
Standalone, or CAN controlled mode.
Solid state pre-charger.
Pre-charge resistor temperature sensor.
Two contactor drivers, with economizers.
Limp home / end charge signal.
Isolated voltage sense of the A and B side.
External current sensor.
Low power sleep mode.
4-bit unit ID (for CAN address / Standalone mode).
5V I2C with interrupt line for future expansion. ;)

Power cables are bolted and torqued to the contactor first, then the power controller board is bolted on top.

Next, I need to build up the Current Sensor boards, and write some firmware, and test.

Then they go in the truck. :D

Here is a video:
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I am running 6 Volt Modules in Parallel (each module being 24S, or 4kWh), directly connected.

And it's a very basic, direct system - a 700 amp logisystem controller and not much else. Nothing fancy, my only readouts are pack voltage (analog) and pack amps.

Your controller would be a nice safety device.

I am also without any BMS.... I would need 6x 24s BMS to monitor/protect the whole pack. Wouldn't it be nice if your safety device was also a 24s BMS!!! I'd be saving for 6 of them...
It is still a work on progress...

In the meantime get 6 TPL-BH fuses (170VDC 200A).
Connect one to each of your positive battery terminals.
Then connect the other side of the fuses together, this will be your main power distribution bus.
Thank you Wolf... I will look into those.

I believe that the stock Volt BMS will work for your system, since it monitors each block individually.
OK that's really interesting. I guess I can try to find that online.... BUT do you know if it was originally integrated into the Volt Battery Pack itself??? or was it part of the car? Because I have one complete pack. When I took it apart, I just put the extra parts (head, cables etc.) in a box. And I'm really not sure how I would get that going... but I would really like to if I can.

There is a 5pk on ebay for $27.50 :)
Search for "TPL-BH"
This is the BMS that sits on top of the battery module:
Cool.. I actually found those same fuses and asked the guy if he could make me a six pack for $30.

So that thing is actually a BMS? I have quite a few of those! You think I can just "plug one in" to the top of one of my modules and it balance the cells?
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