My Stinger chargers also stay warm. The charger circuit is in the flashlight itself, and controls transferance of power from cradle. The Stinger series is in use by different agencies across the US, and is always kept in charger when not carried. Streamlight warranties their batteries, not sure for how long, for use this way. Some people may see a problem with this application, but that is what Stilnger system is all about. If you notice a degregation of output from your batteries after a year then shop around for generic batteries selling for around $8.00 to $11.00 dollars, or have extra batteries to rotate like I do.
Bill
