lithium battery

21 Articles

Fail Of The Week: How Not To Electric Vehicle

December 3, 2018 by 92 Comments

If you ever doubt the potential for catastrophe that mucking about with electric vehicles can present, check out the video below. It shows what can happen to a couple of Tesla battery modules when due regard to safety precautions isn’t paid.

The video comes to us by way of [Rich], a gearhead with a thing for Teslas. He clearly knows his way around the EV world, having rebuilt a flood-soaked Tesla, and aspires to open an EV repair shop. The disaster stems from a novelty vehicle he and friend [Lee] bought as a side project. The car was apparently once a Disney prop car, used in parades with the “Mr. Toad’s Wild Ride” theme. It was powered by six 6-volt golf cart batteries, which let it maintain a stately, safe pace on a crowded parade route. [Rich] et al would have none of that, and decided to plop a pair of 444-cell Tesla modules into it. The reduced weight and increased voltage made it a real neck-snapper, but the team unwisely left any semblance of battery management out of the build.

You can guess what happened next, or spin up to the 3:00 mark in the video to watch the security camera mayhem. It’s not clear what started the fire, but the modules started cooking off batteries like roman candles. Quick action got it pushed outside to await the fire department, but the car was a total loss long before they showed up. Luckily no other cars in the garage were damaged, nor were there any injuries – not that the car didn’t try to take someone out, including putting a flaming round into [Lee]’s chest and one into the firetruck’s windshield.

[Rich] clearly knew he was literally playing with fire, and paid the price. The lesson here is to respect the power of these beefy batteries, even when you’re just fooling around.

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New Lithium Battery Technology Takes Guts

November 1, 2016 by 14 Comments

Researchers have built a prototype lithium-sulphur battery that — when perfected — could have up to five times the energy density of current lithium-ion devices. Researchers in the UK and China drew inspiration from intestines to overcome problems in the battery construction.

In your intestine, small hair-like structures called villi increase the surface area that your body uses to absorb nutrients from food. In the new lithium-sulphur battery, researchers used tiny zinc oxide wires to form a layer of material with a villi-like structure. These villi cover one electrode and can trap fragments of the active material when they break off, allowing them to continue participating in the electrochemical reaction that produces electricity.

Lithium-sulphur batteries aren’t new (in fact, they were used in 2008 in a solar-powered plane that broke several records), but this new technique may make them more practical. You can see a video about ordinary lithium-sulphur batteries below along with more on how this research improves the state of the art.

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Tour De Force Battery Hacking

September 3, 2016 by 23 Comments

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

July 25, 2015 by 12 Comments

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

August 12, 2014 by 21 Comments

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

August 3, 2014 by 14 Comments

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

July 16, 2014 by 35 Comments

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!