Charging batteries in series?

Old 02-06-15, 10:42 AM
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Charging batteries in series?

Hi all,

I have two 12v batteries in series, to create both 12v and 24v output as shown in picture. My question is: Can I charge the system by using two 12v chargers attached to each battery separately?

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Old 02-06-15, 11:28 AM
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Yes, if you disconnect the links between batteries.

When your batteries are connected in series it becomes a 24 volt battery but when you disconnect the link between them they are two 12 volt batteries again and can be charged individually as a 12 volt battery. If you leave them connected together you'd need a 24 volt charger.
Old 02-06-15, 12:21 PM
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Pilot is partially correct. You CAN use two 12 volt chargers but they will in effect be wired in series. You MUST make certain that the combined terminal is connected properly to BOTH chargers. NOTE, this MAY not work with so-called "automatic" chargers.

Note that in your circuit the battery supplying the 12 volt load will discharge faster than the other battery. This is a poor method and you would be better off using a DC-DC step-down power supply to change the 24 volts down to the needed 12 volts so as to cause both batteries to discharge equally. Then recharge them in series using a 24 volt charger.

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