Fighting Back Against Dodgy Dyson Batteries

If you’ve ever worked with multi-cell rechargeable battery packs, you know that the individual cells will eventually become imbalanced. To keep the pack working optimally, each cell needs to be analyzed and charged individually — which is why RC style battery packs have a dedicated balance connector. So if you know it, and we know it, why doesn’t Dyson know it?

It’s that question which inspired [tinfever] to start work on the FU-Dyson-BMS project. As you might have surmised from the name, [tinfever] believes that Dyson has intentionally engineered their V6 and V7 batteries to fail by not using the cell balancing function of the onboard ISL94208 battery management IC. What’s worse, once the cells get as little as 300 mV out of balance, the controller considers the entire pack to be shot and will no longer allow it to be charged.

These missing resistors deserve justice.

Or at least, that’s what used to happen. With the replacement firmware [tinfever] has developed, the pack’s battery management system (BMS) will ignore imbalanced cells so you can continue to use the pack (albeit at a reduced capacity). Of course the ideal solution would have been to enable cell balancing on the ISL94208, but unfortunately Dyson didn’t include the necessary resistors on the PCB. Though it’s worth noting that earlier versions of the board did have unpopulated spots for them, lending some credence to the idea that their omission was intentional on Dyson’s part.

But not everyone is onboard with the conspiracy theory. Over on the EEVBlog forums, some users pointed out that a poorly implemented cell balancing routine can be more problematic than not having one at all. It’s possible that Dyson had some bad experiences with the technology in earlier packs, and decided to move away from it and try to compensate by using higher-quality cells. That said, at least one person in the thread was able to revive their own “dead” battery pack by installing this unofficial firmware, so whether intentional or not, it seems there’s little debate that usable batteries are indeed being prematurely marked as defective.

Proper cell balancing is key even in DIY projects, so we do have to agree that it seems more than a little unusual that Dyson would intentionally turn off this important feature in their packs. But the jury is still out on whether or not Sir James is trying to pull a fast one on his customers — as Hanlon’s Razor states, “never attribute to malice that which is adequately explained by stupidity”.

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When Battery Rebuilds Go Wrong: Understanding BMSs, Spot Welders, And Safety

Batteries are amazing. Batteries are horrible. Batteries are a necessary evil in today’s world of portable everything. If you’re reading this sentence, even if it’s not on a mobile device, somewhere there is a battery involved. They’re that ubiquitous. There’s another thing batteries are: Expensive! And at $350 each for a specialized battery, [Linus] of Linus Tech Tips decided to take battery repair into his own hands.

Rather than do a quick how-to video about putting new cells in an old enclosure, [Linus] does a deep dive into the equipment, skills, and safety measures needed when dealing with Lithium Ion cells. And if you watch the video through, you’ll even get to see those safety measures put to good use!

The real meat of the video comes toward the end however, with its explanation of the different Battery Management Systems (BMS), and a discussion of the difficulty of doing battery repair correctly and safely. Lastly, the video covers something a bit more sinister: Batteries that are made to resist being repaired with new cells; DRM for batteries, so to speak.

Overall we found the video informative, and we hope you do too. You might also enjoy this peek into the chemistry behind your favorite battery types.

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A LiPo Cell Makes A 4AA Pack For A GameBoy

Electronic toys of yesteryear were fantastic objects of desire, but came with the fatal flaw of requiring batteries. Batteries that cost more than the average youngster’s pocket money and for which the pestered parent were usually unwilling to fork out every couple of days to support an incessant playing habit. It’s something [Sen] has addressed for the Nintendo Game Boy, and rather than cutting the device up and soldering wires, the result is a unit that neatly slots into the existing 4AA battery enclosure.

The Nintendo rechargable Game Boy pack.
Much more convenient than Nintendo’s own effort!

Electrically it’s a simple case of wiring up an Adafruit module and a pouch cell, but that’s not the essence of the job in this case. Instead a huge quantity of work and iteration has gone into CAD design to the perfect-fitting pack. It’s sure to be a boon for today’s Game Boy player, but much more than that it should be of interest to owners of far more devices that take four AA cells. Most of us probably keep a few packs of AAs for just those moments, perhaps meanwhile something like this could be a handy thing to have instead.

More traditional conversions resort to extreme measures, as with this Game Boy Color.

Review: Battery Spot Welders, Why You Should Buy A Proper Spot Welder

Making battery packs is a common pursuit in our community, involving spot-welding nickel strips to the terminals on individual cells. Many a pack has been made in this way, using reclaimed 18650 cells taken from discarded laptops. Commercial battery spot welders do a good job but have a huge inrush current and aren’t cheap, so it’s not uncommon to see improvised solutions such as rewound transformers taken out of microwave ovens. There’s another possibility though, in the form of cheap modules that promise the same results using a battery pack as a power supply.

