Upper Ampage limit for battery charging

Hi,

I have a 14s12p 18650 cell battery (42ah). I am currently using a charger set at 6A. The charger has a potentiometer to allow for ampage adjustment. What could it be set to without causing any problems regarding battery life?

Thanks in advance.

It actually depends on specs for the particular 18650 cells in the battery pack. That said, most cells can handle a 1A charge with no problem, so you are probably OK sending as much as 12A (or more) to that pack (1A per paralleled cell). With a 6A charge (0.5A per paralleled cell), I doubt you could do any harm.

The charger itself is only going to be able to handle so much power though, most likely limited by it's ability to shed heat. You might want to keep an eye on the temperature, and upgrade the fan if necessary.

Of course the fan driver circuit will also likely be limited in how much power it can supply, so you might end up having to use a 110/220V AC fan connected directly the mains input. That will work fine but you could end up with a rather noisy charger.

As for that battery, it's pretty large, I'm fairly confident the charger will melt before it harms the battery.

As a general rule of thumb, less than 0.5C on a battery pack is probably safe.

C is capacity, meaning Ah. So if you have a 2Ah cell, it would be a 1A charging rate max. A 4Ah cell would be a 2A charging rate max. A 42Ah pack would be a 21A charging rate max.

Some cells aren't as good, so you have to check the specs of the cells you're actually using.