If you can't, aside from being HF stuff, there are WAY too many points of failure especially with 4 parallel strings of 3 panels in each string! But yes, you could make it useful although at first glance you'll be headed for the dreaded "defecit charging" scenario if you try to use all those 45ah batteries at once.
My suggestion would be to play with only ONE of the kits, AND before buying anything else, get a charger on those ups-style agm's. I'd recommend a NOCO Genius 3500. Charge up all 4, but for now, only use one battery.
Know up front that in your area, you get only about an average of 4.5 hours of "solar insolation", which is sunlight strong enough to actually do some good. So outside the times of about 10a to 2p, your panels won't be running full tilt. What this means is that if you only use 25 percent of your 45ah battery, (about 11ah draw), it will take all day to recharge. If you want it faster, then use TWO sets of those panels attached to just ONE of those batteries.
Also, you'll be wanting to get a decent digital multimeter to make sure your panels are performing properly at 18-20vdc open-circuit, and about 830ma short-circuit each under near perfect sunlight. Also use it to test your thunderbolts. If any of them are reading below 12.5 volts just sitting there (no charge, no load) when you got them, then they have seen better days. Still usable, but you may not really have 45ah batteries due to sulfation, they are now 35ah. Lots of fun ahead!
If you can't take any of this back, then you've got some work ahead. Are you ready? Grab that NOCO charger to keep the batteries healthy when you make a deep-discharge mistake and can't recover from solar in a reasonable amount of time. Goof on the system while reading up here for your real setup later.
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