NOTA BENE: Following this tutorial will most likely result in voiding multiple warranties across multiple devices. If done incorrectly this may result in extreme consequences - including fires, battery and or charger explosions and overheating, short circuits which can have consequences including burning your house or building down. The author takes no responsibility for damage caused by performing this modification.
Do not use the modified adapter on any 15 inch Macbook device, as the Finsix Dart is unable to provide the required output to sufficiently drive the device.
Please note that the final result of this has not been properly tested with lab equipment. Also note that the output of the Dart is 20VDC, while Magsafe 1 power supplies output 16.5VDC. While I have used a Magsafe 1 connector here (mostly because I had a readily available broken power supply to cut the cable off of), I used a Magsafe 2 converter and have not actually charged a Magsafe 1 device with this. If you plan to charge a Magsafe 1 device, it might be worth double checking if the output voltage is a safe setup or not.
TL:DR; for the experienced: 1) Get compatible connectors from eBay or Amazon (Links below) 2) wire up with a donor Magsafe.
Now that we have gone through that...
The Finsix Dart is a compact charger for laptops which comes a large set of tips that allows you to charge almost any laptop on the market. However, this does not include any Apple devices - mostly due to the legal complications for shipping Magsafe compatible devices. (There are rumors of Magsafe tips that shipped to Kickstarter backers, but I was unable to find any proof that these actually exist as none of them turned up in the used market.)
- Magsafe (1 or 2) cable: You can get these from eBay as repair parts, or cut them off of a broken charger. Cut it roughly 10cm from the charger.
- Finsix compatible connectors: Finsix uses a proprietary connector, which is luckily a very simple form factor so finding one that fits isn't too hard. These are mostly sold as "outdoor waterproof LED cables" on either eBay or Aliexpress. Amazon Japan also has these here.
- Electric tape: As we are dealing with 20VDC, you absolutely want proper insulation. Don't cheap out on this.
- Multimeter: Any cheap multimeter that can test continuity (the "beep" mode) should do.
- EMI filters (optional): This isn't strictly necessary, but is a neat trick for hiding electric tape while doing passive filtering. Two birds, one stone. Get one that fits 5mm gauge wire. I used this.
- Solder kit (optional): If you want a slightly more secure connection between the two wires, this is strongly recommended.
- Wire stripper: Any stripper that can handle small gauge wires should work. I used a Vessel 3500 E-2.
- Knife (optional): A standard office paper knife or X-ACTO blade should do.
The Dart uses a connector that looks roughly like the diagram above. It is a circular connector, with one side cut out. This perfectly fits the connector that we are going to use, but as the connector only has a very small ridge to prevent incorrect polarity you need to be careful when connecting it. (Normally, you won't have to do this too often. I use the ridge as a visual indicator for the polarity.)
These LED cable connectors do not come with any standard wire color coding scheme (mind was brown/blue, which makes no sense), so you will need to use a multimeter to find out which one maps to which color, then make sure GND connects to GND on the Magsafe, and VCC maps to VCC.
Normally, if you cut a Magsafe cable - there are two internal cables - one white and one black. Black is GND, which maps to pin 1 and 5, and white is VCC which maps to 2 and 4. 3 is connected to a negotiation chip inside the connector, so there is no wire that corresponds to that pin. If you are using a aftermarket repair cable (e.g. eBay, Aliexpress) the colors may not match the genuine cables, so please test with a multimeter to ensure polarity.
Whatever combination you come up with using a multimeter, strip both sides of the wire around 1cm, connect the two wire pairs, isolate them with a piece of paper so they are not shorted, connect it to the Dart USB cable and test them by checking if pin 1 and 5 on the Magsafe maps to GND on the Dart cable, and 2 and 4 to VCC on the Dart cable.
Depending on the connector you used, you may need to use a shave off a bit of plastic on the compatible connector for a tighter fit.
Test between the two connectors as seen in photo above.
Now that you have everything in place, test continuity between the charger end of the Dart USB cable and the Magsafe pins. Make sure you test these combinations:
- Magsafe 1/5 to GND: Should be connected
- Magsafe 2/4 to VCC: Should be connected
- Magsafe 1/5 to VCC: Should not be connected
- Magsafe 2/4 to GND: Should not be connected
All four tests (or all 8 tests) should pass, otherwise something is wrong. If only one of the pin pairs (e.g. pin 1 connects to GND, but 5 does not) check for continuity, then it is most likely you have a broken Magsafe connector, and might want to throw it out.
When all of the tests have passed, either you can solder the wire pairs for stability or just tape it up with electric tape. After you are done, repeat the same continuity tests again and make sure nothing has changed. Mistakes here can happen, so make sure you test for short circuits.
(Optional) When you are done, wrap it up with enough electric tape so the tape thickness roughly matches up with the original Magsafe wire's gauge, then clip on a EMI filter for a more professional look.