Off-Grid EV Charging

There are plenty of reasons to install solar panels on one’s home. Reducing electric bills, reducing carbon footprint, or simply being in a location without electric service are all fairly common. While some of those might be true for [Dominic], he had another motivating factor. He wanted to install a charger for his electric vehicles but upgrading the electric service at his house would have been prohibitively expensive. So rather than dig up a bunch of his neighbors’ gardens to run a new service wire in he built this off-grid setup instead.

Hooking up solar panels to a battery and charge controller is usually not too hard, but getting enough energy to charge an EV out of a system all at once is more challenging. The system is based on several 550W solar modules which all charge a lithium iron phosphate battery. The battery can output 100 A DC at 48 V which gives more than enough power to charge an EV. However there were some problems getting this much power through an inverter. His first choice let out the magic smoke when it was connected, and it wasn’t until he settled on a Growatt inverter capable of outputting 3.5 kW that the system really started to take shape.

All of this is fairly straightforward, but there’s an extra touch here that makes this project noteworthy. [Dominic] wanted to balance incoming power from the photovoltaic system to the current demands from the EVs to put less strain on the battery. An ESP32 was programmed to only send as much power to the EVs as the solar system is producing at any given time, and also includes some extra logic to make sure the battery doesn’t drain itself from the idle power requirements of the inverter. Right now the system works well but the true test will be when it goes through its first winter. Even though solar panels are more efficient at colder temperatures, if the amount of sunlight or the angle of the panels aren’t ideal there is generally much less production.

Battery Bot Makes Sure Cordless Tool Packs Are Always Topped Up

There was a time not that long ago when every tool was cordless. But now, cordless power tools have proliferated to the point where the mere thought of using a plain old wrist-twisting screwdriver is enough to trigger a bout of sympathetic repetitive injury. And the only thing worse than that is to discover that the batteries for your tools are all dead.

As [Lance] from the “Sparks and Code” channel freely admits, the fact that his impressive collection of batteries is always dead is entirely his fault, and that’s what inspired his automatic battery charging robot. The design is pretty clever; depleted batteries go into a hopper, under which is a 3D-printed sled. Batteries drop down into the sled, which runs the battery out from under the hopper to the charging station, which is just the guts of an old manual charger attached to a lead screw to adjust the height of the charging terminals for different size batteries. When the battery is charged, the sled pushes it a little further into an outfeed hopper before going back to get another battery from the infeed side.

Of course, that all vastly understates the amount of work [Lance] had to put into this. He suffered through a lot of “integration hell” problems, like getting the charger properly connected to the Arduino running the automation. But with a lot of tweaking, he can now just dump in a bunch of depleted packs and let the battery bot handle everything. The video after the break shows all the gory details.

Of course, there’s another completely different and much simpler solution to the dead battery problem.

Continue reading “Battery Bot Makes Sure Cordless Tool Packs Are Always Topped Up”

GaN Charger Teardown Reveals Value Of This New Technology

Every so often, a new technology comes along that offers a broad range of benefits over what we already have. Just as lithium-ion batteries have made nickel-cadmium cells boring and old hat, gallium nitride semiconductors are making silicon parts look unimpressive by comparison. [Brian Dipert] looked at what this means in a practical sense by tearing down a GaN phone charger.

The charger in question is a 30 watt USB-C charger produced by Voltme. It cost [Brian] just $10, as prices of GaN hardware have come down significantly as economies of scale have kicked in. The charger measures just 1.2×1.3×1.2 inches, and weighs only 1.5 ounces. That compact size is thanks to GaN semiconductors, which are able to run cooler at higher power levels than their silicon forebearers.

Cracking into the charger required levering open the case. The back panel came off with some work, revealing the mains terminals, which deliver AC power to the PCB inside via the case holding them in contact. Interestingly, the entire circuit inside is filled with an adhesive thermal goop, which helps pass heat from the hottest components to the charger’s case. [Brian] is able to guide us through the circuit, and he identified many of the major components. However, some of the markings on chips were beyond his research skills, and he asks any knowing readers to contribute their own information.

It’s interesting to see just what makes the high-powered compact chargers of today tick. Plus, it’s a hallmark of progress that what was once considered a wonder material can now be had in a $10 commodity phone charger from Amazon. How times change!

Copy And Paste Lithium Battery Protection

Lithium batteries have, nearly single-handedly, ushered in the era of the electric car, as well as battery energy storage of grid power and plenty of other technological advances not possible with older battery chemistries. There’s just one major downside: these lithium cells can be extremely finicky. If you’re adding one to your own project you’ll have to be extremely careful to treat them exactly how they are designed to be treated using something like this boilerplate battery protection circuit created by [DIY GUY Chris].

The circuit is based around the TP4056 integrated circuit, which handles the charging of a single lithium cell — in this design using supplied power from a USB port. The circuit is able to charge a cell based on the cell’s current charge state, temperature, and a model of the cell. It’s also paired with a DW01A chip which protects the cell from various undesirable conditions such as over-current, overcharge, and over-voltage.

