Jun 28, 2012, 02:17 PM
Registered User
Help!

# How to determine % of battery used without a smart charger?

I bought some new batteries so I wanted to try and determine what my flight times should be. All my batteries are 2,200 mAh, 3 cell packs.

1. I have a couple Align RCC-4CX chargers. I just get a green light for each cell once it's charged. It says the output is 1,000mA. How can I use that along with the amount of time it takes to charge to determine what I put back in.

2. Can I use my Watts Up meter to determine this also? There is an Ah number, is that showing what I've pulled out since plugged in or something else?
 Jun 28, 2012, 02:41 PM Zero Expo Just check the battery voltage after flying and before charging; it should be >3.7V per cell, or you have discharged too much.
Jun 28, 2012, 03:07 PM
Space Coast USA
Quote:
 Originally Posted by SUPERSPORT I bought some new batteries so I wanted to try and determine what my flight times should be. All my batteries are 2,200 mAh, 3 cell packs. 1. I have a couple Align RCC-4CX chargers. I just get a green light for each cell once it's charged. It says the output is 1,000mA. How can I use that along with the amount of time it takes to charge to determine what I put back in. 2. Can I use my Watts Up meter to determine this also? There is an Ah number, is that showing what I've pulled out since plugged in or something else?
Using your meter, read the voltage of the pack and use this chart to determine approximate % of charge left in pack.
For a 3s lipo

Here is my chart on resting (after flight, no load) voltage versus capacity for a 3s pack This is the result of over a hundred measurements with different size, brand, and condition lipo packs.
.
Note - These values will vary ~ +/-5% depending on the age and brand of the pack.
In other words, the 11.4V might represent a % remaining between 38% and 48%

Avg Resting V % Remaining Capacity
12V -- 84%
11.9---77%
11.8---70%
11.7---63%
11.6---56%
11.5---48%
11.4---43%
11.3---35%
11.2---27%
11.1---21%
11.0---14%

After flying and measuring the voltage, see how your pack compares to the chart by calculating the used capacity from the mah put back into it during charging.

By cell
4.00V--84%
3.96---77%
3.93---70%
3.90---63%
3.86---56%
3.83---48%
3.80---43%
3.76---35%
3.73---27%
3.70---21%
3.67---14%
 Jun 28, 2012, 03:24 PM AMA 754 Or.. plug it in to your Hyperion Sentry, it will display both pack and individual cell voltages and percentages. It'll also balance the cells if you like. http://www.allerc.com/hyperion-eos-s...on-p-5701.html
 Jun 28, 2012, 07:19 PM Registered User https://www.hobbyking.com/hobbyking/s...y_Checker.html I have various batt checkers but this is the most versatile. The pic doesn't do it justice size wise. It's big at 5 in. long for my tired eyes Couple of things I like are the backlit screen that you can see in daylight. Tells the % you have left in the batt. No use my repeating what they show on the website but these are a couple of things that turned my crank. Gord.