Lipo Battery Internal Resistance for Different mAh Sizes

MJW

MJW

Well-Known Member
Hi, I was wondering if there's a chart or site that would have the IR of the different sizes of Lipo's,
Like for 7.4 volt 1800mAh 2 cell batteries, mine average 5 to 7 ohms by the meter in an Imax 6 battery charger

Then for the single cell 3.7 volt 1500mAh, I have 5 that range from 24ohms to 300+ohms,

So is there any info for this check?
 
MJW

MJW

Well-Known Member
Morning, I did some more digging and reading, found a good page on the topic of Internal Resistance.
www.rchelicopterfun.com

LiPo Internal Resistance - Are your batteries heathy or ticking bombs?

LiPo internal resistance is a very useful measurement to monitor your LiPo's health - here's why, how & what IR numbers are good.
www.rchelicopterfun.com www.rchelicopterfun.com

And I've answered my question, there are several links to other pages at the bottom of the article that might be helpful to you guys.

If you have a charger that will measure the IR you might find this helpful in understanding why your flight times are less than expected.
 
G

Gray

Member
Thanks for your sharing. But as far as I know, there are some deviation when test a lipo battery with its wire, and there will also be deviation in the test equipment, which will lead to inaccurate results. I'm not very sure with that
 
MJW

MJW

Well-Known Member
Good morning, just to add some info on IR that I've experienced,
I have 9 1S's 350 mAh to compare with, the 5 I've mentioned above and 4 new ones, the new ones arrived with high IR but when charged & used a few times the IR has dropped to an average of 40ohm's each, of the original 5 only one has been a constant good battery, the one with the lowest IR.
The other 4 would take a charge and all be around 4.2v, but when used they provided very poor performance, very short flight times then when checked after the flights those still had high charge voltage values of 3.8.
I tried them several times they did not change, they were the used cells that came with the quad, I then cut the plugs off and totally discharged them for disposal.
I purchased 4 more to replace them with and one of those was a total dud, the seller is replacing that one.
 
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