I have (2) 12v 60amp hour batteries connected in parallel used as backup power for my electronics.

I have (2) chargers, 12V 6amp.
Is it safe to use both chargers at the same time while the batteries are interconnected?

If i decide to expand my parallel connections to 4 or 5 batteries can I use 4 or 5 chargers on each battery while the batteries are all connected?

  • \$\begingroup\$ What battery chemistry do you have? Li-ion? Lead/acid? NiMH? \$\endgroup\$ – John Honniball Nov 11 '14 at 21:16
  • \$\begingroup\$ they are: vmaxtanks.com/servlet/Detail?no=52 \$\endgroup\$ – t q Nov 11 '14 at 21:20
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    \$\begingroup\$ Those are AGM (Absorbed Glass Mat), a type of lead-acid battery \$\endgroup\$ – John Honniball Nov 11 '14 at 21:31
  • \$\begingroup\$ why the downvote? \$\endgroup\$ – t q Nov 11 '14 at 22:37

Connecting battery chargers in parallel is not a good idea. They can interact with each other, e.g. if they momentarily switch off the charge current in order to monitor the battery voltage. This can lead to a charger thinking the battery is fully charged, when it is not, and stopping the charge process.

If your chargers are very crude, with no sensing electronics, then it might work. You'd have to use chargers that were little more than a transformer and a rectifier, though.

Much better to get a bigger charger.

  • \$\begingroup\$ thank you, the recommended charger for this battery was 14.5v 7a. If i went with a bigger charger should i look for 14.5v 14a? \$\endgroup\$ – t q Nov 11 '14 at 22:29
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    \$\begingroup\$ @tq Yes, if you have two batteries in parallel, then you'll need double the current to charge them in the same time. Same voltage, of course. \$\endgroup\$ – John Honniball Nov 11 '14 at 23:14

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