E-Bike Battery Tapped For Off-Grid Laptop Power

May 2, 2023 by Tom Nardi 12 Comments

If you’ve travelling via bike, you’ll know there’s a certain advantage to packing light. But what if you need to take your beefy desktop-replacement laptop with you on one of these trips? These power hungry machines can’t go far without their chargers (or a place to plug them in), which generally makes them poor traveling companions.

Luckily, [transistor-man] came up with a solution to this particular problem by reusing his e-bike’s battery pack as a mobile power source for his Lenovo laptop. The energy demands of this particular computer are too high for USB-C Power Delivery, and as such, he had to hack up a way to feed it 20 volts DC via its proprietary square power connector. His bike’s battery puts out between 30 and 42 VDC depending on charge, so at least on paper, it should work out fine. Continue reading “E-Bike Battery Tapped For Off-Grid Laptop Power” →

Experimenting With 20 Meters Of Outlet Adapters

February 4, 2023 by Chris Lott 100 Comments

You may have seen some of the EEVblog dumpster dive videos, where [Dave Jones] occasionally finds perfectly good equipment that’s been tossed out. But this time, rather than a large screen monitor, desktop computer, or a photocopier, he features a stash of 283 electrical outlet double adapters that he found last year. He decided to perform a test in the parking lot, connecting all 283 adapters in series.

Using a pair of power meters and a 2 kW electric heater as a test load, [Dave] and his son [Sagan] measure the loss through this wild setup. It works out to about about 300 W, or roughly 1 W per adapter. He did a follow-up experiment using a FLIR thermal camera, and confirmed that the power loss is reasonably uniform, and that no single rogue adapter consuming all the lost power. After a back of the envelope calculation, we estimate this chain of adapters is about 20 meters long, making this whole thing entirely pointless but interesting nonetheless. Stick around until the end of the video for a teardown — they’re not as cheaply made as you might think.

[Dave]’s crazy experiment aside, we do wonder why someone had so many adapters to throw away in the first place. What would you have done with 283 adapters — left them in the dumpster or rescued them?

Continue reading “Experimenting With 20 Meters Of Outlet Adapters” →

MagSafe Power Bank From Scrap

August 4, 2017 by Bryan Cockfield 23 Comments

Just a few short years ago, it was possible to find scrapped lithium batteries for free, or at least for very cheap. What most people at the time didn’t realize is that a battery with multiple cells might go bad because only one cell is bad, leaving the others ready for salvaging. Now it’s not a secret anymore, but if you can manage to get your hands on some there’s a lot of options for use. [ijsf] took a step further with this hack, taking a few cells from a Panasonic battery and wrangling them into a MagSafe-capable power bank for a Mac.

The real hack wasn’t scavenging batteries, however, it was getting the MagSafe to signal the computer to use power from the battery bank to run the computer only, and not to use any of that energy for charging the computer’s internal batteries. This is achieved by disabling the center MagSafe pin, which is the computer’s communication line to the power adapter. After that, the battery bank could be programmed to behave properly (a feat in itself for lithium batteries) and the power bank was successfully put into operation.

Not only was this hack a great guide for how to repurpose cells from a “dead” battery, it’s also an unparalleled quick reference for any work that might need a MagSafe connector. Of course, if you’re going to work with these chargers, make sure that you’re using one that isn’t a cheap clone.

Fixing Faulty But Genuine Apple Power Adapters

November 1, 2014 by Brian Benchoff 51 Comments

The standard power adapter for Apple laptops is a work of art. The Magsafe connector has saved more than one laptop owned by the Hackaday crew, and the power brick with interchangeable plugs for different countries is a work of genius. Being a miracle of modern manufacturing doesn’t mean Apple gets it right all the time; the UK adapter doesn’t use the ground plug, leading to the power supplies singing at 50 Hz when plugged in. [Gareth] had had enough of the poor design of his charger and decided to fix it.

The Apple power adapter has two obvious connections, and another shiny metal disk meant for a connection to Earth. In most of the Apple charger ‘extension cords’, this earth connection is provided by the cord. In the smaller plug adapters – even ones where space is not an issue, like the UK plug – this connection is absent.

To fix this glaring oversight, [Gareth] shoved some aluminum foil where the earth terminal on the plug should go. A hole was drilled through the plug to connect this foil to the Earth socket terminal, and everything was covered up with kneadable epoxy.

No, aluminum foil probably won’t do its actual job of preventing horribleness in the event of an insulation failure or short. It will, however, silence the 50 cycle hum emanating from the power adapter, and that’s good enough for [Gareth].

