I have a "Blinky" balancer and it works very well. Can be used before charging, after charging, and during charging. To use during charging you must charge using the discharge leads(Dean's connector). To use "Blinky" with Thunder Power packs you must use an adapter (Astroflight part# 549). Adapter cost $4.50 from Astroflight. "Blinky" will alert you if any cells are too low in voltage so you can take corrective action so as to minamize damage to your pack. "Blinky" is not a fancy device but for 25 bucks it is not bad.