UPS With Dead Batteries Reborn As A Whole-house Power Backup

April 9, 2012 by Mike Szczys 70 Comments

[Woodporterhouse] must deal with regular power black outs in his area. He recently converted a rack-mount uninterruptible power supply to feed a portion of his mains wiring. This one is not to be missed, since he did such a great job on the project, and an equally remarkable job of documenting it. It’s one of the best examples we’ve seen of how to use Imgur as a project log.

The UPS still needs to have a case, but it doesn’t need room for batteries as he’s going to use a series of high-end sealed lead-acid batteries. So he cut down the enclosure to about half of the original size. That’s it mounted just above the new batteries. For this to work you need some type of transfer switch which can automatically patch between incoming line voltage, and the battery backup. He already had one of these switches in place for use with a generator, that’s it in the upper left. The entire system powers a sub-panel responsible for his essential circuits — the electronics in the home and a few lighting circuits (we’d assume this includes utilities like the refrigerator).

One really great feature that the reused UPS brings to the project is a monitoring card with a NIC. This way he can check the server to see if the UPS is being used, and how much of the 14 battery life remains.

[Thanks Ross via Reddit]

Measuring The Capacities Of Different Battery Brands

April 9, 2012 by Brian Benchoff 51 Comments

Being the smart consumer he is, [Denis] usually looks at the price per pound when comparing similar products at the grocery store. When it came time to buy a few AA batteries, he didn’t have any data to go on. To solve his little conundrum, [Denis] decided he would test several brands of batteries and see which one gives him the most bang for the buck.

After bringing home a haul of a dozen different brands of AA cells, [Denis] broke out the Arduino and starting designing a circuit. To test how much energy each brand provides, the Arduino measures the voltage across a load every second until the battery reaches 0.2V. The elapsed time, as well as the voltage, Watt hours, Joules, and ambient temperature are logged on an attached LCD screen and sent over a USB serial link to automate the data collection process.

What’s the verdict? Unsurprisingly, words like ‘super,’ ‘max,’ and ‘ultra’ didn’t connotate a better battery. The best bang for the buck came from an off-brand called RS Power Ultra. The worst battery was the Panasonic Evolta cells that came in at about $1.50 USD per watt-hour.

If you’d like to verify [Denis]’ work, all the code is up on Github along with the schematic.

Another Take On Using ‘dead’ Batteries

February 29, 2012 by Mike Szczys 8 Comments

Here’s another circuit that can be used to squeeze the remaining potential from supposedly dead batteries. Just like the AASaver, we see this as a useful prototyping tool, providing juice for a breadboard even though it’s not reliable enough for long-term use (the batteries are just about through after all).

First off, the image above shows rechargeables instead of alkalines. We don’t recommend this as the circuit has no cutoff feature and the 0.7V input for the boost converter surely is below the recommended low-voltage limit for those cells. But that aside, we like the diminutive board which solders onto the end of a battery pack. It uses an SC120SKTRT which is a variable boost regulator capable of outputting 1.8-5V depending on resistor choices. You can leave the resistors off and it will default to 3.3V, set the output explicitly, or roll in some potentiometers and use your multimeter to tune the output.

This regulator costs more than the MCP1640 used in the AASaver, but it appears to use less passive components making for a smaller footprint. At a total of $3.50 plus the PCB (which will be a snap to etch at home) this is another great option to top off your next parts order.

[Thanks Uwe]

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Things To Do With Your Laptop Batteries When They’re Dead

September 19, 2011 by Mike Nathan 65 Comments

[Roy] over at GeekDad had a dead laptop battery on his hands, and decided he would disassemble it to see what useful things he could do with the cells inside. He mentions in his article that even though your laptop might be convinced that its battery is toast, more often than not just one or two cells are damaged. This may not be news to all of our readers, but is worth pointing out to those who might not be aware.

With the bad cells separated from the good, [Roy] thought up a couple of different uses for his newly acquired batteries. His initial idea was to power an LED flashlight that was made to run on the 18650 cells he recovered from his laptop – not a stretch of the imagination, but definitely useful. The second use he came up with was to pair two of the cells together in order to simultaneously power an Arduino and some small Lego motors.

[Roy] lays out all of the standard caveats you would expect regarding the care and feeding of the lithium cells, and even suggests rebuilding the laptop battery as an option for the more skilled members of his audience.

