Has anyone installed a solar system on the top, using micro-inverters and bringing down 110V to a charger?
My idea is to start building my solar farm on the rooftop with individual micro-inverters, in parallel. It purpose will be mainly to charge my two banks 840 AH.
I would start with two panels and add more gradually up to 6 panels.
Short answer is No, use the solar to charge via DC straight to the batteries.
Solar devices like micro inverters and grid tied inverters generator AC output directly from the connected panels. But there are a few caveats.
Most of them are intended for grid tie, and require stable, pre-existing AC power that they can sync up to. If there isn't a pre-existing source of AC power, they will never even turn on. This is because they are designed to
follow and push AC power, not
create AC power. So if you just connect a micro inverter to a charger, most likely nothing will happen.
This is all a consequent of how a grid tied inverter deals with varying output from the solar panels. It does that by first synchronizing with the grid power, then it pushes all the power it has into the grid. The grid can absorb as much or as little as the inverter wants to provide, and the grid makes up the balance of whatever is needed to power you loads. It just becomes a matter of how much current flows in which directions.
But if there were no grid, all the solar inverter could do is create an AC output, wait for loads, and attempt to power them. If it couldn't power them, then it's only option would be to turn off. The only way for you to keep power on would be to regulate your loads. So getting back to your charger, you would have to constantly adjust it's output to limit power consumption to keep the micro grid running. That's not practical.
There are, however, products that let you do part of what you describe, but that I think are still not practical for your goal. With some products, you can run a battery powered inverter to create AC. Then you can connect something like a micro inverter to the AC output of the inverter, creating a so-called AC-coupled system. Now the battery inverter acts a bit like the grid, though with much less capacity. Plus, the micro inverter power can ONLY be used to supplement power to loads. It's can back-feed through the inverter to charge the batteries. You could now plug your battery charger into this micro grid, and to the extend that the solar products all the required power, you could charge your batteries. But if the solar isn't enough, and there will always be times when it isn't, the charger will continue, and draw any remaining power requirements from the inverter, which is getting it's power from the very batteries that you are trying to charge. At a minimum you would be wasting a bunch of the solar power, and worse case you would drain your batteries instead of charging them.
