battery

404 Articles

Lithium-Ion Battery Circuitry Is Simple

October 10, 2022 by 55 Comments

By now, we’ve gone through LiIon handling basics and mechanics. When it comes to designing your circuit around a LiIon battery, I believe you could benefit from a cookbook with direct suggestions, too. Here, I’d like to give you a collection of LiIon recipes that worked well for me over the years.

I will be talking about single-series (1sXp) cell configurations, for a simple reason – multiple-series configurations are not something I consider myself as having worked extensively with. The single-series configurations alone will result in a fairly extensive writeup, but for those savvy in LiIon handling, I invite you to share your tips, tricks and observations in the comment section – last time, we had a fair few interesting points brought up!

The Friendly Neighborhood Charger

There’s a whole bunch of ways to charge the cells you’ve just added to your device – a wide variety of charger ICs and other solutions are at your disposal. I’d like to focus on one specific module that I believe it’s important you know more about.

You likely have seen the blue TP4056 boards around – they’re cheap and you’re one Aliexpress order away from owning a bunch, with a dozen boards going for only a few bucks. The TP4056 is a LiIon charger IC able to top up your cells at rate of up to 1 A. Many TP4056 boards have a protection circuit built in, which means that such a board can protect your LiIon cell from the external world, too. This board itself can be treated as a module; for over half a decade now, the PCB footprint has stayed the same, to the point where you can add a TP4056 board footprint onto your own PCBs if you need LiIon charging and protection. I do that a lot – it’s way easier, and even cheaper, than soldering the TP4056 and all its support components. Here’s a KiCad footprint if you’d like to do that too.

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Thank Magnesium For Water-Activated Batteries

October 4, 2022 by 16 Comments

Most of the batteries we use these days, whether rechargeable or not, are generally self-contained affairs. They come in a sealed package, with the anode, cathode, and electrolyte all wrapped up inside a stout plastic or metal casing. All the reactive chemicals stay inside.

However, a certain class of magnesium batteries are manufactured in a dry, unreactive state. To switch these batteries on, all you need to do is add water! Let’s take a look at these useful devices, and explore some of their applications.

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Lithium-Ion Batteries Are Easy To Find

October 3, 2022 by 43 Comments

In the first article, I’ve given you an overview of Lithium-Ion batteries and cells as building blocks for our projects, and described how hackers should treat their Lithium-Ion cells. But what if you don’t have any LiIon cells yet? Where do you get LiIon cells for your project?

Taking laptop batteries apart,  whether the regular 18650 or the modern pouch cell-based ones, remains a good avenue – many hackers take this road and the topic is extensively covered by a number of people. However, a 18650 cell might not fit your project size-wise, and thin batteries haven’t quite flooded the market yet. Let’s see what your options are beyond laptops. Continue reading “Lithium-Ion Batteries Are Easy To Find” →

24 Hours Of Le Airplanes

September 27, 2022 by 22 Comments

There’s no more famous road endurance race than the 24 Hours of Le Mans, where teams compete to see how far they can drive in a single 24-hour window. The race presents unique challenges not found in other types of racing. While RC airplanes may not have a similar race, [Daniel] a.k.a. [rctestflight] created a similar challenge for himself by attempting to fly an RC airplane non-stop for as long as he could, and a whole host of interesting situations cropped up before and during flight.

In order for an RC plane to fly for an entire day, it essentially needs to be solar powered. A large amount of strategy goes into a design of this sort. For one, the wing shape needs to be efficient in flight but not reduce the amount of area available for solar panels. For another, the start time of the flight needs to be balanced against the position of the sun in the sky. With these variables more or less fixed, [Daniel] began his flight.

It started off well enough, with the plane in an autonomous “return to home” mode which allowed it to continually circle overhead without direct human control. But after taking a break to fly it in FPV mode, [Daniel] noticed that the voltage on his battery was extremely high. It turned out that the solar charge controller wasn’t operating as expected and was shunting a large amount of solar energy directly into the battery. He landed and immediately removed the “spicy pillow” to avoid any sort of nonlinear event. With a new battery in the plane he began the flight again.

