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Can I mesure how much power is left in my receiver battery just by measuring voltage, or do I need to measure mAh left. If I need to measure mAh, how would I do so? I am using a 6 volt 2000 mAh battery. I searched and read through the old post but just ended up more confused than when I started! Thank you all for your help, again!
redgiki
04-21-2008, 10:15 AM
Can I mesure how much power is left in my receiver battery just by measuring voltage, or do I need to measure mAh left.
The reason it's confusing is that different batteries have different performance characteristics. Your best bet is to pick up a Great Planes Triton charger (or equivalent) that allows you to see how many mAh you put into a battery when you recharge. It also allows you to "cycle" the battery, displaying how many mAh have been burned or charged. This will let you get a handle on the actual capacity of your battery.
The next thing to do is pick yourself up one of these: http://www.voltmagic.com/ . I use them -- or a similar product -- on all of my nitro planes and helis. It's good insurance. Stir the sticks a little before each flight, and you'll get a good idea of whether you need to recharge the receiver packs. Green means 'go'! If the pack voltage drops into red under load, it's time to recharge.
Lastly, you can use a DVM as you suggest. A fully-charged NiCD/NiMH pack reads approximately 1.45v/cell. A fully-discharged pack reads closer to 1.0v/cell or slightly lower. Around 1.1-1.2 and it's still generally safe to fly, but it's better to read the voltage under some kind of load.
EDIT: Checked on the Spektrum's voltage requirements, if you're flying 2.4GHz equipment, better make sure you're at least 4.5v under load before flying. Apply load by fully-deflecting a control surface, then applying gentle pressure with your hand in the opposite direction on that control surface.
Ok, so let me make sure I understand this.
No need to measure the mAh, just the voltage. In due time I will get something similar to the voltamagic unit. I currrently have a Bantam BC6 charger that does a wonderful job of charging and cycling the batteries. Up to this point I have only been using Lipo's however.
Yes, I am using 2.4, Dx7 to be specific. So nothing below 4.5 Volts under load.
Thank you very much!