# Determining remaining Lipo capacity?



## XXXT4me (Apr 6, 2007)

I am using a 7.4v 4000mah 2 cell 20c Lipo to run a Mamba Max 4600kv. Charging on an Integy 16x307. Balancing with a Blinky. I am very pleased with this setup but I do not know how to determine the remaining capacity of the battery. The charger shows volts and amps only. Is there a way I can tell what I have left in the battery. 
Any help would be welcomed.


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## ta_man (Apr 10, 2005)

XXXT4me said:


> I am using a 7.4v 4000mah 2 cell 20c Lipo to run a Mamba Max 4600kv. Charging on an Integy 16x307. Balancing with a Blinky. I am very pleased with this setup but I do not know how to determine the remaining capacity of the battery. The charger shows volts and amps only. Is there a way I can tell what I have left in the battery.
> Any help would be welcomed.


Here's how I did it for one pack.

Charge up the battery, let it rest for an hour and measure the voltage.

Put it on a discharger (be sure the cutoff is set properly for the LiPo) and discharge about 500 mAHr. Let it rest an hour and measure the voltage.

Repeat the discharge/rest/measure cycle until it hits the voltage cutoff. Then you have a table of voltage versus amount discharged. Some simple arithmetic converts it to a table of voltage vs. remaining charge. Now you know.


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## guver (Jul 31, 2002)

An open voltage is a good indicator of sod.

4.2 at the top and 3.5-3.7 at the bottom depending upon who you talk to.

100.00% 4.2	8.4
90 4.13	8.26
80 4.06	8.12
70 3.99	7.98
60 3.92	7.84
50 3.85	7.7
40 3.78	7.56
30 3.71	7.42
20 3.64	7.28
10 3.57	7.14
0.00% 3.5	7


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## XXXT4me (Apr 6, 2007)

Thanks to both of you for the help


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