Just leaving them on?
07-30-2004, 09:13 PM
#1
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Just leaving them on?
I have three tx and ten rx batteries that I would like to cycle. They are all in their respective divices. I won't be flying for a few weeks. Can I just leave them all turned on until they run down? They are all either nicads or NiMhs.
Jeff
Jeff
07-31-2004, 12:07 PM
#4
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RE: Just leaving them on?
You will most probably ruin one or more sets if you do that. while it doesn't hurt a NiCad to be discharged to zero, when you have more than one in series like your transmitter and receiver batteries, the weakest one will discharge to zero but it doesn't stop there. The cells which still have life in them continue to discharge thru this dead cell and literally starts charging it in the reverse direction. This is very hard on that weak cell and will most probably due irrepairable damage to it. The reason for the so called 1 volt rule is just to prevent that, the laws of probability say that if you only discharge the battery to what is approximately 1 volt per cell, the chances of reverse charging that weakest cell is near zero; it is not that discharging a NiCad to zero hurts it as it does not. It should not hurt your batteries to remain idle for a time. Just do a slow charge (at about 0.1C for 15 hours) the next time you get ready to use them; i.e. treat them as you would a new battery. It might take three cycles of this to bring them back to maximum capacity. Another thing to watch out for, if you discharge the transmitter battery by leaving it turned on, be sure to have the antenna fully extended. If you run a transmitter with the antenna collapsed, the SWR (standing wave ratio) goes way up and much of the energy that is normally radiated as RF now just heats up the output transistor and can literally burn it out or at the very least cause degraded performance from that time on. Its okay to do this (run with the antenna down) for very short periods of time like doing a range check but try to keep the time well under a minute.
