Is It Time To Retire The TP4056?

August 8, 2025 by Tyler August 30 Comments

The TP4056 is the default charge-controller chip for any maker or hacker working with lithium batteries. And why not? You can get perfectly-functional knockoffs on handy breakout boards from the usual online sources for pennies. Betteridge’s Law aside, [Lefty Maker] thinks that it may well be time to move on from the TP4056 and spends his latest video telling us why, along with promoting an alternative.

His part of choice is another TI chip, the BQ25185. [Lefty] put together his own charge controller board to show off the capabilities of this chip — including variable under- and over-charge protection voltages. Much of his beef with the TP4056 has less to do with that chip than with the cheap charge modules it comes on: when he crows about the lack of mounting holes and proper USB-PD on the knock-off modules, it occurs to us he could have had those features on his board even if he’d used a TP4056.

On the other hand, the flexibility offered by the BQ25185 is great to future-proof projects in case the dominant battery chemistry changes, or you just change your mind about what sort of battery you want to use. Sure, you’d need to swap a few resistors to set new trigger voltages and charging current, but that beats starting from scratch.

[Lefty Maker] also points out some of the advantages to making your own boards rather than relying on cheap modules. Namely, you can make them however you want. From a longer USB port to indicator LEDs and a built-in battery compartment, this charging board is exactly what [Lefty Maker] wants. Given how cheap custom PCBs are these days, it’s not hard to justify rolling your own.

The same cannot be said of genuine TI silicon, however. While the BQ25185 has a few good features that [Lefty Maker] points out in the video, we’re not sure the added price is worth it. Sure, it’s only a couple bucks, but that’s more than a 300% increase!

We’ve seen other projects pushing alternative charge controllers, but for now the TP4056 reigns as the easy option.

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Upgrading At Least One Component Of A TI Calculator

January 24, 2024 by Bryan Cockfield 12 Comments

Even though Texas Instruments were the first company to produce an integrated circuit and a microprocessor, their success as a company in the 60s and 70s was not guaranteed. At the time there wasn’t much demand for previously non-existent products like these, so to drive some business they built the first hand-held calculator, a venture that they are still famous for today. Since then, though, they’ve become a bit of a punchline for producing calculators with decades-old technology but with modern price tags, so while this business model was quite successful if you want a calculator with a few modern features you’ll have to take a DIY approach like this calculator retrofitted with a LiPo battery.

The modern battery pack, with a lithium polymer battery at its core, includes all of the circuitry needed to integrate it seamlessly into the TI-59 calculator, which is all available on the project’s GitHub page. This calculator originally used a 9V battery, so the new battery pack includes a boost converter to match the 3.7V from the new battery to the needs of the old calculator. It doesn’t stop there, though. The pack is rechargeable from an included USB-C port, has a built-in charge controller, and is housed in its own custom-built case that fits neatly into the calculator where the old battery would sit.

While this wouldn’t be a drop-in replacement for more modern calculators like the TI-83/84 and TI-89, a new case and a different boost converter would solve the problem of the AAA batteries dying during exams. It might make the calculators non-compliant with various standardized testing requirements, though (which TI was also instrumental in developing) so you may want to verify with your testing standard of choice before modifying a calculator you need for an exam. But if all the rules are off, why not add Wi-Fi to it too?

Sun On The Run: Diving Into Solar With A Mobile PV System

January 17, 2024 by Dan Maloney 36 Comments

For obvious reasons, there has been a lot of interest in small-scale residential solar power systems lately. Even in my neck of the woods, where the sun doesn’t shine much from October to April, solar arrays are sprouting up on rooftops in a lot of local neighborhoods. And it’s not just here in suburbia; drive a little way out into the country or spend some time looking around in Google maps and it won’t take long to spy a sizable array of PV panels sitting in a field next to someone’s ranch house or barn.

