Lithium Polymer Battery Monitor for up to 4S. This device plugs into the balance port on your battery.
Should any one of your cells fall below 3.3v the light will change from Green to Red, indicating an unbalanced pack and that your battery should not be discharged further.
Discharging your pack to its normal level when you have an unbalanced pack will cause one cells capacity/voltage to drop too low, resulting in a faulty cell which will very quickly reduce the packs performance.A properly balanced pack can last 600 cycles or more. However, unbalanced packs rarely make it past 100 cycles before at least 1 cell becomes faulty. With this device, you will know immedietly when your pack is unbalanced and should not be discharged further or balanced.