Performing An Autopsy On 15 Dead Battle Born LFP Batteries

February 16, 2026 by Maya Posch 21 Comments

More molten plastic spacers between the bus bar and terminal. (Credit: Will Prowse)

Because size matters when it comes to statistics, [Will Prowse] decided to not just bank on his handful of failed Battle Born LFP batteries when it came to documenting their failure modes. Instead he got a whole gaggle of them from a viewer who had experienced failures with their Battle Born LFP batteries for an autopsy, adding a total of 15 samples to the data set.

Interestingly, the symptoms of these dead batteries are all over the place, from a refusal to charge, some have the overheating terminal, some do not show any sign of life, others have charged cells but a non-responsive BMS, etc. As [Will] notes, it’s important to test batteries with a load and a charger to determine whether they are functional not just whether you can measure a charge.

Although some of the batteries still showed enough signs of life to be put aside for some load testing, the remaining ones were cut open to check their insides. This revealed the typical molten plastic at the terminals, but also a lot of very loose connections for the internal wiring. Another battery showed signs of corrosion inside, which could be due to either moisture intrusion or a cell having leaked its electrolyte.

While the full results will hopefully be released soon, the worrying thing about this latest batch of Battle Born LFP batteries is that they span quite a few years, with one being from 2018. Although it’s comforting that not every one of these batteries is necessarily going to catch on fire within its approximate 8-year lifespan, a lot seems to depend on exactly how you load and charge them, as [Will] is trying to figure out with the upcoming load testing. With the unit that he recently purchased for testing it turned out that lower currents actually made the melting problem much worse.

Between this video and the much awaited follow-up, [Will] actually got his hands on a troubled 300A-rated industrial Battle Born battery. During testing that one actually failed violently with a cell venting and the loose BMS rattling around in the case.

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Why Sodium-Ion Batteries Are Terrible For Solar Storage

October 30, 2025 by Maya Posch 83 Comments

These days just about any battery storage solution connected to PV solar or similar uses LiFePO4 (LFP) batteries. The reason for this is obvious: they have a very practical charge and discharge curve that chargers and inverters love, along with a great round trip efficiency. Meanwhile some are claiming that sodium-ion (Na+) batteries would be even better, but this is not borne out by the evidence, with [Will Prowse] testing and tearing down an Na+ battery to prove the point.

The Hysincere brand battery that [Will] has on the test bench claims a nominal voltage of 12 V and a 100 Ah capacity, which all appears to be in place based on the cells found inside. The lower nominal voltage compared to LFP’s 12.8 V is only part of the picture, as can be seen in the OCV curve. Virtually all of LFP’s useful capacity is found in a very narrow voltage band, with only significant excursions when reaching around >98% or <10% of state of charge.

What this means is that with existing chargers and inverters, there is a whole chunk of the Na+ discharge curve that’s impossible to use, and chargers will refuse to charge Na+ batteries that are technically still healthy due to the low cell voltage. In numbers, this means that [Will] got a capacity of 82 Ah out of this particular 100 Ah battery, despite the battery costing twice that of a comparable LFP one.

Yet even after correcting for that, the internal resistance of these Na+ batteries appears to be significantly higher, giving a round trip efficiency of 60 – 92%, which is a far cry from the 95% to 99% of LFP. Until things change here, [Will] doesn’t see much of a future for Na+ beyond perhaps grid-level storage and as a starter battery for very cold climates.

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Have Li-ion Batteries Gone Too Far?

March 13, 2025 by Navarre Bartz 85 Comments

The proliferation of affordable lithium batteries has made modern life convenient in a way we could only imagine in the 80s when everything was powered by squadrons of AAs, or has it? [Ian Bogost] ponders whether sticking a lithium in every new device is really the best idea.

There’s no doubt, that for some applications, lithium-based chemistries are a critically-enabling technology. NiMH-based EVs of the 1990s suffered short range and slow recharge times which made them only useful as commuter cars, but is a flashlight really better with lithium than with a replaceable cell? When household electronics are treated as disposable, and Right to Repair is only a glimmer in the eye of some legislators, a worn-out cell in a rarely-used device might destine it to the trash bin, especially for the less technically inclined.

[Bogost] decries “the misconception that rechargeables are always better,” although we wonder why his article completely fails to mention the existence of rechargeable NiMH AAs and AAAs which are loads better than their forebears in the 90s. Perhaps even more relevantly, standardized pouch and cylindrical lithium cells are available like the venerable 18650 which we know many makers prefer due to their easy-to-obtain nature. Regardless, we can certainly agree with the author that easy to source and replace batteries are few and far between in many consumer electronics these days. Perhaps new EU regulations will help?

