When observing basic rules will the top quality AGM VRLA batteries last you up to 15 years – we will advise how.
This description could start by a long list of technical improvements of Panasonic batteries. thanks to which they gained a stable place on the top of development in this segment (AGM, expanded positive grid. additives for regeneration from a deep discharge, self-extinguishing container material,…).
However those are things, which can be easily checked up from available internet source or even better from satisfied users. Instead of it, we better bring you a few advices for usage of VRLA/ SLA batteries to serve you as long as possible:
- batteries can be recharged by several ways, but one of the most reliable belongs a „constant voltage/ limited current“ method, i.e. observing max. 2.45V/ cell and a current limitation. It responds 14.7V at 12V battery and a max. current of 0.4CA. This is suitable at so called cycle usage.
- at a stable connection to a voltage source, a voltage per cell shouldn´t exceed 2.3V what is 13.8V at 12V battery. Current limitation should be set to 0.15CA.
- battery lifetime grows significantly with a decreasing temperature, i.e. it is very important to place a battery far from heat sources (transformer,…)
- number of cycles (thus a battery lifetime) is very strongly dependent on a level of discharge before consequent recharging. Dependence is so strong, that for example at discharging to 50% a standard battery will reach a lifetime of approx. 500 cycles, while when discharged in 30% (remains 70% of capacity), the number of cycles will increase up to 1200 (!). The result is, that a choice of a suitable capacity is a key to reach a good lifetime in a given device. Especially in devices, where a battery is daily discharged/ recharged, can a suitable battery (with a higher capacity) significantly prolong a lifetime (thus minimizing costs for replacement).
- if possible, avoid usage of battery on 100% discharge (so called deep discharge). Even though Panasonic batteries manage these statuses and they contain additives for a successful recovery from a deep discharge, but such a usage shortens battery lifetime significantly (to approx. 200 cycles).
- real capacity of a battery (amount of energy, which we´ll get out of it) is strongly dependent on a discharge current. 100% capacity can be reached at a current of 0.05CA/ 20°C. At 0,25CA current it is approx. 75% of capacity and at a current of 1CA it is only approx. 55%. This fact also says for a sufficient sizing of a battery. Especially in applications with a relatively higher power consumption (approx. >0.05CA) we´ll gain by using a 50% bigger battery a resulting battery, with a capacity “increased” in more than 50% (thanks to a relatively lower load of such battery at discharging). Resulting relatively lower discharging current and a lower depth of discharge in every cycle will significantly contribute to a longer lifetime..
- real capacity of a battery also depends on temperature. Difference between a capacity at +20° vs. -10°C is approx. -25%.
- cut-off voltage at which it´s necessary to disconnect the battery is markedly dependent on a discharge current (at a higher current it falls down). That´s why it´s good to set a deep discharge protection in respect to a supposed maximum discharge current.
Above mentioned values apply to standard Panasonic batteries. In the offer of company Panasonic can also be found types with extra long lifetime as well as sa called „Power“ types, suitable for high current devices (UPS,…). On stock we keep a few selected types of Panasonic batteries and upon request, we´re able to provide you any other type. Detailed information about usage and an overview of the Panasonic portfolio can be found in the VRLA Handbook document.
Maintenance-free lead batteries Panasonic will surprise by their lifetime - [Link]
An IR detector that sounds a buzzer when an IR beam is broken, meaning the IR signal is lost. A pulsed IR signal generator is necessary, but not included in this post. This project would be ideal for doorways or hallways to alert when someone enters or exits an area.
The IR sensor responds to pulsed IR, not ambient or continuous IR. This means that another transmitter project is necessary in order to complete this one! Note though that some forms of lighting like fluorescent lighting may interfere with the sensor. For convenience, the the buzzer is internally driven so that a only Vdc is needed to make a sound. In this case, the IR sensor senses 38kHz pulsed infrared light.
Pin 3 of the IR sensor is actually low (0V) while receiving a signal. When the sensor is blocked from receiving the IR signal, the sensor outputs a high signal to the comparator, which then allows current through the LED/Buzzer circuit, and alerting you that the beam is broken. In the Scheme-It drawing the LM311 IC is a grouping of three components, in a functional block diagram style, to show how it functions in the circuit beyond what the pinouts would show normally.
