mic @ wemakethings.net writes:
For a long time I wanted to enter the 21st century by stopping using NiCad or NiMH batteries and upgrading to Lithium accumulators as they provide more power per volume and are cool in general. Constant flow of obsolete cell phones provides a nice source of reasonably high-performance batteries for free – I felt compelled to tap into this resource for my battery operated projects.
Open source Lithium battery charger modules - [Link]
Kennith needed a 1A constant current lead-acid battery charger for his HAM radios so he writes:
Since the SLAs are relatively small, and I only need them charged between radio outings, I opted to build a 1A constant current charger, based on the 555 Battery Charger which won first place in the 555 Design Contest Utility category. Using a 555 is a rather clever way to get two comparators and a Set-Reset latch in a single 8DIP package, which is needed for the high and low trip points. The major difference between my design and Mike’s is that instead of using a relay like him, I use an LM317 as a constant current source to limit my batteries charge rate.
555 based constant current lead-acid battery charger - [Link]
Fully autonomous processors add simple, utility-grade energy measurement and diagnostics to existing designs.
San Jose, CA—January 16, 2013—Maxim Integrated Products, Inc. (NASDAQ: MXIM) today announced that it is now sampling the 78M6610+PSU/78M6610+LMU single-phase energy-measurement processors. These processors are an energy-measurement subsystem in a single chip. They provide simple utility-grade sensing and diagnostics for existing designs without the traditional cost of a utility meter system-on-chip. Both devices contain unique firmware to meet end application requirements. The 78M6610+PSU is specifically designed for real-time monitoring of data centers, servers, and telecom and data equipment, while the 78M6610+LMU is a more general-purpose solution for applications such as white-good appliances, smart plugs, EV chargers, and solar inverters.
The 78M6610 processors enable energy-measurement functionality while reducing both manufacturing costs and time to market. Energy-measurement solutions traditionally required the use of an additional microcontroller, which adds significant design cost and months of development time. The 78M6610 allow users to conveniently add a complete energy meter to an already existing design without significant cost or redesign. Additionally, the processors’ flexible measurement and host interfaces allow for easy integration into any system.
Single-Phase Energy-Measurement Processors Accurately Monitor Power at a Fraction of the Cost - [Link]
With the new AIR 40 wind turbine it is possible to gain 40 kWh monthly – easily and safely.
Advantages / Features:
- high quality wind turbine with 12, 24 or 48V output voltage
- 40 kWh monthly at an average wind speed of 5.8 m/sec
- operation at 3.1-22 m/s wind speeds
- microprocessor based controller
- aluminium body
- composite blades optimized for a quiet operation
- 1.17m rotor diameter
- electronic overspeed protection
- brushless alternator (dynamo) with a long lifetime
Small wind turbines are an excellent electric energy source for all „off-grid“ applications with a low and middle power consumption like telecommunications, lighting, SCADA (telemetry) and other. In comparison to photovoltaic panels, they require only a very simple installation – to tighten to a shaft.
AIR 40 are top quality microprocessor controlled wind turbines with a precise mechanical construction. Thanks to a low weight and an integrated controller, they´re easy to install and provide an energy right after the installation. Composite blades are optimized for a quiet operation, durability and a maximum power in a wide range of wind speeds. A big advantage of Air 40 is a relatively low start-up wind speed – already from – 3.1 m/s. „The heart” of AIR 40 is a brushless alternator dynamo with permanent magnets and with a long lifetime.
Output power of AIR 40 depends from real on-site conditions, however in average it is able to provide 40 kWh monthly, at an average wind speed of 5,8 m/s (21km/h). At higher wind speeds it can be even substantially more. Wind turbines are capable of a standalone operation and they´re also a well-proven complement of PV panels, where they conveniently supplement a decreased power of PV panels, especially in winter season.
Detailed information will provide you the AIR 40 datasheet. In case of interest, please contact us at email@example.com.
