I just picked up the AstroFlight "Blinky" balancer and am very happy with it. It can be used before, during, or after you've charged a lipo. It's a tiny little thing somewhat smaller than a credit card. It features enough pins on it to do up to a 6 (8?) cell lipo pack. I had just recently picked up a Common Sense lipo (3 cell 2000ma 10C (20 amp with 30 burst ability)) for $44 having heard good things about the quality and low price of their packs. While there are a few sources for even cheaper packs out there like my Dymond Motorsports packs of the same specs for $35, they didn't come with a balancing plug already installed like the Common Sense packs do. The Common Sense packs feature a 4 pin Molex plug and they recommend the Astro Blinky for use with it. Fits the Common Sense plug and a few others lipo companies with no modification. For others like ThunderPower lipos you simply move a wire or two on the lipo's plug, or use a harness adaptor that Astro/Common Sense sells. Being so happy with the Blinky thus far, I opened up my Dymond packs to add balancer plugs to them as well (See "Adding A Balancing Plug To A 3 Cell Lipo", or the thread related to Blinky/Common Sense). It was fairly easy to do and now I have confidence that none of my packs are getting out of balance.

The "Blinky" sells for $25 and performs several functions. When you first plug it into the lipo 3 of the leds (for a 3 cell pack) will light up for about five seconds. This is indicating that all three cells are above the minimum safe voltage level for each cell. It will then go into balancing mode. When you see a led light up for a few seconds at a time this tells you that Blinky is bleeding off excess voltage on that cell to get it to match the lowest cell voltage in the pack. It will continue to do this until all 3 cells match. You can also plug the lipo into any lipo charger to charge while Blinky is still doing it's work. After the pack has charged Blinky may still be active for a bit until it's got all three cells to perfectly match. It won't slow down your charge time as it's only bleeding off power to a cell as needed in the 100 m/v range. If you are noticing a much longer charge time then it's because you've got a cell or two that is way out of balance and was false terminating the charge before being balanced by Blinky. Blinky should be done balancing a pack by the time the charge has ended. If, however, a pack is way out of balance it may take longer for Blinky to level things out. That's why I prefer to plug Blinky into the pack before I charge it and let the balancer get things near where they should be before hitching the lipo up to the charger.