Once you’ve selected a battery for your project, don’t forget to manage it if it’s a Li-ion cell. With great power density, comes great responsibility.

Hackaday Links: October 27, 2024

October 27, 2024 by Dan Maloney 14 Comments

Problem solved? If the problem is supplying enough lithium to build batteries for all the electric vehicles that will be needed by 2030, then a new lithium deposit in Arkansas might be a resounding “Yes!” The discovery involves the Smackover Formation — and we’ll be honest here that half the reason we chose to feature this story was to be able to write “Smackover Formation” — which is a limestone aquifer covering a vast arc from the Rio Grande River in Texas through to the western tip of the Florida panhandle. Parts of the aquifer, including the bit that bulges up into southern Arkansas, bear a brine rich in lithium salts, far more so than any of the brines currently commercially exploited for lithium metal production elsewhere in the world. Given the measured concentration and estimated volume of brine in the formation, there could be between 5 million and 19 million tons of lithium in the formation; even at the lower end of the range, that’s enough to build nine times the number of EV batteries needed.

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Autonomous Boat Plots Lake Beds

August 14, 2024 by Bryan Cockfield 5 Comments

Although the types of drones currently dominating headlines tend to be airborne, whether it’s hobbyist quadcopters, autonomous delivery vehicles, or military craft, autonomous vehicles can take nearly any transportation method we can think of. [Clay Builds] has been hard at work on his drone which is actually an autonomous boat, which he uses to map the underwater topography of various lakes. In this video he takes us through the design and build process of this particular vehicle and then demonstrates it in action.

The boat itself takes inspiration from sailing catamarans, which have two hulls of equal size connected above the waterline, allowing for more stability and less drag than a standard single-hulled boat. This is [Clay]’s second autonomous boat, essentially a larger, more powerful version of one we featured before. Like the previous version, the hulls are connected with a solar panel and its support structure, which also provides the boat with electrical power and charges lithium-iron phosphate batteries in the hull. Steering is handled by two rudders with one on each hull, but it also employs differential steering for situations where more precise turning is required. The boat carries a sonar-type device for measuring the water depth, which is housed in a more hydrodynamic 3d-printed enclosure to reduce its drag in the water, and it can follow a waypoint mission using a combination of GPS and compass readings.

Like any project of this sort, there was a lot of testing and design iteration that had to go into this build before it was truly seaworthy. The original steering mechanism was the weak point, with the initial design based on a belt connecting the two rudders that would occasionally skip. But after a bit of testing and ironing out these kinks, the solar boat is on its way to measure the water’s depths. The project’s code as well as some of the data can be found on the project’s GitHub page, and if you’re looking for something more human-sized take a look at this solar-powered kayak instead.

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TDK Claims Solid State Battery With 100X Energy Density

June 18, 2024 by Al Williams 50 Comments

Regulations surrounding disposable batteries have accelerated a quiet race to replace coin cells, which on the whole are not readily rechargeable. TDK produces solid-state batteries and has announced a new material that claims an energy density of about 100 times that of their conventional batteries.

Energy density measures how much energy a system contains relative to its volume. The new battery has 1000 Wh/L. For comparison, old nickel-cadmium cells had about 150 Wh/L. A typical lithium-ion battery usually turns in about 200 – 250 Wh/L.

There aren’t many technical details, but a few things caught our interest. For one, it uses an oxide-based solid electrolyte and lithium alloy anodes. However, what really caught our eye was that it is “intended for use in wearables… that come in direct contact with the human body.” We don’t know if that means the material is safe for your skin or if it depends on being next to your body to operate.

While the energy density is high, keep in mind that the batteries of this type are usually tiny, so the total actual power available is probably not very high. Tiny batteries are definitely a thing. We are always hearing about breakthroughs, but we always wonder if and when we’ll see actual products.

Lithium-Ion Batteries Power Your Devboards Easily

March 14, 2024 by Arya Voronova 25 Comments

Last summer, I was hanging out with a friend from Netherlands for a week, and in the middle of that week, we decided to go on a 20 km bike trip to a nearby beach. Problem? We wanted to chat throughout the trip, but the wind noise was loud, and screaming at each other while cycling wouldn’t have been fun. I had some walkie-talkie software in mind, but only a single battery-powered Pi in my possession. So, I went into my workshop room, and half an hour later, walked out with a Pi Zero wrapped in a few cables.

I wish I could tell you that it worked out wonders. The Zero didn’t have enough CPU power, I only had single-core ones spare, and the software I had in mind would start to badly stutter every time we tried to run it in bidirectional mode. But the battery power solution was fantastic. If you need your hack to go mobile, read on.

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