SolarCharge 200ds230 rev 2 - An unconventional, scalable high efficiency 12V solar power system, a battery charge controller with low voltage cutout to protect the battery. [via]
An unconventional, scalable high efficiency 12V solar power system and battery charge controller with low voltage cutout to protect the battery. (ideal for systems of 50W or less).
The most common solar charger consists of a Schottky diode to prevent the battery from draining into the PV panel and a shunt regulator that effectively short circuits the panel once the battery is fully charged.
One problem with this approach is diode losses and the resulting heat. If a 50W 12V panel supplies 4A to the battery, the Schottky diode will drop about 0,4V across it dissipating about 1,6W of heat. This requires a heat sink and loses power to heat. The problem is that there is no way of reducing the volt drop, paralleling diodes may share current, but the 0,4V will still be there. The circuit uses a MOSFET in stead of the usual diode and the primary power loss is resistive.
Scalable 12V solar power system and battery charge controller - [Link]
Last year I bought a Canon PowerShot SX200 on ebay. I wanted to play a bit with CHDK, the Canon Hack Development Kit to make some timelapse things. Problem was, the battery would hold only up for 2 hours or so. Even worse, the camera has no power jack to attach a power supply. The solution is to buy a battery dummy that has a jack on its back. That costs like 30 euros!
3D Printed Battery Adapter for a Canon Powershot SX200 - [Link]
Measuring Battery Capacity with an Arduino. Dennis writes- – [via]
I needed a couple of AA batteries and found the display at the supermarket where they were all arrayed. Normally when I’m shopping in the supermarket, I tend to look at the price/kg or price/l when comparing similar products. In the case of the batteries, there was no such indicator. Fine, I thought, I’ll work it out myself. I grabbed a few different makes and scanned the packaging for some measure of their capacity. Nothing. Not a single one of the batteries had any indicator of how much energy they would provide. Instead, they all had terms like ‘PLUS’, ‘SUPER’, ‘ULTRA’ and of course had wildly differing prices. So, I decided that it was time for an experiment and bought one pack of every type I could find.
Measuring Battery Capacity with an Arduino - [Link]
Sam Byford writes:
NEC has been developing its organic radical battery (ORB) technology for a while, and today it unveiled the latest iteration. The newest ORB is a 0.3mm (0.012 inch) flexible battery that’s designed to fit into integrated circuit (IC) cards, commonly used for public transport payment, credit cards, and suchlike. Standard IC cards are 0.73mm thick, meaning the addition of a battery shouldn’t prove too taxing on your wallet. Furthermore, the battery can be printed directly onto the IC card as part of the manufacturing process, and the surrounding 0.05mm polymer film can incorporate circuit boards with small components like antennas.
0.3mm thin ‘organic radical battery’ can be printed - [Link]
This is a very simple capacity tester. It consists of single resistor that discharges battery. Arduino measures the voltage drop across resistor. According to Ohm’s Law current = voltage/resistance. Every second value of current is divided by 3600 and summed up to get the capacity expressed in Ah (Amp per hour).
I have used two parallel connected resistors that total resistance is 6.9 ohm. Make sure that they have proper power rating, if you don’t want them to convert to smoke. If voltage across 6.9 ohm resistor is 3.7 V, then current – 0.54 A, power ~ 2W.
Arduino Lithium-ion battery capacity tester/discharge monitor - [Link]
Accutronics has launched two new lithium-ion batteries in its Intellion series of credit card sized batteries. Designed to provide a high level of functionality and safety the CC2300 and CC3800 batteries allow integration of smart lithium ion battery into handheld portable products with minimal effort and cost.
The batteries feature an active electronic protection system that prevents them from being overcharged, over discharged or short circuited and to ensure that the battery will remain safe if externally abused. In addition, they have an impedance tracking fuel gauge that constantly tracks battery status, providing information such as remaining battery capacity, state of charge, run time to empty, battery voltage and temperature. [via]
Smart Li-Ion Batteries the Size of a Credit Card - [Link]
Eric built himself a battery monitoring system based on the ATmega328 Development Kit. He drained a 9V battery with 100mA of current and monitored the voltage drop until total depletion. He used this data to estimate how much time is left until depletion – [via]
The 100mA constant load was chosen because my ProtoStack Arduino Clone with LCD draws about 92mA and I wanted to write a sketch to display a battery bar and the approximate hours battery life left. Since all batteries have an internal equivalent series resistance (ESR), it is important to take that into account when only using a battery’s voltage to monitor its state of charge. Since we discharged the battery through a load that is similar to the ProtoStack board with LCD, the ESR of the battery has automatically been accounted for in the voltage measurements.
Monitoring battery voltage to calculate capacity with an Arduino - [Link]
Here is an interesting project which uses capacitors to store energy instead of chemical,sit uses an different type of capacitors called Goldcap capacitors,GoldCap capacitors offer an interesting alternative power source when compared to conventional disposable or even rechargeable batteries. They can be charged very rapidly and can also deliver a high peak output current. Their voltage rating however is quite low so a little electronic assistance is necessary to raise the output voltage to a more useful level.PP3 (6F22) type 9 V batteries are often used in small portable equipment that require very little current and may only be used intermittently. Under these conditions its often the case that the battery is flat just when you urgently need to use the equipment. NiCd rechargeable cells are not a good choice in these applications because their self-discharge characteristics are much worse than dry cells and often there is no charge left after a long time in storage.
Superfast Rechargable Battery - [Link]
The circuit uses both op-amps of an LM358 to control the charging of a single cell lithium ion battery. Charging automatically stops when the battery is full, and it is possible to charge batteries that have gone below the undervoltage limit. Power is provided through USB or any other 5V source.
Simple USB DIY Li-ion battery charger - [Link]