Solar has gotten to the point where the expense of an installation is no longer a serious barrier to entry, at least if you’re willing to put in a little sweat equity and not farm the project out to a contractor. Doing it yourself requires some specialized tools and knowledge, though, over and above your standard suite of DIY skills. So, in the spirit of sharing hard-won knowledge, I decided to take the somewhat unusual step of writing up one of my personal projects, which has been in progress for a couple of years now and resulted in a solar power system that isn’t on a rooftop or a ground-mounted array at all, but rather is completely mobile: my solar trailer.

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Disposable Vape Batteries Turned USB Power Bank

December 14, 2023 by Tom Nardi 31 Comments

It’s another one of those fun quirks about our increasingly cyberpunk world — instead of cigarette butts littering our streets, you’re more likely to find disposable vaporizers that have run out of juice. Unfortunately, while the relatively harmless paper remnants of a cig would eventually just fall apart when exposed to the elements, these futuristic caltrops are not only potentially explosive thanks to their internal lithium-ion battery but aren’t going anywhere without some human intervention.

So do the environment and your parts bin a favor: pick them up and salvage their internal cells. As [N-Ender_3] shows with this build, it’s cheap and easy to turn the remnants of a few vapes into a useful USB power bank. In this case, the enclosure is 3D printed, which makes it particularly form-fitting, but you could just as easily pack the cells into something else if you’re not a fan of extruded plastic.

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A white longtail cargo bike sits on grass with fenced-in planters behind it. The bike has a basket made of black metal tubes on the front and a passenger compartment behind the rider seat for children made of similar black metal tubes. A white canopy is above the passenger compartment and a solar panel sits atop the canopy.

Solar Powered E-bike Replaces Car Trips

February 7, 2023 by Navarre Bartz 20 Comments

E-bikes can replace car trips for some people, and adding a solar panel can make the fun last longer. [Luke] did some heavy modifications to his RadWagon to make it better, stronger, and faster than it was before.

The first step was replacing the stock 750 W controller with a 1500 W model to give the motor twice the power. [Luke] plans to replace the motor if it gets fried pushing too much juice, but is planning on just being careful for now. To stop this super-powered ride, he swapped the stock mechanical discs out for a hydraulic set which should be more reliable, especially when loading down this cargo bike.

On top of these performance enhancements, he also added a 50 W solar panel and maximum power point tracking (MPPT) charge controller to give the bike a potential 50% charge every day. Along with the OEM kid carrier and roof, this bike can haul kids and groceries while laughing at any hills that might come its way.

Checkout this other solar e-bike or this one making a trip around the world for more fun in the sun.

Ebike Charges In The Sun

October 16, 2022 by Bryan Cockfield 38 Comments

Ebikes are slowly taking the place of many cars, especially for short trips. Most ebikes can take riders at least 16 kilometers (10 miles) without too much effort, at a cost that’s often a single-digit percentage of what the same trip would have been with an internal combustion engine. If you’re interested in dropping the costs of your ebike trips even further, or eliminating it entirely, take a look at this small ebike with integrated solar panels.

While any battery can be charged with a sufficiently large array of solar panels and the correct electronics to match the two systems together, this bike has a key that sets it apart from most others: it can charge while it is being used to power the bike. Most ebikes don’t have charging enabled during rides, so if you want to use the sun while riding to extend the range of the bike you’ll need to find one like this. This bike uses two 50 W panels on the two cargo areas of the bike, attached to a 400 W MPPT charge controller. The Lectric XP 2.0 ebike has a motor with a peak rating of 850 W, but in a low pedal-assist mode the solar panels likely output a significant fraction of the energy used by the electric drivetrain.

Even if the panels don’t provide the full amount of energy needed for riding around, the project’s creator [Micah] lives in Florida, so just setting the bike outside in the sun for six to eight hours is enough to replenish most of the battery’s charge. It’s probably not going to win any solar-powered bike races anytime soon, but for an efficient, quick bike to ride around town it’s not too shabby.

24 Hours Of Le Airplanes

September 27, 2022 by Bryan Cockfield 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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