Laser 4193
Output 120W
Size 122 x 70 x 32mm (LxWxH)
Price £41.90
Web www.lasertools.co.uk
Comments This is one of the smallest inverters we've seen, which makes its 120W of usable power output impressive. Its electrical performance was solid during testing, aside from a tiny flicker from our test lamp during the first few seconds of use. Efficiency was very reasonable, too, and we loved the tiny 0.17A standby current. Our only gripe is that the maximum power of 150W is only marginally higher than the usable output. The 1m-long lead makes the unit versatile and the mains output is a clever combination of three-pin/shaver/europlug socket.
Verdict Versatile and compact. Only its high price stops it getting top marks.

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Ring MP75 Mininverter
Output 75W
Size 132 x 65 x 52mm (LxWxH)
Price £19.99
Web www.ringautomotive.co.uk
Comments With its relatively modest, usable, power output, this is not an inverter you'll be using to run hair dryers, kettles or other power-hungry mains appliances. But the MP75 was never built to be a heavy-duty inverter, permanently wired in place. Instead, it is a super-convenient portable unit that's perfect for powering laptop PCs, small DVD players, TVs, phone chargers and even some shavers. Its diminutive size makes it easy to stash away in a glove box, and the lack of trailing wires means you can get it out to use without dragging the rest of the glove box's contents along, too. Electrically, the MP75 is a great performer, with high efficiency and a low standby current.
Verdict Low-price, top-notch electronics and ease of use, combine to make this inverter our number one choice.

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Ring E:Can
Output 150W
Size 180 x 68 x 95mm (LxWxH)
Price £29.99
Web www.ringautomotive.co.uk
Comments While not quite as neat as its MP75 sibling (p103), the E:Can is better looking than most small inverters. The design is actually more clever than it first appears. For instance, the generous 80cm-long lead can be wrapped around the circular body during storage because there's no risk of any sharp corners straining the wires within. As well as the welcome hike in output, the E:Can's other bonus is its integral USB socket intended to be used to charge modern devices, such as iPods and hands-free phone kits, which are often only supplied with USB charging leads. This inverter came pretty close to being our ‘Editor's Choice' but its patchy electrical performance lost it vital points.
Verdict Promising design with a USB charging point. Electrical performance not so hot, though.
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Clarke CL400
Output 200W
Size 190 x 135 x 55mm (LxWxH)
Price £31.71
Web www.clartkeinternational.com
Comments Clarke rates this unit at 200W output but despite several attempts we never managed to squeeze more than 150W out of it. And, just as with the Clarke CL200 (see p106), the standby current remained at a rather high level of 0.5A. The device is also incredibly large, given the low level of output we experienced. On the positive side it is a good-looking bit of kit and we particularly like the ease of access to the fuse on the rear panel. It scored highly in terms of its practicality, too: the 1.5m-long lead is a genuine boon, making it very versatile, and the crocodile clips, which can be connected directly to your battery, are supplied alongside a lead for the cigarette lighter socket.
Verdict Long leads and the option of direct connection to the battery are the most positive aspects of this inverter.
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Sealey PI 150
Output 150W
Size 165 x 105 x 60mm (LxWxH)
Price £29.93
Web www.sealey.co.uk
Comments This is a good-looking, compact inverter and although not as convenient to store as the Ring E:Can (left) or Laser's 4193 (p103), it has a drilled flange as a permanent mounting point. The rated power of this unit is no higher than that of the Ring or Laser equivalents but this is arguably the more usable product, thanks to its 300W surge capability. This is particularly handy when you consider that many devices demand a start-up current of twice their normal running amperage. However, when we tested the unit at 150W the mains-voltage fell to 209, which made the overall output only 125W. We are at a loss to explain why we couldn't achieve the claimed 300W surge output.
Verdict A well-specified inverter, but we struggled to reach its claimed performance levels.

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Draper 72173
Output 200W
Size 160 x 130 x 55mm (LxWxH)
Price £34.51
Web www.draper.co.uk
Comments If it were possible to combine the best qualities of this unit and Clarke's CL400 (above right), you'd get one very good inverter. The Draper tends to triumph where the CL400 fails, but also lags behind where the CL400 excels. For example, the cigarette lighter plug and crocodile clip leads were stand-out points of the CL400 – and they certainly make Draper's 38cm-long lead seem rather pitiful. But the Draper's electrical performance is more impressive and although our test run didn't return its claimed output of 200W, we got a lot closer than we did with the CL400. Despite this, the Draper's overall efficiency seems marginally lower than the Clarke's and its standby current is still an unhealthy 0.5A.
Verdict A solid performance electrically but its ridiculously short lead counts against it.
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Philex Power Inverter PSI 150 (Screwfix 43494)
Output 120W
Size 125 x 138 x 60mm (LxWxH)
Price £21.99
Web www.screwfix.com
Comments In terms of ‘wattage per pound' this is the least expensive unit we tested. However, we were unable to verify its 120W output rating because when we plugged in an electrical item with a known power rating of 120W, the unit could only muster just over 100W – however, that is quite a bit closer to its rated output than the test results we achieved on some other units here. Also, we were impressed with the flicker-free output and the device's high working efficiency. Despite its low price, the PSI 150 is well specified with a ‘low-battery' warning light, automatic overload cut-out and a 76cm-long 12V lead. Sadly though, these positives were spoiled somewhat by the relatively high standby current of 0.4A.
Verdict Cheap and surprisingly cheerful, with better-responding electronics than many of the other units on test here.
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Frost E165 Sky Tronic
Output 150W
Size 173 x 100 x 60mm (LxWxH)
Price £49
Web www.frost.co.uk
Comments No doubt your first impression of this unit is the same as ours: why does such a basic 150W model cost close to £50? Well, we reckon the price reflects the quality of the components inside. Although we were not keen on its 0.45A standby current, working efficiency was high. And this inverter had no problem in reaching its maximum rated output. Throughout all of the tests, the power supplied was pleasingly flicker free. So why the low score, you may ask? Well, in our opinion, the E165 is not great value, and the surge capability we measured (just 50W more than rated output) would limit what the unit can power. Also, at this price level, the relatively short power lead seems a needless irritation.
Verdict Premium price and electrical performance, but the low surge ability we noted would restrict its applications.
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Clarke CL200
Output 100W
Size 160 x 135 x 55mm (LxWxH)
Price £27
Web www.clartkeinternational.com
Comments This unit is a good-looking entry from Clarke, and that stylish, finned, aluminium case also helps to keep the internal components cool. However, with a unit size of 16x13.5cm, we can't help feeling that this inverter is rather large for its modest, usable, output. Our tests did not fully reveal this model's claimed abilities: although it appeared to provide a good, flicker-free supply to our 100W test bulb, the low 207 mains voltage of the model we tested meant that overall power output was actually less than 83W. The standby current of just over half an amp did nothing to enhance our confidence in this unit's internals, either. Unfortunately, we were unable to test the model's surge capability because we did not know the absolute maximum output of the unit.
Verdict A groovy looking piece of kit, but surprisingly big for its rated output.
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