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Old 03-13-2019, 03:10 PM   #2
DavidM
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City: Litchfield, Ct
Join Date: Aug 2012
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It is needlessly complex and maybe unsafe. With 48 volt nominal batteries, that means that they will be charging at as much as 58 (4*14.5) volts and the solar panels would be delivering 68 volts to the charge controller. You need different wiring techniques for that kind of voltage to make it safe.


How far away is the location of the new batteries from the existing batteries? It isn't a no no to connect two separate banks of batteries if they are wired correctly.


I would use at least two solar controllers and feed each bank from separate controllers. I would connect the two banks in parallel with good sized wire, size depending on what the distance and maximum loads could be, but probably 2/0.


The new bank will probably be discharged less as well as charged less (from non solar sources) than the existing bank due to the tiny voltage drop in the connecting wire. But you can monitor this and it should be a small effect that should be resolved with the independent solar sources.



David
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