What you need to find is a two bank solar charge controller. For secondary rechargeable batteries the stronger battery would charge the weaker one draining itself and wasting energy.
Ess Design Amp Installation Manual Victron Energy
Solar charging batteries in parallel. Remember to keep those lead deep cycle batteries above half charge 3 your solar charge controller will help you convert current into usable voltages and amperages. Batterystuff tech putting batteries in parallel for the sake of charging is not recommend unless the batteries were in parallel to begin with. The more batteries connected in parallel the longer the charge will take. The parallel connection of two identical batteries allows to get twice the capacity of the individual batteries keeping the same rated voltage. Batteries can be wired in either parallel series or both series parallel depending on your application requirements. It is also possible to install solar as a combination of series and parallel circuits to try and maximize the advantages of both types of wiring.
Following this example where there are two 12v 200ah batteries connected in parallel we will therefore have a voltage of 12v volts and a total capacity of 400ah ampere hour. Charging 12 volt batteries wired in parallel requires a 12 volt battery charger. Off grid systems have a bit more flexibility and solar owners will sometimes connect their panels in parallel to meet their battery needs 12 volt solar system to charge a 12 volt battery for example. For example if fast charging one battery usually takes about an hour or two than two batteries connected in parallel takes two to four hours. If you connect rechargeable batteries in parallel and one is discharged while the others are charged the charged batteries will attempt to charge the discharged battery. The process is simple but as the capacity of the batteries increases depending on the number of batteries wired in parallel it can take twice the time to charge two 12 volt batteries and three times as long for three batteries.
Most solar panels come in 122436 etc voltsif you are using a 12v system and want to add extra capacity to your system you will wire your batteries in parallel. 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. There are a few charge controllers that have now added the default option of having two battery banks. If your battery bank consists of 12 volt batteries wired in parallel your recharging current will have a voltage at or a little above 12 volts.
Gallery of Solar Charging Batteries In Parallel
