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7s Lithium Poly. Can't get bms to allow charging. Using the Xiaoxiang-bms software from Overkillsolar

marrib1

New Member
Joined
Aug 27, 2021
Messages
3
Hi,


I cannot seem to get the charging part of this bms to work.
If you have any insight, I would appreciate it. On the software, I used the Polymer Normal defaults.
Ver 3.1.1026. Android phone

1-7 cells. Lithium Poly.
4.2v, 3920mAh 7x 4.2 = 29.4

I have a pwr supply at 29.5 v, .5A.
Neg of pwr supply attached to C-
Pos of pwr supply attached to lead where the red of bms is attached. (Last battery positive)
B- attached to Black lead, lead neg.
Multimeter. Vdc. B- / Lead Neg Zero. No potential
Lead Neg / lead Pos 29.1 (battery potential)
C- / B- = .4 volts. Makes sense, since the battery is 29.1 and the pwr supply is 29.5

I know I have a setting not set correctly to allow charging.
I have connected a power sink and pulled the whole set of batteries to 19.2 v already. (Turned on the discharge part)
I recharged them one at a time via the pwr supply. This is what its at now.
I would appreciate any settings change thoughts.



7sLiPo.jpgBMSpic.jpeg
 
Apparently, there is a 5v differential. All I had to do was drop the pack to a delta of 5v from my input.

FYI. I'm buying another of these. They work very well if (I) know what they are supposed to do.
 
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