ORIGINAL: SLOtyro
Am flying a trainer on average a couple of times a week with a superb instructor - ah the joys of retirement!. I charge both rx and tx batteries overnight each time. Is this overkill? Is it damaging or at least failing to fully develop the nicad capacity? should I not discharge the nicad flight pack peridoically?(700mAH 4-cell nicad) As the tx is NiMH I suppose this is less critical? Do I need a load voltmeter - and if so which one to get? Do I need a battery cycling device? If so any recommendations would be gratefully received.
All less than one year old -Spektrum DX7/AR 7000. It is in a slow flying ARF Nexstar, which is about as agile as the Goodyear blimp...nice motor though, OS .46AX
As I hope this gear will survive whatever insults I visit upon it in for some time I don't want to mess it up needlessly. I get conflicting advice and even what I read is not always consistent.
Thanks. It's great to be back at this stuff again - especially building something more ambitious which will be waiting in the wings...
Your habit of charging your 4.8v 700Mah NiCd receiver pack "overnight each time" may very well have saved your plane. Your AR7000 receiver has a minimum voltage input rating of 3.5v. Flying a 4.8v receiver battery with less than a full charge on it could lead to "brown out" or "lock out" conditions as your receiver resets while flying it if your receiver pack dips below the 3.5v minimum input threshold, even for a split second. This can happen easily enough if multiple servos are drawing maximum power from the battery (say while using your rudder to straighten a out an inside loop while you're managing the throttle) after you've already had a flight or two that day.
You should seriously consider upgrading your receiver battery to a 6v NiCd or NiMH pack. You don't need one with a huge capacity, a 1000Mah or 1200Mah 6v receiver battery will give you even more flying time than your 700Mah 4.8v battery does now. The extra voltage should keep you well above the AR7000's minimum input level, even if you're doing some spirited basic aerobatics on your 3rd or 4th flight of the day. It will also provide insurance in case one of the cells goes bad in your receiver battery; a 4.8v pack drops to 3.6v if just one cell fails, while a 6v pack will still have 4.8v if it loses a cell.
I'm glad you haven't experienced any problems with your current setup so far. I hope you won't wait until you do experience a lockout before you beef up your receiver battery just a bit.
Good luck and good flying!