DIY 12v MacBook MagSafe Charger


As I get more 12v devices setup in my home office/ham shack I have started venturing into more and more electronics projects.

I started researching alternatives to the Apple MagSafe power adapters and did not come up with much. There seemed to be few willing to experiment with powering their expensive laptops from alternate sources.

In looking at my power adapters and Apple laptops I determined that a power source of 16.5v into a MagSafe cord would work. With none of my available power sources supplying 16.5v, I had to purchase a voltage step-up converter that would support the 3.65A load of my 13″ Retina MacBook Pro is rated for. I found one on Amazon that would support a 6A continuous load. I tested it on my bench and verified the output voltage on the built in display with a multimeter and found that it was off by about a tenth of a volt, not a show stopper.

While holding my breath, I connected it to my laptop and… the green light indicating charger was connected lit, and the charger was recognized in OSX. I drained the battery a few percent, and it charged up. I then drained the battery down to about 50% and successfully charged it up. Recharge times were roughly the same as using the AC Adapter. The only apparent difference I have found is that the Apple adapters only put out 6v until a load is present. This no doubt saves power on an adapter that is always plugged in, but I turn my 12v power supplies on and off as I use them.

I mounted everything up in a project box with some hot glue, a PowerPole lead, and a switch. I drilled a few vent holes around where the heatsinks of the voltage step-up converter are to allow for heat dissipation. I rarely feel the housing get more than just warm to the touch, but plan to drill more for a margin of safety.

I used the adapter for several days in my home office with no issues to report. I believe I will be switching back to the AC adapter for day-to-day operations, and will use this adapter for portable operations.

IMG_0796 IMG_0797

Word of warning – fuses are your friend

One time while checking the voltage at the MagSafe connector I shorted it against the magnetic collar. No permanent damage occurred to the power supply, voltage step-up adapter, or the MagSafe connector, but I have since decided to add a fuse to the output to prevent this from being an issue. With the MagSafe pins exposed, using a traditional quick-blow fuse may become an issue because the likelihood of shorting is high. I am going to try out a self-resetting poly fuse and see if the response times are adequate to prevent damage to the electronics.


Project Materials

Voltage step-up converter:

MagSafe2 Cord:

Project Box:

Power Switch:

Lincoln MKX Cabin Air Filter

I went to change my mother’s cabin air filter in her 2007 Lincoln MKX and most of the references online state to use an activated charcoal filter Fram Part# CF10547, however this is not a direct replacement for the filter that is currently installed in the vehicle. Numerous people posted the same issue online, and some felt that they could remove the paper media from the plastic frame and shove the media into the housing, but this is not an acceptable solution for me.

After a little more looking on Amazon I found the ATP FA-14. This appears to be a direct replacement, and is about half the price to boot.

Link for Acceptable replacement: