It includes a built-in safety current that shuts the battery off, to avoid overcharging and damaging the battery and radio.
Spektrum 4000mAh 2S 7.4V Smart LiPo Receiver Battery; IC3 for Losi DBXL 2.0
Spektrum 6s 4000mah 50c Lipo Battery Bundle
Spektrum RC, 3000mAh 2S, 6.6V, Li-Fe Receiver Battery.
Voltz 4000mAh 2S 7.4v 50C Hard Case LiPo RC Car Battery w/Deans Connector Plug
ABM 4000mAh 2S 7.4V 60C rounded case Lipo battery with Deans connector
Voltz 4000mAh 2S 7.4V 50C Hardcase LiPo Battery Stick Pack
