Another two battery question

TomG2 wrote:
I have two 12 batteries in parallel on my travel trailer. My questions is whether I am better off "saving" one battery by disconnecting it when hooked to shore power for months at a time or am I better off leaving them both connected all the time?

If you let one battery get weaker and weaker by use while the other one is disconnected, then when you reconnect that other battery, the weaker one will pull down the less used battery. It is never good to connect dissimilar batteries together. For the same reason it is never good to replace just one battery of a pair...