question

roucoups avatar image
roucoups asked

bms 12/200 inversion

Hello,


BMS 12/200

Lifepo4

Standard starter battery

leds, etc.


What would happen if everything was reversed:

AB chassis: +12V starter battery

LB load minus: +12V leds etc.

Li-ion minus: +12V lifepo4


And all the minus (lifepo4, starter battery, leds, etc.) would be connected together to the vehicle chassis?


Would it work, be hazardous?


Thank you.


Lithium BatteryBMS
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1 Answer
stefancs avatar image
stefancs answered ·

It will not work. I do not have details about BMS 12/200 design of course, but what I can say s the internal wiring of an electronically switched BMS is directional. Either designed to be connected to battery plus or battery minus.

Hazardous? I would think a) it might not power up at all b) you might break the BMS c) it might connect (unlikely), but would then not protect the battery.


In case the background of your question is to avoid the isolated DC/DC inverter from the BMS 12/200 wiring diagram for vehicles, the following solution exists:

  • use a D+ operated cutoff relay or B2B booster between starter battery+ and LFP+.
  • Leave the AB port disconnected.
  • Connect the LB port to vehicle mass.

Of course wiring must be properly dimensioned and charge sources suitable for your battery.

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