IR Beam Breaker Alarm Circuit - [Link]
abhishek7xavier @ instructables.com writes:
Power supply is an utmost essential tool for an electronic lab. It comes in handy for powering up various applications and circuits. However a fixed voltage, fixed current power supply is sufficient for basic needs but a variable one is good to have because different circuits and components operate at different voltages and consumes different current. When it comes to an electronic hobbyist’s lab, a good power supply is must to have. Also if the power supply boosts additional features like on board voltage and current display, it comes in handy as one can know the exact voltage at the output terminals and also the current drawn by the load. But in the electronic market, those power supplies are not economic are meant for industrial purpose . Here in this article I present an economical and cost effective yet efficient variable bench power supply that is capable of providing 1.2 to 25 Volt variable supply up to 5 Ampere through one channel while 5 Volt, 1 Ampere and 12 Volt, 1 Ampere supply through other two channels thus having one variable and two fixed supply channels.
DIY Variable DC Power Supply with Display and PC interface - [Link]
Raj @ embedded-lab.com writes:
A couple weeks ago I received some sample products from Dorji Applied Technologies, a china-based company that make varieties of RF and sensor modules. One of the products I received was their latest DSTH01 sensor module that carries Silicon Labs’ Si7005 digital relative humidity and temperature sensor on board. Things I liked about it are it is inexpensive (available on Tindie for only $6), compact, and most importantly it supports I2C host interface for communication.
Reviewing Dorji’s DSTH01 digital temperature and humidity sensor module - [Link]
Kerry D. Wong builds a digitally controlled power supply based on ATmega328P mcu:
In my previous post, I showed my design of a dual tracking ±30V linear power supply. My goal was to use the transformer (28V+28V, center tapped) from an old Deltron W127G open-frame power supply and build a lab supply that can be digitally adjusted in both constant voltage and constant current modes. I also wanted each of the channels to be able to deliver up to 10 Amps of current so that I could fully utilize the 540VA transfomer from the W127G.
A Digitally Controlled Dual Tracking Power Supply - [Link]
The Stanford University theoretical physicist Shoucheng Zhang and colleagues have suggested that a new material called Stanene, composed of a one-atom-thick sheet of tin, could act much like a room temperature superconductor.
Stanene is a type of topological insulator where the body of the material is an insulator but the surface and edges are electrically conductive. As electrons move around in the surfaces and edges of topological insulators, their spin axis aligns with their direction of flow. This effect (known as the quantum spin Hall state) means that electrons can’t easily reverse direction. In normal conductors when they hit an impurity they scatter and dissipate energy.
Although Stanene and superconductors can both exhibit zero resistance, Zhang emphasized that Stanene is not a superconductor. While the edges of Stanene act as a zero resistance path for electrons, they still encounter contact resistance at their junctions with normal conductors. In superconductors however, electrons travel in pairs, a phenomenon that eliminates contact resistance so that normal conductors effectively act like superconductors when in contact with a superconductor. [via]
Zero Resistance but not Superconducting? - [Link]
DM&P has been producing low-power, x86-based Vortex processors for the embedded market for over ten years. Now in a nod to the Arduino market they have released the 86Duino Zero, a low-cost Arduino Leonardo sized board powered by their latest 300 MHz SoC Vortex86EX Processor.
This is a fully static 32-bit x86 processor board compatible with Windows OS, Linux and most other popular 32-bit RTOS. It integrates a PCIE bus, DDR3, ROM controller, xISA, I2C, SPI, IPC (Internal Peripheral Controllers with DMA and interrupt timer/counter included). The 86Duino Zero’s ports include USB 2.0 host and device coastline ports, a 10/100 Ethernet port and a microSD slot on the bottom of the board. The Zero’s baseboard also provides a 7-12V power jack, a reset button and a PCIe expansion connector.
