18kpv and small generator..

So I have a small 5000w (4000w constant) portable generator that I use for this and that around the ranch when needing power away from the house. It has a L14-30 plug on it so can do 240v.

Now in the 18kpv manual is says the generator should be between 6kw and 21kw.

So the question is if push comes to shove can I connect this small generator to the 18kpv and utilize that 4kw? By push comes to shove I mean the grid is down, battery is flat, it’s night time/solar eclipse/super cloudy and I want coffee. No I do not want a chargeverter for $500. A L14-30 plug and some 10awg would be a lot cheaper. Yes I can plug the coffee machine into the generator directly and thus my world would not end, but if it goes into the 18kpv I can drink my coffee in the kitchen, with the lights on, and warm a muffin in the microwave at the same time and charge my phone and watch internet tv and be really really happy….yes the aircon/stove/oven etc will trip the gen breaker, but I will have coffee. Hot coffee. Did I mention I like coffee?

When on generator power charging batteries, the generator is also passed through to loads, so loads + charging can't exceed the generator output, 4000W.

It's very common for inverters to need 30-50% oversize to allow full use of inverter rated power and charge.

coffee

Easiest approach for small generators is a separate chargeverter. It won't give you AC coupling but you can use whatever is available.

If you can manage your loads and charging, and keep it under 4kw. Then yes, you will be fine. Assuming that the generator power is clean and stable enough to be accepted by the 18kpv.

Try the "gen rated power" setting.

Thanks everyone. Will get the plug and cable and cable it to the 18kpv in the interim so it’s ready. And will have it ready should the need arise so then can just move the generator to it if that unlikely scenario should occur. I guess I will also test it by killing the battery breaker and the grid mains and the pv disconnect at some point soon to get that warm fuzzy feeling. Maybe in fall when the need for aircon is more manageable so I can test for a couple of hours.

EZPZ said:

Thanks everyone. Will get the plug and cable and cable it to the 18kpv in the interim so it’s ready. And will have it ready should the need arise so then can just move the generator to it if that unlikely scenario should occur. I guess I will also test it by killing the battery breaker and the grid mains and the pv disconnect at some point soon to get that warm fuzzy feeling. Maybe in fall when the need for aircon is more manageable so I can test for a couple of hours.

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Definitely test it, the manual seems to indicate that the generator runs the loads and the excess charges the batteries so it may not work as you expect.

Using the 4kW generator should work as long as the load does not exceed 4kW. However, it is highly recommended to use a generator within the 6kW to 21.6kW range and ensure that the Total Harmonic Distortion (THD) is less than 5%.

Also tune down the AC amperage setting so it doesn't try to draw 6000a across a 20a breaker from the generator.

Thanks everyone. I have set the following settings and will wire in the generator cable until I test it in the fall when the aircon isn’t running all day.

Shimmy said:

Easiest approach for small generators is a separate chargeverter. It won't give you AC coupling but you can use whatever is available.

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Chargeverters are only rated for operation at up to 1,500 meters (4921 feet) elevation. That takes out much of the Sierras and most of the second and third tier of western states. (E.g. My Nevada place is at 5,010 feet, about a hundred feet above the limit. And I'm quite low as high desert goes. The sierra passes on the way from Silicon Valley to my place are far higher (Monitor Pass (el. 8,314 ft / 2,534 m), Donner Summit (7,239 feet (2,206 m) at westbound I80), etc. The Rockies are MUCH higher.)

Also: When setting the current limit for draw from your genny, don't forget that they also need to be derated for altitude, which might cost you several tens of percent in max power.

ULR said:

Chargeverters are only rated for operation at up to 1,500 meters (4921 feet) elevation.

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No derating, eh? Doesn't work at all at 5000 feet?

EZPZ said:

Thanks everyone. I have set the following settings and will wire in the generator cable until I test it in the fall when the aircon isn’t running all day.


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Dropped it to 5 for amps dc. I like charging at 0.25c.

wpns said:

No derating, eh? Doesn't work at all at 5000 feet?

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Sometimes you do get exponential decay. Once you lose dielectric isolation you are pretty much done for.

That said, there are AC charge controllers rated for >>8,000'.