Here’s an Instructable about a DIY charger for car’s battery with an analog DC ammeter in the front panel. A PIC12F683-based control circuit is enclosed inside which adds some intelligence to this charger. The PIC MCU checks the terminal voltage of the battery being charged in every ten minutes using one of its analog inputs, and if it is found above a set threshold, the charging process is stopped. A relay switch is included into the circuit to connect/disconnect the charger output and the battery terminals.
PIC12F683 based battery charger - [Link]
It’s holiday season and the chances are some of your gadgets will be also be going along for the ride. The ThinkPower mobile charger by Zettaly has been designed to provide essential recharge capability for USB-charged devices when you find yourself any distance from a mains wall outlet. The ThinkPower itself can be fully charged in just 90minutes and once charged its 10,000mAh high-capacity battery pack can recharge any USB-powered gadget. It has been tested with iPhone, iPad, Samsung Galaxy, Nexus, HTC, Moto, LG, GoPro and many other brands of smartphones, tablets, and cameras (for DIY fans its also tested been tested with the Raspberry Pi :). A fully charged ThinkPower has enough capacity to recharge an iPhone 5 over four times.
Speedy Recharger - [Link]
An all-in-one, water and sand resistant, solar charger, audio speaker system, and sunburn timer calculator by starwisher. Check out the project’s instructables page here:
This Instructable harnesses the power of Arduino, a UV sensor, and simple mathematics to make one nifty gadget sure to boost your outdoor summer fun – and minimize your indoor summer recovery!
Beach Buddy, a 3-in-1 solar phone charger, boombox, and sunburn timer calculator - [Link]
Alan Parekh @ hackedgadgets.com writes:
This video was going to be a repair of this Portable USB Charger but as it turns out there wasn’t anything electrically wrong with it. It didn’t work out of the box but I think that must have been caused by some oxidation on the USB contacts. It seems to work like a champ now. The control chip for the DC/DC converter looks to be this DHMF chip. I have never seen the swoop logo before and can’t seem to find any data on this 5 pin device though. It is probably similar to the LT1302 (PDF) that the Adafruit MintyBoost uses. The efficiency of this circuit doesn’t appear to be as efficient as a proper one built using the LT1302 though since when drawing 500mA from the output it can maintain very close to 5 volts out (2.5 watts) but needs an input of 3 volt at 1.3 amps to do it (3.9 watts). This gives us an efficiency of about 64%, the graph from the datasheet of the LT1302 indicates that it could perform at about 86% under these conditions.
Portable USB Charger Teardown - [Link]
1,6V rechargeable batteries experience “rebirth” and bring several advantages in comparison to 1,2V NiCd accumulators
Experts in electrotechnics might say, that these are a long-time known batteries invented already by Edison thus being no novelty at all. That´s true but in contrast to older tyes is in technological advance of electrolyte and electrodes so as to reach a substantially higher lifetime that few decades ago.
So what´s interesting about these rechargeable batteries? By one sentence, NiZn cell has an output voltage of approx. 1.65V, what´s about 0.4V more than NiMH/ NiCd cells.
At the same time they´re able to provide a high current, similarly like NiCd/ NiMH cells, that´s why they´re also usable in devices with high current demands (conductivity of Zinc is about 15% than Cd). NiZn cells are easily recyclable and they´re very environmentally friendly. Another benefits:
- energy density of NiZn cells is about a third higher than that of NiCd cells (Wh/kg and also Wh/liter).
- higher voltage (1,6-1,8V) enables to reach a higher voltage of „battery-packs“ with a lower count of cells
- lifetime is comparable with NiCd cells
- no memory effect, trouble-free recharge to 100%
- flat discharging characteristics, average voltage aprox. 1,6-1,7V
It is recommended to recharge NiZn cells by C/4 to 1C current (i.e. for example 500 mA to 2000 mA for a 2000mAh cell) while observing a max. voltage of 1.9V/ cell. It´s not recommended to leave cells at a so called “trickle charging” as overcharging might decrease lifetime of cells. Naturally, like in case of almost all rechargeable batteries, the highest lifetime can be reached at operation on a partial discharge (not to a deep discharge). It´s worth to say, that NiZn are not an ideal replacement into devices with a very small power consumption ( e-g- remote controllers), where still win primary alkaline cells.
In our offer can be found NiZn cells themselves: 4AA2500mWh1.6V BP4 and 4AAA900mWh1.6V BP4 as well as a set – charger + cells (4xAA+4xAAA) NizN Charger + Accu. This charger charges by 500 mA current (AA/AAA) and monitors each slot individually. During recharging a LED at agiven slot blinks slowly (1x/s) and after finishing of recharge it shines continuously. In case of a faulty cell it blinks quickly (4x/s).
NiZn rechargeable batteries – when Nickel and Zinc create a strong pair - [Link]
Tutorial – MicroLipo and MiniLipo Battery Chargers @ The Adafruit Learning System.
Sooner or later you’ll need to cut the cord…the power cord! Untether your electronic project from the tyranny of the wall adapter and take it out into the world. That’s where batteries come in, and you may have been seduced by the high power density, large current capabilites and recharge-ability of Lithium Polymer or Lithium Ion batteries. These battery chemistries have quickly become the most popular rechargeable batteries in consumer products, powering everything from keychain mp3 players to huge laptops.
Tutorial – MicroLipo and MiniLipo Battery Chargers - [Link]
7-42VDC Input 5V 2A USB Output Power Supply. Compatible with Raspberry Pi, Arduino, iDevices, Mobile Phones and other USB Devices.
Having to use a Raspberry Pi and other USB Devices in an electronics production environment where 5V isn’t standard, I have noticed a lack of power supplies capable of fitting in. A unit had to be designed to fit into systems where 12V & 24V are the norm or where batteries / solar panels etc are the only supply method available.
7-42VDC to USB Supply/Charger - [Link]
by Ken Shirriff:
Disassembling Apple’s diminutive inch-cube iPhone charger reveals a technologically advanced flyback switching power supply that goes beyond the typical charger. It simply takes AC input (anything between 100 and 240 volts) and produce 5 watts of smooth 5 volt power, but the circuit to do this is surprisingly complex and innovative.
Apple iPhone charger teardown - [Link]
By Tahar Allag, Wenjia Liu:
Cell phones are a good example of how functionality and performance have both increased significantly in portable devices over the last few decades. They have become more complex and can do many basic tasks as well as any computer. The extra functionality that has transitioned the smartphone from a phone-call-only device to a multipurpose portable device, which makes it more power hungry than ever before.
The internal battery pack is the main source of storing and delivering power to portable-device circuitry. Batterycharger ICs are responsible for charging the battery pack safely and efficiently. They must also control the power delivery to the system to maintain normal operation while plugged in to wall power. The battery pack is required to store a large amount of energy and be charged in a short amount of time without sacrificing weight and volume. The increased charge and discharge currents, as well as the smaller physical size, make the packs vulnerable to physical and thermal stresses. Therefore, battery chargers are no longer required to perform just as a simple standalone charger
AppNote: Battery charging considerations for high-power portabledevices - [Link]
Designers of rechargeable battery-powered equipment want a charger that minimizes charge time with maximum charge current by maximizing the power taken from the supply without collapsing the supply. Resistances between the supply and the battery present a challenge. This article explains how to design the charging circuit to achieve the maximum power from the adapter despite the undesired resistances between the supply and battery.
AppNote: Extract maximum power from the supply when charging a battery - [Link]