I should have known you engineering types would loose site of the power cord issue and lock onto my battery swap lines. Yes unconditional. The power my gear sees is not the power coming into the home persay. ... I use a 4000 watt power supply that is always in "service". During brown outs when incoming voltage is 106 my equipment see's 110 volts adjustable from any computer to 120 max. The six am daily phase changes that 'ol CL&P does each morning and night never even slightly affects the output wave. While clocks start blinking on the microwaves my theater room gear is just fine. As to the bigger batteries they are best recharged by a constant voltage type system limited to 10 amps so no problem there. If it fails I will fix it making the charger stronger. As Larry wrote I only need to replace the power used and not in a short time. Eventually my house generator will get fired up if we need it. I have way to much time on my hands these days and I get obsessive about my movie watching......