Born To Burn: The Battle Born LFP Battery

December 25, 2025 by Maya Posch 39 Comments

Would you feel confident in buying US-made LiFePO₄ (LFP) batteries? While the answer here is generally expected to be ‘yes’, especially compared to getting an unbranded LFP battery off eBay from a random seller, the outcome may not be that different. Case in point the 100 Ah, 12 VDC LFP Battle Born battery that [Will Prowse] took a look at to see why its positive terminal gets positively crispy.

Battle Born battery positive terminal. (Credit: Will Prowse, YouTube)

Once the lid was cut off, it’s easy to see what the problem is: the positive terminal is only loosely attached to the bus bar, leading to extremely poor contact. It also appears that there’s a plastic spacer which has properly melted already in this well-used battery that [Will] obtained from a viewer.

This overheating issue with Battle Born batteries has been reported for years now, which makes it a great idea to take a good look at any Battle Born LFP batteries you may have kicking around, as they may be plagued by the same design flaw. Trying to make use of the manufacturer’s warranty could be complicated based on the commentators in the DIY Solar Forum thread, as Battle Born likes to claim that the overheating issue is an external problem and not a design flaw.

Either way, it looks like an incredibly sketchy way to design a battery terminal on an LFP battery that is supposed to surge 100+A. [Will] is requesting that anyone affected posts details in the forum or similar to get all information together, as he looks to push Battle Born on this issue.

What makes this issue worse is that shortly after releasing that first video, Battle Born responded to some concerned customers with a response that claims that their terminal design is a ‘thermal fail-safe’, but as can be seen in [Will]’s follow-up video, it absolutely doesn’t look like one.

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Printing With Metal On The Ender 3 Using Only A Friction Wheel

December 24, 2025 by Maya Posch 9 Comments

Printing metal as easily as it is to print with thermoplastics has been a dream for a very long time, with options for hobbyists being very scarce. This is something which [Rotoforge] seeks to change, using little more than an old Ender 3 FDM printer and some ingenuity. Best of all is that the approach on which they have been working for the past year does not require high temperature, molten metals and no fussing about with powdered metal.

Additive manufacturing using friction welding. (Credit: Ruishan Xie, et al., j.mtcomm, 2021)

Rather than an extruder that melts a thermoplastic filament, their setup uses metal wire that is fed into a friction welding tool head, the details of which are covered in the video as well as on the GitHub project page. Unlike their previous setup which we reported on last year, this new setup is both safer and much riskier. While there’s no more molten metal, instead a very loud and very fast spinning disk is used to provide the friction required for friction welding, specifically friction and rolling-based additive manufacturing (FRAM) as in the cited 2021 paper by [Ruishan Xie] et al. in Materials Today Communications. By the same lead author there’s also a 2025 paper that explores more complex implementations of FRAM.

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Abusing X86 SIMD Instructions To Optimize PlayStation 3 Emulation

December 24, 2025 by Maya Posch 6 Comments

Key to efficient hardware emulation is an efficient mapping to the underlying CPU’s opcodes. Here one is free to target opcodes that may or may not have been imagined for that particular use. For emulators like the RPCS3 PlayStation 3 emulator this has led to some interesting mappings, as detailed in a video by [Whatcookie].

It’s important to remember here that the Cell processor in the PlayStation 3 is a bit of an odd duck, using a single regular PowerPC core (PPE) along with multiple much more simple co-processors called synergistic processing elements (SPEs) all connected with a high-speed bus. A lot of the focus with Cell was on floating point vector – i.e. SIMD – processing, which is part of why for a while the PlayStation 3 was not going to have a dedicated GPU.

As a result, it makes perfect sense to do creative mapping between the Cell’s SIMD instructions and those of e.g. SSE and AVX, even if Intel removing AVX-512 for a while caused major headaches. Fortunately some of those reappeared in AVX2.

The video goes through a whole range of Cell-specific instructions, how they work, and what x86 SIMD instructions they were mapped to and why. The SUBD instruction for example is mapped to VPDPBUSD as well as VDBPSADBW in AVX-512, the latter of which mostly targets things like video encoding. In the end it’s the result that matters, even if it also shows why the Cell processor was so interesting for high-performance compute clusters back in the day.

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Silicon-Based MEMS Resonators Offer Accuracy In Little Space

December 24, 2025 by Maya Posch 2 Comments

Currently quartz crystal-based oscillators are among the most common type of clock source in electronics, providing a reasonably accurate source in a cheap and small package. Unfortunately for high accuracy applications, atomic clocks aren’t quite compact enough to fit into the typical quartz-based temperature-compensated crystal oscillators (TCXOs) and even quartz-based solutions are rather large. The focus therefore has been on developing doped silicon MEMS solutions that can provide a similar low-drift solution as the best compensated quartz crystal oscillators, with the IEEE Spectrum magazine recently covering one such solution.

