Getting power from battery pack question

tmho

1 kW
Joined
Jan 9, 2011
Messages
343
Location
Richmond, BC, Canada
My battery pack is with BMS. When getting power to the motor, it should be through the BMS and that is the use of BMS. I want to know if there are some situations that we need to get power directly from the battery pack instead of through the BMS.
 
tmho said:
I want to know if there are some situations that we need to get power directly from the battery pack instead of through the BMS.

Sure. Any time you want to risk damage to the cells by overdischarging them by not monitoring them during use. ;)

Assuming the BMS is sized for the pack and the pack is sized for your usage, and the BMS is functional, then there is zero reason to bypass the BMS.
 
If you have a controller that draws more amperage than the bms is rated to output and it trips the bms off then you may want to bypass the bms output and use a direct connection to the battery. This assumes the actual battery pack is capable of the max amperage of the controller without exceeding its specs.
 
Thanks for your comments.
But sorry may be I did not make myself clear. Actually, I mean other than the controller/motor, will there be some other equipment (such as headlight, CA, pre-charge circuit etc) should be connected to the battery directly instead of through the BMS.
 
It doesn't matter--the exact same things already said apply to EVERYTHING you hook to the battery, for any reason, at any time, under any conditions.
 
If you tapped 12v for example, from part of the pack by bypassing the bms, you will drive the pack horribly out of balance. This can overwork and fry your bms. So your lights need to run on pack voltage through the bms, or on a voltage converter that runs through the bms.

CA, pre charge, etc run through the bms.

Always through the bms, until you have an emergency where the bms died. Then, very carefully, you could run without. But only as a last ditch thing.

You could tap you pack for very very small draw stuff, like charge your phone. but not much more.
 
Back
Top