My first top balance and capacity test

Rogermija

New Member
Joined
Apr 12, 2021
Messages
18
Thank you for the response. The cables are questionable but the random current variance is troubling. I used the recommended set up...turn off ps, set 3.4 voltage/set current to 10a, connect cables, turn on ps. The battery voltage was 3.3v before starting. The voltage was very near the set point but the current bounced around. Did your current hold constant or did it vary randomly? Thank you.
 

meetyg

Solar Enthusiast
Joined
Jun 4, 2021
Messages
256
Thank you for the response. The cables are questionable but the random current variance is troubling. I used the recommended set up...turn off ps, set 3.4 voltage/set current to 10a, connect cables, turn on ps. The battery voltage was 3.3v before starting. The voltage was very near the set point but the current bounced around. Did your current hold constant or did it vary randomly? Thank you.
No, mine was constant. If it randomly fluctuates (say up and down) maybe your PSU is actually faulty.
Do you have something else, other than a battery, that you could test the load with? For example a battery capacity meter?
 

Rogermija

New Member
Joined
Apr 12, 2021
Messages
18
I have a different brand coming in a few days. You are the first responder to acknowledge current variance. Thank you.

Chuck
 

Tlovell

New Member
Joined
Mar 28, 2021
Messages
12
I just happen to be top balancing another set of 4 LF280K cells. Firstly, I turn on the power supply before connecting it to the cells. I set the voltage to 3.60v using the course and fine knobs. Then I turn the amperage knobs all the way up. Turn the power supply off and then connect it to the cells. The result is in the picture. It will put the full 10amps in until the voltage of the cells reach 3.60v. Once it gets to 3.60v, the amps will reduce to near 0.
IMG_20211220_090335.jpg
 

DJSmiley

Solar Addict
Joined
Aug 13, 2020
Messages
470
I just happen to be top balancing another set of 4 LF280K cells. Firstly, I turn on the power supply before connecting it to the cells. I set the voltage to 3.60v using the course and fine knobs. Then I turn the amperage knobs all the way up. Turn the power supply off and then connect it to the cells. The result is in the picture. It will put the full 10amps in until the voltage of the cells reach 3.60v. Once it gets to 3.60v, the amps will reduce to near 0.

thats how it should be and sounds pretty normal.

Not archieving full amps untill 99% SOC or so indicates crappy wires or crappy connections. Check/upgrade wires, crimps and terminals.
 

chrisski

Solar Boondocker
Joined
Aug 14, 2020
Messages
2,681
I have the power supply in post 24. The current will jump when it’s nearly top balanced, but only because 1/10th amp. I consider this normal especially because it’s an uncalibrated power supply.
 

Just John

Photon Sorcerer
Joined
Aug 15, 2020
Messages
2,442
I have asked this question before...but... Depending on SOC my current, for example, would fluctuate between 5.15 and 5.70 rather randomly. I was expecting a constant charging current but current trending downward. I'm suspecting a bad ps. What was your experience? Thank you.

If you are using a 10 amp supply and only getting 5 amps, replace the cables and connectors. Do not use the ones provided with the supply.
 
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