In this instruct-able I will show you how to charge your KOBO vox anywhere you can get 2A of usb power.
If you own a Kobo Vox, you will know it comes with only an AC recharger with a 2 ft power cord, and kobo doesn't sell replacements, nor do they sell car chargers, and your included USB to PC cable is DATA only.
You may think, no worries! There are hundreds of 3rd party suppliers. However, once you try them you will be disappointed. The Kobo has a non standard pin out that is incompatible with any charger other than the one the Kobo ships with.
If you use a greater than 2 amp charger, it will charge, however you will have to remove the back cover in order to press the soft reset button for the Kobo to realize it's been charged. Also annoyingly the battery charge level indicator will not change, and the battery charge light will not indicate that it is charging
I examined my Kobo charger and noticed that the cable to the micro USB connector is a simple 2 conductor wire. Therefore the pin out must be altered only in the connector, and there should not be any signalling from the AC power adapter. With this deduction I decided to cut the connector off, and affix it to a regular USB end so that it could be plugged into any USB port, like for example my 2.4A USB charger that fits in my car's lighter socket.
.I also decided I wanted to keep the AC charger, so where I cut off the original micro USB connector, I spliced on a female USB port.
Step 1: Parts List
The parts you will need:
- Kobo Vox (if you don't have one, what's the point?)
- Kobo Vox Power Adapter
- USB donor cable, preferably one from a high power device that has a female at one end, and 2 male at the other. If you can't find a female you won't be able to keep the wall wart but can still salvage the micro connector as male USB ends are dime a dozen if you don't mind cutting up a cable.
- 3/16" heat shrink tubing
- Electrical Tape
- Solder rosin core
I highly recommend getting the beefiest USB cable you can, something off a scanner, external hard drive/CD ROM will most likely have the thickest gauge conductors which you will need to carry the 2 A. I used a extender cable from a USB CD ROM.
Tools you will need:
- Soldering iron
- lighter or heat gun
Step 2: Prep Donor Parts - AC Charger
Start with the Kobo Charger, cut the cable off about 3 inches (10cm) or so from the wall wart. As you can see I cut mine a bit short which made heat shrinking problematic when attaching the female end.
Step 3: Prep Parts - Donor Cable
Cut the Female end off your extender cable, or if you are using a normal cable, cut the useless end off.
Remove some sheathing from the USB connectors, and do the same for the AC adapter
Step 4: Prep Parts - Testing Connections
With the wire on the AC adapter stripped, ensure they are not touching, and plug it in.
Use a multi meter to check which is positive and which is negative. Usually the wire with the dashed white is positive.
Then plug the male end of your donor cable into a powered usb port and also find the positive and negative leads. These will be the 2 heaviest gauge wires, usually black and red.
Step 5: Prep Parts - Soldering
Now that you have identified which conductors in each half are positive and negative, we need to solder them together.
We will use a technique called an extension cable splice. The goal is to stagger the individual splices so that if they manage to rub through the heat shrink tubing, they will not come into contact.
1) Cut them so that the joins are staggered as in pic 1.
2) Cut 3 pieces of heat shrink. Place one over the whole cable on one side, and one on each conductor on the other, the idea is to have a piece of heat shrink on each join, then a final one to cover the entire section as in pic 2 and 3.
3) twist the wires together as required, keeping positive with positive, neg with neg. dab on some flux, then using your soldering iron heat the wire and add some solder. the joins should suck in the solder and become nice and shiny as in pic 4.
Step 6: Parts Prep - Heat Shrink
For each cable.
Place the 2 pieces of heat shrink over each join, and being careful not to affect the main covering piece of heat shrink, heat the 2 pieces to fasten them to their respective joins. Pic 1 (sorry for bad quality)
Place the final main covering piece over the 2, and then heat it. Pic 2
Because I accidentally cut my cords too short on the AC charger portion, I also added 2 layers of electrical tape to clean it up a bit and to add some strain relief. Pic 3
Step 7: Testing - Modified AC Charger
Now you should have both cables completed.
Plug the AC adapter in, plug your modified micro USB cable into it and plug it into your Kobo Vox.
If all is well the charging light should turn on, and your status under Settings>About>Status should display Charging under Battery Status.
Plug the Modified USB cable into another USB charging device that provides more than 2A, and the same should happen.