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Well I saw a used 3000VA isolation trans on eBay today, and the price is right to get this project squared away. But it would be good to travel in this RV, and the weight of a proper US dual split inverter likely would be less than the Growatt 5000 plus true iso trans. Not to mention less...

Should I just sell the Growatt and get one for US power? I spoke with Ian from Watts247 on the phone today because I had bought it from him. He didn't think I needed to sell it, but perhaps he didn't fully understand my setup.

I don't understand the implications of defining ground, sorry. Kinda new at this. But the autotransformer balancing the grid should be mitigated by the 10A upstream breakers and thermal switches no? What would be the implications of this? I don't understand sorry.

This is what I mean. My two autotransformers look like this. I'd plug the 110V loads directly into the 110V outlet on the front panel.

I think I'm safe then by virtue of the fact that the 110V loads won't go through any breakers at all but are directly connected to each autotransformer's neutral by extension cords. But I'd like to see your drawing to verify.

Is this also the case with two autotransformers, as I have? Back to the original question. Would it be possible for you to draw out what you were describing in scenario #2?

Correct, but the 240vac air con is only one portion of my system. Have a look at my graphic, I've also got 110V loads on the right side.

Afraid that didn't help clear things up. I'm hoping to use a 5000ES 240V Euro inverter in North America, using two plug-in Rockstone 3000W autotransformers, and the loads would be run from extension cords. Air conditioner is a 220V mini-split, 110V loads run off the two autotransformers. I'll...

I'm struggling to picture what you're describing, would you please share a drawing? Even a crude back-of-the-napkin drawing would help.

Yeah, the more I think about this, the more I realize it's likely wired the same as in the video. The neutral and ground are bonded inside the Growatt and therein lies the problem.

Today I became aware of the dangers of using 240V inverters in North America through Ian's video below. Do the risks he addresses apply to all autotransformers? I'm hoping to use a pair of plug-in Rockstone 3000W portable autotransformers for 110V loads, and their ground pin would be connected...

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And a few nice long threads :) https://diysolarforum.com/threads/design-review-growatt-spf-5000-es-grid-backup-neutral-bonding.29717/ https://diysolarforum.com/threads/safety-hazard-w-growatt-5000es-european-version-when-connected-to-american-grid.33975/page-11...

What are some isolation transformers that would be recommended for a 3000W 120V load?

Both Will and Signature Solar have responded to the controversy of using the 5000 ES in the United States. I just found these videos and have yet to digest them.

If it's a 50A RV it's running on 220V, that's the only way it would work. The 220 gets divided inside the RV to run each air con. If you can run both classic air cons at your RV park, it's going to be 220.

Sorry, I bought all the equipment including the 5000 ES but haven't had the time yet to connect it. Looking at the video, I think he's right. The air con should be just fine on the Euro inverter; But I also had hoped to connect other loads as well, and so I bought an autotransformer. And a...

Not really. The BMS does do overcurrent protection but I've got two step-down transformers on two separate branch circuits and the BMS wouldn't know when only one transformer is overloaded. Also, sometimes I'll be on grid power, not battery.

I hate reinventing the wheel particularly for as you said, safety. But in this case it's not for safety, it's to prevent equipment failure, which would not be catastrophic in terms of fire. I'm using normally-open relays so it fails safe, and I already have the microcontroller in place for other...

I not only found a breaker with exactly that value, I linked to it in the opening post. Don't anticipate constant tripping; Once the family understands they can't just plug in anything they should figure it out. The total current allowed would be about the same as a standard wall outlet in a...

Good news. I misread the manufacturer's instructions; They want the max to be 50% higher than continuous. Since it's a 3,000W max transformer, 3,000 / 150 x 100 = 2,000W continuous. So I have some overhead. If I use the 10A breaker with a 1.25x thermal overhead that's 8A continuous from the...

I don’t know for 100% certain that the problem is overheating, I only know the manufacturer says don’t exceed 1500W. But a thermostat is a great idea; Already reading the air temperature and controlling a fan with an Arduino; Adding a second thermometer and relay in the mix in addition to a...

And breaking the connection is what I want. Want the family to learn not to push it.

I’m no expert at this but how’s your grounding? Especially because of the “love kisses” it gave you.

I want to push no more than 6.9A continuous through one of my circuits; Do I need an exactly-sized 7A breaker, or a slightly oversized 10A breaker to accommodate some startup surge current? I've got a Growatt SPF 5000 ES (outputs 220V euro) and a step-down transformer. The transformer's...

That's the one I use, so to make sure I really understand, I want to confirm: The numbers on that calculator imply round-trip drop yes? So if I put 100 feet it's calculating for 200 feet total?

If my panels are 100 feet from the charger, do I calculate voltage drop as round trip and 200 feet (100 positive and 100 negative) or 100 feet total? If 200 feet that means I need some beefy wires...

It's an annual average of 4.5 hours as shown by this map. Yes I can add more panels, no problem. A string of 3 will indeed do just fine.

No problem running larger gauge and in fact I just found there are 8 gauge 100 foot wires, which puts me at 3.12%.

Looks like I may need to accept a 4.75% voltage drop on my run of two Renogy 175W flexible panels in series. (23.9Voc/19.5Vmp/9.5A Ioc/8.98A Imp) Single string, both in series. But is this acceptable when connected to a Renogy Rover 40A MPPT controller and Sok 12V 100Ah LiFePo4 battery? I won't...

It's a dumb BMS. Confirmed with the seller that a 14s would not work on a 13s setup. So I bought some Daly 13s dumb BMSes and I will craft a low temp cutoff using a thermostat or Arduino.

They do make soft starters for air cons though. NetworkRV’s SoftStartRV and Microair’s EasyStart, but also on eBay is an up-and-coming contender that’s half the price: Search for applianceandair’s RV-AC-Starter.

So each 100V/50A controller has two 405W panels, and these are paralleled into a 24V bank, did I understand that correctly? What is the Voc of your panels? Should be listed on the rear or in the spec sheet. Yes in theory the alternator can charge as well, though I believe you’re going to need a...

How do you turn “off” the resistors? I wouldn’t think you’d want them enabled all the time.

Yeah get me in touch :)