Charging Batteries in Command Control Launch Controller

I recently picked up an old Radio Shack 18V RC battery charger that plugs directly into the jacks on the back of the Command Control launch controller. The instructions with the charger state the output for charging Ni-Cds is 90 mA. Approximately long will it take to charge the Ni-Cd batteries which are 1800 mAh?

Thanks.

-Dan

DickyMoe said:

I recently picked up an old Radio Shack 18V RC battery charger that plugs directly into the jacks on the back of the Command Control launch controller. The instructions with the charger state the output for charging Ni-Cds is 90 mA. Approximately long will it take to charge the Ni-Cd batteries which are 1800 mAh?

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20 hours if the 1800 mAh pack is dead, and if the pack capacity is good so it really is about 1800 capacity (over time rechargeable batteries lose some capacity. Some of the capacity is lost from how many charge cycles, some due to age, some due to charge abuse, and overall a combination of those three. Plus the wildcard of quality batteries versus poor quality batteries).

Anyway, the basic math for the answer of 20 hours if the pack really is 1800 and dead:

(1800 mAh / 90mA = 20 hours)

About 10 hours if the pack is literally half-charged (50%, or 900 mAh).
(900 / 90 = 10)

The charge rate of 90 mA, for an 1800 mAh pack, is a 1/20 rate, so an "overnight" charge rate. So, it won't tend to hurt the battery pack if you charge it a bit longer. But do not leave it charging for days.

- George Gassaway

Thanks for the helpful information George.