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Old 09-19-2013, 09:01 AM   #24 (permalink)
Graviteesuks
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Quote:
Originally Posted by Tahoe Ed View Post
As a general rule you don't want to put more than 80% of the capacity of the Lipo. For example if you are using a 2650mAh 4S lipo, when fully charged, you want to put back about 2220 mAh. If you put back more then you are over discharging your lipo and could shorten it's service cycles. If you are going to be in this sport, the best charger that you can buy will pay dividends in quicker charges and more flying time. I can charge 2 2650 in about 15-20 mins.
I know this is an old thread but I disagree with this.

According to battery manufacturers, it's the other way around. Don't "Discharge the battery more than 80%", in other words, if you have a 2600mah battery, don't take more than 80% out during the flight. It's fine to charge it back to "Full", if you've not over "Discharged" it, it should only take 2080 milliamps to recharge it to "full" at 4.2 volts per cell. Take millamp measurements at recharge and if it takes 2200, then cut your flight time down.

You can just divide the milliamps put back by the number of minutes flown to find out how many milliamps you use per minute on average and adjust accordingly to only draw 2080 milliamps or close to it during the flight. If you fly the same way each time, using time shouldn't be an issue but keep in mind that new batteries will get stronger as you cycle them, then at some point they will start losing strength after many times of charging. Try to charge at 1C most of the time (If it's a 2600 milliamp battery, only charge it at 2.6 amps).
If it's like the Hyperion batteries, you can charge them at 5C or even 6C if it's labeled for that but I wouldn't do that too often, once in a while would be OK.
Also, at first the battery will charge at whatever you set it at (5C or 13 amps for a 2600 milliamp battery for instance) but as the battery charges, it will lower the charge current on it's own if you've got a good charger.

Most good chargers are preset at 4.2 volts per cell as standard and is typical. Also, good chargers won't let you overcharge them unless you up the target charge voltage.

Over "Discharging" is the real killer for Lipos. Over "Charging" can be just as bad so if you leave it at 4.2 volts per cell, it'll be just fine.

I hope this helps!
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