Charge 2x12V Battery

[Flash_Cro]

Hi all,

I need your help with charging two 12V batteries (serial connection). I have two 12V 7.2Ah from FIAMM , it's lead acid battery.
So, I need max. current and max voltage for charging two batteries connected in series because I need 24V voltage. Is it charge current of max 1.5, and charge voltage of 30V o.k. for charging, or should I use greater voltage, or should I charge batteries in parallel ?

Thanks in advance,

 

[ericgibbs]

Hi all,

I need your help with charging two 12V batteries (serial connection). I have two 12V 7.2Ah from FIAMM , it's lead acid battery.
So, I need max. current and max voltage for charging two batteries connected in series because I need 24V voltage. Is it charge current of max 1.5, and charge voltage of 30V o.k. for charging, or should I use greater voltage, or should I charge batteries in parallel ?

Thanks in advance,

hi,
From the 7.2AHr rating I suspect that they are sealed lead acid.
The max charge is 13.8V to 14Vmax for this type of battery.
You can charge two batteries in series with 27.6V or 28V maximum.

I doubt that a 7.2AHr will charge at 1.5A for any length of time, it most likely fall to about 0.3/0.4A, this is normal.

Never let the batteries discharge to less than 10.8V per battery.

What are the batteries being used to power.?

 

[Flash_Cro]

Hi thanks,

They are for backup powering of VHF NAV/COMM transceiver on aircraft, which have 27.5V regulated power from main bus.

Regards,