Looking for some advice. I am looking to upgrade my current battery in my 5th wheel. the unit came with a 2000w inverter that only inputs 12v so I was going to buy 2 200ah 12v batteries to start with. Then add batteries as I can afford them. I also want to upgrade my inverter in the future so its bigger and can run on 24v. My question is can I buy a couple 12v batteries now and then at a later time buy some more batteries that are 24v and integrate into the system? So I would potentially have 2 12v batteries in series and then 2 24v batteries in parallel with the series 12v battery.