AA Battery Performances Tested, So Get The Most For Your Money

January 10, 2025 by Donald Papp 38 Comments

[Project Farm] has a video in which a wide variety of AA cells are analyzed and compared in terms of capacity, internal resistance, ability to deliver voltage under load, and ability to perform in sub-freezing temperatures. Alkaline, lithium, and even some mature rechargeable cells with a couple thousand cycles under their belt were all compared. There are a few interesting results that will can help you get the most from your money the next time you’re battery shopping.

The video embedded below demonstrates a set of tests that we recommend you check out, but the short version is that more expensive (non-rechargeable) lithium cells outperform their alkaline peers, especially when it comes to overall longevity, ability to perform under high-drain conditions, and low temperatures. Lithium cells also cost more, but they’re the right choice for some applications.

Some brands performed better and others worse, but outside of a couple stinkers most were more or less comparable. Price however, was not.

As for how different brands stack up against one another, many of them are more or less in the same ballpark when it comes to performance. Certainly there are better and worse performers, but outside of a couple of stinkers the rest measure up reasonably well. Another interesting finding was that among rechargeable cells that were all several years (and roughly 2,200 charge-discharge cycles) old, a good number of them still performed like new.

Probably the single most striking difference among the different cells is cost — and we’re not just talking about whether lithium versus alkaline AAs are more cost-effective in the long run. Some brands simply cost twice as much (or more!) than others with comparable performance. If you’re in a hurry, jump to [Project Farm] presenting the final ranked results at 19:45 in.

Relying on brand recognition may save you from buying complete junk, but it’s clearly not the most cost-effective way to go about buying batteries. These findings are similar to an earlier effort at wide-scale battery testing which also determined that factoring in price-per-cell was too significant to ignore.

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Playing Around With The MH-CD42 Charger Board

December 27, 2024 by Tom Nardi 11 Comments

If you’ve ever worked with adding lithium-ion batteries to one of your projects, you’ve likely spent some quality time with a TP4056. Whether you implemented the circuit yourself, or took the easy way out and picked up one of the dirt cheap modules available online, the battery management IC is simple to work with and gets the job done.

But there’s always room for improvement. In a recent video, [Det] and [Rich] from Learn Electronics Repair go over using a more modern battery management board that’s sold online as the MH-CD42. This board, which is generally based on a clone of the IP5306, seems intended for USB battery banks — but as it so happens, plenty of projects that makers and hardware hackers work on have very similar requirements.

So not only will the MH-CD42 charge your lithium-ion cells when given a nominal USB input voltage (4.5 – 5 VDC), it will also provide essential protections for the battery. That means looking out for short circuits, over-charge, and over-discharge conditions. It can charge at up to 2 A (up from 1 A on the TP4056), and includes a handy LED “battery gauge” on the board. But perhaps best of all for our purposes, it includes the necessary circuitry to boost the output from the battery up to 5 V.

If there’s a downside to this board, it’s that it has an automatic cut-off for when it thinks you’ve finished using it; a feature inherited from its USB battery bank origins. In practice, that means this board might not be the right choice for projects that aren’t drawing more than a hundred milliamps or so.

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Good Lighting On A Budget With Cordless Tool Batteries

December 12, 2024 by Dan Maloney 11 Comments

It’s perhaps not fair, but even if you have the best idea for a compelling video, few things will make people switch off than poor lighting. Good light and plenty of it is the order of the day when it comes to video production, and luckily there are many affordable options out there. Affordable, that is, right up to the point where you need batteries for remote shoots, in which case you’d better be ready to open the purse strings.

When [Dane Kouttron] ran into the battery problem with his video lighting setup, he fought back with these cheap and clever cordless tool battery pack adapters. His lights were designed to use Sony NP-F mount batteries, which are pretty common in the photography trade but unforgivably expensive, at least for Sony-branded packs. Having access to 20 volt DeWalt battery packs, he combined an off-the-shelf battery adapter with a 3D printed mount that slips right onto the light. Luckily, the lights have a built-in DC-DC converter that accepts up to 40 volts, so connecting the battery through a protection diode was a pretty simple exercise. The battery pack just slots right in and keeps the lights running for portable shoots.

