Transmitter & radio battery life, plane sat for years

[BlackB12]

My radio hasn't been used in about 5 years. I charged everything up and all works, but I'm wondering if I should replace the battery packs to be safe. Any ideas how long they work. The radio was only used about 3 flights before it sat for 5 years. It's a Tower hobbies 4 channel system, again new in fall 1999.

Mike

[Rodney]

Give everything a good visual inspection, especially in the battery compartment area. Either obtain or borrow a good battery cycler and run at least two, preferably three, cycles on the batteries by charging them at 0.1C for 15 hours followed by a discharge at 0.5C. If, after the second or third cycle, the capacity is at least 80% of rated capacity, it will most probably be okay to use them. If it were mine however, I'd just start out with new batteries unless the plane has little or no great value. The electronics should all be okay unless there is visible corrosion on the connectors or in the battery compartment.

[BlackB12]

Is it possible to cycle the batteries without a cycler? Charge it up and leave it on? Or is there not enough drain to properly cycle them?

Mike

[Dave Robelen]

Hi Mike,
The really prudent thing to do would be to get fresh batteries. Nicads lose their capacity over a few years whether they are used or not. This is why professional outfits change the packs in their walkie talkies on a schedule before they go sour.
Cheers, Dave

[aeajr]

Is it possible to cycle the batteries without a cycler? Charge it up and leave it on? Or is there not enough drain to properly cycle them?

Mike

Yes. Use the charger that came with it, or another charger that will charge it at 1/10C, approximately, and charget for 10-12 hours.


Once charged, keep these points in mind:

1) pull the antenna up 1 or two sections - don't run it for long periods with the antenna fully collapsed, it over heats things in teh radio

2) While your radio is on, you could be interfering with another flyer so I suggest you do this in the basement, if you have one, or somewhere else that will help to block the signal. Having only one or two sections up will also limit the signal range.

Don't turn it on and go to bed. That will drain the batteries down further than you want. Put it on and wait for the low battery signal, whether it is a meter, a beep or a light. Typically a standard set of batteries will give you 2-3 hours of transmitter time.

Finally, record how long it lasted. If you are getting 2-3 hours of run time then you are probably fine. Less than 2 hours and your batteries may be weak and need replacement.

This is how I would approach it without cycling equipment.

[Rodney]

aeajr, You really need to keep the antenna fully extended, not just partially, when running for more than a minute or two. SWR (standing wave ratio) goes way up with the antenna not fully extended which causes all the energy that would normally be radiated as rf is now reflected back and heats up the output stage, possibly to the point of failure, at the very least reducing mean time to failure rates. For best transmitter health, ALWAYS keep the transmitter antenna fully extended accept for that brief time you do a range check.

[Dave Robelen]

Hi,
This is all well and good for the transmitter, but the flight pack is at least as critical, and not all that expensive to replace. Again, as was mentioned, it will be necessary to monitor trhe discharge to turn stuff off when the battery starts to drop.
Regards, Dave

[moster]

I would recoment to purchace a expanded scale voltmeter ( make sure it loads the batteries)...never fly with out checking your batteries for each flight.
You can use this, with your watch to check battery capacity. Note: do not fully discharge batteries, (at least when they are in a pack) this will kill them...what happens is when the "weak" cell in the pack goes dead, the stronger batterys will reverse charge it ( and damage it). Additionally, The nicad battery "memory" scare is bogus..you will never charge and discharge the batteries 'exactly' the same amount consecutively so there is nothing to "remember".
The receiver battery is key...if one battery goes dead, it is all over...the Rx will not function on 3.6 volts. I use alkalines in my RX..they have a predictable discharge curve (not the sharp drop off as compared to nicads or niMH). I will get a whole flying season out of 4 cells ( approx $1.50).