Catch the wind into a net (or into a battery) - [Link]
The LT®3651-8.2/LT3651-8.4 are 2-cell, 4A Li-Ion/Polymer battery chargers that operate over a 9V to 32V input voltage range. An efficient monolithic average current mode synchronous switching regulator provides constant current, constant voltage charging with programmable maximum charge current. A charging cycle starts with battery insertion or when the battery voltage drops 2.5% below the float voltage. Charger termination is selectable as either charge current or internal safety timer timeout. Charge current termination occurs when the charge current falls to one-tenth the programmed maximum current (C/10). Timer based termination is typically set to three hours and is user programmable (charging continues below C/10 until timeout).
LT3651-8.2 and 8.4 – Monolithic 4A High Voltage 2-Cell Li-Ion Battery Charger – [Link]
This teardown article will delve into the architectural design and components of a solar inverter card starting from the Solar panel DC inputs and working our way through the DC to AC conversion process to the AC output that is sent out to the power grid. We will show what features need to be implemented into such a design to meet various safety and other performance standards as well as stringent power company demands upon the signal that is put onto their grid.
Teardown: The power inverter – from sunlight to power grid - [Link]
Bryon Moyer writes:
The development of wireless sensing technology has made possible tasks that would have been unthinkable in years past. Sensors can be installed where it is impractical or impossible to run a communication wire; their ability to communicate wirelessly, as long as they are within range of a hub, means that it is possible to gather data in places or situations that were previously inaccessible.
The inability to run a communication wire to the sensor also means no power line as well. Sensors need power both to sense and to communicate, so that has typically meant using a primary battery. While you would presumably select a battery with as long a life as possible, the battery is still unlikely to outlast the life of the sensor, meaning that someone will have to go out and replace the battery at some point – which can be expensive.
Managing the Energy and Lifetimes of Thin-Film Batteries - [Link]
This is a simple li-ion charger without a dedicated li-ion charger IC. This circuit can be used to efficiently and intelligently charge any single cell Li-ion battery pack like mobile battery, digicam battery, etc.
- Charging via mini-USB connector which is very common.
- Charging status display by LED
- Simple circuit by using opamp, resistor, and not by any complex dedicated IC or micro-controller.
- Charges completely drained (0V) battery packs.
- Max charging current 500mA (limited by USB supply), depending on battery.
Simple USB DIY Li-ion battery charger - [Link]
Planning on powering that next über-low-power board of yours from a measly CR2032 coin cell? Read this app note to understand exactly what the limitations of coin cells are: [via]
When designing a small wireless sensor node to be powered by the popular CR2032 coin cell, some sources claim there is a 15mA “limit” and that drawing more current is not possible or will “damage” the battery. This may give the impression that at 15mA everything works perfectly and battery capacity is great, while at 16mA nothing works. There is little public information available to explain why such a limit exists (if it indeed does exist), and little information explaining why 15mA would be a “magic number”.
Understanding Coin Cell Limitations - [Link]
The TPS92510 by Texas Instruments is a 1.5-A constant current DC/DC buck converter with a combo of frequency synchronization, pulse-width modulation (PWM) dimming and thermal foldback firsts. Used with the WEBENCH LED Architect, users rapidly design a power management circuit to drive a string of up to 17 high-brightness LEDs at up to 97% power efficiency in automotive, industrial, and general lighting applications.
The TPS92510 operates with fixed frequency by using its internally generated clock or via synchronization to an external PWM clock source. Thermal foldback ensures light output remains even in an LED over-temperature condition, adding safety. [via]
- 3.5-V to 60-V input voltage operating range supports a wide variety of DC LED lighting applications, including area and street lighting.
- Fixed switching frequency range from 100 kHz to 2.5 MHz can be synchronized to optimize for efficiency or solution size.
- LED thermal foldback with external negative temperature coefficient (NTC) protects LED array from over-temperature while maintaining reduced light output.
- Dedicated PWM dimming input from 100 Hz to 1 kHz adjusts LED brightness without color shift or perceivable flicker.
Buck converter drives high-brightness LEDs - [Link]