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cc to HP conversion

12415 Views 19 Replies 9 Participants Last post by  Glenn M
Hi Folks,

Looking at a Generac GP 3250 generator for emergency power use. It has a 207cc engine. Googled "convert cc to HP" and came up with "15-17 cc = 1HP. Doing the math, 207/15=13.8 HP? I had a 5500 Watt Homelite with a 12 HP engine. So, a 3250 watt generator with a 13.8 HP engine?

Is the above mentioned conversion applicable for small gas engines or am I missing something? I know that Generac is a good machine, but that much overkill?

Thanks for your time,

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The 196cc engines on our mini bikes are also labeled 6.5 HP.
I've got a 4000 watt Onan that I took out of a '73 motorhome. I have it built into a custom box outside the house and we use it for our backup. It works just fine to run the fridge, microwave, lights and TV. I see them on CL every so often.

As for the computer, you have to be very careful about the voltage fluctuation of a generator. You should really use a digital inverter type generator to provide clean power.
also, if you plan on running electronics off the generator i highly recommend getting a good UPS. power the UPS from the genny and the electronics from the ups. you can potentially fry them them if you don't.
I've got an APC Smart UPS 1400 but I still don't trust it enough to use my computer when we're on generator. Generators provide really dirty power compared to what normally comes from the grid.

But that's just me.
that is what the UPS is for, it cleans up the AC. some will not run off generators at all they stay on battery!
That's pretty much what mine does, it either wants to run on battery, or run on the generator and beep while flashing lights due to any minor fluctuation in voltage. All in all, a disappointing surfing experience.

I can usually go for a day or two without the computer by keeping busy with all the other 'power outage' issues. My daughter? Not so much... :)
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