Generator

[Legacy Posts]

I'd like to purchase a generator for my 17' Bigfoot trailer, which has the 11,000 BTU rooftop air conditioner. Will the Honda 2000 generator do the job? Or is there another generator that would work better?

Cheers,

[Legacy Posts]

How many amps does the A/C draw? It should be on the unit somewhere.

Then multiply it by, oh I don't know, 1.3 or 1.5 to account for startup load. That'll give you surge start up amperage. If you have access to a multimeter that measures inrush amps you can measure it directly.

How many watts does the Honda provide? (That information is on the Honda website) 2000 watts is 16.7 amps surge (2000watts/120v AC=16.7) I'm going to guess 1800 watts continuous or 15 amps (1800/120). If the A/C is under 16.7/15 amps startup/continuous then the Honda ought to handle the load. Get the specs to do a proper calculation.

What did your search of the site reveal? Lots of discussion about generators and A/C in the past.

Good luck! Stay cool!

[Legacy Posts]

Make a deal with your Honda generator dealer: tell them that you would like to test the unit and see if it will power your trailer's A/C. Take your trailer to the dealer, and plug it into the generator.

I'd guess that an 11000 BTU A/C will be working the generator at nearly 100 percent capacity. Also, if you turn the A/C off and immediately back on, the compressor in the A/C will probably not start when using the generator. If you turn off the A/C, and wait 5 minutes before restarting, this should not be a problem.

Let us know how things turn out.

-- Dan Meyer

[Legacy Posts]

The Duo Therm manual says that my generator should be 2.5 KW minimum. Elsewhere it says that the Compressor Rated Load Amps is 10.7. If I multiply 10.7*1.5=16.05. Is that the figure you were talking about? If so then the Honda should work I guess.

[Legacy Posts]

Hello,

the rule of thumb is to have 2 times (or a bit more) generator watts more than the AC unit is rated in watts.

Reason is that after an AC compressor pump has been run there is a pressure differential that requires the compressor motor to start against that this surge very high.

[Legacy Posts]

I like Dan's suggestion. If at all possible, try before you buy. He also makes a good point about not turning the A/C on and off quickly in order to test the system.

Honda's have an economy switch and the A/C might not be able to spool up quick enough during startup loads. You might need to run the generator on normal mode.

My sense is that doubling the running load in order to estimate the starting load is one way to guarantee having enough power but that the actual start up load will be somewhat less. I also believe that doubling the running load accounts for the 'power factor' loss associated with using a modified sine wave generator. The Honda 1000 & 2000 (and the smaller Yamahas) generate (almost) pure sine wave current and you may be able to squeak by with the 2000 instead of the recommended 2.5kw.

'Power factor' is an electrical term that describes how motors relate to the alternating current driving them.

I agree: If you're going to spend the money, test it out first.