Review on Tenergy TN456 Intelligent Universal Battery Charger: 4 Slots, LCD Display, USB Output, Power Adapter - Ideal for Li-ion, NiMH, and NiCD Rechargeable Batteries by Kenneth Stanford

This is a convenient universal charger with 4 dedicated charging slots (each slot can charge the battery independently, no need to insert batteries in pairs). It works with almost every type of battery on the market including NiMH, NiCd and Li-Ion. Each slot has a spring retainer that is used to hold the batteries in place while charging. I love the versatility of this charger. It can be used not only for battery charging, but also as a tester/maintainer. The normal operating mode is charging, but with a single press of the "mode" button I can select the "TEST" mode, which will discharge and charge the battery to measure actual battery capacity. It also supports various charging rates including 300, 500, 700 and 1000mA (the charger will automatically switch to 300mA mode when the battery is fully charged to protect the battery).