Need help adding a battery to Ipod amp.

Thread Starter


Joined Jul 29, 2010
I am building an Ipod amp/speaker system as a hand made gift for my daughter this Christmas. Basically I am using PC speakers with built-in amp (12W, 15v 1.1A power supply). I'm planning on running an Apple AC charge adapter to an Apple docking station with a line level output. I would like to add a 14.8V LiPo and a charger to run the system when it is not plugged in. My thought was just to add a smart charger to the system as I don't want to have to remove the battery to charge it.

Question 1: What is the best way to have the system switch between AC and DC? I could do it with a switch but I would prefer; if it is plugged in and off-it charges battery, plugged in and on - it runs off AC, unplugged and on - it runs off battery.

Question 2: Charger would be wired in parallel with the amp power supply and connected to battery. Can I just leave charger connected to battery and power the amp in parallel off the battery? Or do I need to have the charger electrically disconnected from the battery when the battery is in use?

I would appreciate any help. I am an electronics hobbyist; good at building circuits but not very adept at circuit design. Thanks, Greg


Joined Sep 9, 2010
The typical solution for #1 is a switch built into the power plug socket. This disconnects the battery when the plug is inserted.

IMHO, it's fine to charge the battery while using it. But I suppose it depends on the charge circuitry, which must have the capacity to do both.