Aluminium-Sulphur Batteries For Local Grid Storage?

September 5, 2022 by Dave Rowntree 45 Comments

Lithium-Sulphur batteries have been on the cusp of commercial availability for a little while now, but nothing much has hit the shelves as of yet. There are still issues with lifetime due to cell degradation, and news about developments seems to be drying up a little. Not to worry, because MIT have come along with a new battery technology using some of the most available and cheap materials found on this planet of ours. The Aluminium-Sulphur battery developed has very promising characteristics for use with static and automotive applications, specifically its scalability and its incredible charge/discharge performance.

The cell is based upon electrodes constructed from aluminium metal and sulphur, with a electrolyte of molten catenated chloro-aluminate salts. With an operating temperature of around 100 degrees Celsius, you’re not going to want this in a mobile phone anytime soon, but that’s not the goal. The goal is the smoothing out of renewable energy sources, and localised electricity grid balancing. A major use case would be the mass charging of battery electric vehicles. As the number of charge points increases at any given location, so does the peak current needed from the grid. Aluminium-Sulphur batteries are touted to offer the solution to ease this, with their high peak discharge current capability enabling a much higher peak power delivery at the point of use.
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Hackaday Prize 2022: A Backup Battery Pack

September 5, 2022 by Lewin Day 10 Comments

These days, we’re all running around toting smartphones and laptops that could always use a bit more charge. Portable battery packs have become popular, and [Anuradha] has designed one that packs plenty of juice to keep everything humming.

The pack is designed to be charged via solar panels, at 18 V and up to 5 A of current. It’s intended to work with a Maximum Power Point Tracking module to ensure the maximum energy is gained from the sunshine available. For storage, the pack relies on 75 individual 18650 lithium cells, arranged with 3 cells in series, each with 25 in parallel (3s25p). They’re spot welded together for strength and good conductivity. Nominally, the output voltage is on the order of 10-12 V. The included battery management system (BMS) will allow an output current up to 100 A, and the pack can be used with an AC inverter to power regular home appliances.

Overall, it’s a tidy pack that’s more than capable of keeping a few devices charged up for days at a time. If you’re building something similar yourself, though, just be sure to package it well and keep it protected. So many lithium batteries can quickly turn fiery if something goes wrong, so store and use it appropriately! Fear not, however – we’ve got a guide on how to do just that.

Water Monitor Measures The Cost Of Your Shower Thinking Time

August 26, 2022 by Danie Conradie 18 Comments

The shower is one of the top thinking places for many of us, but can get a bit out of hand with water wastage and utility bills if you go down a deep rabbit hole. To be more mindful of his water usage in the shower, [GreatScott!] created a power sipping water monitor that lives there.

The device is built around a cheap 1/2″ brass water flow rate sensor connected to his shower hose, which outputs pulses as a small wheel passes an internal hall effect sensor. The datasheet didn’t contain any spec for pulses/volume, so [GreatScott!] had to experimentally determine this by filling a one-liter container with water and counting the pulses. He found that the pulse count per liter was dependent on the flow rate, so he narrowed down the variables and just determined the average count at his shower’s pressure and flow rate.

The sensor is connected to a battery-powered ESP8266 housed inside a sealed 3D-printed enclosure in the shower. To reduce power usage to a minimum, a flow switch was added in series with the flow meter, which only switches on the ESP8266 when water starts flowing. A latching circuit keeps the ESP powered after the water stops, giving it enough time to transmit the data before shutting down. This type of circuit is very handy for any battery-powered project connected to an external switch or sensor.

It is programmed with ESPHome and outputs the data to a local Home Assistant server, so no data is saved on someone else’s server.

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Building A Spot Welder From 500 Junk Capacitors

August 20, 2022 by Dave Rowntree 5 Comments

[Kasyan TV] over on YouTube was given a pile of spare parts in reasonably large quantities, some of which were useful and allocated to specific projects, but given the given the kind of electronics they’re interested in, they couldn’t find a use for a bag of 500 or so low specification 470uF capacitors. These were not low ESR types, nor high capacitance, so unsuitable for power supply use individually. But, what about stacking them all in parallel? (video, embedded below) After a few quick calculations [Kasyan] determined that the total capacitance of all 500 should be around 0.23 Farads with an ESR of around 0.4 to 0.5 mΩ at 16V and packing a theoretical energy total of about 30 joules. That is enough to pack a punch in the right situation.

