MC2002 Charger: Multi-use unit

Model Airplane News, Oct 2002 by Cawley, Bernard Jr

PRODUCT WATCH

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GWS

MC2002 Charger

Multi-use unit

Grand Wing Servo (GWS) has added an inexpensive and flexible battery charger to its ever expanding product line. Designed for NiMH and Ni-Cd packs of from 4 to 12 cells and with an adjustable charge rate of from 0.25 to 6 amps, this unit is suitable for a wide variety of electric-power batteries. I can use it to charge the batteries for every plane I fly, from the 7-cell, 300mAh NiMH packs I use in my Tiger Moth up to the 10-cell, 3000mAh NiMH packs and 2400mAh Ni-Cd packs that I use in my Jeti Phasor-powered Sig Kadet LT-25. I can also use it to charge my transmitter battery and the AA-size NiMH cells that power my digital camera. And it costs less than $50!

The charger has a large heat sink on its back, and on its face is a 0 to 6A meter, a current-adjusting knob and a switch for selecting between two cell-count ranges (4 to 8 and 6 to 12), and two LEDs marked "Trickle" and "Fast." Power input is via a lead of a reasonable size that ends in a pair of small alligator clips that you clamp to the supply battery. Output is via a pair of spring terminals such as those commonly found on stereo speakers. Output leads ending in bare or tinned wire ends are easily connected to these terminals. It also comes with JST, Tamiya and Futaba-J leads. Plugged into the left side of the charger case is a 20A, automotive-type input fuse.

Operating the MC2002 is extremely simple; just hook it up to a 12V power source (the charger operates on 9 to 15 volts DC). The red "Fast" LED will flash a few times, indicating that the charger is going through its power-up self-check. Select the cell-count range that's appropriate for the pack you want to charge, and turn the current-adjust knob to the left. After you've connected the pack, the red LED will light and, 6 seconds later, the fast charge will actually start. At this point, adjust the knob to set the desired charge current. When the battery has reached its peak, the red LED will go out and the green "Trickle" LED will light. The charger remains in the trickle mode until you disconnect the battery you were charging. That's all there is to it.

The trickle mode of the MC2002 is unusual. Instead of a steady but reduced current, it puts the full selected charge rate into the battery for about 2 seconds every minute, effectively giving a trickle charge of 1/30 the selected charge current. For example, if you have set it to charge a pack at 1 amp, it puts a 2-second burst at 1 amp into the battery every minute. I have found that this keeps the battery just slightly warm for an indefinite period.

The peak detection is sensitive enough for NiMH batteries, and when charging the batteries at 1.5C rates, I find that 300mAh to 3000mAh NiMH cells are warm but not hot when the unit ends the fast charge. Speaking of 1.5C charge rates, this charger has a 45minute time-out on fast-charging, so you must charge at about 1.5C or higher for the battery to be fully charged before the safety timeout kicks in-disappointing if you want to be really conservative and charge your NiMH packs at IC or less.

Another minor quibble is that the meter's 0 to 6A scale makes it a little difficult to precisely set the low charge rates that are suitable for slow- and park-flyer-type batteries. The gradations are in 0.2A increments, so setting the charger for 0.3 versus 0.5 amp is a matter of only one line on the scale. But for me, having a wide range of available output current overrides this concern.

The MC2002 is easy to use and flexible, and it's very attractively priced. It can handle a wide range of cell counts and capacities; you can use it to charge batteries for park flyers and also for 400W, 12-cell airplanes. I like mine so well that I got a second one to keep in my pickup so I'll be able to take better advantage of impromptu flying opportunities. Take a look; you'll be glad you did.

-Bernard Cawley Jr.

GWS; distributed by Horizon Hobby Distributors (800) 338-4639; horizonhobby.com.