sujinvipin; no iron core transformer. perry

Perry is correct.

The newer power supplies (switched mode) don't need a large transformer. You can get the same power output with far less weight.

K, in a battery charger ie. Boost and float Chargers, normally what should be the time required for boost charging and for float charging. How do we do this float and boost charging using a battery charger?

Please correct if i m wrong for boost and float charging. Boost charging ( constant current ) is to charge the battery to its 80% full charge after discharge. After that the battery is charged at constant voltage to its full charge . While Float charging is done at full charge to compensate for self discharge condition.