Battery Charging

If you are using the 2 batteries in series, then there is no problem charging them in series.

I am assuming that you have them arranged so as to provide 24 Volts.

Be aware that it is not a good idea to tap the "center" to provide 12 volts, as that will cause the batteries to be unbalanced and as a result when you are charging at 24Volts the low side battery will not charge properly, and the high side battery will be overcharged.

If you are using the batteries to provide a "split" rail supply (+12V 0V -12V) then you should charge them individually.

thanks sir but will be please clear me with "split" rail supply (+12V 0V -12V)??

A split rail supply, is where you have both a postive supply and a negative supply with reference to "Ground" or return.

In the situation with your batteries, if you considered the jumper connection between the two batteries as your ground, then you would have a +12volt rail and a -12volt rail. Which I expressed this way +12V 0V(middle connection) -12Volt.

You might like to explain the use of the 2 batteries, as the application may have a bearing on the charging technique.

i am not using center tapping output from the battery. actually sir, i want to use switch between the battery charging circuit and the application circuit.so, there will be no connection from the application circuit with the battery, while batteries are being charged.i want to take three different outpu voltages from the 24v,7ah output.

I=C-ah/10 [ A ] for 16Hours slow charge