Generator w/ High THD -- Safe for All-in-One Charge Controller?

yinzer

New Member
Joined
Apr 9, 2021
Messages
4
Greetings all!

TL;DR version of the question: how important is the THD rating of a generator when used to supplement solar for charging a battery bank through an all-in-one charge controller/inverter? Will 'harmonics' (more like modified square waves, in my case) on the input pose a risk to the charge controller? Im comparing generators with <5% and <20% THD ratings.

Detailed version:
I'm getting started on my offgrid project and need some power to get things going. I'm looking for a generator that meets the following requirements:

* An EFI generator (i'm at 8000' so carbs are challenging)
* High output (generator will run at around 25% rated output due to elevation)
* Enough output to run my welder (max 6,900 watt draw, so ~11kw output after efficiency and elevation losses)
* Safe as a backup/top-off generator for future solar system

This is pretty limiting set of requirements, unless I get into massively expensive commercial units. I've found two options:

* A-iPower SUA13000EFI
* Champion 100485

Any other good options I'm missing?

The A-iPower is very nice, but not readily available. It has slightly more output, runs pretty quiet, and has great THD (<5%). Besides being unobtainable, only other downside is the 6.6gal fuel tank that limits run-time to 8.5hr. The engine is from an unknown-to-me Chinese maker (a Senci SC460), but new engines are only $165 on Ali.

The Champion is cheaper, but has lower power and makes more noise. But it's available and has 35% longer run-time. But it has a THD of up to 20%!

I mentioned a welder -- it's an inverter-based unit so THD isn't as much an issue as on transformer-based units, but I'm still not sure what the threshold is. If that alone is a deal breaking, then score one for the A-iPower!

FWIW, this is possibly a short-to-mid term problem. Once I get a battery bank and some panels up, I'd like to run everything through the batteries and just use the generator to supplement their recharge, if i can get comfortable with that much draw. But this is a problem for Future-Me

Thanks all!
 
Last edited:

rhino

Solar Addict
Joined
Jun 6, 2020
Messages
522
Location
Minnesota
20% is pretty high. I would check with whatever all in one you are planning to use to ask them what the maximum acceptable THD is. With that high it may simply refuse to accept the power to allow charging.
 

yinzer

New Member
Joined
Apr 9, 2021
Messages
4
I haven't selected a AIO yet since the product space is moving so quickly and I don't need it yet. That said, I'm sold on avoiding high THD generators in general. The A-iPower is a gamble on quality, and on back order but not many other options given my constraints. I'm on the wait list. Will report back on how it holds up!
 

yinzer

New Member
Joined
Apr 9, 2021
Messages
4
Thanks for looking out, I really dig what they are doing with their custom generators using a mix of the best components at a much better price than the brand-names. Very cool!

I never considered running 2 generators in parallel -- didn't even know that was an option! That's really a game-changer for me, since my environmental conditions drastically reduce the generator's output, but I rarely need my highest output. I'm doing some research now -- so many question on balancing the inputs and getting the load to distribute across multiple generators equally. Very cool stuff!
 
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