Batteries > Charging

Q-1: In my "Battery Basics" article (in the October 2003 Model Aviation ) I wrote the following: "The advantage of trickle charging is that the batteries are available the moment you want to fly. However, you can only maintain a charge level at trickle; you can't recharge a battery that has been used at the trickle charge rate." A reader was confused by the words "that has been used." He went on to point out that after reading this, he assumed that after returning from flying he should only put the battery on trickle charge! Answer ...

Q-3: "I tried using my ACE Power Pacer cycler to check my Futaba transmitter battery and found it wouldn't work," wrote one reader. "Didn't I read something to the effect that most RC transmitter battery circuits contain a blocking diode that prevents you from measuring the battery voltage at the charging jack? Should I remove the battery from the transmitter for testing purposes?" Answer ...

Q-5: "I own a Hobbico Accu-Cycle which has output charge rates of 50 and 125 mA (milliamperes)," wrote a reader. "Recently I purchased an 1800 mAh (milliampere-hour)-capacity four-cell receiver battery. I read what you said about always charging at the C/10 rate (which would be 180 mA in this example) but wondered if I could charge this new pack at the 125 mA and just settle for less than the rated capacity?" Answer ...

Q-8: I noticed in your series that you refer to four- and five-cell receiver battery packs, but I have a single-cell pack rated at 4.8 volts and was wondering what voltage can it reach before needing to recharge? Answer ...

Q-25: I acquired a Global Hobbies ProMax Activator Peak Digital charger. I am just getting into electric power, but would like to use this charger on my regular RC transmitter and receiver batteries. It states in the instructions that you should set the charge current to two or three times the rated capacity of the battery pack. Is that okay? You also said in your "Battery Basics" article (October 2003 Model Aviation) that a battery pack is bad when it is depleted to 20% of its rated capacity. How do I know when I get there? Can you straighten me out? Answer ...

Q-38: After discharging my batteries (either by flying or when simply discharge testing them), should I recharge them before storing or just leave them in a discharged state? Answer ...

Q-39: I have an "onboard" glow-driver battery for my twin-cylinder engine that requires two cells in series. Can I, without damage, charge this battery on the receiver side of a regular transmitter/receiver charger? What about the receiver side of a Sirius charger? Answer ...

Q-41: I own an ACE Digipulse battery charger which you have recommended on several occasions. My question is, do all six outputs of this charger work independently of the other? Also, how long can I keep my battery packs attached to the Digipulse (in a pulsed trickle mode) without it affecting the life of my batteries? Answer ...

Q-57: I recently read about using a 24-hour appliance timer to operate a power strip, to which I can plug in a series of RC-system chargers. The idea is to set the timer to come on for something like one hour in each 24-hour period. This effectively provides a trickle charge on the batteries. Is that a good idea?

I also have a question on battery cycling. I’m on a low budget so I’m not ready to buy a fancy device to discharge my batteries. What kind of an inexpensive load can I use to discharge-test my batteries? How low should I allow the voltage to go during a test discharge?  Answer ...

Q-81: I took your advice and bought an AstroFlight 109 Lithium Charger (the one with the green label). I certainly am pleased with the overall operation. But one thing bothers me. When I attach the two alligator clips to my automobile battery, the sparks go flying!
I don’t like having sparks fly in close proximity to battery gas vapors or even gasoline fumes. I’m sure if a main power switch was incorporated into this charger, I wouldn’t have any problems. Do you have any suggestions? Answer ...

Q-82: I just purchased an FMA Direct/Kokam Li-Poly battery pack. It only has two wires coming out of the pack. Do I assume one is for charging and the other for operating my electric motor (discharging)? Answer ...

Q-84: I’m afraid that constant charging of my Ni-Cd and NiMH RC-system batteries is going to prematurely wear them out and force an early replacement. To help this situation, I usually bring my RC transmitters out to the field three of four times before I resort to recharging them.
Do you think to be on the safe side I should resort to field fast charging those batteries for a short time, to make sure I have enough power to fly at a particular field session? Answer ...

Q-110: I have a perfectly good Hitec 335 charger that I purchased several years ago to charge Ni-Cd battery packs. Now I also have several NiMH battery packs and wonder if I can use this same charger. I understand from what I’ve found on the Web that NiMH cells have a different peak voltage than Ni-Cd cells, and that as a result, my charger may have difficulty in detecting it.  Answer ...