Honda EU10i Genset

I must confess, I'm blown away by the level of technology in Honda's 0.9kVa EU10i. Honda's new offering is the first truly viable alternative to permanent onboard gensets, for owners of cruisers and yachts alike who want to run frequency-sensitive equipment.

The EU10i produces such a high quality of electricity supply, that not only can it run stereos and TVs but also PCs unlike all other portable gensets, where the frequency fluctuation can damage these!

Unlike conventional gensets, where the engine drives a separate alternator at a steady 3000rpm to produce 240V and 50Hz (cycles per second) of frequency, the EU10i uses a sinewave inverter. Honda does not give technical information in the owner's manual wiring diagram on how the inverter works, so I contacted my local electronics wizard, Richard Ardizzone.

For example, the old sidevalve Honda EX1000 (which produced a continuous 750W at 50Hz) weighed 26kg, while even Yamaha's OHV EF1000 (700W at 50Hz) weighed 25.2kg.

The EU10i weighs only 13kg, and measures a compact 450mm long, 240mm wide and 380mm high.

The inverter also runs the unique dual throttle settings. One setting provides the normal rated engine speed, while the other is known as the 'Eco Throttle' and via a 'stepper engine' control allows the engine to run only as fast as needed to power the appliance at hand.

In fact, the EU10i can be run all day on very little load. There's a slight hesitation as the engine steps to its next level as load increases, but the microcomputer control ensures there's no fluctuation in electricity supply.

The old gensets needed much larger engines to develop their rated outputs. The EX1000 had a 97cc powerhead, while the EF1000 could get away with 84.4cc. However, because the EU10i revs out to 5500rpm, it needs only a 1.8hp, 50cc OHV unit.

The powerhead itself is a 3.2mm smaller bore-version of the 57cc OHV unit used in Honda's BF2D outboard with the same 0.25lt sump but has pressure lubrication, can use normal multigrade automotive oils and operate at temperatures up to 40?C. It also has sensors for loss of oil pressure or low oil level, which either shutdown the engine or prevent it from being started.

Fuel consumption is way below fixed-rev gensets. For example, at 75W it's a mere 0.20lt/hr, or a whopping 59% less than the EX1000 and 53% under the EF1000 on this load. At 225W or one-quarter load the consumption is 0.30lt/hr.

But at half load or 450W, about that consumed by a PC, the consumption jumps only 10% to 0.33lt/hr, still giving 6.9 hours from one 2.3lt tankful. I can only presume this figure is so low because the motor is at or near its optimum timing advance and running at peak efficiency.

At 675W and three-quarters load the engine revved much faster and used 0.43lt/hr, 46% under the EX1000 and 14% under the EF1000. Surprisingly the revs didn't increase much to 900W or maximum continuous load, where the EU10i used 0.52lt/hr.

The Eco Throttle also allows the engine to be warmed-up at idle speeds, before load is applied or the maximum revs are required. This should increase engine lifespan.

The other primary windings supply power to the CD ignition system and the DC battery charging circuit. Unfortunately the latter requires the EU10i to be run with the Eco Throttle off, is not regulated and produces a constant eight amps, so it should only be used with normal marine starting batteries and never deep-cycle batteries. At least it can be used in conjunction with the AC circuit, so you can charge your boat's batteries while watching TV!

Starting the loan unit is normally first pull, hot or cold. We ran-in the loan EU10i for the first 10 hours by varying load every 15 minutes (not exceeding 450W) and over the first 10 hours, consuming an average of 0.3lt/hr.

After this period and an oil change, we conducted the 675 and 900W trials.

More recently, the loan unit has undergone several more trials including fuel consumption tests with the Eco Throttle off.

When the Eco Throttle is switched off as needed for running equipment such as power drills which are regularly switched on and off, and fridges which have a fair amount of starting current the engine maintains maximum revs of 5500.

At 900W the EU10i consumed 0.58lt/hr, still way under a fixed-rev sidevalve genset. For example, my own 1kW Dunlite portable genset, which is powered by a 4hp Briggs & Stratton engine, consumed 1.33lt/hr on 900W and a whopping 129% more than the EU10i!

Due to the sophisticated inverter, the loan unit was able to start and run a 396W 3/8-inch drill and sander while powering three 150W Portaflood lights, and is the only genset under 1kVa capable of doing this. Over a test 'loop' of 75% Eco Throttle 'off' operation and 25% drill use, averaging 360W the consumption was 0.33lt/hr, the same as 450W with the Eco Throttle on. Surprisingly the unit would also start and run a 150W camping fridge while powering four 150W Portafloods.

After the 10-hour break-in period, we changed the oil and opted for API SG semi-synthetic Valvoline Syn Gard. Having an SAE 10W50 rating, it should provide better cold-start lubrication than a 20W50 car oil and can be used in the EU10i from -10 to 40?C the maximum operating temperature for this unit. The next oil change interval is every 100 operating hours or six months, while valve clearance adjustment is recommended every 300 hours.

From the trials we conducted, I have no hesitation in recommending Honda's EU10i as a viable alternative to a permanent onboard genset. And as it weighs just 13kg, you can easily carry it ashore and also use it for camping and fishing holidays!