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?
A-39: When you write in, please mention the size (or type) and the
capacity of the batteries you are mentioning. That information will help me
provide the best possible answer to your questions.
I’d guess that you are using 1 or 2 amp-hour (Ah) Ni-Cd or NiMH cells. Most
dual-output RC-system chargers provide only 50 mA current for an eight-cell
transmitter battery pack or a four-cell receiver pack. That low of a charge
current would never really charge the battery properly. If you did have a 1 Ah
(same as 1000 mAh) cell, it would need 100 mA for an overnight rate.
For fast charging, you would use a 3C charge rate for Ni-Cd cells, which would
be 3 amps for roughly 20 minutes, or a 2C rate for NiMH cells, which would be 2
amps for 30 minutes.
If you want to use an overnight (C/10) rate, I recommend the ACE Dual Digital
Variable Charger, or DDVC (www.acehobby.com/acehobby/products/electronics/chargers/superDDVC/index.html),
which has two variable outputs that can handle one to at least 10 cells at
currents from 0 to well more than 300 mA.
For fast charging, the Sirius charger (I believe) is intended for four or eight
cells. There is also one that starts at three cells, but none, to my knowledge,
will handle a two-cell battery as you have. For fast charging, I recommend the
AstroFlight 110 Deluxe (www.astroflight.com). It can handle one to 24 Ni-Cd or
NiMH cells at current levels from 50 mA continuously variable up to 8 amps.