Part of the DARPA H6 program, [Everestus Ezike] et al. developed a solution that was stable to ±25 parts per billion (ppb) over the course of eight hours. This can be contrasted with a commercially available TCXO like the Microchip MX-503, which boasts a frequency stability of ±30 ppb.

Higher accuracy is achievable by swapping the TCXO for an oven-controlled crystal oscillator (OCXO), with the internal temperature of the oscillator not compensated for, but rather controlled with an active heater. There are many existing OCXOs that offer down to sub-1 ppb stability, albeit in quite a big package, such as the OX-171 with a sizable 28×38 mm footprint.

With a MEMS silicon-based oscillator in OXCO configuration [Yutao Xu] et al. were able to achieve a frequency stability of ±14 ppb, which puts it pretty close to the better quartz-based oscillators, yet within a fraction of the space. As these devices mature, we may see them eventually compete with even the traditional OCXO offerings, though the hyperbolic premise of the IEEE Spectrum article of them competing with atomic clocks should be taken with at least a few kilograms of salt.

Thanks to [anfractuosity] for the tip.

Exploring Modern SID Chip Substitutes

December 23, 2025 by Maya Posch 13 Comments

The SIDKick Pico installed on a breadboard. (Credit: Ben Eater)

Despite the Commodore 64 having been out of production for probably longer than many Hackaday readers have been alive, its SID audio chip remains a very popular subject of both retrocomputing and modern projects. Consequently a range of substitutes have been developed over the decades, all of which seek to produce the audio quality of one or more variants of the SID. This raises the question of which of these to pick when at first glance they seem so similar. Fret not, for [Ben Eater] did an entire video on comparing some modern SID substitutes and his thoughts on them.

First is the SIDKick Pico, which as the name suggests uses a Raspberry Pi Pico board for its Cortex-M0+ MCU. This contrasts with the other option featured in the video, in the form of the STM32F410-based ARMSID.

While the SIDKick Pico looks good on paper, it comes with a number of different configurations, some with an additional DAC, which can be confusing. Because of how it is stacked together with the custom PCB on which the Pi Pico is mounted, it’s also pretty wide and tall, likely leading to fitment issues. It also doesn’t work as a drop-in solution by default, requiring soldering to use the SID’s normal output pins. Unfortunately this led to intense distortion in [Ben]’s testing leading him to give up on this.

Meanwhile the ARMSID is about as boring as drop-in replacements get. After [Ben] got the ARMSID out of its packaging, noted that it is sized basically identical to the original SID and inserted it into the breadboard, it then proceeded to fire right up with zero issues.

It’s clear that the SIDKick Pico comes with a lot of features and such, making it great for tinkering. However, if all you want is a SID-shaped IC that sounds like a genuine SID chip, then the ARMSID is a very solid choice.

Thanks to [Mark Stevens] for the tip.

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Be Wary Of Flash-less ESP32-C3 Super Mini Boards

December 23, 2025 by Maya Posch 30 Comments

Everyone loves tiny microcontroller boards, and the ESP32-C3 Super Mini boards are no exception. Unfortunately if you just casually stroll over to your nearest online purveyor of such goods to purchase a bunch of them, you’re likely to be disappointed. The reason for this is, as explained in a video by [Hacker University] that these boards are equipped with any of the variants of the ESP32-C3. The worst offender here is probably the version with the ESP32-C3 without further markings, as this one has no built-in Flash for program storage.

Beyond that basic MCU version we can see the other versions clearly listed in the Espressif ESP32-C3 datasheet. Of these, the FN4 is already listed as EOL, the FH4AZ as NRND, leaving only the FH4 and FH4X with the latter as ‘recommended’ as the newest chip revision. Here the F stands for built-in Flash with the next character for its temperature rating, e.g. H for ‘High’. Next is the amount of Flash in MB, so always 4 MB for all but the Flash-less variant.

Identifying this information from some online listing is anything but easy unless the seller is especially forthcoming. The chip markings show this information on the third row, as can be seen in the top image, but relying solely on a listing’s photos is rather sketchy. If you do end up with a Flash-less variant, you can still wire up an external Flash chip yourself, but obviously this is probably not the intended use case.

As always, caveat emptor.

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Surviving The RAM Apocalypse With Software Optimizations

December 23, 2025 by Maya Posch 97 Comments

To the surprise of almost nobody, the unprecedented build-out of datacenters and the equipping of them with servers for so-called ‘AI’ has led to a massive shortage of certain components. With random access memory (RAM) being so far the most heavily affected and with storage in the form of HDDs and SSDs not far behind, this has led many to ask the question of how we will survive the coming months, years, decades, or however-long the current AI bubble will last.

One thing is already certain, and that is that we will have to make our current computer systems last longer, and forego simply tossing in more sticks of RAM in favor of doing more with less. This is easy to imagine for those of us who remember running a full-blown Windows desktop system on a sub-GHz x86 system with less than a GB of RAM, but might require some adjustment for everyone else.

In short, what can us software developers do differently to make a hundred MB of RAM stretch further, and make a GB of storage space look positively spacious again?

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