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Old 06-21-2010, 04:56 AM   #1
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Default Charge rate for Lipo batteries

What amp level should I charge my batteries at? When I look at documentation, it says that a 5000mah battery rated at 1C charge rate should be charged at 5A. What is this "C" value and how do I find out what the battery can do? One my batteries it says things like 35C, does this mean it could be charged at 35 times the 1C rate described before, or is this something different?
The reason I ask is that I now have a charger capable of going up to 9 amps and am wondering if I can safely use higher amp charge rates to get a faster charge if needed.
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Old 06-21-2010, 06:24 AM   #2
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the C rating i believe is the mAh divided by 1000 which comes out in amps. the 35C rating on your battery is a discharge rate so a 5000mAh at 35C can supply 175A. You need to look at your battery closely to find the max charge rate or look on the manufacturer's site for help. Otherwise you would be safe up to 1C atleast
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Old 06-21-2010, 07:27 AM   #3
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Quote:
Originally Posted by cslewis View Post
5000mah battery rated at 1C charge rate should be charged at 5A.

Yes

The reason I ask is that I now have a charger capable of going up to 9 amps and am wondering if I can safely use higher amp charge rates to get a faster charge if needed.
Short answer NO it's not safe at all.
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Old 06-21-2010, 08:19 AM   #4
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^^^^ 1C charge rate for thet battery is 5amps. If the label says 1C stick to it manufacturer has made that recommendation for a reason - your safety and the longevity of the lipo.

Don't get the discharge rating (what the lipo is supposed to be capable of discharging) - the 35C confused with the C used in charging where you will not see anything more than 5 or 6C. You try charging a lipo at 35C you would have a exploding lipo and prob a fire on your hands.
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Old 06-21-2010, 09:09 PM   #5
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you didn't say what battery you have so I'm going to say stay at the 1C charge rate. However I've bought batteries that are advertised as being able to be charged at more than 1C and all the "safety crap" that comes with them says 1C so I can see how it can be confusing.
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Old 06-22-2010, 04:34 AM   #6
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Thanks for all the replies, I now understand the difference between the low C number quoted for charge (input) rate and the high C number quoted for how much current the Lipo can output in to a motor. I'll verify what each of my batteries are quoted as for charging rate and stick with 1C charging unless the manufacturer explicitly states it can be charged at a higher rate.
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Old 06-22-2010, 06:07 AM   #7
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Even if your manufacturer says you can charge higher it is a good idea to charge under it at 1C unless you are in a rush to get racing because the lipo will last longer that way
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Old 06-22-2010, 06:18 AM   #8
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Don't mess around with LiPo batteries. Charge them at the the recommended rate.

I have heard from a lot of people who charge 5000mah batteries at 8.5 amps... I wouldn't. 5000 @ 5a, 3500 @ 3.5 etc..

LiPo batteries can be very explosive. Below is video footage from the security system at my race track. I'm the guy on the left flinching out of the way.

This was a 20C 2S LiPo in a safety bag. FF to 45 sec into the video. (That battery was unplugged from the charger when it did that.)

+ YouTube Video
ERROR: If you can see this, then YouTube is down or you don't have Flash installed.
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Old 06-22-2010, 07:14 AM   #9
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Good advice, thanks, I'll stick to the 1C charging rate
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Old 06-30-2010, 03:36 PM   #10
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Quote:
Originally Posted by Drusillus View Post
Don't mess around with LiPo batteries. Charge them at the the recommended rate.

I have heard from a lot of people who charge 5000mah batteries at 8.5 amps... I wouldn't. 5000 @ 5a, 3500 @ 3.5 etc..

LiPo batteries can be very explosive. Below is video footage from the security system at my race track. I'm the guy on the left flinching out of the way.

This was a 20C 2S LiPo in a safety bag. FF to 45 sec into the video. (That battery was unplugged from the charger when it did that.)
I like how the guy comes in all calm with the fire extinguisher a few seconds later and puts it out like that happens all the time.
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Old 07-12-2010, 07:16 AM   #11
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4 amps is a great charge rate for what you are looking to charge. it's always better to have your charge take a little longer and keep the battery cooler.
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Old 07-12-2010, 08:38 AM   #12
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Quote:
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4 amps is a great charge rate for what you are looking to charge. it's always better to have your charge take a little longer and keep the battery cooler.
OP is talking about a 5000mah LIPO. There is NO heat issue charging at 5 amps and no reason to charge a 5000mah lipo at 4 amps
Your post makes me quesion your knowledge of lipo's......not flaming you
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Old 07-18-2010, 07:36 PM   #13
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Smile balance charge

Hi all,

I have mixture of recommendation of charging LIPO battery. For me i always charge my LIPO battery with balance charge with 1C rating. Local racer will recommend not to balance charge all the time which will cause the battery to loose "punch" power. Is that true? Our local racer always do normal charge (without balance) and only do balance charge once in a full moon. That way, they claimed that it will have "more punch" of power. I need opinion from you guys of which method of charging lipo battery is the best. Thanks.
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Old 07-18-2010, 10:08 PM   #14
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If your lipo's get hot while charging then there is something wrong with yours.Lipo should never get hot while charging.The new thunderpowers can be charged at 30 amps and run cool,but i wouldn't charge any batteries at 30 amps and most of us would be taking out a loan to buy one of those chargers.LOL.
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Old 07-18-2010, 10:12 PM   #15
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I charge my tunigy 4s 5000mah 40-50c battery at 10 amps and they charge fine,You find the max c charge rate on the back of most lipo's.My 2 and 3cell lipo's i only charge at 1c or 5amps because they have less cell and are physically smaller.
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