Advice on inverter

Genius

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the off grid geeks have great worksheets for system requirements. Lots of variables are unknown, power demand, battery capacity, equipment needs (true sine wave?), etc. What do you intend on using it for? Personally, I would buy a true sign wave inverter.
 

tsharac

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I'm one of those off-grid geeks.

Your url doesn't work. What's the brand and model? Xantrex is really good, I use a Xantrex Prowatt SW 1000 watt inverter all day, all night for years on end. I second the use of a true sign wave.
 

Genius

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I'm one of those off-grid geeks.

Your url doesn't work. What's the brand and model? Xantrex is really good, I use a Xantrex Prowatt SW 1000 watt inverter all day, all night for years on end. I second the use of a true sign wave.
think he has the description and the hyperlink backwards. Copy the description to the browser search. Off grid stuff is pretty cool!
 

tsharac

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Thanks. That link copy-paste trick worked. Yeah, I have a solar, off-grid cabin and a small generator I've been using for the last 10 years. Looking to build a real house someday and keep it off-grid as well.

The lesson I learned so far is, calculate what you need, then triple the capacity to meet that need. Plus, have a backup.
 

CaptMD

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CaptMD

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Genius

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I plan on using it to run LED cockpit lighting, obviously keep the batteries charged, have an electric outlet in the galley for small appliances like a single burner, run a small heater (900W) or fan in the cabin. Not a whole lot, no fridge or AC. Just a few small conveniences. Oh, charge phones, blutooth speaker, laptop maybe, a USB flashlight, etc
All that except the heater can be done on 12VDC. Unless you are dead set on getting an inverter (they are handy), I'd recommend doing it without it. FYI the heater is a bad idea, they draw too much power. I have a small 300watt inverter that I picked up years ago. I use it to run a hot knife and charge an iPad. Plans are to upgrade someday, and I will most likely go to a 3-4kw unit. Some other AC loads that are higher power ratings with intermittent loads I'd like to run.
 

Genius

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What is the difference bvetween a true sine wave and modified sine wave? (besides price)
It is the shape of the sine wave generated. A modified wave is real choppy looking. It's my understanding that some electric motors are sensitive to the AC profile. Early inverters were all modified sine wave, now it is more common and economical to pick up a full sine wave inverter.
 

tsharac

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What is the difference bvetween a true sine wave and modified sine wave? (besides price)
When you plug in a LED bulb or florescent bulb into a modified sine wave inverter, the lights will flicker. When you try to use a modified sine wave with a GFCI, it'll keep clicking and/or just not work correctly. Sometimes appliances buzz when connected to modified sine waves. Plug a variable speed fan or drill into a modified sine wave and it acts funny.

True sine wave inverters don't have these weird problems and are a bit stronger under load.
 

tsharac

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Is this a marine inverter?
I don't know what a marine inverter implies. I can't imagine any of these inverters are designed to get splashed if that's what you're thinking. I've had mine in a deck box outside for 5 years about 300' from a tidal marsh and stream, it's in a very humid environment (Eastern shore Virginia), but doesn't get rained on.
 

tsharac

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I plan on using it to run LED cockpit lighting, obviously keep the batteries charged, have an electric outlet in the galley for small appliances like a single burner, run a small heater (900W) or fan in the cabin. Not a whole lot, no fridge or AC. Just a few small conveniences. Oh, charge phones, blutooth speaker, laptop maybe, a USB flashlight, etc
What's your battery bank like?

Single burner and a small heater, while possible, may drain your batteries in a matter of a few minutes.

You have a single 175 watt panel. On a moderately sunny day, you may get 175 divided by 2 = ~80 watts/hour * 4 hours = 320 watt-hours per day. You plug your laptop in for 6 hours (60 watts/hour) and you're running a deficit of 360-320 = 40 watts. Now you turn on four 10 watt lights for 2 hours, there goes 80 watt hours.

At my cabin I have four 240 watt panels and four 420 amp-hour batteries. It runs a laptop 10 hours a day, wifi router, sometimes run a fan, a small newer style super efficient microfridge, and LED lights.

What I've learned with solar is you'll never match the amount of power you want with the setup you have so you learn to be miserly with the capabilities of your system. Plus when you start to run an electric deficit it takes a long time to recover. Big loads, even for very short duration really make the system's voltage struggle to recover. I used to run a 1/2 hp well pump, but no longer do because just 30 seconds and the system always seems flat afterwards for days later.

It's a math problem that depends on the available sunlight and how much you use the system. If you get 3 days straight without much sunlight, then that's 3 days you should not use your system and should wait until the sun comes back otherwise you'll run a deficit you can't recover from.
 

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AJ2020

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I have a renogy 2000w inverter, works great...pure sine, runs on all 4 batteries without issue...
 

CaptMD

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