DIY Off-Grid Solar Upgrade - Solar Edge Auto-Transformer 

Agree the solarc is way too expensive for a 100% off-grid scenario. If you have grid power and can sell it back to pay for itself then it makes sense. That is why it's called a hybrid inverter

What's interesting is that the Victron autotransformer documentation says to not connect the source neutral to the AT when using it in a balancing scenario, only use the neutral from the AT to connect to the load panel.

​@@NeverTakeNoShortcuts Victron is correct. But this NOT Victron equipment and it is NOT a typical Victron design. There are very good reasons for not connecting two active neutrals together. In this video, he is masking a limitation/problem in the Sol-Ark.

Scott Hunt @engineer775 explained to me the loss/draw was negligible. It doesn't limit your load. It will only balance so much but generally speaking an unbalanced load isn't that big of a problem except in unusual circumstances like running a 30 amp RV. A 30 amp RV draws everything off of one leg. A 50 amp RV pulls from both legs.

@@stvbird ok cool thanks

Thanks! Do you have a link? I'd like to see that.

ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-EYIzEW54_bY.html at around 20:50

David Poz has a video with this same AT and sol-ark setup. He was able to demonstrate perfect balance once he removed the neutral from the sol-ark. I've got questions about Sol-Ark's support for this undocumented configuration though.

@@yamlcase230 I've pretty much pulled away from the Sol-Ark but thanks for refreshing my memory on the Poz video. Here in California the Grid tie side of things is getting touchy. Straight off grid solutions are becoming more popular with a grid backup. So there is less need for the bells and whistles Sol-Ark offers. Can get more out of a pair of Growatt 240v 5k's

Lol. It's only being used because of a broken buried 2-2-2-4 load leg that I don't feel like digging up and replacing at the moment. It's not a Solark problem. It's just so I can pull more through one leg until that feeder line is fixed.

@@stvbird Look at the reviews about Sol-Ark unbalanced leg problems. There's a lot of people complaining about it. Professional installers are trying not to use them because of it.

The only reason I needed this was we had a buried 2-2-2-4 feeder line go dead on one leg, so until I replace it we've been drawing everything on that line from one load leg. Otherwise, it's never been an issue. However, this little thing has completely fixed our current issue until we can get around to replacing the 2-2-2-4.

That's my pond behind it. I live about 1000' above most of the state. I'm not really floodable barring something biblical. That building is also on a permanent concrete pier foundation, not blocks, and it's bolted to each of them.

If the well pump is 240v, it would be a balanced load, pulling from both legs, so that wouldn't create a problem at all.

@@stvbird Ok thanks.

If you currently have grid power, which I’m assuming you do as most people do, you’re loads in your homes breaker panel are balanced by the transformer on the pole near your house. This is basically doing the same thing. I’m not sure how a surge protector would solve this problem. A 240 system is just two 120 lines coming from the same source. In my case, the Sol-Ark. If too much draw/load comes from one side of the breaker box (each row of breakers represents a 120 leg of those two loads, unless you’re using a 240 breaker, then it contacts both sides of the breaker box to give you 240. Anyway, if you pull more from one side than the other, the load is unbalanced, but in an on-grid world, that balancing is done in the transformer on your pole as stated earlier. Where my problem came from isn’t so much the limitations of a Sol-Ark, it’s from a failed 2-2-2-4 feeder line that’s buried underground. One of the load legs has a broken wire underground, so to power our 50 amp/240 RV, I’m having to use a 30Amp RV adapter to run our power box off of a single load leg (50 amp RV’s are both legs, 30 amp RV’s use a single leg). That’s where our unbalance came from. We’re powering two refrigerators, two air conditioners, two microwaves, TV’s, and a washer and dryer all off of one leg. In a normal world, or in a world where I replace that buried line, our power imbalance won’t be an issue, but the autotransformer is helping me avoid my problem until I can fix it right.

You don't need to hook it to your inverter. You run it through your load panel. You can use it to step 120 up to 240, or wired like mine, with L1 in one side of a 240 breaker, and L2 into the other input of the same breaker, it essentially contacts both loads in your breaker box (left side and right sight of the box) and balances it out. Essentially each load leg of your breaker box flows into it and are balanced between each other inside the auto transformer.

Btw... My Sol-Ark 12K is 240 based, so my breaker panel is already 240. This just balances it all out and makes the L1 and L2 from the Sol-Ark be pulled on more evenly in cases where you're pulling more from one side of the breaker panel than the other. You can use this to double a single 120 line into 240, that's just a different use than what I'm doing.

@@stvbird Thanks

Yeah, I looked at that one, too. Maybe when I stack a second Sol-Ark that capacity will be just what I'm looking for. Thanks.

I cant find the solar edge anymore. Looking fir a different solar project.

The bigger Victron 100 amp Autotransformer does NOT provide any more balancing amps vs their smaller Autotransformer. In this situation, the Victron 100 amp AT would be a waste of money.

@@MrSummitville It's never a waste of money to plan for future expansion and with the added breaker and fan included more so .