With a love of putting the cheaper end of the global electronic marketplace through its paces for the entertainment of Hackaday readers I couldn’t resist, so I parted with £15 (about $20), for a “Mini Spot Welder”, and sat down to wait for the mailman to bring me the usual anonymous grey package.

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How To Run Alternative Batteries On The DJI Mavic Mini

Rechargeable batteries are ubiquitous these days, freeing us from the expense and hassle of using disposable cells. However, this has come with the caveat that many manufacturers demand their equipment only be used with their own official batteries. [aeropic] wasn’t a fan of this, so built a circuit to allow his DJI Mavic Mini to fly with any batteries he pleased.

The Mavic Mini uses I2C to communicate with official packs, making the hack relatively straightforward. [aeropic] built a board nicknamed B0B, which tells the drone what it wants to hear and lets it boot up with unofficial batteries installed. The circuit uses a PIC12F1840 to speak to the drone, including reporting voltage on the cells installed. Notably, it only monitors the whole pack, before dividing the voltage to represent the value of individual cells, but it shouldn’t be a major problem in typical use. Combined with a few 3D printed components to hold everything together, it allows you to build your own cheap pack for the Mavic Mini with little more than a PCB and a few 18650 cells.

It’s always good to see hackers getting out and doing the bread and butter work to get around restrictive factory DRM measures, whether its on music, printer cartridges, or drone batteries. We’ve even seen the scourge appear on litter boxes, too. Video after the break.

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Battery Swap Gives Nissan LEAF New Lease On Life

It’s often said that one of the advantages of owning an electric vehicle is reduced maintenance costs, and for the most part, that’s true. That is, until the vehicle’s battery pack starts to show its age. Then you might be on the hook for a repair bill comparable to swapping out the engine on your old gas-burner. Depending on the age of the vehicle at that point, you might find yourself in the market for a new ride.

But in his latest video, [Daniel Öster] demonstrates that you can replace the battery in a modern electric vehicle without breaking the bank. While it’s not exactly an easy job, he manages to swap the pack in his 2012 Nissan LEAF from the comfort of his own garage using common tools and with the vehicle up on jack stands. The old battery wasn’t completely shot, so he was even able to recoup some of his costs by selling it; bringing the total price of the operation to approximately €2,122 ($2,500 USD).

Splicing on a new diagnostic connector.

While that wouldn’t be a bad deal even for a simple swap, the operation was actually an upgrade. The car was originally sold with a 24 kWh battery, but [Daniel] has replaced it with a 30 kWh pack intended for the 2017 LEAF. His car now has a greater range than it did the day it rolled off the assembly line, though as you might expect, the installation was more complex than it would have been with a contemporary battery.

[Daniel] has produced a kit that has all the adapters required to perform your own battery upgrade, including a module that translates the diagnostic signals from the newer battery into something the older vehicle can understand. With all the electrical bits simplified, all you’ve got to worry about is drilling the new battery mounting holes in the frame.

The battery pack is truly the heart and soul of an electric car, so its no surprise that mechanics and hackers alike are eager to learn as much about them as possible. They’ll have their work cut out for them, as the technology is only going to get more advanced with time.

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Building An Open Source ThinkPad Battery

If you own a laptop that’s got a few years on the clock, you’ve probably contemplated getting a replacement battery for it. Which means you also know how much legitimate OEM packs cost compared to the shady eBay clones. You can often get two or three of the knock-offs for the same price as a single real battery, but they never last as long as the originals. If they even work properly at all.

Which is why [Alexander Parent] decided to take the road less traveled and scratch built a custom battery for his ThinkPad T420. By reverse engineering how the battery pack communicated with the computer, he reasoned he would be able to come up with an open source firmware that worked at least as well as what the the third party ones are running. Which from the sounds of it, wasn’t a very high bar. From a more practical standpoint, it also meant he’d be able to create a higher capacity battery pack than what was commercially available should he chose to.

A logic analyzer wired in between one of the third party batteries and a spare T420 motherboard allowed [Alexander] to capture all the SMBus chatter between the two. From there he wrote some Arduino code that would mimic a battery as a proof of concept. He was slowed down a bit by an undocumented CRC check, but in the end he was able to come up with a fairly mature firmware that even allows you to provide a custom vendor name and model number for your pack.

The code was shifted over to an ATtiny85, with a voltage divider wired up to one of the pins so it can read the pack voltage. [Alexander] says his firmware still doesn’t do a great job of reporting the actual battery capacity remaining, but it’s close enough for his purposes. He came up with a simple PCB design to hold the MCU and support components,  which eventually he plans on putting inside of a 3D printed case that actually plugs into the back of his T420.

This project is obviously still in a relatively early stage, but we’re very interested to see [Alexander] take it all the way. The ThinkPad has long been the hacker’s favorite laptop, and we can think of no machine more worthy of a fully open hardware and software battery pack.