Updated: 15-Aug-2011

Miscellaneous

Battery Charging Tips

Battery Charging Tips	Battery Comparison	Battery Types
Example Costs	Rechargeable Batteries

These tips are aimed at maximising battery charge efficiency and battery life and apply primarily to nickel metal hydride batteries.

Don't mix different types of battery in the same charger.

It is also recommended that different manufacturers batteries are not mixed as different manufacturers can use different methods of defining the capacity.

Store batteries at 20C or less wherever possible to minimise leakage.

NiMH batteries can lose up to 25% of their charge at room temperature over a month. The rate of leakage increases with temperature.

Make sure that batteries are cool before charging.

The charging process is most efficient below 20C, allow batteries that have been in the sun to cool before charging.

Do not charge batteries in warm areas or in sunlight.

Charging at higher temperatures reduces the amount of charge a battery can hold. Make sure the charger is well ventilated with a good airflow to help cooling. BAtteries do get warm during charging.

Use the right type of charger for the battery.

Using the wrong type of charger will shorten the life of the battery and may be dangerous.

Always use a timer with battery changers to limit the charge time.

Overcharging shortens battery life. This is true of both trickle chargers and fast chargers that switch to trickle charge when charging is complete. This will also save wasting electricity. A similar effect will occur with solar powered chargers.

Do not recharge batteries more often than needed.

Charging nearly flat batteries is better for battery life than top-up charging. Repeated charging of nearly fully charged batteries will shorten battery life.

Battery testers do not reliably indicate the amount of charge left in a rechargeable battery.

The battery tester is unable to differentiate between a partially discharged new battery and a fully charged older battery.

Don't leave batteries in chargers.

There is likely to be a small leakage current even when the charger is off which will drain the batteries over time and could lead to one or more cells being reversed charged which is very detrimental to battery life.

Don't fully discharge batteries before charging.

It only contributes towards reducing the number of cycles. So called memory effect is not significant with NiMH batteries.

Don't try and recharge obviously damaged batteries.

It could be dangerous.