Apple is a great company in many ways, but they are often frustratingly proprietary too.
One of Apple’s niftiest proprietary technologies is the MagSafe power cable tip that has been used on all of Apple’s recent laptops. The MagSafe holds the power cable to the side of a MacBook with a magnet so that you (or your pet!) tripping over the power cord does not risk hurling your laptop to the floor. It is indeed an ingenious bit of technology, and it has probably prevented an untold amount of damage over the years.
I love the MagSafe tip. I really do. But….
One particular frustration that has vexed me for over three years now is that there is no “official” way to power any MagSafe-equipped Apple laptops directly off of 12v power. As full-time technomads living in a small solar-powered trailer, we have ample access to 12v DC, while 120v AC is a rare luxury for us. Sure, we could use an inverter – but (as you will see) that inserts a lot of overhead and inefficiency. We would much rather run our lives directly off of 12v as much as possible.
Unfortunately, Apple has not released a 12v car-charger of their own, and they have threatened to send an army of lawyers after any third-party power supply manufacturer that dare introduce a MagSafe-compatible power cable. There is no technical limitation preventing Targus, Kensington, or iGo from producing MagSafe compatible tips for their universal notebook power supplies. But without a license from Apple, they just aren’t going to chance it.
But there is an alternative…
Mike Lee of Mikegyver.com has made a business of taking genuine Apple MagSafe tips, and splicing them onto 12v compatible power supplies.
His cheapest option ($60) involves you sending him your laptop power supply to convert, or for $165 he will include a new Apple power brick that he has modified for you. And for $229 you can get a MagSafe-equipped Kensington or iGo universal power supply that is slim, light, and runs off of both AC and DC, including from EmPower jacks found in many airliners. These supplies offer a true go-anywhere replacement for Apple’s power brick, only they are much more versatile.
We checked out the Kensington All-In-One, and it has quickly become one of the most indispensable items in our technology arsenal. We have been particularly thrilled with no longer needing to power up our DC-to-AC inverter to power our laptops.
I took some measurements to see how much power we are saving by using a DC-to-DC power supply, rather than needing to convert from DC-to-AC-to-DC via an inverter and the standard Macintosh power brick:
|Configuration||Mikegyver||Small Inverter||Big Inverter|
|MacBook Pro Sleeping||0.1A / 1W||0.7A / 9W||1.9A / 24W|
|MacBook Pro In Use (Fully Charged)||2.2A / 28W||3.0A / 38W||4.1A / 52W|
You’ll notice that our small Xantrex 400W inverter inserts about 10 watts of overhead, and our large 1500W Xantrex Freedom 458 Inverter/Charger wastes over 20 watts of power just by being fired up!
Here are a few other interesting notes and observations…
- The Apple power brick has a parasitic drain of 0.3A (4 watts) when plugged in, even when no laptop is connected. This is an example of why you should never leave wall-wart power supplies plugged in when you are not actively using them!
- The measurements in the table above are from Cherie’s laptop, a mid-2008 2.4GHz MacBook Pro, with the screen on full brightness. My early-2006 2.16GHz MacBook Pro is significantly more power hungry, despite the half-as-bright screen. It typically burned nearly 20 additional watts of power under a similar load!
- Power consumption while charging varied depending on how thoroughly drained the laptop is. I measured as much as 89W of power consumption while charging a fully drained laptop via the Kensington power supply!
- The Kensington power supply comes with two tips you can use – the N2 and the N3. The N2 puts out 16.5 volts (equivalent to the MacBook 60W power supply), and the N3 puts out 18.5 volts (equivalent to the 85W MacBook Pro power supply). According to Mikegyver.com you should not use the N3 tip on EmPower equipped airplanes because you risk overloading the 75 watt maximum of the airline jacks. But in my testing of charging a fully drained MacBook Pro, the N2 tip consumed 85 watts, and the N3 89 watts. In daily use, I have found the choice of tip seems to make no practical difference.
- The Kensington power supply has a low-voltage cutoff to protect you from draining your battery below 12 volts. This is great for use in a car, but can be frustrating if you have a solar setup and deep cycle batteries that can handle a deeper drain. Reportedly the iGo power supply does not come with this “feature”. (Read the update posted below to discover just how frustrating this “feature” proved to be for us…)
- If you are handy with a soldering iron, Mike also publishes a free “Do It Yourself” guide to doing the conversion of an old Macintosh power supply on your own, and he sells the parts (including the DC power supply) in his store for $65 to help you do this. Stuart Schmitt has published his own alternative description of the conversion process here.
- Another company, HyperMac, is taking preorders on their own MagSafe compatible 12v power supply for $149. Even though they have not shipped yet, they are claiming to be “the world’s first and only” – despite MikeGyver.com having been in business for years. For now, I suggest avoiding them. UPDATE: Be sure to read the comment thread to this post for much more information on the HyperMac, and look for an in depth review to be posted here soon.
- Mike often has some great deals on his refurbs page. Right now you can get a Kensington kit just like ours for $119!
The Mikegyver solutions are indeed expensive, but considering that Apple forces Mike into buying an entire power supply just to get the cable tip, the cost is not that unreasonable.
And if you live in a 12v world and are often away from AC power, we have discovered the Mikegyver solution to be truly invaluable. I have actually wired ours semi-permanently into our Oliver trailer (mounted in one of the under-seat storage bins), so that we have a charging cable always on hand.
UPDATE: After a month with the Kensington All-In-One, the low-voltage cutoff “feature” proved to be unbearably frustrating. Mike Lee of Mikegyver.com graciously sent us an iGo Everywhere to try out as an alternative. Read my thoughts and analysis of this solution here.
February 2010 Update: Our Mikegyver iGo Everywhere has bit the dust as of a couple months ago. Currently, it’ll run our laptops but not charge them. Our Mikegyver lasted less than 6 months of usage, which we don’t find all too impressive.
May 2010 Update: Our HyperMac has also bit the dust- the 12v connector melted in the socket. We ran it fairly regularly for less than a year. Thankfully, no permanent damage to our trailer or computers – but wow. Not good. Afraid at this point, we have no reasonable recommendations for 12v power supplies for MacBook Pros. If you have one.. we’d love to hear about it!