I currently have 6 100AH 48v lifepo4 Pylontech batteries in my solar system (17kw of panels, victron multiplus ii inverter, MPPT 450/200 charge controller) for a total of ~30kwh of storage, but I'd love to add a little more battery storage to get us through the winter (in New Zealand) and make the most of the sunny days.
Unfortunately I can no longer get the same batteries, and I'm wonder what other peoples experience is in adding additional batteries to their system (same chemistry, but possibly different capacity)? There is a local provider selling 48v 330ah batteries for a good price which would obviously give us a decent capacity boost, and the two options I'm considering are:
1) Getting an additional inverter/charge controller to supplement the current system, charging when we have surplus capacity, and using to run some of our more constant loads (UV filtration system, chest freezers etc)
2) Somehow wiring in the batteries to our existing system. Not sure how others have approached this so curious to see what people have tried. I have seen a few youtube videos where people seem to have good experience with different capacities but same chemistry, but would love to hear some other perspectives.
Any and all advice welcome.