With the 1/24 scale of my PS Decoy (1.2 M LOA as the model), I was limited or restricted with the physical size of the 12 volt battery and ended up with a 7 amphour gelcel sealed lead acid battery which can be laid on it's side up fwd

Down aft I can fit a 3 amphour gelcel sealed lead acid battery, but that is where the questions commence

Naturally the 7 + 3 will give me 10 amphour capacity total when wired in parallel and I understand that current draw is relative to both battery condition (voltage) and internal resistance

However what happens in the real world when discharging and recharging batteries of dissimilar capacities?

a) Does the 7 A/h battery provide a higher proportion of current until the level reaches that of the 3 A/h and the both discharge at a similar rate until voltage actually drops?

b) The reverse question applies when recharging in parallel

A colleague of mine (mechanical not electrical) questioned why I had not chosen 3 or 4 of the 3 A/h batteries thus eliminating the question or problem

My response was that the 7 A/h was A$39.00 and the 3A/h is A$35.00!!

Can anyone offer constructive comment to the questions?

regards - Derek