The only way to properly charge two 12v batteries that have different loads is with two independent 12vbattery chargers. A 60 volt charger will recharge five 12 volt batteries.
Solar Ray Wirediagrams
Charging 2 12v batteries in series. For a plethora of information. One basic configuration for charging batteries in series is to connect the positive charger output in red to the positive end of one of the batteries. The easiest way to fix a voltage difference is to charge the pack fully then bring up the lowest battery with a 12v charger placed on just the lowest battery. To charge two 12 volt batteries in series youd need a 24 volt charger. Voltage if there is one. If the load is 24v no power taken from the tap between batteries then a single 24v charger will work.
In theory a 6 volt 5 ah battery and a 12 volt 5 ah battery connected in series will give a supply of 18 volts 6 volts 12 volts and 5 ah. Two 12 volt batteries wired in parallel continue to produce 12 volts but the capacity doubles. Thats the pat answer. You need to overcome the total voltage of the series batteries 12 v 12 v 24 v to drive electrons. A 6 volt battery is often three 2 volt cells and a 12 volt battery is usually six 2 volt cells. Discharging and over recharging described and shorten the life of the larger battery through under charging.
The two 12v batteries connected in series have one load of 24v. Batteries may be wired in parallel or in series. The series connection of two identical batteries allows to get twice the rated voltage of the individual batteries keeping the same capacity. You do not need to disconnect the series connections to do this as long as you can access just the lowest battery. Connect the appropriate voltage charger across the positive terminal at one end of the series and the negative terminal at the other end of the series. For the final battery connect the negative end of the battery to the negative output in black of the charger.
Following this example where there are two 12v 200ah batteries connected in series we will have a total voltage of 24v volts and an unchanged capacity of 200ah ampere hour. Charging time will be the same as charging a single battery. These are available in 12 24 36 48 and 60 volt models. Charging 12 volt batteries wired in parallel requires a 12 volt battery charger. Two 12 volt batteries wired in series produce 24 volts but the capacity remains the same as one for a 12 volt battery. Next time you charge you should see the batteries are then closer in voltage at the end of the charge cycle.
Then connect the negative end of the battery to the positive end of the next one and continue to do so for the rest of your batteries.
Gallery of Charging 2 12v Batteries In Series
