By Karl Oehling
Zbattery.com
June 18, 2004 Many battery packs are made up of individual battery cells. When batteries are purchased to be made into a pack it is a good idea to equalize the charge on the batteries before building the pack.
Equalizing the batteries is nothing more than ensuring the voltage on each cell is within a very close range at the same state of charge (i.e. fully charged).
If you do not equalize the batteries properly before building a pack, the charge and discharge cycles will be harder on some of the cells and will effectively shorten their life. Once a cell fails the entire pack will be weaker because of the one defunct cell.
There are a couple of ways to equalize a set of batteries:
The first way is to connect the set that will go in the pack in a parallel configuration. Leave them in this state for at least 24 hours. The cells that have a higher charge will charge the ones with a lower charge and they will all equalize.
The second way is to put them in a parallel configuration again, but charge them together at 1.4V, current limited to total capacity divided by 40 (e.g. 3000mAh/40 => 75mA current limit). This may be faster than equalizing via the previously mentioned parallel method and you will start with a charged set of cells when you make the pack. Be sure to have an accurate voltmeter to check the charge voltage. |
