Multi Purpose Backup/Auxillery Power Supply




Introduction: Multi Purpose Backup/Auxillery Power Supply

This device can be used to power your cell phone, iPod, Nintendo DS, PDA, PSP, wireless router, laptop, or just about any low voltage device.

Step 1: Tools

These are the tools you'll probably need.

-Misc screwdrivers
-wire cutters
-needle nose pliars
-solder & soldering iron
-drill & bits
-dremmel tool(depending on your case)
-multi meter
-electrical tape

Step 2: Matierials

youll need:

-a switch
-an led(with mounting hardware)
-a 12v sealed lead acid battery
-a case
-a transformer and a charge board for the battery
-a chassis mount connector
-battery clips
-fuse holder
-1-5 amp fuse

Step 3: The Battery

Thease batteries come in many shapes and sizes, you need to choose the battery for your needs.

things to conciter:
1)Battery size & weight
thease factors can dictate the size of your case and portability.

you need to know the power consumption of the device you are planning on using.

for example:
your ipod requires 200ma to charge.

batteries capacity is allways marked on the side, a 1 amp hour battery can safely supply 1 amp for one hour, or it could supply 200 milliamps for 5 hours.

Step 4: The Features

There are many things to add, depending on what you need., the parts described in part 2 are useless without some sort of add on, view the pictures to see my suggestions, then we will get onto construction.

Please note, the first pic is a suggestion on how to lay out the controlls.(how mine is layed out)

Step 5: The Main Circuit

hook it all up in accordance with this diagram

Step 6: Chose Your Add Ons

at the very least you should add a 12vdc out port to your creation

for the battery tester, goto step 7, for the regulator goto step 8 for usb goto step 9

Step 7: Battery Tester

refer to this website:

if you want the three led version,connect pin 9 to positive and only connect the green led to pin 10, the yellow to pin 14 and the red to pin 1

Step 8: Regulator Board

a regulator board is really easy to make, simply chose the voltages you need and put regulators on for each one.

7805 is 5v
7806 is 6v

Step 9: Usb Port(for Chargeing)

This is so you can charge usb devices with your power supply

Step 10: Case Mods

Now all you need to do is drill the nessisary holes in the case to attach all of the components

note, the 2nd and 3rd immages are for an older version of the power supply, this one did not include the charge regulator or the rotery switch.

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    8 Discussions


    8 years ago on Introduction

    heat sync? huh heat sync? no no no no no. heat sink you know


    11 years ago on Introduction

    Great reuse of the Radio Shank alarm box. Better now than when new!


    11 years ago on Introduction

    Would you be able to use solar power to charge the battery, without removing it from the case? And a generator?


    11 years ago on Introduction

    how long does the power supply last when in use? My husband has a power supply using a auto battery that he is going to test for me... I need power for most of a day but my laptop battery is only good for about 2 hours...


    Reply 11 years ago on Introduction

    If you have an auto charge/power cord for your laptop, have you husband measure how much current it draws while powering your laptop. Additional batteries can be added to extend the usable time period of the backup supply. But first you need to determine the power demands of the devices you hope to power.


    12 years ago on Introduction

    Great idea! (Could use some kind of carrying handle, though.)


    Reply 12 years ago on Introduction

    I actually have a shoulder bag for it. It weighs about 25 pounds though.