Safety

Safety.

Not my forte!

The battery should be fused with a large fuse or breaker as close to the battery terminal as possible. This should be rated to the max your inverter will draw under load + a fudge factor you are happy with. This is to prevent you accidentally shorting out the whole battery with a spanner for instance. This results in a very melted spanner.

When working on your battery its best to use fully insulated tools. I have an adjustable where the only exposed metal is the adjustment wheel and the actual face of the jaws on the spanner. Another tip is to keep the bus bars of your battery more than a spanners width apart.

For example if you have a 5000 watt inverter on a 24v battery, it could theoretically draw much more when starting a heavy load such as a large motor as much as double for a well built inverter. 

So applying ohms law

W=VI

So

I = 10000/24 = 416 Amps

A slow blow 500 amp fuse would be suitable. These high power fuses are typically used for electric forklift trucks or even very loud car audio equipment so are commonly available.

How ever drawing this amount of power for a sustained period would be very hard on any normally sized lead acid battery thanks to Peukerts law

A really good heavy duty battery isolator switch is very useful. But remember to disconnect your controllers before using it as then they will no longer be connected to the battery but still have power coming in from the panels, if still connected to the inverter this could cause a voltage spike which would damage components such as capacitors

You also should have the output of the solar charge controller fused to a little above the rating of the controller.

I have also installed appropriately sized breakers between the solar PV and the charge controller as this makes isolating the panels for servicing, or other works much easier.

When  servicing or rewiring. First disconnect solar panels from the controller using a suitable breaker and if super safety conscious by putting a blanket over them first. Then disconnect the controllers from the battery. Then finally use the battery isolator.

For MPPT controllers the manual will almost always say connect the battery and then connect the solar, the solar will go open circuit and the voltage will go very high which the controller does not like. Most will have protection for this. But protection is there for emergencies not every day use.

Different batteries have different risks. Lead ones give off corrosive gasses. Lithium ones are capable of delivering very high current and some chemistries can be fire risk.

Make a box for your batteries with a lid. Make the lid hinged at fairly steep angle so that no one uses it as a convenient shelf.