Batteries Lipo Internal Resistance

bigone5500

Well-Known Member
I got a 1s lipo that has an internal resistance of about 512 mOhms. Is that high? I'm seeing on other sites that about 6 to 12 is good. I can't find a definite answer.
 

bigone5500

Well-Known Member
I charged it with my iCharger and after it finished, I checked the capacity which turned out to be 4.14v and 95%.
 

Tony

Staff member
I think @murankar has done some testing like this. I have never really cared what a multimeter said, I always just looked at it through the charger lol.
 

bigone5500

Well-Known Member
That's where I got the number from. If you hold the stop button down for a few seconds then press left you will get this reading.
 

murankar

Staff member
Just so we are talking apples and apples.

Chargers are not an ideal method of testing IR readings. What you need is an ESR meter to take the readings. Next you want the packs at or about 72 degrees F. This is the ideal situation for the most accurate reading. If your into that thing.

Chargers tend to take readings during the charge cycle which is way different than on a discharge. Not saying its wrong just not as accurate.

Now at the end of the day it really doesn't matter. What matters is that you do it the same way every time to get your numbers.

What I don't know is what a good reading is. If you want to know for sure you will need to get in touch with Justin pucci on facebook and see if he will share his battery database data with you. Once you go through that you should see where your packs fall in the good bad scale.

For all the powerlab guys if you run the battery cycle function it will return a fairly accurate capacity reading. Is it dead on? My guess is no but it will at least give you and idea as to where your packs are.
 

bigone5500

Well-Known Member
I charged it and then put it in storage mode immediately and the voltage was about 4.01 and capacity was at 75%. I don't know, I'll just continue to do the same thing like I have always done. I can only trust the charger to do what it is supposed to do.
 

murankar

Staff member
I am not saying your way is wrong. Just keep doing it the same way every time. That way you get a solid base line to track. Even the temps matter when doing IR readings. If you

If you really want to nerd out on the topic you can. There are a few things you can try to do.

here is a listing for a 2S paxk from the data base

Username Brand Cell Count (S) Capacity (mAh) Nameplate C Rating IR Measuring Device Temperature Measuring Device Pack Temperature (C or F) Cycle Count (if known) Average IR (mOhm) Maximum Safe Current (A) Apparent C Rating

Robert Montee Thunder Power 2 2700 20 TP820CD IR Thermometer 71F 100 6 52 19.2

this is a thunder power 20C name plate pack. According to the data he has a 6 megOhm reading after 100 cycles, took the reading at 71F and had a 19.2 amp draw. I would say your pack is on par for normal.
 
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