Internally there is a standard 17Ah battery (makes the thing very heavy, the only downside) connected to a charger, and an inverter the charge switch connects the battery to the charger and the power switch connects the battery to the inverter. We were planning on using somthing like
this for the power and charge swiches, but due to time constraints we used 2 30A double pole switches
Also the power led, and the power button are soldered directly to the motherboard of a small laptop later i can post a picture of the (less than flattering) internals