quote:

Originally posted by trapper189:
5000 watts seems to be the break between 120 and 240 generators. I misspoke saying 115/230, I was thinking 110/220. I’ve been looking at generators a lot these last few days. It seems the inverter type are the ones you run in parallel but that only doubles the amperage, not the voltage. That works with travel trailers and 5th wheels because most only use 110v equipment. It won’t work for my house though.

You’re close in your thinking. When buying a generator, don’t even consider amperage. Wattage is the unit to express power. Wattage in a circuit is determined by multiplying the amperage x voltage, often written as P=V*I, where P=watts, V=volts, and I=current(amps). Watts can also be calculated by using Ohm’s law by multiplying the square of the amperage by the resistance (P=I^2*R) or dividing the voltage squared by the resistance (P=V^2/R). For the purposes of this discussion about generators, the first method is the most relevant since we generally should know the watt rating of the generator.

In summary, doubling the voltage will reduce the amperage by half. So 20 amps at 240v will be 4800 watts (P=I*V, or 4800=20*240), whereas 20 amps at 120v will only be 2400 watts). This is why running a 240v motor on 120v power has the potential to double the amperage, depending on what it does to the resistance.

Two pole portable generators make horrible power. If you were to test your portable generator with an oscilloscope, you’d probably see a nasty sine wave. This didn’t matter in the past because most loads were resistive (motors, incandescent lights, resistive stove elements). Electronics, OTOH, aren’t happy with this dirty power. This is the real benefit of inverter generators. They run the dirty power off the generator head through an inverter to clean it up. The easiest way to tell that your generator makes irregular AC power is if your LED bulbs flicker. Everything has electronics in it now, even appliances. If you must use a portable, at least get a true sine wave battery backup for your sensitive electronics, like what is sold by CyberPower or APC, to use during the time you’ll be on generator power.

The idea of using a battery “generator” at night as suggested above is a good one that I had never considered. Is it possible to use and charge one at the same time? Can you hook a portable generator to it and feed it power while you are also feeding a load from it? IOW, can it be used as a real-time power conditioner? That would be cool if it could.

Motors are inductive loads ..

Yea, but the post was already getting tedious. Inductive loads also don’t care about the sine wave, and the post was already feeling pedantic, so I didn’t bother with the distinction.

quote:

The idea of using a battery “generator” at night as suggested above is a good one that I had never considered. Is it possible to use and charge one at the same time? Can you hook a portable generator to it and feed it power while you are also feeding a load from it? IOW, can it be used as a real-time power conditioner? That would be cool if it could.

Most of the ones I see advertised now will do "pass-through charging". Mine will charge the batteries while powering loads at the same time, from solar or AC. It's a Bluetti AC200P.

quote:

Originally posted by Some Shot:]
Most of the ones I see advertised now will do "pass-through charging". Mine will charge the batteries while powering loads at the same time, from solar or AC. It's a Bluetti AC200P.

A friend if my dad’s brought over one of those to run my dad’s fridge. He couldn’t get it to work. For whatever reason the solar panels wouldn’t charge it.

Assuming they could get it to work and assuming we used it with my fridge. It would run my fridge for about 6 hours. The three 120 watt solar panels would just barely run my fridge leaving no ability to recharge the unit’s batteries. It costs $2,400.

Or buy the $1,200 Honda inverter generator and 400 gallons of gas. At the Honda’s 1/4 load rating of 8 hours per gallon, will run the fridge for 8x400=3,200 hours or 133.33 days.

$2,400 won’t run it for a day or $2,400 and run it for 133 days.

Or my pool pump at 1000 watts. That Bluetti would run the pool pump for about 2 hours. The 400 gallons of gas and the Honda at about five hours per gallon: 5x400=2000 hours or 83 days.

This message has been edited. Last edited by: trapper189,

quote:

Originally posted by trapper189:

A friend if my dad’s brought over one of those to run my dad’s fridge. He couldn’t get it to work. For whatever reason the solar panels wouldn’t charge it.

Assuming they could get it to work and assuming we used it with my fridge. It would run my fridge for about 6 hours. The three 120 watt solar panels would just barely run my fridge leaving no ability to recharge the unit’s batteries. It costs $2,400.

Or buy the $1,200 Honda inverter generator and 400 gallons of gas. At the Honda’s 1/4 load rating of 8 hours per gallon, will run the fridge for 8x400=3,200 hours or 133.33 days.

$2,400 won’t run it for a day or $2,400 and run it for 133 days.

Or my pool pump at 1000 watts. That Bluetti would run the pool pump for about 2 hours. The 400 gallons of gas and the Honda at about five hours per gallon: 5x400=2000 hours or 83 days.

Sorry they couldn't get it to work.

My unit will run my fridge and a small freezer for over 12 hours. You might need a larger battery.

It could charge up to 700 Watts from solar, or charge from your noisy generator.

The unit I bought is listed on Amazon for $1599 and an additional $200 off coupon.

Best of luck in improving your situation.

yes

quote:

Originally posted by TMats:
Our well is somewhere in the neighborhood of 480’ deep. I’m trying to imagine a mechanical pump that would pull water from that depth, or how you could have both down in the well.

They do make 'em, but they can be spendy.

I'm at 250ish and have a hand pump on order. Unfortunately, the well folks around here are so busy that it's anyone's guess when they'll get to me. Price is roughly $2K with install.

quote:

Originally posted by sigcrazy7:
Trapper, all the windings would be energized (single phase inductive motor only has start and run windings), but the motor will only have 1/4 the HP of 230v power. Chances are, it wouldn’t even overcome rotor lock. If it did manage to start, it may burn up from the doubling in amperage caused by halving the voltage. I don’t know what it would do to the run capacitor. I don’t know enough about caps to understand how their voltages work (what makes voltages to the cap 370 or 440v, for example).

Assuming the parallel generators can make enough power and the motor doesn’t have an inrush requirement greater than the generators can supply, it would be better to use a 120/240 step-up transformer to power the well pump. I don’t think they’re that expensive, $200-300 dollars. In all reality, this is more awkward than just getting a generator capable of 240v output.

Brain fart on my part. I was thinking of motors that can be wired for 120 or 240. I believe these have two windings (not counting starter windings) that would be hooked up in parallel for 120 and series for 240.

This is also how my generator makes 120 and 240; two sets of 120 windings each hooked to separate legs when the switch on the generator is set to 240 and both hooked to one leg when the switch is set to 120.

Next question, which dawned on me this morning: with the switch on the generator set to 240 and my 4-prong cord from my house plugged into the generator each side of my electrical panel is being fed by separate 120 windings from the generator. Does this mean each side of the panel only receives half the amps? In other words, my 5800 watt generator can provide 48 amps at 120 volts or 24 amps at 240 volts, but when the switch is set to 240, each side of my electrical panel is supplied with 24 amps max, will it overload the generator to try pulling say 3500 watts from one side of the panel?

It would explain an issue I had with one of my ceiling fans. Sometimes it would work and sometimes it wouldn’t. The times it wouldn’t, I was nowhere near 5800 watts total, but very well could have been over 2900 watts.