(30-08-2012, 05:19 PM)gbanger Wrote: If you stuff that up you will short out your battery or blow up your charger.... not good!!
If your charger came with a cell balance pin adapter then you just plug it into the right hole and you can't stuff that up.
Ahem, I (or at least HobbyKing) found a way. Just in case anyone else gets caught by this...
Even though you can only fully insert the plug in one way, the pins on at least one of the charging boards HK sells are slightly too proud - if you attempt to connect the balance plug in the wrong way, contact can be made with the balancer plug pins before you're prevented from inserting the plug in all the way. And, if you've already plugged in the main power plug, things get sparky.
Blew out the trace on the underside of one of my boards that way, one time I was absent-mindedly plugging-in by feel instead of looking. Easy fix, but now I
always check visually before plugging the balancer in.
(30-08-2012, 06:33 PM)BenR Wrote: If I select balance charge, am I doing that at 1C as well (eg 2.2A for a 2200 mAh battery)? Or is it something that is done at very low amps to let some cells charge and others that are high stay the same/discharge?
The bulk of the balance charge would still be done at 1C (2.2A in your example).
What happens towards the end of charge varies from charger to charger, but more or less what you'd expect to see is that as the first cell hits 4.20V, the charger will begin to ramp the current down to whatever is needed to maintain that cell at 4.20V. (i.e. initially 2.1A, 2.0A, and so on, falling away to zero).
At some point, zero amps are required to keep that cell at 4.20V (i.e. that cell is fully charged), but the other cells are slightly lower (e.g. 4.17V). At this point, the charger will switch from supplying current via the main power plug, and will instead supply the final balancing current to each of the not-quite full cells at a reduced rate through the balance plug, until each is registering 4.20V at zero amps (i.e. until all cells are fully charged).
There are variations on this (for example, I believe the most common chargers only ever supply charging power through the main power plug, and instead use the balancing plugs to resistively bleed power off the higher-voltage cells), but that's the basic idea.