Home solar system to charge coach batteries

[LarryB]

What do I need to charge my coach batteries from my residential roof top commercially installed solar  system?Asuming there will b no AC grid power available, long term. 
This is to be prepared for worst case scenario like earthquake. 

[Benjamin]

Not a simple answer.  You'd need to know how your array is installed.  It most likely has either higher voltage strings to one main inverter, or else it has microinverters at each panel that produce AC to transmit down to the connection with the AC grid.  Neither of those is designed to charge 12V lead acid.  If your solar system will island, or run when the there is no grid power available, then it will be easiest to plug the RV in and use the existing charger.  Most commercial grid tied systems won't island that I'm aware of. 

If you have higher voltage DC series strings of panels, then you could find a MMPT charge controller that would charge directly from that DC output.  Legality and codes would be over my pay grade.   If you have micro inverters on each panel, then you'd have to re wire an output to each panel you wanted to use, and could use either a PWM or MMPT charge controller.   In a SHTF scenario, you could hack the panels and hook directly to the battery bank, then remove connections when charged or at night. 

[jacwjames]

I'd just plug it into the house residential circuit.  20 amp outlet would be enough and just let the inverter/charger keep the batteries charged. 

[Rocketman3]

We full-time in our RV. I have 1400w of solar. Plenty in summer - spring & fall usually it’s enough- winter it’s barely enough in AZ with panels tilted. 
 

A lot depends where you live. You could buy a  large solar charge controller and wire it up to your rig - then if you ever need it (have instructions already figured out) unplug part of the house and plug into the rig.  As was said above - a lot depends on how your house solar is engineered - it could be easy - it could be difficult. 
 

you could also look into adding a house battery- then on normal days - charge battery during the day - then use battery in the evening and night.

Good Luck

[dl_racing427]

"you could also look into adding a house battery- then on normal days - charge battery during the day - then use battery in the evening and night. "

That would be the best solution.   That way, you keep your whole house livable instead of having to live in the RV.