You haven t said what kind of batteries they are and that matters as to how they should be charged.
One solar panel two batteries.
Notice the two discrete battery connection points on both sides of the solar array connection on the back of the above controller.
There are a few charge controllers that have now added the default option of having two battery banks.
But i d suggest you use a proper charger circuit to do it.
The parallel connection of two identical batteries allows to get twice the capacity of the individual batteries keeping the same rated voltage.
To power a dual battery system you ll need to connect the panels in parallel.
This parallel wiring configuration is needed in case of 12v system i e.
One at the front for the trolling motor 80 ah and 2 smaller batteries in parallel at the rear for electronics 30 35 ah combined.
Connect the negatives to the negatives and positives to the positives.
In addition the two parallel connected solar panels will charge the batteries quickly and power up extra load.
If both panels are rated at the same maximum voltage then you ll get maximum output.
Most solar charge controllers will only allow you to charge one battery.
The two banks are charge separately using the same controller and solar panels.
I have two 12v lead acid batteries on my boat.
You can charge two batteries together you can charge them either in series or in parallel.
Connecting two solar panels in parallel.
However there s one consideration.
I want to put a solar panel on my garage so i can hook the batteries up when i get back from the lake to recharge them and to keep them maintained.
Looks to me you ll be charging them in series because that s the way they ll be connected.
For this reason two or more solar panels as well as batteries each of 12vdc are connected in parallel.