Adding a charging capability

Hey everyone. I have a project which requires the use of a 12v battery powering a solenoid. It came with an external charger and at the moment I have to disconnect the battery from the arduino circuit in order to charge it. I’m looking for a way to be able to still use the external charger to charge the battery without blowing anything up lol. Thanks for the feedback

I don't understand why you have to disconnect it.

PeterH:
I don't understand why you have to disconnect it.

So what you're saying is I could just connect the leads on the charger to the battery at the same point on my breadboard? I'm new to micro controllers and was afraid the charger would backfeed into the circuit.