The Zero supplies 14 digital I/O pins, half of which can provide 32-bit resolution PWM outputs and six 11-bit analog input pins. Each standard I/O pin supplies 16 mA while the 3.3 V pins can supply up to 400 mA. Like the Intel Galileo development board announced several weeks ago the 86Duino Zero marries Intel architecture to the Arduino platform. Its $39 price tag makes it an attractive proposition. [via]
The 86Duino Zero Runs Linux on x86 - [Link]
Universal multimeter UT139C with a high resolution will be appreciated at development and everywhere, where you need to find out a situation in a given device accurately
Imagine a situation, when you need to check or set a voltage of 3.3V or 5V usual at digital electronics (AD converters reference,…). Or to measure the end of recharging of Li-ion/ Li-Pol batteries at 4.20V when it really matters on every miliVolt. In these cases, with usual multimeters you´ll face one cardinal fact – regarding that the most of them has a max. display reading of 1999, you´ll measure in hardly the first quarter of a range, thus with a significantly lower resolution. For example instead of desired 4.001 V (3 decimal positions), you´ll only see 4.00V. Naturally, we don´t always need such a high resolution but many times an improvement of resolution in one magnitude can provide us a worth information about a real situation in a measured circuit. In these situations it often doesn´t matter on the absolute accuracy that much, but right on a resolution, especially when comparing voltages in two points, increase/ decrease…
From this point of view is the novelty in our stock UT139C an excellent device providing besides a high resolution (5999) also another features worth to notice, for example: TRUE RMS measurement in a range of 45Hz-1kHz (to 400 Hz with VFC filter activated), measuring of high-capacity capacitors up to 99.9 mF (99 999 uF), measuring of duty cycle in a range of 0.1% – 99.9% and other. Not quite common is also measuring of uA and mA even in AC range. Function Rel is useful even at measuring of small capacitors, where it´s able to eliminate “offset” caused by a capacitance of testing leads.
A thermometer (K type) with arrange of -40 to 1000°C can also be useful at development. From some point of view it´s advantageous supplying by two AA cells, not by a classic 9V battery (AA cells have a better capacity/ price ratio).
UT139C is also able to serve as a non-contact AC voltage tester (NCV), indicating in 4 steps a proximity of >100VAC voltage. . Indication is by a red LED in the upper part of display, by a display (-,–,—,—-) and by a buzzer.
Further information will provide you the UT139C datasheet.
With the UT139C you´ll find out why 5999 is better than 1999 - [Link]
A small, simple AM receiver project. This AM receiver can pick up medium wave stations in your area
This circuit can use general purpose transistors, and in this example there are 3 BC109C transistors. In this schematic and BOM there is a 200uH inductor and a trimmer 150-500pF capacitor, though these parts can be salvaged from an old AM radio, to preserve the directional nature of a tuning coil, and an adjustment knob (plate capacitor) that work well for radio reception.
The 120k resistor is for regenerative feedback between the Q2 NPN transistor and the input to the tank circuit. The value of this resistor is important to the performance of the entire circuit. In fact, it may be better to replace the fixed value with a variable resistor paired with a fixed resistor to adjust the oscillation and sensitivity of the circuit. All the connections in this circuit should be short to minimize interference.
Performance of the circuit will vary depending on stray capacitance in your layout, the inductor winding/core/length, etc. Changing values of some of the capacitors, or adding them, as well as a potentiometer in the feedback loop can help with the performance of the receiver. With such a small circuit that is affected so much by its construction and its environment, a lot of hand tuning and experimentation will be fun, instructive, and possibly necessary to make it work best.
Simple AM Receiver Project - [Link]
by Publitek European Editors:
Monitoring is the key to unlocking the energy production of the solar cell. It is easy to lose efficiency through the use of circuit architectures that assume constant energy production when the solar environment is constantly changing.
The change in current-voltage properties as a solar module heats up or receives more light can be an important source of efficiency losses in solar arrays. If the inverter that generates grid-compatible electricity is not tuned to the output voltage and current conditions, it will waste more of the electricity than it should. In response, electronics companies have produced ICs that perform the maximum power-point tracking (MPPT) needed to optimize energy conversion as well as bypass electronics to prevent temporarily unproductive modules from disrupting the output of active cells.
Maximizing the Output from Solar Modules - [Link]