Virtually all good quality radios made in the last 10 years come with 'Intelligent' chargers. The radio/battery can be dropped into the charger for a rapid recharge and it can be left in the charger without worry about overcharging. It will quickly re-charge a battery and keep it in a ready-to-use state. No thought or special procedures are required to keep the battery in good condition.
Intelligent chargers can be identified by a charging light that changes colour when the battery is fully charged. Any radio with a Lithium Ion battery will also have an intelligent charger even if the charging light does not change colour.
How Intelligent Chargers Work
They are intelligent because they complete the charging process in the following order:
- Check the battery to see if it is fit to be re-charged. (Not too hot or cold and in good condition)
- Rapid charge the battery to about 80 to 90% of fully capacity. (2 to 4 hours)
- Top-up charge to bring to 100%
- Float charge to keep the battery near to 100% without overcharging.
Lithium Li-Ion, Li-Poly Chemistry Batteries
Any battery with Lithium in its chemistry should never be allowed to become fully discharged if at all possible. Charge it as soon as practical and store it charged. Lithium batteries do not have any 'memory effect' and happy to be part discharged before re-charge.
Nickel Metal Hydride. NiMh Chemistry Batteries
These do suffer from a very small memory effect so perhaps once a year should be discharged before a full charge. They also self-discharge very quickly so for occasional use are best charged a day or so before use
Nickel Cadmium NiCd Batteries
These are no longer in use in the UK for radio batteries. In most products they can be replaced with NiMh batteries. NiCd batteries do suffer from the memory effect and should frequently be fully discharged.
Older or cheaper radios have Trickle (or Dumb) chargers. These can be identified by a charge light that does not change colour when the battery is fully charged.
Trickle chargers are not so easy to use because they only charge the battery slowly (12-14 hours) and they still continue to charge the battery even when it is fully charged. This can result in the battery getting hot which alters the battery chemistry damaging the battery.
For best battery life use a trickle charger as follows:
- Do not leave a radio/battery on-charge longer than overnight.
- For holiday periods a time switch is a useful way to prevent long periods on charge.
- Trickle charged NiMh batteries should be run almost flat at least twice a year.