MPPT charge controller and DC distribution
This seems like a simple question, and maybe it is, but I can't seem to find it clearly answered anywhere.
Let's assume an off-grid cabin. Let's say I've designed for a controller/inverter combo box to handle the 48 volt solar installation. So we're talking about a straightforward setup in terms of distributing inverter AC power throughout the cabin.
But, what if I want to also distribute DC power? The combo boxes don't include a robust DC Load output like a few of the discrete charge controllers I've seen. So, I would have to tap right at the battery bank; I could hook in an LVD and a DC-DC down-converter, which would smooth everything out, and then use fat wire to run DC through the cabin.
Which would be fine, but wouldn't this confuse the MPPT charge controller? The absolute last thing I'd want to risk is battery damage. If I'm drawing variable chunks of current directly from the batteries without the charge controller knowing anything about it, won't it confuse the heck out of the controller? Won't it sense those voltage drops and jiggle things that don't need jiggling, or am I worrying needlessly?
(BTW, the whole point of all this is efficiency. The easiest approach is to just convert inverter AC power to DC, but that seems woefully inefficient; if I could use a DC-DC converter, I'd only be incurring a single conversion loss, whereas converting to AC and then converting to DC seems... a little extravagant.)
Any help appreciated.
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