Trace Engineering originally built the DR's and SW's. Trace merged with Xantrex and Xantrex built the SW Plus. The SW Plus has more surge and overload capacity, non-volatile memory, external GSM (Generator Start Module), and several other improvements over the SW Series II. Xantrex replaced the SW Plus single phase models with the XW-series split phase models.
Schneider Electric bought Xantrex. The mobile and marine market is marketed under the Xantrex brand. The renewable energy models are now called Conext XW's.
Several Xantrex/Schneider dealers still have brand new in the box SW Plus inverters in stock. I verified with Schneider Customer Support that they will still honor the new product warranty on those units, and they will. We have a two year factory warranty on our new inverter.
I selected the SW Plus because it has more overload capacity than the XW's. We paid more for it than I could've gotten a new XW for. But to this day there is nobody that has matched them for reliability and raw overload capacity. That's why I wanted it.
Our bank is 24 Rolls T12-250's. They are 200 ah @ the 20 hr rate. It takes four of them to make 48 volts. I have six strings in parallel. Each string is 200 ah. Six strings is 1,200 ah or 58 kW.
Generator support is where the inverter can sync with the generator and use both generator and battery power to meet heavy loads. The overload capacity of the inverter allows you to start a heavy load with the inverter running in overload. It calls for help from the gen and starts it, the gen comes online and takes over the bulk of the load while the inverter supplies what the gen can't. When the load goes away the inverter watches it for a time that you program into it and shuts the generator off if the load has remained below the Load Start threshold.
This allows you to use a much smaller and more fuel efficient generator than what you would have to use with an inverter that only do pass-thru transfer.
There are very few inverters ever built that have gen support. The Trace/Xantrex/Conext line have it. The Outback Radian, and Magnum Energy will be coming out with one soon. Reportedly, SMA has some models that can do it but I haven't verified that, nor do I know of anybody who is actually using it on a SMA inverter.
We use gen support, with an automatic start generator, almost exclusively here to operate our big loads.
I just got our ICM/25 Remote installed yesterday in the kitchen where our biggest loads typically are. We're pretty happy with the new setup. It handles our loads without even breathing hard.
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Chris