All flooded lead acid or all agm. In parallel you should use diodes to connect the batteries to the ups.

Building A Battery Bank Using Amp Hours Batteries
Can you mix batteries with different ah. However you can connect batteries of different ah in parallel using diodes. Lets suppose you have 3 different 12v batteries wired in parallel to supply 12v power to your rv. You can safely mix and match battery sizes in one bank. As stated already you should only connect batteries of same typeagebrand in series. The rough thinking is that the new batteries will tend to take the load because they have lower internal resistance and more active plates as they are new and will tend to cycle more and deeper than the rest of the bank. Electric ezgo electric ez go marathon medalist txt and rxv.
Best to buy a couple of new sets and keep them as batteries of err batteries. Can i combine diferent ah batteries. If you must you can but be gentle with them and expect shorter charge life and shorter battery life. Generally once the batteries are probably more than a few months or a year old it is usually not a good idea to mix old and new banks. They can have different capacities on account of size or age but the same chemistry eg. Electric ez go marathon medalist txt and rxv.
No you cant connect batteries of different ah in series with a good result. It has previously been said that this is not a good idea. 15v alkaline 13v nimh and 12v nicads are cells. Also sabre yachts does this from the factory. Age is important but size is not. 9v alkalines are batteries theyre 6 15v cells in one pack.
A single cell is tied to other cells to form a battery. How battery charging works with a parallel battery bank. However we have done some pretty extensive lab testing and we can find no differences in the batteries. Mixing different ah batteries in your pack electric ezgo.