Reviving a Stubborn Laptop Battery

Panasonic Toughbook CF-28

We’ve all gotten bored of certain toys and left them on the shelf for months on end. But what do you do when this prolonged period kills the batteries? Well if you’re [Andrew] you take apart the battery pack and bring it back to life!

[Andrew] picked up one of those Panasonic Toughbooks awhile back and although it’s hardly a top of the line laptop specs-wise, it does have some pretty cool features: it’s shock-proof, splash-proof, and extreme-temperature-proof. It even had a touch screen before touchscreens were cool. Despite its durability, however, the laptop was left to sit for a bit too long, and the battery pack no longer accepted a charge.

[Andrew] quickly disassembled the battery pack and began measuring the cells with his trusty multimeter, assuming just one cell had gone bad. Curiously though, no cells reported 0V. What he did find was that each cell and sub-pack reported 2.95V, which is 0.05V below the “safe operating limits” of typical lithium ion cells. [Read more...]

$1 Coin Cell Charger

LiR2032-charging

Sure, coin cells usually last a long time — but do you really want to buy new ones and throw the old ones out? The LiR2032 coin cell is a rechargeable lithium battery, for which you can build a charger at around $1.

The 5 minute hack starts with a TP4056 lithium charging circuit, which is a great DIY board designed to charge high-capacity cells at about 1A. Luckily, it is pretty easy to modify the board to charge lower capacity batteries. It’s just a matter of replacing resistor R4, and a little bit of soldering! [Read more...]

Bicycle Generator for Emergency Electricity

hackettBikeGenerator

[Hackett's] back at it, this time with some practical advice for the next power outage to hit your city: why not prepare for the worst by building your own bike generator? You’ll no doubt recall that hurricane Sandy devastated New York City’s grid, even flooding substations and causing massive explosions. [Hackett] experienced the Sandy outages first-hand, and knows the value of having this simple build ready to roll.

The project uses a permanent magnet DC motor (around 250 watts), which you can find in electric wheelchairs or other mobility scooters. His setup’s gear reduction spins the motor 50 times for each revolution of the bike wheel. The apparatus [Hackett] built to press-fit the wheel to the motor’s spindle is particularly clever: a threaded rod adjusts the position of the motor, which is bolted onto a hinged platform, with the other part of the hinge welded to a larger frame that supports the bike wheel.

The motor is connected to a home-built charge controller based on Mike Davis’s design, which monitors the deep-cycle batteries and both kills the charge when it’s full as well as turns charging back on after it’s reached a set level of discharge. The rest is gravy: with the deep cycle battery connected to a power inverter, [Hackett] can plug in and keep phones charged, music playing, and even (some of) the lights on. If you’re a fan of [Hackett's] straightforward, practical presentation style, check out his tripod build and his demonstration of stripping pipes of their galvanization.

[Read more...]

Modifying a knock-off battery charger to be safer

i-tv5pN2R-X3

Sometimes buying a low-cost clone off of eBay is a great option, but [Martin] wisely decided to test his counterfeit IMAX B6AC, and found it grossly lacking. His detailed breakdown shows an alarming array of problems, including poor design and construction, and a lack of warning if the balance circuit fails. In addition, the charger wasn’t properly calibrated. By using a precision multimeter, Martin found that the charger actually brought cells above critical voltage. So really, using a charger like this out of the box can both destroy your battery pack and/or start a fire. One other interesting detail – this model can only be calibrated once. Sweet features.

[Martin] detailed his fixes in a well-illustrated blog post. He first had to re-enable the calibration menu using this method which requires bricking the device first! Once un-bricked, however, he could do the recalibration using a voltage divider and a reliable power source.

This project really underscores the need for a precisely calibrated multimeter. Not only would [Martin] not have been able to test his charger properly, but the re-calibration wouldn’t have been as accurate as needed. As hobbyists, this is a reminder that we can only trust our tools if they are accurate.

Sustainability Hacks: Solar battery/smartphone charger

[Michael] took a battery charger meant to be connected to mains power and converted it to work with a solar panel. This was a traditional 4 cell charger which charges the batteries in pairs. He kept that functionality, but added USB charging with a special over-current feature. That’s because his Android phone has a fast and slow USB charging mode. The slow mode makes sure that it draws 500 mA or less to stay within USB specifications. But the fast mode draws more current when the phone detects that the USB connection is attached to a wall charger. [Michael] added a switch that patches a pull-up resistor to the data line, signaling to the phone that it’s okay to switch to fast charging mode.

As for the power supply itself, you can see that [Michael] snapped off the part of the circuit board that housed the original regulator. He’s added his own 5V switching regulator which offers a wide input voltage range. This is connected to two banana plug sockets which can be connected to the solar panel.

Getting more information from your battery charger

echo_6_battery_charger_serial_hacking

[Dane] bought a reasonably cheap ($17) Hobbyking Echo-6 battery charger and wanted to see what sort of information he could pull from the unit. Since the charger is designed for a variety of battery chemistries and sports an LCD screen, he figured that it contained a fairly decent microcontroller which he could tap into for some useful data.

He disassembled the unit and started looking around for any useful items. He discovered that it used an ATMega32 microcontroller and had quite a few unpopulated areas on the PCB, which led [Dane] to believe that the Echo-6 shared its main board with a more robust charger. He tapped into the ATMega’s UART and began seeing data immediately. Once he figured out what was coming over the serial line, he piped the data into LogView, resulting in some nice graphs showing off the charge/discharge processes in detail.

Tapping into the Echo-6 seems easy enough for any skill level, and we assume that just about anyone would benefit from getting kind of information out of their battery charger.

Quick & Dirty USB phone charger

usb_phone_charger

Hackaday forum member [Dan Fruzzetti] wrote in to share a simple, yet useful hack he built just the other day. He and his wife both have Evo 4G smartphones and they were pretty disappointed in the lack of portable charging solutions available.

Instead of buying something and modifying it to his needs, [Dan] decided to build a quick and dirty charger instead. His ghetto-mintyboost was built into a cheap project box he found at Radio Shack, which is stocked with a set of four D-cell batteries. The batteries were wired in series and connected to a pair of salvaged USB ports mounted on a small piece of protoboard.

Knowing that most portable devices get 5.7v from their chargers already, he was not worried about hooking his phones straight into the 6v battery pack he built. He says that the phones actually charge pretty quickly, and that he estimates he should be able to get about 50 charges out of the box before he needs to swap the batteries.

This is not a complex hack by any means. It is quick & dirty, solves an annoying problem, and it’s dead simple to build. That’s exactly why we like it.