I have 4- 225 watt Truepoint solar panel's at 36 vdc VOC & I was wondering if I could Sereies/Parallel these panel's for a 72 vdc VOC?

Patrick, of course you can. I have to ask, are you really using an MPPT charge controller? I don't know any offhand that run on 72 volts open circuit. If you have one that does, then yes, wire 2 panels in series, then the next two in series, and then parallel the two pairs together so the controller is getting 72 volts from both pairs of panels. The controller also has to be programmed for 24 volts nominal voltage, just check the specs to make sure.

You said the 5th panel is to charge a pair of 12 volt batteries with another MPPT controller. I've never heard of an MPPT controller that converts 36 volts to 12, usually they run at higher input voltages than this, like 100 to 200 volts. If the controller indeed has a range of input voltages that 36 volts fits into, then it will work fine.

I have to add that Mike does have a point. I know you want to use that inverter, but it might be a lot simpler to simply buy a 60 amp 12 volt controller, wire all the panels in parallel into the one controller, and use the large battery bank to provide 12 volt power for your LED lights and small electronics and such, and then just shop for a 12 volt inverter for when you need AC power, they don't cost much. Also, batteries don't get along well with each other if they are dramatically different in age. This is why boat owners go through batteries so fast. They have one that won't hold a charge in the spring, so they put a new one in parallel with the 2 year old one that is still good. Then the new one fights with the older one and wrecks it, so a year later they replace that one, and the process reverses. If you are going to hardwire lead acid batteries in parallel, it's best to get them all within a year of each other. Don't take my word on this though, go to the library and check out Richard Perez' book, "The Complete Battery Book." Just read the chapters on lead acid batteries, he explains this in depth. Richard is the founding editor of Home Power Magazine by the way, a great periodical on just this sort of thing. Good luck Patrick, and take care, Rudydoo

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I think it is a hideously complicated plan including switching the batteries in and out with different charging levels as they age. You should wire the panels in parallel, match them to a similar voltage battery pack and buy an inverter that runs off of that voltage to get your 120 volt.

YES, TOTAL IS 72V 450W