Light loading leading to failure of the Honda EU26i.

Trouble with the Honda EU26i

Of all the Honda inverters, the machine that I see most commonly suffering loss of electrical output is the Honda EU26i. These failures seem to be fairly evenly divided between stator and inverter pack failures.

So is there a generic flaw with the EU26i? I don’t think so. I am quite sure that the reason the EU26i suffers more failures than its stable mates like the EU20i and the EU30is is simply that it’s a middle of the road machine. It gives a bit more power than the EU20i yet slightly less at significantly less expense than the EU30is. Someone buying a EU26i clearly doesn’t feel they are likely to need 3kw but will not always be able to get away with the 1600w continuous output of the EU20i.

This middle ground status results in the EU26i being used in situations where it might spend a lot of time running very light loads like lights and a TV and be infrequently required to top up a fridge freezer or perhaps run an air conditioner or similar heavier load. The details are not relevant, only that these machines often spend the greater part of their life running lightly loaded.

Light loading is a problem for generators at the best of times but for a silent running inverter with ECO throttle it’s a curse and this is why.

Silent running generators have larger mufflers than standard generators and these large mufflers have a lot of metal in them that takes a lot of heating up. If you fire hot exhaust gases into a cool muffler the result is condensation. That’s not just condensation of water but of carbon and anything else contained within the exhaust gases. The condense coats the inside of the muffler and begins to restrict gas flow through the engine. The problem is further compounded in the EU26i by the fact that the air that has cooled the engine is ejected from the machine through the same cavity in which the muffler is housed thus serving to cool the muffler further.

All that is a recipe for a blocked exhaust but then we have ECO throttle. That ingenious bit of wizardry that slows the engine so that it runs just fast enough to supply the load applied. Of course this exacerbates the light loading problem by reducing the heat being transferred from engine to muffler even further.

All of this conspires to reduce engine power by restricting the flow of gases and then the inverter pack is faced with the task of trying to supply loads that the engine is no longer capable of supporting. It’s all too much for the inverter pack and all its parameters are strained to the max resulting in failure or in burnout of the stator.

I have seen a fair few of these eu26i failures and in every case it has been accompanied by low engine power.

The simple answer is prevention and all that takes is regular running with a full rated load to get the muffler up to temperature thus burning off any carbon build up. After a few minutes running at full load you will probably be able to feel particles of carbon being ejected from the exhaust. Just keep running until the particles stop coming. Do this every 100 hours and your Honda EU26i will not fall victim to the light loading disease.

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