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FX3048T with Honda EU3000IS as backup

Posted: Wed Dec 06, 2017 9:49 am
by raysun
Our off-grid system includes a FlexPower One with FX3048T inverter. For backup power, we use a Honda EU3000IS generator. The Outback documentation states the generator should be capable of carrying the entire power load of our system, and for the most part the EU3000IS does that.

On occasion, with the generator running, a load spike (like a pump turning on) will cause the FlexPower One to temporarily drop the generator and provide the demand from the batteries. After a moment, the system seems to "catch its breath" and switch back to the generator to supply the load.

My question is: Does the cycle of dropping the AC Input, momentarily switching to (inverter) battery power, then using the AC Input cause excessive "wear and tear" on the Flexpower One?

Re: FX3048T with Honda EU3000IS as backup

Posted: Wed Dec 06, 2017 10:20 am
by Jorge Guzman

The internal transfer switch is a mechanical relay so just like any other, it does have a life expectancy. When it transfers from generator to Inverter mode, inside the relay tends to have some arcing which may promote wear and tear. However being "excessive" is depending on the amount of current being transferred.

Ideally, you want your generator to be able to handle not just your loads but also surge and battery charging.


Re: FX3048T with Honda EU3000IS as backup

Posted: Wed Dec 06, 2017 11:01 am
by raysun
Thanks for the response Jorge. I agree the EU3000IS is underpowered in some situations - eg: full "house power" load added to full battery charging load can well exceed its capacity. If we think that will be the case, we adjust accordingly - generally turning off or scaling back the inverter charger demand - letting PV do the charging while taking the load off the batteries by running the house loads off the generator. Even then, our Grundfos 1.5 HP pump will trip the switching event, even though total power demand other than the pump may be well under 500 watts, and the Grundfos purports to have a "soft start" technology to minimize startup demand. (The operative thought here being what does "minimize" actually mean?)

Fortunately, these high current switching events are relatively rare, and if eventual relay replacement is the main concern, we'll live with it.