Now we understand that dismantling and re-using old laptop cells is not necessarily groundbreaking, but it’s definitely something that’s worth a bit of discussion. [Roy] admits that his two ideas fall far short of the “18650 Things” his article title suggests, so how about adding a few of your own?

If you have stripped down some laptop batteries to salvage the cells, let us know what you did with them in the comments – we would be interested in hearing about it.

Engine Hacks: Electrified Datsun Is The Ultimate Engine Swap

September 2, 2011 by Mike Nathan 57 Comments

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Forget the Tesla Roadster, we want an electric car like [John Wayland’s] White Zombie!

If it wasn’t plastered with sponsor stickers and the like, you would never realize that this otherwise unassuming ‘72 Datsun 1200 is an absolute beast of a car. The gas engine that used to provide a mere 69 horsepower was swapped out for a pair of custom-built electric motors which propel the Datsun to 60 miles per hour in under two seconds.

The electric motors supply 500 horsepower and a staggering 1250 foot pounds of instant torque, providing one hell of a ride. The car is powered by 12 custom 29.6V battery packs which provide 2,400 Amps of current each! Aside from laying down a quarter mile in under 11 seconds, White Zombie can make a 90 mile trek before requiring a recharge.

Needless to say, this impressive car takes plenty of people by surprise each time [John] hits the track. Continue reading to watch one poor sap learn the hard way that his brand new Maserati is no match for White Zombie.

[via Discovery]

Continue reading “Engine Hacks: Electrified Datsun Is The Ultimate Engine Swap” →

Apple Laptop Batteries Vulnerable To Firmware Hack

July 23, 2011 by Mike Nathan 45 Comments

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When you think about hacking laptops, it’s highly unlikely that you would ever consider the battery as a viable attack vector. Security researcher [Charlie Miller] however, has been hard at work showing just how big a vulnerability they can be.

As we have been discussing recently, the care and feeding of many batteries, big and small, is handled by some sort of microcontroller. [Charlie] found that a 2009 update issued by Apple to fix some lingering MacBook power issues used one of two passwords to write data to the battery controllers. From what he has seen, it seems these same passwords have been used on all batteries manufactured since that time as well. Using this data, he was subsequently able to gain access to the chips, allowing him to remotely brick the batteries, falsify data sent to the OS, and completely replace the stock firmware with that of his own.

He says that it would be possible for an attacker to inject malware into the battery itself, which would covertly re-infect the machine, despite all traditional removal attempts. Of course, replacing the battery would rectify the issue in these situations, but he says that it would likely be the last thing anyone would suspect as the source of infection. While using the battery to proliferate malware or cause irreversible damage to the computer would take quite a bit of work, [Charlie] claims that either scenario is completely plausible.

He plans on presenting his research at this year’s Black Hat security conference in August, but in the meantime he has created a utility that generates a completely random password for your Mac’s battery. He says that he has already contacted Apple to in order to help them construct a permanent fix for the issue, so an official patch may be available in the near future.

[Thanks, Sergio]

Fixing Motorized Window Shutter Battery Problems

June 12, 2011 by Mike Nathan 4 Comments

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Living in a brushfire-prone area, [Erich] had a set of roller shutters installed to protect his home. Mains power can be spotty in emergencies, so the shutters are powered by NiMH batteries which are housed inside the shutters’ remote control units. After encountering a good handful of dead batteries, he decided it was time to search around for a better means of powering the shutters rather than pay another $80 AUD for batteries that he knew would fail in short order.

After disassembling the shutters and the remotes, he found a litany of problems. The remotes are ATMega-based, so he assumed the programming was robust, but he found that the charging algorithm was quite poorly implemented. The batteries were allowed to get extremely hot while charging, a result of the fact that charging was done for a set period of time rather than monitoring battery voltage. Additionally, the shutter motors required a 4 amp instantaneous current when activated, something that seemed to contribute to the quick draining of the 1500 mAH battery packs.

To remedy his issues, he upgraded to a much larger sealed lead acid battery pack, which he mounted in a wall cavity. The remotes were tweaked to add a modular power plug, enabling him to easily connect and disconnect the remotes as needed. Not only did he save a ton of money on constantly replacing batteries, he’s got a nice 12v power supply in the wall that he can tap into at will.