The best thing about this design isn’t the design itself, but that [DIY GUY Chris] built the circuit schematic specifically to be easily copied into PCB designs for other projects, which means that lithium batteries can more easily be integrated directly into his other builds. Be sure to check out our primer on how to deal with lithium batteries before trying one of your own designs, though.

Continue reading “Copy And Paste Lithium Battery Protection”

Reverse Engineering Reveals EV Charger Has A Sense Of Security

As more and more electric vehicles penetrate the market, there’s going to have to be a proportional rise in the number of charging stations that are built into parking garages, apartment complexes, and even private homes. And the more that happens, the more chargers we’re going to start seeing where security is at best an afterthought in their design.

But as this EV charger teardown and reverse engineering shows, it doesn’t necessarily have to be that way. The charger is a Zaptec Pro station that can do up to 22 kW, and the analysis was done by [Harrison Sand] and [Andreas Claesson]. These are just the kinds of chargers that will likely be widely installed over the next decade, and there’s surprisingly little to them. [Harrison] and [Andreas] found a pair of PCBs, one for the power electronics and one for the control circuits. The latter supports a number of connectivity options, like 4G, WiFi, and Bluetooth, plus some RFID and powerline communications. There are two microcontrollers, a PIC and an ARM Cortex-A7.

Despite the ARM chip, the board seemed to lack an obvious JTAG port, and while some unpopulated pads did end up having a UART line, there was no shell access possible. An on-board micro SD card slot seemed an obvious target for attack, and some of the Linux images they tried yielded at least a partial boot-up, but without knowing the specific hardware configuration on the board, that’s just shooting in the dark. That’s when the NAND flash chip was popped off the board to dump the firmware, which allowed them to extract the devicetree and build a custom bootloader to finally own root.

The article has a lot of fascinating details on the exploit and what they discovered after getting in, like the fact that even if you had the factory-set Bluetooth PIN, you wouldn’t be able to get free charging. So overall, a pretty good security setup, even if they were able to get in by dumping the firmware. This all reminds us a little of the smart meter reverse engineering our friend [Hash] has been doing, in terms of both methodology and results.

Thanks to [Thinkerer] for the tip.

The Ease Of Wireless Charging, Without The Wait

Historically, there have been a few cases of useful wireless power transmission over great distances, like a team at MIT that was able to light up a 60 W bulb at several meters, and of course Nikola Tesla had grand dreams of drawing energy from the atmosphere. But for most of us wireless power is limited to small, short-range devices like cellphone chargers. While it’s not a lot of work to plug in a phone when it needs a charge, even this small task can be automated.

This build begins with a 3D printed cradle for the smartphone to sit in. When the device detects that the phone has been placed in the cradle, it uses a linear actuator to drive a custom-built charging cable into the phone’s USB port. Similarly, when the phone is lifted from the cradle the cable is automatically removed. It appears that there is some play in the phone’s position that lets the charger be plugged in smoothly, and the project’s creator [Larpushka] points out that the linear actuator is not particularly strong so we don’t imagine the risk of damage is very high.

While wireless charging still may have the edge when it comes to keeping debris out of the port, we still really enjoy a project like this that seems to be done for its own sake. There are some improvements that [Larpushka] plans to make, but for now we’re delighted by this build. For anyone looking to add true wireless charging to any phone that doesn’t have it, though, it’s not too difficult to accomplish either.

DIY Arduino Based EV Charger Saves Money, Looks Pro

Electric vehicles (EVs) are something of a hot topic, and most of the hacks we’ve featured regarding them center on conversions from Internal Combustion to Electric. These are all fine, and we hope to see plenty more of them in the future. There’s another aspect that doesn’t get covered as often: How to charge electric vehicles- especially commercially produced EV’s rather than the DIY kind. This is the kind of project that [fotherby] has taken on: A 7.2 kW EV charger for his Kia.

Faced with spending £900 (about $1100 USD) for a commercial unit installed by a qualified electrician, [fotherby] decided to do some research. The project wasn’t outside his scope, and he gave himself a head start by finding a commercial enclosure and cable that was originally just a showroom unit with no innards.

An Arduino Pro Mini provides the brains for the charger, and the source code and all the needed information to build your own like charger is on GitHub. What’s outstanding about the guide though is the deep dive into how these chargers work, and how straightforward they really are without being simplistic.

Dealing with mains power and the installation of such a serious piece of kit means that there are inherent risks for the DIYer, and [fotherby] addresses these admirably by including a ground fault detection circuit. The result is that if there is a ground fault of any kind, it will shut down the entire circuit at speeds and levels that are below the threshold that can harm humans. [fotherby] backs this up by testing the circuit thoroughly and documenting the results, showing that the charger meets commercial standards. Still, this isn’t a first-time project for the EV enthusiast, so we feel compelled to say “Don’t Try This At Home” even though that’s exactly what’s on display.

In the end, several hundred quid were saved, and the DIY charger does the job just as well as the commercial unit. A great hack indeed! And while these aren’t common, we did cover another Open Source EV charger about a year ago that you might like to check out as well.

Continue reading “DIY Arduino Based EV Charger Saves Money, Looks Pro”