SolarEdge Auto-Transformer W/ Sunny Island 6048

[Jakobw]

Hi all,

First major post here, been a lurker for a long time. Have a question for any of you that have experience with SolarEdge systems and specifically their SEAUTO-TX-5000 Auto-Transformer.

I'm needing an Auto-Transformer to go between a single 120V Sunny Island 6048 and a 220V Sunny Boy 6000US. Typically I would look to Midnite or Outback for an auto-transformer but I'm curious if the SEAUTO-TX-5000 would be a drop-in replacement as it's significantly cheaper.

Unfortunately SolarEdge is fairly light on specs and when I asked them about a configuration like this (120V-240V step-up/phase duplication) they simply said they couldn't help or provide insight (I was just looking for a yes or no answer) as it would be a non-warrantied configuration. I figured that would be the case, no fault to them. They are just protecting themselves.

So I'm looking for anyone who has installed or used these on a SolarEdge installation and if there is any reason they couldn't be used on another system or in the configuration I'm looking at. Based on their manual and a couple of YouTube videos (yes, I know), they simply have a 3 wire hookup (120V-0-120V by the looks of it) and a 2 twisted pair from a builtin temp sensor.

Based on what I see/read I think it should drop-in without issue but perhaps I'm missing something. Any insight would be super. Thanks a bunch.

Here are a couple of relevant PDFs:

https://d3g1qce46u5dao.cloudfront.ne...sheet_na_1.pdf
https://www.solaredge.com/sites/defa...tasheet_na.pdf

[solarix]

Haven't tried that SolarEdge unit, but had same problem and did not want to put in the high dollar SMA "Smartformer" so just bought a basic 6kW autotransformer off Ebay and wired it double the Sunny Island. (why oh why did they make it a 120Vac output?) Have used the Smartformer in the past as well but it is not only expensive with all the bells and whistles, I'm not sure if they even still sell it.

[Jakobw]

@Solarix Yeah I'm basically in the same situation. Looking for a low cost 6KW auto-transformer. When I found the SE AT I thought it might work as long as I don't exceed 5kVa but I would prefer something rated for 6KVa.

Do you happen to have a link to the one you have? I've been having trouble finding generic ones in that size on eBay.

If it comes to it, I figured I can pickup a 3 kVa 480/240x240/120 standard transformer and wire each set of windings in parallel (respectively). I could just use the secondary in series but then I'm still stuck with only 3kVa.

[Mike90250]

If you know what you are looking for, flea bay is a good source for used electrical gear, I've bought quite a few 4-12 KVA transformers from there, and the larger dealers often have free shipping, which for +40 lbs of transformer, can be a bargain. My favorite find was a 480-240CT which I use as a autotransformer with a small inverter generator, to step up 120 to 240 which my inverter likes.

20180130_110038_TransformerLabel.jpg

[Jakobw]

Thanks Mike. That's exactly what I was thinking of doing. I'm currently looking at the Victron series of Autotransformers and the main advantages I can see is the fact they are toroidal transformers with an efficiency of around 98% and I'll have less power loss than using a standard transformer as an auto-transformer.

In your specific configuration, are you just using the secondary windings in series and leaving the primary windings untapped?

[Mike90250]

Yep, not using the 440 winding.