Lipo's in transmitters ? ? ?
07-09-2009, 01:17 PM
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Location: Orange County,
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RE: Lipo's in transmitters ? ? ?
ORIGINAL: slopoke
Just yesterday a person at our field was flying a new plane , landing and taking off several times. The voltage was 10.1 at the beginning. When the transmitter started beeping for low voltage. The pilot thinking that he had a couple of minutes to land was trying to set up for a perfect landing. Just before touchdown the throttle went wide open and the plane rolled to the left. No damage but the transmitter was completely dead. The Lipo had timed out.
When lipos go they go quickly.
slopoke
Just yesterday a person at our field was flying a new plane , landing and taking off several times. The voltage was 10.1 at the beginning. When the transmitter started beeping for low voltage. The pilot thinking that he had a couple of minutes to land was trying to set up for a perfect landing. Just before touchdown the throttle went wide open and the plane rolled to the left. No damage but the transmitter was completely dead. The Lipo had timed out.
When lipos go they go quickly.
slopoke
Most transmitters do not shut down until around 8.5 volts. If he had a 3S lipo in it that is 2.8 volts per cell, well below the typical recommendation of stopping at more like 3.5 volts per cell, or 10.5 volts. So he was below a safe point when he started. The problem is that near the end of use the lipo drops like a rock, which is why you do not take them down too close the their end voltage.
A NiMH is considered discharged at 0.9 volts per cell, or 7.2 volts for an 8 cell pack. Stopping at 8.5 volts or before is safer with the NiMH than flying a lipo below 10.5 volts for the reasons of what happens at the end of the discharge curve.
