12/18/2011

by Kurt Moser 

iMAX eFuel 20 Amp Switching Power Supply

Good things come in small packages 

It seems that every hobbyist needs a way to power small bench devices to cut, drill, true, weld, and do countless other tasks in the pursuit of their chosen hobby.  The better the power supply, the more tasks can be performed, and the more that husbands everywhere can procrastinate when it comes time for all the tasks that their wives have planned for them this weekend.

Enter the iMAX eFuel 20 amp switching power supply.  At 908 grams (a hair over 2 pounds), it packs quite a punch for its small size.  According to the specs, it can pump out 20 amps (plus or minus 1 amp), and has a continuously variable range of 6 volts to 15 volts.  This is good for just about any bench tool requiring DC power, with enough juice to handle some fairly high amperage motors.  Voltage is adjusted by way of a knob mounted on the faceplate, next to the digital display for voltage and amperage read-out.  The read-out is angled upward for easy viewing, though there is no backlight.

Power delivery comes via two pairs of output jacks, capable of handling 3mm banana plugs.  Loose wire ends can be screwed down as well, so you’re not restricted to the banana plugs.  To make it a little easier to use, the unit ships with four self-adhesive rubber feet, so it won’t do the SuperBowl Shuffle off your workbench during operation.

One much-appreciated feature is the separate power cord that can be detached for easy storage during transport.  Some units have a permanent cord which can be damaged when a heavy power supply pushes against the cord, bending it against the supply’s casing.  With the detachable cord, it’s a simple matter to remove the cord, tuck the power supply into a box and head out the door.  Portability is one of the eFuel’s strong points, and to make transport even easier, the case of this lightweight power supply has compact dimensions: 7.25” x 3.5” x 2”.  The plug receptacles and power switch stretch the length a bit, and the rubber feet make it stand a fraction over 2 inches high, but overall, it’s downright tiny.  Pictures have been included to give you a sense of scale, and since this review is intended for slot car fans, the comparison photos show the power supply with a 1:32 scale slot car box from Carrera.  The power supply is considerably smaller than the slot car box – about half the height, not as deep, and if it weren’t for the output plugs, it wouldn’t be as long, either.

Some of you may want to know if this power supply would also be good for powering a typical 1:32 slot car track.  It certainly has the numbers – the right voltage range, and more than enough amps – but it’s not a regulated power supply, so don’t get your hopes up.  Since it isn’t regulated, I’d expect amps to momentarily drop off when the load is increased, but since I haven’t tested it, I can’t say for sure.  I expect to try it as a track power supply after the holidays, just to be sure.  It may not be regulated, but it does have some good built-in self-protection features, like short circuit, over-load, and temperature protection.

My first experience with this power supply involved going mobile, popping it into a box, and taking a tire truer along for race night.  The truer manufacturer recommends 10 amps, and it turns out that a 10 amp supply is fairly tough to find at a good price, at least until finding the eFuel.  The eFuel drove the Area 3 tire truer without a hitch, and the two worked together very nicely.  The combo was very easy to use, and convenient enough that I’m planning on taking it with me consistently on race night, at least until other guys start keeping tire truers at their tracks.

So far, I’m very pleased with the purchase.  This power supply brings a new level of flexibility to the entire club.  You may find it just as useful, especially for the price.  Hobby Lobby lists it at $89.99 US (retail), but it’s been spotted on sale for $69.99.  We’ll see over time if the durability is there, but based on what I've seen so far, this is a tremendous value for the hobbyist.

- Kurt