A PCB was constructed to wire 168 of the little cans in parallel, with hefty wide traces, reinforced with multiple strands of 1.8mm diameter copper wire and a big thick layer of solder over the top. Three such PCBs were wired in parallel with the same copper wire, in order to keep the total resistance as low as possible. Such a thing has a few practical uses, since the super low measured ESR of 0.6mΩ and large capacitance makes it ideal for smoothing power supplies in many applications, but could it be used to make a spot welder? Well, yes and no. When combined with one of the those cheap Chinese ‘spot welder’ controllers, it does indeed produce some welds on a LiPo cell with a thin nickel plated battery strip, but blows straight through it with little penetration. [Kasyan] found that the capacitor bank could be used in parallel with a decent LiPo cell giving a potentially ideal combination — a huge initial punch from the capacitors to blow through the strip and get the weld started and the LiPo following through with a lower (but still huge) current for a little longer to assist with the penetration into the battery terminal, finishing off the weld.

[Kaysan] goes into some measurements of the peak current delivery and the profile thereof, showing that even a pile of pretty mundane parts can, with a little care, be turned into something useful. How does such an assembly compare with a single supercapacitor? We talked about supercaps and LiPo batteries a little while ago, which was an interesting discussion, and in case you’re still interested, graphene-based hybrid supercapacitors are a thing too!

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Toddler EV Gets Big Boy Battery Upgrade

July 29, 2022 by Ryan Flowers 13 Comments

No matter the type of vehicle we drive, it has a battery. Those batteries wear out over time. Even high end EV’s have batteries with a finite life. But when your EV uses Lead Acid batteries, that life is measured on a much shorter scale. This is especially true when the EV is driven by a driver that takes up scarcely more space in their EV than a stuffed tiger toy! Thankfully, the little girl in question has a mechanic:

A 3d printed adapter sends go-juice to the DC-DC converter

Her daddy, [Brian Lough], who documented the swift conversion of his daughter’s toy truck from Lead Acid to Li-Ion in the video which you can see below the break.

Facing challenges similar to that of actual road worthy passenger vehicles, [Brian] teamed up with [bitluni] to solve them. The 12 V SLA battery was being replaced with a 20 V Li-Ion pack from a power tool. A 3d printed adapter was enlisted to break out the power pins on the pack. The excessive voltage was handled with a DC-to-DC converter that, after a bit of tweaking, was putting out a solid 12 V.

What we love about the hack is that it’s one anybody can do, and it gives an inkling of what type of engineering goes into even larger projects. And be sure to watch the video to the end for the adorable and giggly results!

Speaking of larger projects, check out the reverse engineering required in this Lead Acid to Li-Ion conversion we covered in 2016.

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The charging station on the table, with twelve powerbanks plugged into it, charging. A small meter on the front panel shows 4.73 volts and 4.38 amps.

A Simple Charging Station For Twelve Powerbanks

July 25, 2022 by Arya Voronova 13 Comments

[jasonwinfieldnz] uses twelve small powerbanks day to day – powering LED strips around his trampoline, presumably, to avoid the mess of wires and make the assembly easily portable. However, if you have twelve powerbanks, you’ll find yourself hogging all the household’s microUSB cables every so often, as they eventually discharge. This was not good enough for our hacker, and he decided to build a charging station to refill them all at once.

If you need 5 volts and many amps, an ATX PSU isn’t your worst bet. From there, he only had to add twelve microUSB connectors to – and condensed the entire contraption into a beautiful charging station. For the microUSB part, he hacked some microUSB cable ends off and embedded them into the case. An embedded voltage and current module is of big help – letting you see at a glance when charging has really finished. Using copper tape as bus bars and banana plugs for charging input, this project is easy to build and solves the problem well.

The 3D printing files and cutting templates are right there on the project page, so if any of us hackers has a problem that twelve powerbanks could help with, [Jason]’s project is quite repeatable. If your devices are more diverse, you could use a pegboard to build a stylish charging station for them! If, on the other hand, you have a single device you need to plug multiple cords into, moldable plastic is there to help.

Adding A Battery To Extend Speaker Life

July 23, 2022 by Bryan Cockfield 14 Comments

Perhaps the weakest point in modern electronics when it comes to user servicability is the lifecycle of the batteries included from the manufacturer. Without easily replaceable batteries, many consumer goods end up in the landfill when they’re otherwise working perfectly. If you’d like to get more out of your devices than the manufacturer intends, you might have to go to great lengths like [Théo] did with his JBL speaker.

This was a Bluetooth device produced by JBL nearly a decade ago, and while the original device boasted several hours of battery life, after so many years of service, it was lucky to get a half hour before the battery died. To replace it, [Théo] removed the original battery and extended the case to be able to hold a larger cell phone battery. He also decided to use the original battery management circuit from the speaker with the new battery after verifying the voltage and chemistry were close enough to the original.

Since the phone battery is a proprietary Samsung device, [Théo] also decided to build a version that uses standard 18650 cells instead, although he prefers the slimmer design with the phone battery for his use case. Straightforward as this build may be, it does go a long way to demonstrate the principle that if you can’t fix your devices, you don’t really own them.