Battery Charging advice

[Steve_switch]

I used to have a 12v off grid system and bought a 12v battery charger. Now I have upgraded my off grid system to a 24v system. I have two LiFeP4 12v batteries in series. What I'm wondering is can I connect my 12v battery charger across one of those 12v batteries to charge both 12v batteries?

 

[TomC4306]

No.
The only way to use that charger is to disconnect the batteries from one another and charge them individually.

 

[Steve_switch]

Thank you TomC4306 for responding to my inquiry. Do you know this from experience or does my question seem counter intuitive. The reason that I'm questioning your response is because it seems to me that with the series connected cabling in place, wouldn't the two batteries self balance. I guess I could go ahead and try it, but I would like to hear from a few other off grid aficionados' out there about this, in order to form a consensus. If my thinking on this not logical, please explain what would happen.

 

[mikefitz]

wouldn't the two batteries self balance. I

No they won't. Will only self balance in parallel.
You could charge each seperatly off load, then reconfigure in series. Idealy you need a 24 volt charger. With two 12v in series there will be performance drift between the two over time, leading to overcharge on one and under charge on the other. To rectify this, either add a battery balancer to the system or every several weeks charge each to full with a 12v charger . (assuming normal charge is with a 24 volt charger)

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[TomC4306]

See post 2.
But if you want to try it, please make sure to set up the video camera first. We'd love to see the result .

 

[740GLE]

Thank you TomC4306 for responding to my inquiry. Do you know this from experience or does my question seem counter intuitive. The reason that I'm questioning your response is because it seems to me that with the series connected cabling in place, wouldn't the two batteries self balance. I guess I could go ahead and try it, but I would like to hear from a few other off grid aficionados' out there about this, in order to form a consensus. If my thinking on this not logical, please explain what would happen.

Draw out a diagram of what you’re proposing and see where the current flows.