Of course, if you don’t already have DeWalt batteries on hand, it might just be cheaper to buy the Sony batteries and be done with it. Then again, there are battery adapters for pretty much every cordless tool brand out there, so you should be able to adapt the design. We’ve also seen cross-brand battery adapters which might prove useful, too.

Sniffing Around Inside A ThinkPad Battery

December 4, 2024 by Tom Nardi 24 Comments

For most people, a battery pack that’s misbehaving simply means it’s time to get a new battery. But when the battery in their ThinkPad wasn’t able to muster up more than 20 minutes of runtime, [Shrinath Nimare] saw an opportunity to dig deeper and do a bit of investigating.

The problem seemed to be that the battery pack was reporting that it was 100% charged at just 11.7 V instead of the correct 12.3 V. As it turns out, that 11.7 V figure is only slightly above what the battery should be when its run flat — so in reality, the battery was never actually getting a charge and would report that it was dead after just a few minutes of use. But why?

With a logic analyzer attached to the pins of the battery, [Shrinath] set out to sniff its communications with the ThinkPad. Even if it wouldn’t lead to fixing the battery pack, the information obtained would potentially be useful for other projects, such as creating a custom high-capacity LiFePO4 pack down the line.

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OSHW Battery Tester Aims To Help Tame Lithium Cells

December 3, 2024 by Tom Nardi 13 Comments

It’s no exaggeration to say that the development of cheap rechargeable lithium-ion batteries has changed the world. Enabling everything from smartphones to electric cars, their ability to pack an incredible amount of energy into a lightweight package has been absolutely transformative over the last several decades. But like all technologies, there are downsides to consider — specifically, the need for careful monitoring during charging and discharging.

As hardware hackers, we naturally want to harness this technology for our own purposes. But many are uncomfortable about dealing with these high-powered batteries, especially when they’ve been salvaged or come from some otherwise questionable origin. Which is precisely what the Smart Multipurpose Battery Tester from [Open Green Energy] is hoping to address.

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The Automatic Battery Charger You Never Knew You Needed

December 2, 2024 by Jenny List 47 Comments

When we saw [Max.K]’s automatic NiMh battery charger float past in the Hackaday tips line, it brought to mind a charger that might be automatic in the sense that any modern microcontroller based circuit would be; one which handles all the voltages and currents automatically. The reality is far cooler than that, a single-cell charger in which the automatic part comes in taking empty cells one by one from a hopper on its top surface and depositing them charged in a bin at the bottom.

Inside the case is a PCB with an RP2040 that controls the whole shop as well as the charger circuitry. A motorized cam with a battery shaped insert picks up a cell from the bin and moves it into the charger contacts, before dumping it into the bin when charged. What impresses us it how slick this device is, it feels like a product rather than a project, and really delivers on the promise of 3D printing. We’d want one on our bench, and after watching the video below the break, we think you will too.

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Building Experience And Circuits For Lithium Capacitors

December 2, 2024 by Bryan Cockfield 22 Comments

For the cautious, a good piece of advice is to always wait to buy a new product until after the first model year, whether its cars or consumer electronics or any other major purchase. This gives the manufacturer a year to iron out the kinks and get everything ship shape the second time around. But not everyone is willing to wait on new tech. [Berto] has been interested in lithium capacitors, a fairly new type of super capacitor, and being unwilling to wait on support circuitry schematics to magically show up on the Internet he set about making his own.

The circuit he’s building here is a solar charger for the super capacitor. Being a fairly small device there’s not a lot of current, voltage, or energy, but these are different enough from other types of energy storage devices that it was worth taking a close look and designing something custom. An HT7533 is used for voltage regulation with a Schottky diode preventing return current to the solar cell, and a DW01 circuit is used to make sure that the capacitor doesn’t overcharge.

While the DW01 is made specifically for lithium ion batteries, [Berto] found that it was fairly suitable for this new type of capacitor as well. The capacitor itself is suited for many low-power, embedded applications where a battery might add complexity. Capacitors like this can charge much more rapidly and behave generally more linearly than their chemical cousins, and they aren’t limited to small applications either. For example, this RC plane was converted to run with super capacitors.