Hi, i bought a Burstner which had just 1 70AH AGM battery fitted with 120W solar panel. I have bought a 120AH to replace it to give a little more. I was going to sell the 70ah but just thinking maybe keep it but obviously cant connect in parallel as its a different size. Do i fit a dc-dc charger just for that 1 battery or get another solar panel just for that battery? Im thinking i could just let that be the wifes battery for her hairdrier when off grid with a inverter as i have told her no way can she use the 120ah for that luxury. Any tips etc appreciated.