Let your batteries charge until the charger indicates they are fully charged. Notice the two discrete battery connection points on both sides of the solar array connection on the back of the above controller.
Note 3 Battery Charger Kit Two Batteries Charger
How to charge two batteries at once. The two banks are charge separately using the same controller and solar panels. Some chargers have a light that illuminates once charged. Repeat this process for the other battery with the second battery charger. An example method of charging batteries in parallel is to use one branch of the parallel circuit to charge each battery with a single charger. In figure 8 a single 24 volt charger is connected to a 24 volt battery pack. Video of the day.
Clamp the black negative clamp from that battery charger onto the negative terminal of the first battery. Most solar charge controllers will only allow you to charge one battery. This ensures an even charge through all the batteries. Others have a meter that shows the charge rate and once its near zero your batteries are charged. Connect the charger to the first batterys until its charged then place the chargers on the second batterys and charge. Connect a battery charger across the positive terminal of the battery at one end of the row and the negative terminal of the battery at the other end of the row.
Connect the red positive clamp from one battery charger onto the positive terminal of the first battery. Connect the positive output of the charger to the positive terminal of the first battery and connect that positive terminal to the positive terminal of the second battery. Two batteries in parallel one charger batteries connected in series strings can also be recharged by a single charger having the same nominal charging voltage output as the nominal battery pack voltage. Charging two batteries at the same time you dont have to disconnect anything on the 24v battery bank to charge each battery. If this is not possible connecting across one battery works but is less efficient. You can easily start with one battery and add a second bank later.
When a charging voltage is detected on the start battery some units will immediately combine the house and start batteries to charge both while others will wait until a preset voltage is reached at the start battery before combining them. Two 12 volt batteries in parallel one 12 volt charger figure 9. There are a few charge controllers that have now added the default option of having two battery banks. Turn on your charger ensuring it is set to charge at 12 volts.