In order to validate our BMS system at the same time as building our battery, we need to make a board that will give all the same voltages as a 36S battery would. With this, we will be able to connect our AFEs, BMS carrier, and BMS current sense to it and validate the battery system.
We will build a 36S 1P battery system with spare cells in 18650 cell holders. Each of these cells will emulate a module in the actual battery pack.
This test rig should have:
- 36 cells connected in series with voltage taps on each one
- A thermistor on each cell to measure the temperature
- A mount for the current sense resistor and board
- A fuse to protect the batteries
- Switch to easily turn on/off the stack
- Contactor on + and - connections to be consistent with the car implementation
Fuse
Fuse should be rated to around 15-20A, fast blow. Should probably use the same Cooper-Bussman series as we are using for the actual car. Need to find purchase and get the fuses. Ask Joshua Rong for more details on fuses.
Contactors
- Charge Input +
- Output (Motor Controller) +
- Common GND Side -
- Secondary contactor to emulate the coil sense contactor, coil wired in parallel with main contactor
For Contactors 1,2,3 I am thinking TE EVC 80 contactors or the solar contactors. Need to check prices and find digikey/mouser links
Switch
We should be able to manually turn the battery on or off. Should be rated for at least 20A, probably more for a safety factor. Should also be satisfying to turn on - big switches are nice.
Current Sense
Should we have the option of switching in a larger current sense resistor to measure the current more accurately - then we might not have to change current set points when switching code as the reading scales according to the resistor chosen.
Connectors + Cables
- 12V Input - Molex Ultrafit, 2 pin, +/- consistent with the rest of the boards, 22AWG
- CAN - 2 ports, with BMS carrier in Daisy Chain Config - Molex Duraclik 2 pin, consistent with the rest of the boards, 22AWG
- Charge Input - 2-pin Molex MX150L, 14AWG
- Power Output - 2-pin Molex MX150L, 14AWG