5.9 12v seems to need less maitenance!!
Barely, 24v or36v in series is better
No
No
No
If you want to convert 24v AC into 12v Ac, it's simple. Just get a transformer to convert 24 volts into 12 volts. This is called a stepdown transformer. If you want to convert 24v DC into 12v DC, it's more complicated. First you have to change the 24v DC into 24v AC by a switching converter that changes DC into AC. Then you would use a stepdown transformer as in the former example. Once the 24v AC is converted to 12v AC, then you use a rectifier bridge to change the 12v AC into 12v DC.
The voltage is written on the fuse.
You don't. 2 12v panels together don't make 24v - doesn't work that way. If you need 24v you need to get 24v panels.
y not?
You need a 24v to 12v converter. Truck stops either keep them in stock or can get you one.
No, you need a 24 volt charger.
Wire the batteries in "series". Place jumper from neg (-) terminal to the pos (+) terminal on the other battery. You will have 24V across the remaining terminals.
12v in cars. Can be 24v in lorrys. 6v cars were phased out in the 50's.