QSKJ voltage down converter tap

[anontrol]

So, I've got one of those $15 cree oversized rubber band strap-on headlights, along with the QSKJ 60v->?v (turns out to be about 8.5v) down converter.

...and the only question is where to tap the 48v-54v main battery.... then I noticed that the charge connector has some voltage on it.

How badly would I screw up the battery and/or BMS if I tapped the charge port for about an amp's worth of juice for the headlight via the down converter?

 

[dnmun]

you can put the DC converter on the main battery output. use a fuse if you can. that means connect the positive of the DC converter to the red lead of the battery and the negative of the DC converter to the P- spot on the BMS. for some BMSs that is the same as the C- spot.

 

[amberwolf]

How badly would I screw up the battery and/or BMS if I tapped the charge port for about an amp's worth of juice for the headlight via the down converter?

Technically it probably wouldn't hurt the battery or BMS at all, directly.


However, if your BMS is designed so that it's LVC shuts off hte discharge port but not the charge port, then you could continue to drain the pack to the point of damage if you use the charge port to discharge from.

 

[anontrol]

How badly would I screw up the battery and/or BMS if I tapped the charge port for about an amp's worth of juice for the headlight via the down converter?

Technically it probably wouldn't hurt the battery or BMS at all, directly.


However, if your BMS is designed so that it's LVC shuts off hte discharge port but not the charge port, then you could continue to drain the pack to the point of damage if you use the charge port to discharge from.

Good to know.

I'll probably tap at the control head if at all possible (now that I have an opened BBS02 control head with no obvious broken components).