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[thingstodo]

Going completely off grid costs a fair bit of cash. From a solar array or wind gen or both, to expensive batteries, to the electronics.

I have a storage building that cannot be serviced by the grid, since it is intended only to store equipment and is zoned that way. But I checked before I bought it - solar is not against the rules. So I have three 250W panels, charge controller, a 12V LiFePO4 pack and a 3000W modified sine wave inverter. It runs 12V lights, or 120V LED lights (kinda wastefully), and it'll run a tablesaw, a compressor, and charge my USB stuff while I'm working there.

And it STILL cost me almost $1000 out of pocket. I bought the panels, charge controllers and inverter. I used a re-purposed LiFePO4 battery pack, and most of the rest of the stuff I had already and recycled or upcycled.

[oil pan 4]

Modified sine wave inverters are junk.

[Snax]

Originally Posted by oil pan 4

Modified sine wave inverters are junk.

I've had 3 of them fail on me over the last ten years under moderate use. (Two of which my employer purchased.) Hoping that pure sine inverters are better engineered . . particularly since I just ordered a Goal Zero Yeti 1000. 1500W continuous should provide enough capacity for a day of keeping the fridge running.

I decided to go that route in basically building a standalone system for a shed I will be building in the spring. 400 watts of 12V portable panels should be enough to keep it going during normal use without leaving me dead out of power when I don't want to / can't run the generator during an outage.

I'm trying to essentially build a versatile backup system that could charge my car (10k generator), charge a separate battery, or be basically useful for camping and other light use.

Honestly, it's something my original PV installer rep advised me people are doing as an intermediate SHTF power lapse backup. I wasn't originally convinced, but the more I have done the math on it, the more it made sense to me short of building everything DIY and all of the hassles that go along with engineering it. (I had to figure what my time is really worth as part of that cost.)

If I can just find a relatively inexpensive larger propane tank at this point, I'll be pretty much set on that.

[thingstodo]

Originally Posted by Snax

If I can just find a relatively inexpensive larger propane tank at this point, I'll be pretty much set on that.

My brother has visited the local recycler often in the past few years. People drop off expired propane tanks that are not empty - when they move, or get different BBQs. 25 lbs is not a lot of propane, but if you are around to change tanks, and you have a few tanks available ... it's cheap

[thingstodo]

Originally Posted by oil pan 4

Modified sine wave inverters are junk.

They likely are, as a general rule.

I've only killed a couple of little ones (75W, 400W) when I wasn't paying attention and let them get too hot.

I've had a 1500W running very intermittent (once a month maybe) for a couple of years. This 3000W will run a bit more often, but is hugely over-sized for all but the compressor.

I'll let you know when they die (notice, I didn't say IF)

[Snax]

Originally Posted by Snax

I'm trying to essentially build a versatile backup system that could charge my car (10k generator), charge a separate battery, or be basically useful for camping and other light use.

Starting to rethink the 10k generator part today though. The Yeti can be charged fully in just a few hours with a small 900W propane generator. Between the two, the lowest 110V charge rate for my i3 would get me usable range in a pinch, which is really all that I am looking for there.

[oil pan 4]

Have you looked at the charge difference between 120 and 240v power on the same charger?
Notice how 120v charging takes more than double the time to charge.
Why do you need a 10kw generator you can get evse units that oitput little as 8 amps.
Even my lowly converted Panasonic made granny charger will do about 2.9kw. A 7kw generator should be able to handle that no problem.

[Grant-53]

My house is not well sited for PV due to shade trees. Community solar would be my best avenue. I would consider a wood gas generator on a trailer for disaster relief.

[Snax]

Originally Posted by oil pan 4

Have you looked at the charge difference between 120 and 240v power on the same charger?
Notice how 120v charging takes more than double the time to charge.
Why do you need a 10kw generator you can get evse units that oitput little as 8 amps.
Even my lowly converted Panasonic made granny charger will do about 2.9kw. A 7kw generator should be able to handle that no problem.

That's basically where I am at with it now. 6A maximum draw from my i3 on the lowest 120V charge setting should be no problem for even the smallest propane generator. (Looking at the Ryobi FWIW.) It would take 24 hours for a full charge of my car, but I wouldn't be needing anywhere near that range unless it was bug-out time. Not really planning for that scenario though!

The nice thing is that the Yeti provides some flexibility there with being able to charge by generator power and provide from the battery simultaneously. So my little 900W generator could conceivably be providing a real world 1500W sustained until the Yeti battery drained even if the Yeti can really only take about 400W sustained charge power. That's really probably only an hour of boosted output, but as attractive as 10kW sounds, it's clearly not practical.

EV use out of the picture, a few 12V solar panels and the Yeti should be all I need to keep the fridge and lights on unless the weather is absolutely horrible.

[Snax]

Originally Posted by Grant-53

My house is not well sited for PV due to shade trees. Community solar would be my best avenue. I would consider a wood gas generator on a trailer for disaster relief.

Community solar is such an awesome concept. I've thought about trying to get my HOA to do solar awnings for a private park area we have established. I'm not familiar with others' experiences with doing that though. We aren't really close to a point where that is likely to happen for a few years anyway.