Hacking A Mac Magsafe Jack Into A PC Ultrabook

November 23, 2013 by Marsh 34 Comments

zenbookAir

Something’s fishy about the above-pictured ultrabook: it’s an Asus Zenbook that [WarriorRocker] hacked to use a MagSafe power connector typically found on Macbooks. Most of us probably consider it standard procedure to poke around inside our desktop’s tower, but it takes some guts to radically alter such a shiny new ultrabook. It seems, however, that the Zenbook’s tiny power plug causes serious frustrations, and [WarriorRocker] was tired of dealing with them.

Using information he found from an article we featured earlier this summer on a MagSafe teardown, [WarriorRocker] hit up the parts drawer for some connectors and got to work. He had to modify the MagSafe’s housing to fit his Zenbook while still holding on to the magnets, but he managed to avoid modifying the ultrabook’s case—the connector is approximately the same size as a USB port. Deciding he could live with just one USB connection, [WarriorRocker] took to the board with a pair of side cutters and neatly carved out space for the MagSafe next to the audio jack. He then soldered it in place and ran wires from the VCC and Ground pins along a the channel where the WiFi antenna is routed, connecting them to the original power jack’s input pins.

[WarriorRocker] regrets that he fell short of his original goal of getting the MagSafe’s protocol working: he instead had to hack on his own adapter. We’re still rather impressed with how well his hack turned out, and it did manage to solve the charging problems. Hit us up in the comments if you can provide some insight into the MagSafe’s otherwise obscure innerworkings.

Simple Power Adapter Thumbs Its Nose At Proprietary Connectors

June 5, 2012 by Mike Szczys 19 Comments

[Mike Worth] wanted to use his camera for some time-lapse photography. Since it’s used to take many pictures over a long period of time, he doesn’t want to deal with batteries running low. But there’s no standard power jack on the side; instead the official charger consists of an adapter that is inserted in place of the batteries. Rather than break the bank with the special cable, [Mike] made his own battery compartment A/C adapter.

You can see that it is made up of two parts. The first is a standard wall wart that outputs the correct voltage and has an acceptable current rating. The other part is the adapter cable that connects to the camera on one end, and has a barrel jack on the other. [Mike] rolled some paperboard around a pencil until it matched the diameter of a AA battery. Once of the cylinders has a thumb tack for the negative lead, and the other uses a screw and washer for the positive side. He soldered some wire to these and he’s in business.

He must be snapping photos frequently enough to avoid the auto-shutoff feature. That or he’s disabled it with the use of some custom firmware.

IPhone Charger Teardown Shows Astounding Miniaturization.

May 20, 2012 by Brian Benchoff 24 Comments

There’s no question that Apple has their industrial design down pat; comparing a cell phone charger made by Blackberry or Motorola to the tiny 1-inch-cube Apple charger just underscores this fact. [Ken Shirriff] posted a great teardown of the Apple iPhone charger that goes through the hardware that makes this charger so impressive.

Like most cell phone chargers and power supplies these days, Apple’s charger is a switching power supply giving it a much better efficiency than a simple ‘transformer, rectifier, regulator’ linear power supply. Inside the charger, mains power is converted to DC, chopped up by a control IC, fed into a flyback transformer and converted into AC, and finally changed back into DC, and finally filtered and sent out through a USB port.

The quality of the charger is apparent; there’s really no way this small 1-inch cube could be made any smaller. In fact, if it weren’t for the microscopic 0402 SMD components, it’s doubtful this charger could be made at all.

Comparing the $30 iPhone charger of a cheap (and fake) iPhone charger, the budget charger still uses a flyback transformer but there are serious compromises of the safety and quality. The fake charger doesn’t use a power supply controller IC and replaces the four bridge diodes for a single diode to rectify the AC; a very efficient cost-cutting measure, but it does lead to a noisier power supply.

There’s also the issue of safety; on the Apple charger, there is a (relatively) huge physical separation of ~340 VDC and your phone. With the off-brand charger, these circuits are separated by less than a millimeter – not very safe, and certainly wouldn’t be UL approved.

It’s worth pointing out that [Ken] compares a similar $7 Samsung charger favorably to the $30 Apple charger. Both are functionally identical, but Apple also has their marketing down pat, to say the least.

Tip ‘o the hat to [George] for sending this in.

EDIT: In case a 1-inch cube wasn’t impressive enough, check out the euro version of the iPhone/iPad charger. It supplies 1A @ 5V, and isn’t much thicker than the USB port itself. Thanks [Andreas] for bringing this to our attention. If anyone wants to do a teardown of the euro version, send it in on the tip line.