Off Grid Wiring for Charging Battery and Solar Generator

[aaceve7]

I'm trying to figure out how to wire my 12V system to charge a 100AH AGM battery while also having the option to use the same solar array to charge a Bluetti AC200 solar generator. The AGM battery will be used to power shed lighting, a greenhouse fan, and occasional tool battery chargers and is the primary use of the system. I currently have my off grid system wired like the attached diagram. Is it possible to add a switch/disconnect that would allow me to use the same solar array to charge the Bluetti, which has its own built in charge controller and battery? I assume the main 100AH AGM system would have to be completely disconnected from the array and would therefore not be charging at the same time since these batteries are not the same type or capacity.

My main system has the following components:
4 - 75W panels
Renogy Rover 60 A MPPT Charge Controller
Samlex 300W Inverter
SunXtender 100AH AGM Battery
Midnite Solar 300V Surge Protector
Midnite Solar 63A 150V GFP Device
2 - Suntree 1P 50A Breakers
1 - CHTAIXI 2P 50A Breaker
Renogy 200A Breaker Box

[Bala]

You could set up a change over switch system to use the same panels but i would not consider it a viable option.

If it were me I would get some second hand grid tie panels for the bluetti.

[jflorey2]

I would:

1) Get another panel to charge the Bluetti. Panels are cheap.
2) Wire the battery disconnect so it disconnects the battery 100% so you can safely work on your 'main' system.

[aaceve7]

You could set up a change over switch system to use the same panels but i would not consider it a viable option.

If it were me I would get some second hand grid tie panels for the bluetti.

I figured as much. I'll just get separate panels. Thanks!

[aaceve7]

I would:

1) Get another panel to charge the Bluetti. Panels are cheap.
2) Wire the battery disconnect so it disconnects the battery 100% so you can safely work on your 'main' system.

Thanks! I'll definitely get another panel. As for the the battery disconnect, would you be able to show a diagram that shows the wiring configuration you're referring to? Does the wiring diagram I used not have the battery disconnect wired properly?

[chrisski]

DC switches are a bit tricky and would get expensive. Even the popular bluesea battery switches rated to 350 amps or 500 amps are not rated to switch on or off under load. All loads shut down, then switch off, with the switch rated to run 350 or 500 amps through it after its turned on.

I’ve found that the solar generators like Bluetti tend to have a narrow voltage input and max amperage along with non-standard connectors that make finding the correct combination difficult to get the max solar input with cold temperature adjusted inputs. The cable connectors can be changed to go into the generator which is not difficult, but adds a cost, especially if you need to buy a new tool or two.

If you go with a battery disconnect, same thing applies. Make sure it’s rated for the correct voltage / amperage / wattage. I saw a low voltage cutoff switch that I wanted to use as a battery cutoff, but found out that it was designed for small loads and intended to be something like trigger a remote off switch on an inverter. That of course was not in the product specifications but someone showed me where that tidbit was hidden in a different model’s product data. If you build your own, getting the proper relay rated for amps in DC is important.

[littleharbor2]

Would an A B switch fit the bill?
Perko Dual Battery Switch. For use with two or more batteries. For systems under 50 volts. Permits selection between batteries for starting and charging or operation of both in parallel.250 amps continuous/360 amps intermittent

Perko A B switch.jpg