Battery Charge Times

[NATOAho]

I've never had airsoft and I just got 2 ECHO guns, an AK and an M4, and they came with weird instruction manuals that didn't seem specific for the guns themselves, and were more general. They also didn't specify anything about battery charge times.

Is there a way to figure out mathematically a good time to charge the batteries? The batteries for each gun are the same, consisting of seven 1.2V 1500mah cells, but the chargers are different.

The chargers are
1. 8.4v and 450 mah
2. 12v and 300 mah

There a way to figure out how long to charge each of them?
and yeah, yeah, Google's my friend, whatever... I've been searching for a while and coudln't find a site that expained this, so, I figured I'd ask the guys who know these things best. Thanks.

-NATO

[KNIVEZS]

Divide the battery capacity by the current of the charger to get the hours needed for charge. i.e. 1500mah batt and 500ma charger = 3 hour charge.