View Full Version : Volt meter and checking your LiPo's

Ben Hedrick
06-20-2007, 06:34 PM
What is the best way to check your LiPo's with a digital volt meter after you've flown with them? For Volts and mAh's...

Thanks, Ben

06-20-2007, 08:07 PM
You can't check mAH with a volt meter.

You can check the pack voltage, which for my 3S packs is a bit over 11 volts after cooling off.

You can also use one to check the balance, but be careful to not short across two connectors.

Ben Hedrick
06-20-2007, 08:30 PM
I took a reading off of my 3 pack 11.1v 2100 mAh lipo and the volts showed 11.42 and my alarm on my heli was going off. I only got about 4-5 minutes of basic hover time off of it.

06-21-2007, 06:29 AM
There is a difference between static voltage and load voltage. Your heli was measuring load voltage ..... and under load your voltage dropped below your set point and the alarm went off.

I've had small lead batteries (like the ones for PC power back-UPS) read 12 volts on a meter and then when you attached a 12 volt light bulb the voltage dropped to almost nothing ..... battery was shot.

BTW Hovering is pretty hard on a battery. Forward flight is the easiest on a battery. 3Dz is the hardest on it.

Ben Hedrick
06-21-2007, 06:35 AM
Thanks Bob, that make sense. Should I be charging my LiPo's to only 80% of their capacity? Say for a 2100mAh battery, charge it to 1680?

06-21-2007, 08:00 AM
You should be discharging a maximum of 80% of their capacity (Mah rating), and re-charging them to 95-100% capacity. If you start with a fully charged 2100mAh battery you should never put more than 1680 back in. For safety I would shoot for never putting back more than 1600. Having a charger that tells you how much it puts back in is the only way to go.

Ben Hedrick
06-21-2007, 08:15 AM
I do have a charge that shows what it is putting in it, although I'm not sure if I have paid enough attention to it when I first start charging it to see what it started with. I do run a alarm on my helo that I follow to the T and land it as soon as I hear it start beeping. I am not sure what its voltage is set at though. How would I check that? Thanks for your help, Ben

PS: I have a Triton Jr. LiPo charger, if you know that one.