I'm not sure you gain much with the transformer-looking at specs for current amp offerings from Crown they show input voltages of 100-240 VAC-with no de-rating for incoming voltage. I would expect a universal voltage device to simply draw more current at lower voltages. If your goal is max power and max life adding a transformer introduces some losses (probably minor) that would result i some of the available energy simply being used to heat up the transformer.
Agreed, won't gain much of anything with the amps other than some "margin". Amps this setup will be powering are ART SLA-2 in each of the racks and a ART SLA-4 in one rack paired to the SLA-2 and in the other rack a pair of restored Carver PM-300' s paired with the SLA-2. Racks in question also contain 4x 80mm cooling fans & an Ashly 3.6SP Controller.
Heat loss in the line boost autoformer will be so minimal as I would be hard pressed to measure it - basically insignificant in this application. Primary load at rated output on the transformer is 0.05 kVA.
https://www.ebay.com/itm/204190950820Heat loss is probably 5-10 watts.
Gaining some additional margin on the supply voltage side will take the concept from "good enough" to "best practice" which is where I like things.
I powered up the rack with the SLA 2 & SLA 4 amps, Ashly 3.6SP & 4x fans - rack idles at 120W on a 120V line or ~1A as measured by a Kill-A-Watt. Then brought out the Jackery and it went down to 91W on the 108V source voltage. Most likely the load from the cooling fans changes with input voltage.
It's assumed the other rack with the Carver PM-300's in it will be similar in power demand to the SLA 4 - it will be confirmed once the rack assembly is completed.
