Air Land Sea Hobbies

How’s Your Nicads?

The Nicad batteries that we use in our transmitters and aircraft wear out with time. If you have a battery pack that is more than three years old, you should be keeping a close check on it by cycling every month. If it is five years or older, you should replace it and be sure to properly dispose of the old cells. So, how do we tell the age of our batteries?

Most Futaba battery packs and individual Sanyo battery cells (which most OEM radio manufacturers use) have a two-letter date code stamped somewhere on the pack or cell. The first letter of the code is the year of manufacture and the second letter is the month of manufacture. 1996=A, 1997=B, 1998=C, etc. January=A, February=B, March=C, etc.

 If you have a battery or pack with a date code of IB, it was manufactured in February of 2004. Probably still okay but keep a close check on it. The pack in my 8UAF transmitter was ZF, or June of 1995 so I replaced it. I found one pack with a date code of WC which translates to 1992; replaced that one without question.

A short time ago, a modeler wrote Ed McCollough (your humble technical editor) the following:

“Noticed and noted on the foot of page 66 of March Model Aviation underneath the picture of the Spektrum/JR flight logger, it is recommended that six-volt battery packs be used on ALL 2.4 GHz receivers. Called Horizon Hobby on the phone; they confirmed this statement. It was suggested the same six volt usage for other brands also. Would like to suggest the general membership be made aware of this when 2.4 GHz receivers are used in glow/gas airplanes/helis to preclude possible in-flight loss.”

When I read this, I agreed with him and wrote him I would get on the problem. Please, read what he wrote and consider it very, very carefully. Unfortunately, the answer to his question hasn’t been that quick or easy, but for the time being, here it is:

If you are flying a 2.4 GHz system, follow the manufacturers’ specifications for the voltage. If you are using a separate voltage pack for the receiver, be absolutely sure it has enough voltage to run the receiver. A common 5.0-volt receiver pack may not have sufficient voltage to run your particular receiver. Actually, if you used a six-volt pack and it was adequately charged, it should be sufficient, regardless of the manufacturer.

There is one problem, when using a six-volt pack if it isn’t required by the manufacturer of your system. That problem will likely happen if you are using digital servos. If you drive some digital servos with six volts, there is a high probability you will damage the servos because of the higher voltage. Remember, if the servos fail, it won’t make much difference that your receiver is still working.

You always need to be flying with a functional receiver pack, one that is as close to fully charged as possible. Remember, insufficient volts to the receiver and you crash.

Lastly, as in all things, and in all cases, read the instructions.

Someone suggested that the use of a soldering gun was safer than other types because it would not roll off the workbench and burn you. It should also be mentioned over and over that soldering guns have a very strong alternating current magnetic field around the tip. When brought in proximity to electric motors and servos, this magnetic field de-gausses (demagnetizes) the magnets inside the motors and servos and causes permanent damage. I have seen several people come to the flying field with a new electric-powered airplane that does not have enough power for flight. When asked if they soldered the wires to the motor with a soldering gun, the answer is usually “yes.” Also you should never stick the tip of a soldering gun into the airplane’s radio compartment while soldering pushrods and etc. as it will presently damage the motors inside the servos. If you must use a soldering gun, you should stay well away from electric motors and servos, meaning at least 24 inches just to be safe

—From the Rogue Eagles RC Club, Medford, Oregon