Can I convert a grid tied solar inverter for off grid use, and, if yes, how?

[DannyT]

I currently have a 5.1 kw solar system set up on my rooftop. It has 18 Hyundai 285 watt panels, with a hybrid inverter from SAJ (more specifically, I am using the H1-6k-S2, technical details can be found here).

Now, I have another 8 Hyundai panels lying around and I was thinking that if I could easily convert my inverter for off-grd use, I could use that for a mobile PV setup and save myself the cost of buying an extra inverter.

However, as I began looking into it, I realized that I am woefully ignorant on the subject. So, to humor me for this thought exercise, what would you recommend for a setup where I can utilize 8 285W panels for a mobile setup?

I know this is just a hypothetical, so feel free to educate me on how it actually works. I've got a couple ideas on it, but I need advice from someone with more experience than myself. Let me know if it helps to provide any pictures of my setup.

 

[Otter Spotter]

Sounds as though you will need to tow a trailer to carry all the panels !

I am sure someone wiser than me will reply soon

 

[Lenny HB]

Raul is the man to ask.

 

[Off da Grid]

I’ve got a grid type panel from a solar farm on my van, it’s huge but only 255watt.
The panels are the same in respect of what they do regardless of size or manufacturer.
As long as the solar controller/inverter only uses the battery power to work and not a 240v then It will work fine.
To clarify my solar controller needs a battery voltage of 12 or 24 v to work as the electronics need power to do their stuff.
If yours needs mains power then it won’t work as when the solar goes down when it’s dark you have no power to run it.
The grid tie systems that don’t have battery backup/ storage don’t work when there’s a power cut.
Hope this helps.
You would need a lot of roof space on your vehicle for all those panels.
Keep us informed of your progress with this one.

 

[autorouter]

There's lots of details to consider, but the important thing is the SAJ H1 hybrid inverter can operate in 'island mode'. That means it will continue to supply power to the house even if the grid supply fails completely. Many grid-tie inverters (including the 3kW one for my house roof panels) simply shut down if the grid fails, and won't operate in island mode.

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[autorouter]

You'll need to think about many different conflicting requirements. I'm sure you could come out of this with a superb mobile off-grid system, but you'll have to be careful.

The inverter only takes 48V lithium batteries, which can be 48V units like Pylontech, or 4 '12V' batteries in series. So you'll need to think about how that interfaces with the vehicle system, which will be 12V (or could be 24V if a big RV), and the habitation system, most likely 12V stuff.

The inverter startup voltage is 120V, so you'll need at least 4 panels in series (volts add together, amps stays same as one panel) to wake it up. The maximum voltage is 360V, so I think all 8 panels in series won't take it over that value. Better check the panel spec sheet though, I might be wrong on that. Or you could wire them as two 'strings' of four series panels. The inverter has two string inputs.

 

[DBK]

I'm not sure why you would want around 2kW of solar on a MH. Most folk get away with less than 200W although a bit more does no harm of course.

My suggestion would be to put one panel on the roof, two if there is room and buy a suitable MPPT solar controller. You could sell your unwanted panels to help pay for it.

 

[XxAnthxX]

When exactly is enough solar really enough…..

 

[autorouter]

When exactly is enough solar really enough…..

But that's ten panels. He's only talking about eight, which would fit nicely

 

[autorouter]

I'm not sure why you would want around 2kW of solar on a MH.

In years to come that will rank with Bill Gates's classic: Why would anyone need more than 640k of memory?

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[XxAnthxX]

In years to come that will rank with Bill Gates's classic: Why would anyone need more than 640k of memory?

More likely the classic line from JAWS……….’Your gonna need a bigger boat motorhome’

 

[Raul]

As Autorouter already said that inverter can operate in island mode, off grid. The issue here I see is 2kwp array on a 6kw inverter. At only 1/3 loaded, very inefficient. If you ok with that, no problem. Also the 120v start up, needs 4 panels min in series, that’s fine you can wire 4 on each mppt. It will work with a Li compatible battery. You will need to find out what comms protocol uses the inverter, mod buss? so it can communicate with the battery bms. From top of my head, pylontech, BYD, low voltage (48v) battery packs. The high voltage are 400v for AC coupling storage. Your inverter is low voltage 48v storage.

ps; just noticed, this inverter is the same as goodwe and sofar. Goodwe sells in Australia, sofar in UK and takes Pylontech 48v modules. You can get pylontech US 2000, US2500 and the newer US 3000 3kw modules. You can rack up to 6 modules with their proprietary cables up to six. Set one as master when more than two, and the rest as slave.