Thread: batteries left in chargers

A very general rule is : nicd no, lion yes.
This site might be useful.
http://batteryuniversity.com/learn/a..._battery_table

I have always worked with - It depends on the charger, the battery type and the device being charged.

Another way to check is to see if your charger is labeled as a 'smart charger'.

My understanding is that they are called 'smart' because those models are able to tell when the battery has been charged, and so they will either stop charging, or they will run a break-in cycle, or a maintenance cycle. This is particularly with regard to new model Lithium Ion batteries.

One of the biggest battery killers is heat. If your battery is still hot after a couple of days in the charger you are probably shortening its life span.

this depends on the charger and the battery.

crude simple NiCad chargers have no end charge sensing and just continue to apply current untill the battery is removed.......leaving batteries in this type of charge will kill the battery in short order.

the slightly more sofisticated NiCad chargers ( like th old 7.2 and 9.6 volt makitas have a heat sensor in the pack...when the battery is fully charged the battery heats up, te sensor triggers a circuit in the charger and the charge current is removed.......these chargers will have 3 tereminals on the battery and a charge light that goes out.....leaving batteries in these chargers is fine.

then there are the smart chargers ( whatever that means) these have some sort of multi stage circuit with multiple indicator lights.....these also should be fine left in the charger.

Lithoum batteries in general must have some sort of charge termination in the charger otherwise they will burn or explode.

cheers

The longer Lithium type chemistry stay fully charged(4.2v per cell) the faster the cells deteriorate. For a happy long life Lithium pack, don't let it sit fully charged for extended period of time.