Tour de Force Battery Hacking

Lithium-Ion batteries are finicky little beasts. They can’t be overcharged, overdischarged, overheated, or even looked at funny without bursting into flames. Inside any laptop battery pack, a battery charge controller keeps watch over all the little cells, and prevents them from getting damaged.

Of course, any “smart” device will sometimes make the wrong choices, and then it’s up to us to dig inside its brains and fix it. When [Viktor] got a perfectly good battery pack with a controller that refused to charge the batteries, he started off on what would become an epic journey into battery controllers, and the result is not just a fixed battery, but a controller-reprogramming tool, software, and three reversed controller chips so far.

devbBattery controller chips speak SMBus, and [Viktor] started out by building a USB-SMBus tool. It’s a clever use of a cheap eBay development board for a Cypress CY7C68013A USB microcontroller. Flashed with [Viktor]’s firmware and running his software on the host computer, a SMBus scan is child’s play.

The rest of the story is good old-fashioned hacking: looking for datasheets, reading industry powerpoints, taking wild guesses, googling for passwords, and toggling the no-connect pins while booting the controllers up. We’re not going to argue with results: the bq8030, R2J240, and M37512 controllers have all given up their secrets, and tools to program them have been integrated into [Viktor]’s SMBusb tool.

In short, this is one of the nicest hard-core hacks we’ve seen in a while. Kudos [Viktor]! And thanks for the SMBus tool.

Field Expedient Stick Welder from Cordless Tool Battery Packs

The self-proclaimed and actual “smartest idiot on YouTube” is back with another entry from the “don’t try this at home” file. [AvE] recently did a teardown of a new DeWalt cordless drill-driver, and after managing to get everything back together, he was challenged by a viewer to repurpose the 20V battery packs into an impromptu stick welder.

AvE_short[AvE] delivered – sort of. His first attempt was with the two battery packs in parallel for higher current, but he had trouble striking an arc with the 1/8″ rod he was using. A freeze-frame revealed an incredible 160A of short-circuit current and a welding rod approaching the point of turning into plasma. Switching to series mode, [AvE] was able to strike a reasonable arc and eventually lay down a single splattery tack weld, which honestly looks better than some of our MIG welds. Eventually his rig released the blue smoke, and the postmortem teardown of the defunct packs was both entertaining and educational.

While we can’t recommend destroying $100 worth of lithium-ion battery packs for a single tack weld, it’s interesting to see how much power you’re holding in the palm of your hand with one of these cordless drills. We saw a similar technique a few years back in a slightly more sophisticated build; sadly, the YouTube video in that post isn’t active anymore. But you can always stay tuned after the break for the original [AvE] DeWalt teardown, wherein blue smoke of a different nature is released.

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Electric Longboard Roundup

ev longboards everywhere!

Everybody and their grandmother is longboarding electric-style these days: here are some of the most recent developments in the world of kickless cruising.

First up, [comsa42] has punched up an excellent step-by-step visual guide for first-time EV hopefuls, detailing the basics of a battery-powered longboard setup and thoroughly explaining the particulars behind component choices. His build is relatively straightforward: combine a board with a low(ish) kV outrunner motor, some LiPo batteries, an ESC (Electronic Speed Controller), a transmitter/receiver, and a few custom parts for gearing and mounting. This build should be commended not only for its simplicity but also for its frugality: [comsa42] estimates a final cost of around only $300, which is a staggering difference from commercial alternatives such as the Boosted Board and newcomer Marbel.

[comsa42’s] other significant contribution is a low-key and low-cost cover to house the electronics. He simply fiberglassed a small enclosure to protect the expensive internals, then mounted and painted it to blend seamlessly with the rest of the deck. You can find loads of other useful goodies in his guide, including CAD files for the motor mounts and for the wheel assembly.

But wait, there’s more! Stick around after the jump for a few other builds that ditch traditional wheels in favor of a smoother alternative. There’s also a smattering of videos, including comsa42’s] guide overview and some excellent cruising footage of the other board builds doing what they do best.

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Repurposed Laptop Batteries With a Twist

Arduino with lithium ion battery

Lithium ion batteries are becoming more and more common these days, but some of the larger capacity batteries can still carry a pretty hefty price tag. After finding Acer’s motherboard schematics online and doing a little reverse-engineering, [Tiziano] has found a way to reuse batteries from his dead laptop, not only saving the batteries from the landfill but also cutting costs on future projects.

These types of batteries have been used for many things in the past, but what makes this project different is that [Tiziano] is able to monitor the status of the batteries and charge them using I2C with an Arduino and a separate power supply, freeing the batteries from the bonds of the now-useless laptop.

With this level of communication between the microcontroller and the battery pack, there is little chance of the batteries catching on fire when they’re used in another project. Since the Arduino can also monitor the current amount of charge in the batteries, there is also a reduced risk that they will be damaged from under- or over-charging.

This wasn’t just as simple as hooking up the positive and negative leads of a power supply to the battery. [Tiziano] also had to model the internal resistance of the motherboard that the battery expects to see, and get the supply voltage just right so the battery’s safety protocols wouldn’t kick in to prevent them from charging. After a few other hurdles were jumped, [Tiziano] now has a large capacity lithium ion battery at his disposal for any future projects.

Finally, an Easy To Make Holder for Lithium Ion Batteries

Lithium Ion Battery holder

For projects requiring a bit more juice, the mass production of those small rectangular lithium ion batteries for cell phones, cameras and other electronics are extremely useful — the problem is, how do you mount them, short of soldering the terminals in place? With a bit of perfboard of course!

[Jason] came up with this idea when he was trying to figure out a way to mount small lithium cells for a battery fuel gauge for another one of his projects. He found if you use good quality perfboard you can use a 90 degree male pin header to contact the terminals, and a strip of female pin header as a kind of battery stop at the other end. This allows you to very snugly squeeze the battery in place — you may need to adjust the length of the male pins though in order to fine tune the fit!

Now you can add a nice wire terminal, solder up the connections, and there you have it, an easy to make, extremely useful battery holder!