Although charger technology has moved on from the basic Mardave charger I remember from my youth (it was little more than a lead, large crocodile clips for attachment directly to your car battery & a couple of cement resistors) and of course the early clockwork Acoms units (which ran from the cigar lighter plug - remember when those were standard?), there's still a need for a 12v source when chargers without a built in transformer are used anywhere with a roof and a mains power supply.
That's where LogicRC's "Fusion" range of power supplies come in. The 6 variously spec'ed units run from a 100W/8 Amp tiddler (the PS100) right up to the 600W/40A PS600ADJ. The PS200ADJ reviewed here is in the middle of the range, it has a backlit LCD display & the power is adjustable from 5 to 15v DC and 0-15A, but at 200W lacks the power of the heavyweights.
I've been using a hotwired ATX PSU as a charger power supply (also doing double duty in providing 12v for the LED strips fitted to my RC display), but when it failed suddenly & I didn't have a spare, it made more sense to buy a self contained, ready to use unit.
Main power is supplied by a standard "figure 8" style lead. This is a plus for me, it's a lot easier to replace a lead when it can simply be unplugged, and cable failure is not that uncommon in small consumer transformer type equipment, if it gets used infrequently & put away with the cables wrapped around it in the mean time ...
Output is via two colour coded, gold plated 4mm "banana" plug sockets, which double up as bare wire/screw down terminals.
Controls on the front are a simple on off switch, and two dials, one each for setting the voltage (nominally 5 to 15v) and the maximum amperage (0 to 15A). These are a little fiddly to set despite being topped with caps in a rubber like substance, and it should be noted that these seem to be omitted on the current model - if you regularly need to tweak the voltage for some reason this may be an issue.
It should be noted that the controls are not independent - I had initially thought that the "Current Limit" setting would be an absolute, i.e. the unit would cut out if the amperage was exceeded, but it's actually a lot more clever than that - if the amps drawn exceed the value set, then the unit reduces the voltage to a point where the current is within that set. If you remember that current, volts and resistance are all interrelated under Ohms law (Cub Scout "electricity" badge, GCSE Physics, etc) then of course that makes sense, but it's more subtle than I expected at this price point.
The backlit LCD display is a simple 2 line affair showing the voltage currently being provided (on the top line), and the Amps being delivered (on the bottom), both to one decimal place. The display is a pleasant enough blue shade & the brightness level (which is not adjustable) seems to have been well chosen, being bright enough to still be visible in anything but the brightest sunlight, and yet not light a room in near darkness.
In comparisons with my multimeters (cheap Draper analogue & Gunsons digital) the voltage display is accurate to + or - 0.3v, depending on where you are in the voltage range and the load on the unit, but then it's not a regulated/laboratory power supply and you wouldn't expect one at this price point.
Voltage Accuracy: Load Test
I've already noted setting the dials and comparisons with a multimeter, but how the unit performs under load is more important.
I set the PS200ADJ maximum amps and to an indicated 12v (12.03V on the multimeter) at no load. Adding a 2.1 Amp load (just under 10 meters of LED strip lighting) saw the voltage indicated on the unit remain at 12.0v on the unit, but drop to 11.82v on the multimeter.
Adding an Imax B6 charging an 8.4v NiMH pack at 5 amps saw the unit indicate 12v and (7.0A), and the multimeter reading drop to 11.79v.
Adding a 2nd B6 (this time charging a 7.2v NiMH at a peak of 5.0A) resulted in the PS200ADJ continuing to read 12.0v and up to 11.5A, with the multimeter showing the actual voltage had dropped to 11.73v - a drop of 2.25% volts at an 11.5 Amp load (70 percent of its nominal rating) is actually pretty impressive.
This is noteworthy, as I know the "laptop" power supplies often touted as being suitable for this type of charger cost an awful lot less, but even though they're rated at 5 Amps, try pushing them to that sort of load and the voltage will drop, sometimes to below the level at which the charger will actually run at.
I make no apologies for the dull graph, I get fed up of flashy graphics & fiddled with scales attempting to obfuscate and mislead...
It would have been nice (or at least fun) to push the PS200ADJ up to and even way beyond its ratings, but I paid for it with my own money & I do want to be able to use it again afterwards!
Inside the Box
There's no "warranty void if removed" sticker on the case, but the upper and lower mouldings are held together by a variety of security screw - challenge accepted!
A little work with a Dremel was needed to notch a screwdriver blade to fit, but that and a bit of accurate locating down the recessed holes soon had the 4 screws out.
I have to say I was a little disappointed at the size (and weight) of the components inside, they don't particularly fill me with confidence. That said this is only a 200W PSU so the magic smoke holders don't have to be particularly chunky.
Remember, kids: don't try this at home!
Did I Mention ... it Sucks!!!! ;)
All good so far, but there's a major problem as far as I'm concerned - it makes a loud, droning, swooshing, sucking noise. It starts quite noticeably, but gets louder, not vacuum cleaner loud, but enough to be irritating, even over a less than quiet desktop PC and a radio on at a low to moderate level.
It's not (directly) the fan, I've had that out of the case and it runs smoothly & quietly despite its diminutive size - but once installed it's a different matter. The exhaust seems to be reasonably free flowing, and there doesn't seem to be any sort of vibration and/or resonance, the only thing left is the size and shape of the intake slots.
In other environments (the average set of pits, for example) it wouldn't that much of an issue, but I've found it to be a real problem for home use.
So far my efforts to quieten it down have been:
- using resistor(s) to slow the fan down & therefore reduce airflow & reduce noise, but enough voltage so the fan starts still result in the same pitch of noise, just a little quieter;
- fitting a switch on the back to turn the fan off entirely when the unit is only being used for lighting, and back on when charging, or when I feel I can tolerate the noise. The problem here is that the unit does heat up - not particularly quickly or alarmingly, but I feel it does need some active cooling. Note: In extended testing at a 2 Amp load (8 hours at 20 Celcius) the temperature reached 40 Celcius after an hour & stayed there; however I can't recommend this, especially when charging.
I think the next step will be to slightly open up the cooling intake slots & round the edges. Theorising that the noise is a form of whistling, that could help. I'll let you know how I get on.
My only other issue (good or bad) with the PS200ADJ is the price ... personally it seems just a touch too high for what you get. I suspect that's just me getting old though, as having looked at other manufacturers offerings, you can't get more power without spending more, and even then those units don't have the same range of features.
That said, you can get a Power Supply with the same rating for less, but not one that's adjustable or has a display.
Overall though, price is a "plus" too.
This is a really tough one to rate - given the standard of voltage control and other features vs price, ordinarily I'd have no hesitation in giving it a 5 out of 6, but the banshee like howling pretty much rules it out for the sort of use I bought it for without modification, so despite all the good aspects, a 3 or even a 2 would be more appropriate.
Taking everything into account, my final rating is 4 out of 6: good, but some more development needed.
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Guide price: LogicRC "Fusion" PSU range 16 to 90 GBP; best price on PS200ADJ model around 38 GBP (+ postage)
Written by TB member Jonny Retro