Portable Pandora Charger!

[Sander Hoksbergen]

What you need:

Hot-glue gun
Soldering iron
Solder
Soldering grease
A few cables
1x LM7805 or similar
1x Heatsink of some kind
1x 100µf 10v+ capacitor
1x 10µf 10v+ capacitor
1x 104 ceramic capacitor
1x USB Female
1x 9v battery connector
1x non-momentary power switch
Optionally 1x led and matching resistor

Now connect it together!


schematic in a bit...

Result:

5v USB charger, charge anything that can charge via usb, on the go!

Can a 9v alkaline battery provide much of a charge? Most 9v batteries only have a few watt hours in them. Can it provide the current? Maybe a rechargeable 9v battery would be better (since a rechargeable provide more current). If anything, I think it would better to make it use AA or possibly AAA batteries.

Chris

The amount of Ah is the same as a regular AAA battery except at 9V (Does not last long). Gizmo then proceeds to dump 4V over a linear regulator. So what exactly is the power equivalent? A bit more than 3 AAA batteries connected in series. How long will this last you ask? 15-20 minutes MAX.

A better idea would be to use a switching regulator. This requires switching logic (plenty of analog chips available), a coil with the correct inductance range and a capacitor to reduce output ripple. If you do the math and find some nice components you could make a specifically adjusted regulator with ~95% efficiency. Actually, I once made a DC-DC converter from 12V(Car battery) input to 16V(Laptop) output in a university project, capable of sourcing 4A and still 93% efficient.

 

[GizmoTheGreen]

The amount of Ah is the same as a regular AAA battery except at 9V (Does not last long). Gizmo then proceeds to dump 4V over a linear regulator. So what exactly is the power equivalent? A bit more than 3 AAA batteries connected in series. How long will this last you ask? 15-20 minutes MAX.

A better idea would be to use a switching regulator. This requires switching logic (plenty of analog chips available), a coil with the correct inductance range and a capacitor to reduce output ripple. If you do the math and find some nice components you could make a specifically adjusted regulator with ~95% efficiency. Actually, I once made a DC-DC converter from 12V(Car battery) input to 16V(Laptop) output in a university project, capable of sourcing 4A and still 93% efficient.

ugh, math D:

gimme link to a good guide and a good place to buy the components, lol :3

 

[TitanUranus]

I picked up one of these in Maplins on sale for £10 a few weeks back:

http://products.cametest.com/index.php/index.php?option=com_sobi2&sobi2Task=sobi2Details&catid=18&sobi2Id=65&Itemid=&lang=en

It takes 4xAA NiMH batteries (also got on sale, 8x25000mAh AA's for £9.99). You can use it to charge up any USB device. It also charges from a USB, or of course charges in the sunlight - good for camping I suppose. It's pretty small and neat, should add some life to the Pandora when my city gets flooded again and the power gets cut off. Damn global warming!

 

[jasay]

It takes 4xAA NiMH batteries (also got on sale, 8x25000mAh AA's for £9.99).

25 Thousand mAh each? Yeah, that should add a bit of battery life. Where do I pick up some those?

 

[atomicthumbs]

Soon I plan to make something similar, but it'll use a switching regulator (for efficiency), supply the Pandora with enough current at the right voltage to charge it through the AC adapter port, and it'll use one of these 7ah lead-acid batteries I have lying around.

 

[urjaman]

One Word: MintyBoost