Introduction: Portable Laptop Charger (Cheap and Easy)

By Digital Naturalism
About: I want computers to be wilder. Running a Jungle makerspace in Panama. https://www.instagram.com/digital.naturalism.labs https://twitter.com/HikingHack https://www.youtube.com/user/blorgggggg https://github.com…

Charge your LAPTOP with inexpensive 5-volt cellphone battery packs! Get crazy long lasting power anywhere, planes, trains, jungles! It's also only about $5 more than a regular cellphone charger. The total cost is only about $10-$30!

You don't even need to solder, you just need to screw some wires together!

You can actually purchase battery packs that are meant to charge laptops already. For instance these battery packs that I have used before, have 19V modes for charging laptops. The problem is that because they are in such smaller demand than regular 5V charger packs, their prices are CRAZY HIGH. These batteries usually cost between $150-$300. E.g. http://www.amazon.com/gp/product/B00BB5VQCE?psc=1&...

Also i suspect that they are little more than just a regular Li-Po battery pack with an integrated voltage booster (which is exactly what we are building here for 1/10th of the price!).

Step 1: Background

This project was developed during a Hiking-Hack Art, Tech, and Science project. (See the video and we explain more). We create mobile physical computing "maker" laboratories in the middle of the forests around the world. A key problem is being able to keep our laptops powered for the many days we are out there. We need dense, portable power; and since these expeditions usually have a shoestring budget (if any), we also need this power to be cheap.

As mentioned before, you can buy existing battery packs for charging something like a laptop, but BOY they are expensive! For much less money, you can get the same energy capacity and charge your devicesfor 1/5th to 1/10th of the price!

So we tried it out on a hack and had great results! This big fat battery packs that I could find deals for $12 each, would give us 26 amp-hours each! Several of these were enough to keep our laptops running for 9 days! (We also augmented with a bit of solar, but not much). You can tap into many 5V power-outlets also, and various sizes of 5V battery chargers (though a couple mysteriously won't work, might have lame current-draw protection).

It's also just super handy to have such devices when traveling anywhere! USB DC power will fast become the universal power-source, and if you can tap directly into it, you are golden! This project will open up lots of possibilities for you hopefully!

Step 2: Materials

At its most basic, all you really need is a cheap battery pack, a voltage booster, and a cable for charging your laptop.

Core

There are a couple extra things that make building this a bit easier. For instance if you have an apple laptop, they sell really cheap cables for them that are already split out into two leads.

Helpful Accessories

Step 3: Assembly (easy) - Input

A lot of people might get scared once they start seeing wires, but it is really easy! You don't even have to solder, you can just use the screw terminals.

Input Hookup

  1. Chop your USB cable and isolate its positive and negative power leads (black and red) (or just use one of these USB connectors: https://www.sparkfun.com/products/437 )
  2. Connect the positive and negative USB leads to the Input side of the power-booster (to the + and - respectively)
  3. Plug the USB into the battery to see if it turns on (should light up with the display)
  4. Turn the small screw potentiometer until the output display shows around 19-20V (it will bounce around a bit, don't worry). Also check to see what voltage your laptop needs (most want about 18-20V)

Step 4: Assembly (easy) - Output

Output Hookup

  1. Now take that repair cable that charges your computer and connect its positive and negative ends to the + and - of the Output side (if you just have a spare AC adapter for your laptop, chop off the end leading to your computer and strip out its positive and negative ends)
  2. Connect to your laptop!

If all goes well, your laptop should start getting fed extra juice!

Now some laptops are much more power-hungry than others,and will react in different ways. For instance, my macbook retina 15inch will display the power connection as "Plugged in, not charging" and will still make the laptop last for 14+ hours. Other smaller laptops, like my macbook air, are much less power-hungry, and actually start charging from this. They also charge quicker (if that's what you are looking to do), while they are turned off.

Step 5: Use Case: 24-Hour Airplane Video Games

Just as an illustration of how awesome this is, I kept my power-hungry macbook pro retina running and playing SNES Zelda all the way from Atlanta GA, USA to Manila, Philippines. This means you have enough time to easily defeat all the castles in the Light-World, and 3 of the dungeons in the dark world in an otherwise really boring flight.

There was a guy sitting next to me who kept getting angry at me because he wanted to plug his laptop into the power plug where I was charging my laptop. I kept trying to explain that I wasn't using a power plug, and that there WAS NO POWER PLUG. I showed him the charger system, but he still kinda refused to believe me.

The only possible downside to this hack is if you use the one with a built-in voltage display, it might be alarming to others to see these bright numbers flickering on an airplane.

So i just kept it in the seat pocket :)

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