Mobile Power

How do I make a 12 volt mobile power supply from 9 volt batteries?

I need engineering help with the electrical components. It’ll prob require some kind of transformer and resistors but I don’t know which I’m trying to add it to a GigaWare mini projector. It is usually plugged into the wall but I’ve always wanted it to be wireless.

It depends on how much current your projector will draw.

I was browsing through Fry’s today, and I was admiring the 12 volt sealed batteries in their collection of interesting stuff. Could you use one of those? Or perhaps connect a few AA batteries in series (they also have holders for 2, 3, and 4 AA batteries), and place them in something like a decorative sock (?) or something for aesthetics?

Or would you prefer to work with 9 volt batteries because you have a box full of them and they’re wanting something to do?

Mobile Power Charging Station for iPod Touch & iPhone (Portable Battery Charger)

ULTRALITE 355 CAR BOOT ELECTRIC MOBILITY SCOOTER,POWER WHEELCHAIR,POWERCHAIR £0.00

TOYOTA ESTIMA PREVIA AUTO POWER DISABILITY MOBILITY ACCESS REAR CHAIR LOW MILES £0.00

New Mobile Power Station Battery 1900mAh backup Charger for iPhone 3G 3Gs 4G £0.00

Solar powered Mobile phone Nokia Sony Ericsson charger £0.00

Solar Powered Jewellery Rotating Display Stand Turntable Jewelry Mobile Phone £0.00

500W USB Mobile Car Power Inverter DC 12V to AC 220V £0.00

Battery for Mobile 100 Reflexes Use only with Power Supply 3BN78319 700 mAh Ni-M £0.00

4 Way Black In Car Charger Power Splitter Adapter DC 12V 5V for USB Mobile MP3 £0.00

Power Monkey Multi Mobile Phone Charger £0.00

1900mAh Mobile Power Charger for Apple iPhone 4 4G Station Portable Black £0.00

Power cord fr Mobile radio FT-1802M FT-1807M 1.5M DC1 £0.00

In Car Charger Power Splitter 3 Cigarette Lighter Port USB for MP3 iPhone Mobile £0.00