Portable speaker boombox wiring help?

Hi guys,

I'm currently in the planning/semi-begun-building stage of my first DIY electronics project, which is in the form of a portable boombox based around the lepai 2020A+ amp and the Sure APT-X Bluetooth 4.0 module (which both run off 12v). Despite searching the entire internet up and down, I just can't seem to make the electrical/power side of the wiring clear in my head. And to be honest, I'm a little worried about burning a house down/killing a battery and would be very grateful for some help.

I'm looking at incorporating a cig lighter 12v socket for charging accessories like phones/audio players/whatever through a classic car to usb device as the stepdown, as well as a 2.1mm DC jack that can be used to charge the battery via AC mains (240v in Australia) as well as via a small solar panel. I am sort of hoping that I could be playing music and charging accessories while the solar panel or AC mains is plugged in... basically I can have anything plugged in/not plugged in/left overnight by accident and the house wont burn down.

I have attached a mock wiring diagram that worked in my head, but I really do doubt if this is actually an acceptable circuit. There are also a couple of components I have left off there because I simply wasn't sure where to put them.

The first is a simple power switch, so that when off nothing can drain the battery. Is this a simple case of wiring in line on the positive lead between the battery and the solar charge controller?

The second is a small volt/ammeter (http://www.ebay.com.au/itm/251498991739?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649) that I would desperately like to use to know both when the battery needs recharging, as well as how much current the amp is drawing. I have absolutely no idea where to begin with this one. The yellow wire is scaring me even though the product hasn't arrived yet! Can anyone help with this?

Am I at least on the right track?

I hope you understand my misunderstandings, and are accepting to an enthusiastic novice's questions


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