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Home > Archive > Electrical Engineering > March 2006 > basic Questions on Power engineering
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basic Questions on Power engineering
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| vandra 2006-03-25, 2:21 pm |
| Hello!
--> I was wondering how a battery charger really works? Does it provide
the same amount of voltage and current to the battery that battery
provides?
--> how do I calculate the time it needs for the battery to be charged?
thanks!
vandra
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| On Sat, 25 Mar 2006 10:13:41 -0800, vandra wrote:
> Hello!
> --> I was wondering how a battery charger really works? Does it provide
> the same amount of voltage and current to the battery that battery
> provides?
No, it must provide more voltage than the battery provides. The current
must flow into the battery to charge it. If the voltage were the same no
current would flow.
> --> how do I calculate the time it needs for the battery to be charged?
The specifics depend on the battery technology and the battery design, but
generally the time needed would be equal to the charging current divided
by the capacity of the battery with some inefficiency thrown in (which is
a function of the charging current and the battery). A double-A NiCd,
for instance, might have a capacity of 2000mAh. If you charged it with
100mA for twenty-four hours (2400mAh) it would be pretty close to
being fully charged (2400/2000 = 20% wasted as heat).
--
Keith
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| vandra 2006-03-29, 9:21 pm |
| Thanks !!
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