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Old 11-21-2009, 11:18 AM   #1
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Default Lipo charge times

right now I have a a 2s 4600 lipo and my charger only charges up to 3 amps. I don't want to get a new charger but would like to get a larger voltage battery. Does a 3s take longer to charge then a 2s with the same mah rating or does the #of cells does not make a difference on charge time.
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Old 11-21-2009, 12:11 PM   #2
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As long as your charger can deliver a 1C charge, charge time won't be any longer for a 2C or 5C lipo. Should be about an hour.

However long your 2S is taking now, should be about same timer for a 3S of the same mah assuming your charger can charge at 3amps for the higher voltage. This is where the chargers power output comes into things - as long as 3amps and 12.6volts (~38watts) is within the chargers output power raticng, it'll charge at 3amps.
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Old 11-25-2009, 07:33 AM   #3
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You can work out charge times of a battery and charger by looking at the mah of the battery that will be written on it and the mah OUTPUT of the charger that will be written on the charger.

Dividing the mah of the battery by the mah of the charger will give the charge time in hours. For example, if the output on the charger was 300mah and the battery was a 650mah then 650 divided by 300 would give 2 hours and 10 minutes.
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Old 11-25-2009, 08:43 AM   #4
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That works and provides an approx for NiMh or NiCd, but since lipo charging is a two step charge, (CC/CV), it won't be close. I've charged everything from 800mah to 5000mah, 2S to 6S and roughly it takes 45-60min for a significant charge (discharge was+/-80% of capacity).

You can get the same kind of estimate by dividing capacity in mah by the charge rate in millamps (amps x 1000) and get hours for charging. This ignores any capccity left in batt and IR (internal rsistance) of the batt itself.

If you're just topping on off (discharge < 10-20% capcity), charge times ar shorter, but still longer than you'd expect. This shortens the CC part of the charge, but doesn't affect the CV part which is where the most time is taken.
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Old 11-26-2009, 10:46 PM   #5
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having a good power supply also will help in reducing charge time.
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