Even after all of that, [Daniel] still had some issues stemming from the aerodynamic nature of this plane specifically. There were some issues with wind, and with the flight controller not recognizing the correct “home” position, but all in all it seems like a fun day of flying a plane. If your idea of “fun” is sitting around and occasionally looking up for eight and a half hours. For more of [Daniel]’s long-term autonomous piloting, be sure to take a look at his solar tugboat as well.

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Lithium-Ion Batteries Are Your Friends

September 6, 2022 by 56 Comments

Need some kind of battery for a project? You can always find a few Lithium-Ion (LiIon) batteries around! They’re in our phones, laptops, and a myriad other battery-powered things of all forms – as hackers, we will find ourselves working with them more and more. Lithium-Ion batteries are unmatched when it comes to energy capacity, ease of charging, and all the shapes and sizes you can get one in.

There’s also misconceptions about these batteries – bad advice floating around, fearmongering videos of devices ablaze, as well as mundane lack of understanding. Today, I’d like to provide a general overview of how to treat your LiIon batteries properly, making sure they serve you well long-term.

What’s A Battery? A Malleable Pile Of Cells

Lithium-Ion batteries are our friends. Now, there can’t be a proper friendship if you two don’t understand each other. Lithium-Ion batteries are tailored for human needs by the factory that produced them. As for us hackers, we’ll want to learn some things.

First thing to learn – a single LiIon “unit” is called a cell. An average laptop contains three or six Li-Ion cells, a phone will have one, a tablet will have from one to three. What we refer to as “battery” is typically one or multiple cells, together with protection circuitry, casing and a separate connector – most of the time all three of these, but not always. The typical voltage is 3.6 V or 3.7 V, with maximum voltage being 4.2 V – these are chemistry-defined, the same for most kinds of cells and almost always written on the cell. Continue reading “Lithium-Ion Batteries Are Your Friends” →

$800 Mountain Bike Seat Post Chopped In Two

August 29, 2022 by 16 Comments

For those unfamiliar with the sport of mountain biking, it’s a wild hobby that is rife with hacking. It started in the early 70s when the first dedicated mountain bikers were hacking road bikes together to ride on trails to varying levels of success, but only in the last decade or so have there been a lot of electronics appearing in various bike parts that we can all tinker with as well. This video discusses some of the downsides with a very expensive electronic seat post on a mountain bike, and attempts to solve its shortcomings by cutting it in half.

This build involves a dropper seat post, which is an adjustable seat for mountain biking that functions like an office chair. By pushing a button on the handlebars, the seat post can be rapidly adjusted up or down on-the-fly. Normally these seat posts use a cable to actuate, but this expensive version is wireless. The only problem is the battery will occasionally fly off when hitting big jumps, so [Berm Peak Express] decided to cut the existing proprietary battery system out and create a new housing for it. The new housing has a wired extension for the battery in its new location under the seat instead of behind it, and this gives it the clearance it arguably should have had from the manufacturer.

While not the most involved project of all time, it does take a certain mentality to take a hacksaw to a bike part that costs more than a large percentage of bicycles. It’s a niche product to be sure, but it also shows that some of the biggest annoyances with proprietary parts are not too difficult to overcome. And, it is interesting to see the ways that some people are hacking bikes outside of admittedly clever ebike conversions.

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Batteries Get Tiny

August 20, 2022 by 18 Comments

Steve Martin had a comedy routine that focused on the idea of “getting small.” That probably didn’t inspire the researchers at the Institute for Integrative Nanoscience when they set out to create a sub-square-millimeter microbattery. As you might expect, you won’t be starting your car with a battery the size of a grain of sand anytime soon, but these batteries do have a surprising capacity.

The key is creating what they call “micro-swiss rolls” where the electrodes are wrapped in a tiny cylinder. This isn’t a new idea. However, creating workable rolls at the scale where a grain of rice looks huge isn’t trivial.

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