If I have an existing 12V Lithium battery bank and decide to upgrade to an Integrel system later do I need to change my 12V lithium bank for a 48V system or can I use my 12V batteries and add to that whatever is necessary when we install the system?

You can (theoretically) use your existing 12V Li Batteries.  The limitation will be you need them in lots of 4 connected in series to make the 48V bank.

So either 4 batteries, 8 batteries (2 strings of 4 batteries in series, connected in parallel) and so on.

HOWEVER, we only recommend using certified batteries. These are:

• Mastervolt

• Victron

• MG Energy System

We are working on certify more batteries. We have rejected many, as unsafe for heavy duty marine use.