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Automatic transfer switch with Sunny Island

Justenuf

New Member
Joined
Sep 29, 2021
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6
I'm looking for a brand and model recommendation of an ATS that will function with a 200 amp master panel and two 6 kw Sunny Island battery invertors (12kw) with 30 kwhr LIFEPH battery bank and 9 kw solar. Generac and others don't seem to relate to battery backup, only their own generators or battery packs. It would have to programable to provide the 5 second delay on switchover as required by SMA. Certainly some one out there has conquered this problem. If all else fails, I'll go with a manual switch, but would prefer automatic if I can configure it.
 
Not sure if this product would be use. You didn't include any details of what type of interface you are looking for. Is the transfer switch to be controlled in the customary way with utility being available or unavailable? What controls the inverters? Are they just on all the time in stand-by or would the transfer switch have to remotely turn them on when utility power is lost. Providing a few more details produces better answers.

 
The Sunny Islands would be on in standby mode. They see the grid voltage. When the grid voltage drops, they turn on in a few milliseconds. I would think a programable interface would delay switching for the 5 seconds, once the grid drops out, and the invertor power would be there for the switch over.
 
The Sunny Islands would be on in standby mode. They see the grid voltage. When the grid voltage drops, they turn on in a few milliseconds. I would think a programable interface would delay switching for the 5 seconds, once the grid drops out, and the invertor power would be there for the switch over
The purpose of a transfer switch (could also be referred to as an A/B switch) is to isolate each source of power from the load so only one can be connected at a time. How would the inverter "see" the grid if its connected to the "B" side of the the transfer switch while the grid is connected to the "A" side of the transfer switch? Perhaps what you actually need is an automatic disconnect or shunt trip breaker. The Sunny Island inverters don't have an internal disconnect? If they switch on in milliseconds why do you need a 5 sec delay? Sorry just not understanding what the goal is.
 
Thank you for your input. To clarify the situation, the sunny island has a grid tied input that is connected on the meter side of the grid, not after the transfer switch, in order to sense the grids presence for battery charging purposes, as well as an indicator so it knows when the grid is down, and to start acting as a battery powered invertor. The transfer switch utilizes the output of the invertor or the grid to provide power to my master panel for a whole house backup. My problem was I was having difficulty finding a transfer switch that would function without connection to a generator, as most are designed to do so. I finally located a unit that is programmable that will function to provide the delay requested by SMA for the change over. The sunny islands will provide 12kw plus solar of 8 kw, so I will be able to cover all of my needs most of the time with a 30kwhr battery pack., and if needed, a small generator to charge the battery pack, and living in sunny Florida, and having no electric bill for the last 10 years, I should be ok.
 
Would you mind sharing the brand and model # of the transfer switch you chose. This issue has been discussed previously on the forum, I'm sure there are others who would benefit from a programmable ATS and I am maintining a Word doc with a listing of products for specific functions. Thx
 
I would be glad to share, as I have been looking for two weeks to find something that would work for me. The item is a BTB automatic transfer switch model BTB2p2ud200 which is a 2 pole, 200 amp rated programable automatic or manual transfer switch. It can be found at MTSpowerproducts.com and is a pricey at $1825 from this supplier, maybe less elsewhere, but most of my searches have found them all to be pricey.
 
I would think the tons of 100a and 200a generac transfer switches out there could be modified w/ a few relays to do the delay and auto-transfer. I haven't done mine yet, but I have a 100a transfer switch for my generac that is not being used right now.
 
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