Help!!! Smoke during top balancing

[moonlitsouls]

I am back in parallel now at 3.65 volts constant voltage charge on two power sources crosswired pulling 4.2 amps, I’d be surprised if cell one and two aren’t ruined. I’m leaving this shit like this until they teach 3.65

Currently reading 3.38-3.39 on each cell. They have hardly charged at all

 

[moonlitsouls]

In parallel now current from the power source is dropping and cells have increased from 3.38 to 3.42 rather quickly , I think this is a good sign.

 

[DerpsyDoodler]

In parallel now current from the power source is dropping and cells have increased from 3.38 to 3.42 rather quickly , I think this is a good sign.

have you lightly sanded the terminals then wiped them down with isopropyl alcohol?

 

[moonlitsouls]

Oh shit they’re all up to 3.50!!!!!

 

[Just John]

Was able to get it charging in series, cell 2 got up to 3.6 so I switched back to parallel, then retested cell 2 and only getting 3.38 volts.

Why would cell 2 show 3.6 in series and then reduce in parallel ?


What’s interesting is that in series - cell 2 climbed drastically from 3.5 to 3.6 quick. Something is not right with these batteries or I must have damaged them.

When in parallel with good connections they should all read the same voltage.

 

[Just John]

Then to make matters worse, when I had them in series I was about to disassemble to go back to parallel, I accident touched a busbar on the main battery negative to the positive of cell 2 , big sparks ruined two of the screws that screw into terminal, I’m fucked ,I just wasted $500

If it just ruined the screws you can get more. Probably didnt hurt the cells if it was just a split second.

 

[Just John]

In parallel now current from the power source is dropping and cells have increased from 3.38 to 3.42 rather quickly , I think this is a good sign.

Yes, once you hit 3.4 you are over 90%. Closer to 95%.

 

[moonlitsouls]

If it just ruined the screws you can get more. Probably didnt hurt the cells if it was just a split second.

Ok great. John I think I’m on the home stretch, current reducing down to 1.2

 

[Just John]

Ok great. John I think I’m on the home stretch, current reducing down to 1.2

Yes, the climb to 3.4 is very slow, then it just takes off. When you get under an amp, just let them sit with no power until tomorrow, should settle to 3.5 or above. About 60 seconds after you put a load on them, they drop to 3.4.

 

[Bud Martin]

Once the Voltage starting to climb you should keep close eye on it and hope that nothing will not go wrong with the power supplies, I.E lost its Voltage regulation.

 

[moonlitsouls]

Yes, the climb to 3.4 is very slow, then it just takes off. When you get under an amp, just let them sit with no power until tomorrow, should settle to 3.5 or above. About 60 seconds after you put a load on them, they drop to 3.4.

Why don’t they stay at 3.6?

I charged them up to 3.61 , each cell is exactly the same. I believe they’re perfectly balanced. When I check them over the next few days, what can I expect? They won’t stay at 3.61?

 

[Just John]

Why don’t they stay at 3.6?

I charged them up to 3.61 , each cell is exactly the same. I believe they’re perfectly balanced. When I check them over the next few days, what can I expect? They won’t stay at 3.61?

Really between 3.4 and 3.6 you are at the top of the curve, only 1% of the battery capacity is there. Cells will self discharge over time, and you also don't want to keep them there for too long. The objective of top balancing is to get them all to the top at the same state of charge. That way when you put them in a pack and discharge them, when you charge them back up the cells all get full at the same time.

 

[John Frum]

Why don’t they stay at 3.6?

I charged them up to 3.61 , each cell is exactly the same. I believe they’re perfectly balanced. When I check them over the next few days, what can I expect?

Cells naturally "settle".

They won’t stay at 3.61?

They will almost certainly settle lower than that.
Settling is kind of like the foam on a pint.

 

[moonlitsouls]

Really between 3.4 and 3.6 you are at the top of the curve, only 1% of the battery capacity is there. Cells will self discharge over time, and you also don't want to keep them there for too long. The objective of top balancing is to get them all to the top at the same state of charge. That way when you put them in a pack and discharge them, when you charge them back up the cells all get full at the same time.

Morning, yes they did drop from 3.61 to 3.53 overnight. Thanks again for all the help.

 

[Just John]

Settling is kind of like the foam on a pint.

Nice analogy.

 

[DerpsyDoodler]

Cells naturally "settle".

They will almost certainly settle lower than that.
Settling is kind of like the foam on a pint.

? to settling!