P.S. ThunderPower do a neat little 10 cell stand-alone balancer - the TP-210V http://www.westlondonmodels.com/product1098/ThunderPower-TP-210V/http://www.westlondonmodels.com/prod...Power-TP-210V/

The technique I would recommend for achieving a good result with such a balancer is:

1) If the pack is badly out-of balance, connect the balancer to the pack (without charger) and leave to balance for a few hours.
2) Charge normally (1 to 5 amps) with balancer still connected. Cut-off at 3.6 to 3.7V per cell.
3) Switch to trickle charge of around 30 mAmps and leave to balance for as long as necessary, but check regularly that the pack voltage does not exceed 3.7 Volts per cell. Switch off the trickle charge if it does.

This ensures that the balancing occurs when they are fully charged - the only place where it matters. You cannot accurately tell if a pack is balanced by looking at the votages when the pack is only partly charged.

The most common out-of-balance situation with these cells is one or two low cells in a pack. This quite often happens if you leave the packs for a few weeks. This takes quite a long time to rectify with most balancers, because they have to disharge all the other cells down to the voltage of the lowest one.

John