Automatic 24 volt battery switching circuit needed. When the run battery gets low I should be able to have the circuit switch to the 24 volt charge battery. Will use two battery's to work. One charging. The other running. Circuit should be able to sense the output of the run battery when it needs the recharge and switch it. I will be using two 12 volt hi amp battery's in series to get the 24 volts. Two pairs of battery's.

Any circuit help will be appreciated.

Thanks

 

TL431 makes a sensitive, accurate voltage sensing switch. See application notes section of its data sheet.

 

TL431 makes a sensitive, accurate voltage sensing switch. See application notes section of its data sheet.

The operating current range of the TL431 is; Min, 1mA - Max, 100mA.

Don't forget the standing current for the resistor divider that programs the voltage.

The sense input has an impedance of about 100k or so.