Advice on top balancing

[james1]

I just finished balancing the first of 16 lf280k. I followed the above from the forum PDF.

I periodically checked the voltage as it charged at 3.6 volts(the charger doesn't have 2 decimal places). When it reached .15 amps the cell voltage was 3.68. I know I should have stopped when they reached 3.65. But ten minutes earlier they were at 3.58 volts.

My question is how to proceed. Perhaps this charger should only be set to 3.5 volts? And monitor the cell voltage more closely to catch it before it hits 3.65 (perhaps it won't say this setting).

 

[james1]

I just finished balancing the first of 16 lf280k. I followed the above from the forum PDF.

I periodically checked the voltage as it charged at 3.6 volts(the charger doesn't have 2 decimal places). When it reached .15 amps the cell voltage was 3.68. I know I should have stopped when they reached 3.65. But ten minutes earlier they were at 3.58 volts.

My question is how to proceed. Perhaps this charger should only be set to 3.5 volts? And monitor the cell voltage more closely to catch it before it hits 3.65 (perhaps it won't say this setting).

I meant perhaps it won't reach 3.65 volts at the charger setting of 3.5 volts

 

[james1]

I meant perhaps it won't reach 3.65 volts at the charger setting of 3.5 volts

Now the second cell just reached .21 amps and cell voltage is 3.61 volts

 

[james1]

Now the second cell just reached .21 amps and cell voltage is 3.61 volts

Forgot to say that I am charging one cell at a time with 2 separate chargers

 

[timselectric]

It's not really balancing if they're done separately.
The goal is to balance them with each other.

 

[james1]

It's not really balancing if they're done separately.
The goal is to balance them with each other.

Understood. But this was mentioned in the PDF from the forum

 

[time2roll]

Yes by all means charge them up individually to 3.50 - 3.60 volts. Then the parallel charge together to 3.65 should be fairly quick.

 

[james1]

Yes by all means charge them up individually to 3.50 - 3.60 volts. Then the parallel charge together to 3.65 should be fairly quick.

Sounds good. But i am putting together 16 but only have enough busbars for 8 at a time. Use the busbars on 8 and custom matching leads on the other 8? 8awg?

 

[timselectric]

Understood. But this was mentioned in the PDF from the forum

Not sure what PDF you are referring to.
But what @time2roll said makes more sense.
But it will take the same amount of time either way.
And 17 times the hassle, in my opinion.

 

[time2roll]

Bare copper #14 wire is fine for the finish at very low amps. Connect the charger at each end of the stack for better balance.
Easy to verify any voltage differential between the cells with a separate voltmeter to keep you occupied during the final run.
I would just run the wire under the screw.

 

[james1]

Not sure what PDF you are referring to.
But what @time2roll said makes more sense.
But it will take the same amount of time either way.
And 17 times the hassle, in my opinion.

Yes makes sense. The PDF is from a downloadable link that someone posted. I can't find it at the moment

 

[james1]

Bare copper #14 wire is fine for the finish at very low amps. Connect the charger at each end of the stack for better balance.
Easy to verify any voltage differential between the cells with a separate voltmeter to keep you occupied during the final run.
I would just run the wire under the screw.

Sounds good. Thanks

 

[Ampster]

Perhaps this charger should only be set to 3.5 volts?

Yes, that is what I would do. Then charge them together to 3.60-65 as @time2roll suggested.

 

[james1]

Yes, that is what I would do. Then charge them together to 3.60-65 as @time2roll suggested.

Thanks