Okay, time to talk about "technical aspects" of the Powerbox 40-24 units.

You can get 2-3 different versions of this Powerbox 40-24 piece, the "Professional" which lists for $225 from Aircraft International WITHOUT the required dual external switches (for an additional $75), the "Competition" version which handles 7 channels but still only 24 separate servo connections, and the "Competition-Lithium" version which is basically the same unit being sold by Duralite. Both of the "Competition" units sell for $325.

First off, the "Professional" unit, which is the same as the one I have. Power to the unit is through two external 20 amp switches, that directly switch the battery pack they are attached to. This power is fed to the unit, and DIRECTLY to the servos, with no voltage regulation to the servos (they get whatever the battery is putting out) the voltage IS, however, "balanced" between the two power inputs, with the higher input biased toward to give power, and the lower level input waiting it's turn. This allows both packs to discharge at an equivalent rate. Power to the RECEIVERS, however, is voltage regulated to 5.0 volts, through two 1.5 Amp rated regulators. All servo signal wires are filtered and separate, preventing feedback on the signal wires. This is a decent "Basic" unit, without too much going on besides rudimentary signal amplification to the servos, as well as high-current capable voltage distribution, with a regulated voltage to the receivers. A lot of "feedback" prevention is also provided by using ferrite rings on the receivers pigtails, to suppress rf noise. The voltage indicator LED's are programmed for EITHER 4 OR 5 Cell packs, from the manufacturer. (I've had two of these. . the first one lost one string of LED's due to a circuitry failure inside the unit, the first time I installed it. Aircraft International replaced the unit for free)

The "Competition" units (include lithium version) are a bit more sophisticated, using fixed 6 volt regulators to BOTH Servos and Receivers (so the receivers are sharing power with the servos again, instead of being regulated lower) The switch changes to a single "idiot proof" (safety) switch with recessed buttons, and is "Electronic" The box itself still shows the plugs for the older style direct-voltage inputs from two switches, so maybe Michael Glavin can clarify whether the current actually passes through tis "Electronic" switch, or if the switch controls an electronic switch inside the unit itself.. Channels are upped to 7 channels in-out, with 4 of the channels feeding 3 servos each, and 3 channels feeding 4 servos. Current capacity of the unit is still 40 amps, and amplification/isolation circuitry to the servos is basically the same as for the "Professional" unit, with a re-routing of signals to include a 7th channel. This unit is focussed more toward high-end turbine aircraft, and is touted as such.

Both units come with 5-LED voltage level indicators on the face of the unit, with the "Competition" units featuring a "Low voltage/inflight error" memory so that the user can check the lowest voltage levels during a flight. Both units also have ports for "Low Voltage Warning LED's" to plug into. These LED's undicate when the voltage from the battery packs has dropped a pre-determined "safe" level, and are mounted in an easily visible place on the plane.

Weight of these units is approximately 5 ounces, and they are rather small, measuting about 4" x 3" by less than 1" thick. They come with mounting grommets and instructions (of course), and the low-voltage indicator LED's. The switch setup for the "Professional" unit must be purchased separately ($75), and the single switch for the "Competition" units handles both battery packs (and appears to handle all the current for the unit as well. . up to 40 amps)

A technical breakdown of the Powerbox 40/24 can be found on the Aircraft International website: http://www.aircraftinternational.com/
You will have to go to "Catalog", then click on the "Powerbox" label/icon. The information is in a downloadable file for Adobe.


Next I'll review the basics of the Emcotec box.