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Old 12-07-2015, 20:52   #16
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Re: What size generator?

I have a 7.5KW that easily runs 2 fridges, 3 AC Units, all my nav stuff a TV and probably a hair dryer if I tried. On shore I have a 50 amp set up.

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Old 13-07-2015, 05:20   #17
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Re: What size generator?

Originally Posted by ASolangeM View Post
Hello! New member and boater here. I have a 38' 1989 Trojan tri cabin and I need a generator that will run 2 mini fridges, a/c, lights, radio/satellite TV, ice maker and maybe a couple of phone chargers simultaneously. And occasionally in addition to all of that a cook top, microwave, coffee pot or blender. I was thinking 42-43 kW but from what I've been reading that may be a bit much. I don't want to over load the generator but I also don't want to have double the power needed. Please help. Amy advice will be appreciated.
Ps. I'm in the USA.
Our 8 kW genset runs 2 fridges, 2 16K BTU ACs (with soft start), 2 110V lights (but most of our lighting is DC with LEDs), 2 TVs/DVDs or whatever other stereo equipment we feel like at the moment, multiple phone/tablet/computer chargers, two-burner electric cooktop (not induction), convection/microwave oven, water heater, and coffee maker. All simultaneously.

I think I remember from genset specs ours provides 66 amps at peak.

Our normal shorepower service is 50A/250V (so 100 amps total from both legs combined.)


Selby Bay, South River, Chesapeake Bay, USA.
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Old 13-07-2015, 05:54   #18
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Re: What size generator?

We do pretty good with 2.4kw (don't miss the decimal place) for just slightly lower power demands. With a couple mini-fridges and an ice maker, maybe 3.0 to 4.5kw would do the trick.

Of course the big wild card is what is the size and power demand for your air/con. I'm just running a single 12k btu unit.

Also, the question regarding your available shore power is to determine what your available power is when at the dock. If you have a 30amp shore power cord, you have around 3.6kw (actually a bit less) at dock, so if that is fine, 3.6kw should be plenty when on the hook.
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Old 13-07-2015, 08:06   #19
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Re: What size generator?

Originally Posted by ASolangeM View Post
Any suggestions on a pro in the Tennessee area that would be reliable and honest and not charge an arm and a leg?
You could pay someone who can read and add the power demands of the equipment you might simultaneously use. However, any elementary school graduate should suffice.
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Old 15-07-2015, 10:58   #20
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Re: What size generator?

thanks everyone! You have really helped me understand better. I was on some website before finding this forum that had m adding up all of these huge numbers. I just discovered I have a 6.5 kW now. But it's not running. I am adding a few more gadgets in the future so I'm thinking a 8 would give me a little more juice for when I need it. Any recommendations on brand? Or where to buy from?
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Old 15-07-2015, 14:49   #21
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Re: What size generator?

If you already have a 6.5 i would think that should do nicely. I would look into having that one fixed, overhauled or replaced with one just like it. It will save a lot of money on the installation / modifications.
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Old 15-07-2015, 14:56   #22
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Re: What size generator?


Likely to be a little over $20,000 USD including accessories and labor.
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Old 15-07-2015, 16:34   #23
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What size generator?

If your boat is gasoline I recommend Kohler, Onan or Westerbeke. If diesel then Northern Lights or Westerbeke. There are several other good diesel choices. Diesel should be 1,800 RPM for 60Hz. Gasoline will probably be 2,400 RPM for 60Hz.
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Old 15-07-2015, 18:09   #24
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Re: What size generator?

Only thing I would add is don't go too over powered or your generator will be at risk of not having enough load on it.

I already worry about my 5.5 KW nextgen running only my battery charger so usually turn on the AC as well to load it some. But with water heater, charger, and AC i still could likely run a smaller genset.
I would avoid the 3600 RPM diesel generators. An 1800 will be most robust and likely most durable, but also heaviest and largest as it will require a larger engine block to get power out at lower RPM. Nextgen is an interesting compromise. One was already installed on my boat but I am coming to appreciate it. It has a reduction belt so it only turns at 2700 RPM which sounds a lot less frenetic than 3600 RPM. But still lightweight and compact.

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