Battery Charge Time

It is quite necessary to know the scientific battery charge time with more and more Ni-MH battery, Ni-Cd battery, lithium battery and other rechargeable batteries in the market.

In the current market, rechargeable battery is charged with CC chargers, that is, with input current marked on the charger. Because battery will generate a counter EMF, based on different proportional relation between battery capacity and charge current, charge time should be calculated as follows:

Battery capacity refers to the battery external marking.
Charge current refers to the input current marked on the charger.
1. When charge current equals or less than 5% of battery capacity:
Battery charge time (hrs)=battery capacity(mAh)/charge current(mA);
2. When charge current higher than 5% and equal or less than 10% of battery capacity:
Battery charge time (hrs)=battery capacity (mAh)*1.5/charge current (mA);
3. If charge current higher than 10% and equal or less than 15% of battery capacity:
Battery charge time (hrs)=battery capacity (mAh)*1.3/charge current (mA);
4. For charge current higher than 15% and equal or less than 20% of battery capacity:
Battery charge time (hrs)=battery capacity (mAh)*1.2/charge current (mA);
5. Charge current higher than 20%:
Battery charge time (hrs)=battery capacity (mAh)*1.1/charge current (mA);

Also there is a fast battery charger in the market. This fast charge has equipped with control circuit or IC chip to control battery charge time because over heat can happen when fast charge discharges under high current. When battery is close to be fully charged, control circuit will automatically turn to trickle charge mode so overcharge can be avoided.