In many systems the inverter will be the deciding factor as to the size and voltage of the battery.
It seems people who want a large system usually want a 3Kw/13Amp 220/240v supply, just like a “normal” house, almost. If this is true then it almost automatically dictates that you have a 24 volt battery. As well as needing a large battery to power the inverter for any length of time, ”doubling” the battery voltage halves the current (Amps), and therefore size of cable needed to connect the inverter to the battery.
When choosing an inverter, most of the time the customer will give the “solar person” a list of what they want to use, and then your solar person should guide the customer through a shortlist of suitable equipment from which to make their selection.
If the customer is looking to buy a 3Kw inverter it will almost certainly be of the “ pure sine wave” type, and if so may well be an Inverter/Charger. This feature is very useful as even with large solar systems they will often have a generator to either back up the system during bad weather or for doing the washing and reducing the load on the battery. If they choose an Inverter/Charger the inverter can synchronise with the generator when it is running and use it not only to power the large load and use any left over energy to charge the battery, it can also be used solely to charge the battery.
