DIYer needs correct charge controller for my system

[Richa]

I am a newbie to this site.  I am a retired electrical technician & endeavoring to learn more about off-grid solar.  I have been using solar on my 10 acre New Mexico property since '02.  I have 2 strings of 6 x 100W panels and 1 string of 5 x 140W panels for a total of 1,900W, all connected in parallel.  Two years ago I decided to try AGM batteries in a bank of 8 x 155Ah batteries.  I purchased 3 x Morningstar TS-45 MPPT charge controllers for my 3 strings of panels.  My Inverter/Charger is a 12V 3500W Aims Power unit.  During the summer of '18, my system took a lightning strike which my undersized lightning arrestor could not handle, adversely affecting 2 of my 3 C.C.s.  I switched to my 3 previous TrackMax 40A C.C.s and got another year's worth of use out of my AGMs.  Now they are failing, I think due to insufficient charging.  For replacements, I have found U.S. Battery 6V-420Ah L-16s to be the best price.  I need 6 of these to provide 1260Ah to supply my appliances & electronics.  So, can you suggest a C.C.(s) to fit my system?  Crown Battery info says for every 100Ah of battery bank, 8-12A of deliverable current(minus correction factor) is necessary.  If so, then that figures to be 100.8A to 151.2A of deliverable current.  I am open to all suggestions.  Thanks in advance.  Richa

[mike90045]

36V inverters are a pretty odd size.   I'd suggest getting 2 more batteries and going to a 48V system.  Yes, you will need a new inverter, but you will save $ on cable and charge controllers.

A single string at 48V only needs 42A of charge current.   To get that, you need about 2500w of PV  and just 1 60A mppt controller.
The PV should be wired to about 80V - 110V strings.