I just purchased a Yamaha ef2000is generator. It is a 2000W generator with s sustained 1600W rating; can go higher for small period of time. I hooked it up to our camper this afternoon and had it running for 30 minutes or so, I then ran the microwave in the camper and it worked fine. Tonight I plugged the camper into the generator and stared the generator and went into the camper and tried the microwave; it ran for about a minute (past the initial startup) then the generator went into overload (red light) and stopped the AC output. I did this several times; then decided to let the generator run 10 minutes; then try the microwave; and it ran fine for several minutes which was enough to pop a bag of popcorn. The microwave in the camper is rated at 1300w. I had nothing else on (running) in the camper to cause a load on the generator.. The questions I have are:1. Do these ef2000i or other generators build up a reserve so they need to run a few minutes before putting a heavy load on them? 2. Do others use 2000W generators and have issues running the microwave?

Hi,My Yamaha owner's manual suggests running it for five minutes before putting on a heavy load.I suspect your converter (battery charger) was drawing a few hundred watts.

Electric water heat and fridge are off?1300w is cooking power or input power?

+2 for all the above. The converter can be drawing 5 or so amps (600 watts) if you battery is not charged. Reefer and HW also can be an issue. I ran my microwave all summer with my Honda EU2000i without an issue but I made certain the reefer was on gas, same with HW. Also would be certain that my battery was pretty well charged. BTW that was at 7000' where the genny would have been less efficient.

I run my microwave with my Honda 2k but it flat maxes it out very loudly. I much prefer my 3k Honda to run any high out put stuff. It just purs a little faster.A much quieter generator.

2000w Generator Running Microwave? | Good Sam Community

2oldman
Explorer II
Aug 25, 2014
Is your converter on?
pianotuna
Nomad III
Aug 25, 2014
Hi,

My Yamaha owner's manual suggests running it for five minutes before putting on a heavy load.

I suspect your converter (battery charger) was drawing a few hundred watts.
time2roll
Nomad
Aug 25, 2014
Electric water heat and fridge are off?

1300w is cooking power or input power?
jmcgsd
Explorer
Aug 25, 2014
+2 for all the above. The converter can be drawing 5 or so amps (600 watts) if you battery is not charged. Reefer and HW also can be an issue.

I ran my microwave all summer with my Honda EU2000i without an issue but I made certain the reefer was on gas, same with HW. Also would be certain that my battery was pretty well charged. BTW that was at 7000' where the genny would have been less efficient.
jaycocreek
Explorer II
Aug 25, 2014
I run my microwave with my Honda 2k but it flat maxes it out very loudly. I much prefer my 3k Honda to run any high out put stuff. It just purs a little faster.A much quieter generator.
Bcamper
Explorer
Aug 25, 2014
Thanks for the great feedback already. To answer a few of the questions. The only thing on in he camper while I was testing the microwave was the "converter" which was probably charging the battery. The fridge, hot water heater and everything else was off.

I didn't realize the converter charging the battery could be causing a heavy load (600w). While the generator is running; can I just turn off the converter which would stop the battery charger? I'm assuming since the microwave is AC and the generator is AC the converter is not doing anything for the microwave; but it is the one charging the battery. If I turn it off; does it stop all power going thru it or will the AC still run thru it? I guess I can check my manual or just try it.
valhalla360
Navigator
Aug 25, 2014
Presumably your battery was partially drained so the converter took some of the generator power to charge your battery. The converter is a seperate draw from the microwave. Net result was both the microwave and the converter were pulling power and it overloaded the generator. There should be a breaker to shut off the converter.

Especially if you just turned on the generator the converter may be topping up the battery even if it didn't seem like you used much 12V power off the battery. If you didn't use much 12V letting the generator have 10 minutes to get the battery topped up may be enough to address the issue. (If you have a battery that won't fully charge, the converter could stay on all the time, which is also bad because doing so will boil off the water in the battery)

Letting the generator warm up for a few minutes can also help if you are pushing the limits as they will handle slightly higher loads when warmed up (but not by a lot)
W_E_BGood
Explorer
Aug 25, 2014
My Yamaha ef2000is routinely runs the factory Dometic micro, even in eco-mode. You must have had something else putting a load on it as others have already suggested.
ktmrfs
Explorer II
Aug 25, 2014
the converter, depending on the model and battery state of charge can draw as much as 13Amps, 8-10 amps on a somewhat discharged battery is not uncommon

Couple that with the poor power factor for microwaves and converters and the two together do not make a nice combination for a 2000W generator. It should be able to easily run one or the other.

BTW a 1000W microwave will draw 1600+VA which is what generators care about and usually within the continous rating of a 2000W generator.
2oldman
Explorer II
Aug 25, 2014
Bcamper wrote:
can I just turn off the converter which would stop the battery charger? .. If I turn it off; does it stop all power going thru it or will the AC still run thru it?
yep. Ac will run fine. The converter is simply another 120v appliance in parallel with everything else.