RC India

I have Life 1500mah 1C transmitter pack, and I can see different voltage number when checked with voltage meter and when I attached it to Trunigy accucell 6 charger. ???

Voltage with voltmeter : 3.40 V

What Accucell 6 shows me : 3.49 V

Also, When I am charging battery, voltage of 2 cell start dropping right after full charge. does it mean battery is dead? Is there any way we can rescue it? or do I have to get new one? >:(

With full battery charge I can see voltage drops from 10.8V to 10.1V in about ~10-15 mins and then it is holding 10.1V for about 30-40 mins.

I tried charging individual cell with balance connector, but every time I charge  2 of  cells voltage start dropping immediately after charging.

thanks in advance

That is normal for an LiFe pack. They have very steep discharge curves, meaning that the voltage drops to 3.3V per cell soon after charging (fully charged is 3.6V per cell) and then holds there until the pack is almost empty. All the cells should discharge at an approximately equal rate though. These cheap cell checkers are usually not very accurate, so a little variance is normal. Balance charge the pack. Charging individual cells is bad practice, and should only be done if the pack is badly imbalanced. I also hope you are charging in LiFe mode and not LiPo or LiIo.

Thank you for reply  :hatsoff:

I am charging it in Life mode, I just charged individual cell once since one of cell was at 3.57V and other cells were at 3.42V and 3.40V respectively.

Now, I am confuse which voltage should I refer? usually I go with Accucell 6. Is it possible to change reference voltage for Accuccell? e.g. if multimeter found cell voltage to be 3.45V and if accucell is showing me 3.50V then what should I do?

What multimeter are you using? How many years old? Do you have a known voltage reference to test against(like a constant voltage regulator or something)?

Regards,
Raj Gunaseelan James

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I am using Mastech MAS830L multimeter. I have just purchased it 3 months back. I dont have known reference voltage reference.

Hello Niteenk,

As per the multimeter spec, for 20V range, the error can be +/- 0.5% of the reading. It is also mentioned "Accuracy is specified for a period of one year after calibration". If we assume another 0.5% error on accucel, a 3.49V can vary till 3.455V(theoretical worst case, practical worst case depends temperature, humidity, etc.,etc,). Having said that, I checked on my cheap Mastech multimeter and Imax B6 mini charger, they read the same for atleast 2 decimal places. Maybe one of your meters is not correct. Only option I can think of is to check with one more multimeter to find the odd one out. Till then, it is better stick to the safest among values given by these two meters.

http://grobotronics.com/images/datasheets/MAS830L%20MAS830.pdf


Regards,
Raj Gunsaeelan James

Thank you Sir, I will check with another multimeter. thanks for help