I have two return pumps in my system. They draw a total of ~150W@2.5A: Danner Mag Drive 7 Rated 115V/65W/1.5A -- Kill-a-Watt: 43W@1.05A ATB FlowStar 1800 Rated 115V/80W/?A -- Kill-A-Watt: 75W@1.3A I would like to put both of these onto a battery backup that will last for several hours. I have a generator for longer term backup, and I have been lucky in that I have been home within an hour of my longer power failures. I would like something that gives me more time of no one home with the water circulating. My current plan for the tank is cuttles and I have three tanks plumped together, so I am reluctant to rely on Vortechs with their backup battery since these are expensive and I would need one for each tank. My current tank plan does not need a powerheads other than the main return since it is a soft coral tank with a rather hefty main return pump. Here is what I am thinking: Code: [AC]------------------------> [Transfer Switch]---------[Digital Aquatics PC4]--> to Pumps [Battery]---->[Inverter]------| Some questions and ideas: 1) Battery Since this will be inside, I am thinking I want a non-vented totally sealed Advanced AGM battery. These seem to be the safest and most efficient batteries on the market. I assume that an RV battery like this one GPL-24T with an 80Amp Hour rating would work for more than a day (80AH for 2.5A = 32 hours). Is this overkill? 2) Inverter I have never bought a power inverted, so the main thing I am unclear on is whether I need a pure sine wave inverter to run a digital aquatics PC4 (i.e., is this sensitive electrical equipment?). Also, since I only need 150W, I assume a 300W inverter is OK. This seems like it would fit the bill: 300W Pure Sine Wave Inverter. 3) Transfer Switch Can I find an inverter with a built in "transfer switch" or do I need to add this after the inverted? I have seen reference to them with built-in transfer switches, but these seem to be hire end models. Also, these seems expensive. I assume they provide uninterrupted switch over, but I don't think I need 4) DA PC4 I assume if all of these pumps are set to default on, that this plan will work ok when the power goes out.