Balancing: Why and How?

[skeeler]

Hello,

I'm hoping to do a 1/8th buggy conversion soon, and I plan to use LiPo, LiMn, or Li-Ion batteries. I don't have any experience with these battery chemistries, and I'm not sure how best to care for them.

Can anyone tell me (or point me to a link explaining) how cell balancers work and why they are needed? Furthermore, can anyone suggest any good balancers or chargers with built-in balancers?

Thanks in advance.

[BrianG]

Balancers simply monitor each cell voltage and apply a low load to any that are higher in voltage. After a while, the high cell(s) discharge so they are at the same level as the others.

Some have other features, like auto shutoff above/below a certain cell voltage, mainly to help protect against a charger malfunction.

Because the act of balancing discharges cells, most people balance while charging so the pack can get the max charge it can and still be balanced.

The Hyperion LBA10 is generally accepted as a very good balancer and has a few neat features as well.

[pinolelst]

I balance every couple few cycles and find that works fine. If I did it every cycle it seemed like the batteries were still balanced enough that the balancer was hardly working. I have both the Astroflight Blinky and the Thunder Power TP-10 (??) 10 cell balancer and both work fine.The Blinky cost 1/3 of what the TP one did and It does up to 6 cells at a time.
Make sure the balancer and battery taps are compatible.The Thunder Power taps for instance have a narrower pin spacing than most other packs I have and I have to either use the TP-10 balancer or an adapter for the Blinky

Have Fun

Steve

[MetalMan]

Just to add, here are some reasons why balancing is a good idea:
-A balanced pack will last longer
-A balanced pack will potentially be safer
Both of these are the way they are because when all cells are the same voltage, then there is no deviation. If an unbalanced 2s pack has one cell at 4.15v and the other at 4.25v, the cell at 4.25v will degrade faster than the cell at 4.15v (4.25v is pushing the cell further than it should be pushed). The cell at 4.15v will discharge to a lower voltage than the other cell (assuming both cells have the same capacity and IR). This too will cause damage to the cell (even if it's a small amount).

[skeeler]

Thorough replies. Thanks.