ok batteries
The ‘smart’ battery
The battery has the inherit problem of not being able to communicate with the user. Neither weight, color, nor size provides an indication of the battery’s state-of-charge (SoC) and state-of-health (SoH). The user is at the mercy of the battery.
Help is at hand in breaking the code of silence. An increasing number of today’s rechargeable batteries are made ‘smart’. Equipped with a microchip, these batteries are able to communicate with the charger and user alike. Typical applications for ‘smart’ batteries are notebook computers and video cameras. Increasingly, these batteries are also used in biomedical devices and defense applications.
There are several types of ‘smart’ batteries, each offering different complexities and costs. The most basic ‘smart’ battery may contain nothing more than a chip that sets the charger to the correct charge algorithm. In the eyes of the Smart Battery System (SBS) forum, these batteries cannot be called ‘smart’.
What then makes a battery ‘smart’? Definitions still vary among organizations and manufacturers. The SBS forum states that a ‘smart’ battery must be able to provide SoC indications. In 1990, Benchmarq was the first company to commercialize the concept by offering fuel gauge technology. Today, several manufacturers produce such chips. They range from the single wire system, to the two-wire system to the System Management Bus (SMBus). Let’s first look at the single wire system.
The Single Wire Bus
The single wire system delivers the data communications through one wire. This battery uses three wires: the common positive and negative battery terminals and one single data terminal, which also provides the clock information. For safety reasons, most battery manufacturers run a separate wire for temperature sensing. Figure 1 shows the layout of a single wire system.
Figure 1: Single wire system of a ‘smart’ battery.Only one wire is needed for data communications. For safety reasons, most battery manufacturers run a separate wire for temperature sensing.
The single wire system stores the battery code and tracks battery readings, including temperature, voltage, current and SoC. Because of relatively low hardware cost, the single wire system enjoys market acceptance for high-end two-way radios, camcorders and portable computing devices.
Most single wire systems do not provide a common form factor; neither do they lend themselves to standardized SoH measurements. This produces problems for a universal charger concept. The Benchmarq single wire solution, for example, cannot measure the current directly; it must be extracted from a change in capacity over time. In addition, the single wire bus allows battery SoH measurement only when the host is ‘married’ to a designated battery pack. Such a fixed host-battery relationship is only feasible if the original battery is used. Any discrepancy in the battery will make the system unreliable or will provide false readings.
The SMBus
The SMBus is the most complete of all systems. It represents a large effort from the electronics industry to standardize on one communications protocol and one set of data. The Duracell/Intel SBS, which is in use today, was standardized in 1993. It is a two-wire interface system consisting of separate lines for the data and clock. Figure 2 shows the layout of the two-wire SMBus system.
Figure 2: Two-wire SMBus system.The SMBus is based on a two-wire system using a standardized communications protocol. This system lends itself to standardized state-of-charge and state-of-health measurements.
The objective behind the SMBus battery is to remove the charge control from the charger and assign it to the battery. With a true SMBus system, the battery becomes the master and the charger serves as slave that must follow the dictates of the battery.
Battery-controlled charging makes sense when considering that some packs share the same footprint but contain different chemistries, requiring alternative charge algorithms. With the SMBus, each battery receives the correct charge levels and terminates full-charge with proper detection methods. Future battery chemistries will be able to use the existing chargers.
An SMBus battery contains permanent and temporary data. The permanent data is programmed into the battery at the time of manufacturing and includes battery ID number, battery type, serial number, manufacturer’s name and date of manufacture. The temporary data is acquired during use and consists of cycle count, user pattern and maintenance requirements. Some of this information is renewed during the life of the battery.
The SMBus is divided into Level 1, 2 and 3. Level 1 has been eliminated because it does not provide chemistry independent charging. Level 2 is designed for in-circuit charging. A laptop that charges its battery within the unit is a typical example of Level 2. Another Level 2 application is a battery that contains the charging circuit within the pack. Level 3 is reserved for full-featured external chargers.
External Level 3 chargers are complex and expensive. Some lower cost chargers have emerged that accommodate SMBus batteries but are not fully SBS compliant. Manufacturers of SMBus batteries do not fully endorse this shortcut. Safety is always a concern, but customers buy them because of low cost. Serious industrial battery users operating biomedical instruments, data collection devices and survey equipment use Level 3 chargers with full-fledged charge protocol.
Among the most popular SMBus batteries are the 35 and 202 form-factors (Figure 3). Manufactured by Sony, Hitachi, GP Batteries, Moli Energy and others, these batteries work (should work) in all portable equipment designed for this system. Although the 35 has a smaller footprint than the 202, most chargers accommodate both sizes. A non-SMBus (‘dumb’) version with same footprint is also available. These batteries can only be charged with a regular charger, or one that accepts both types.
Figure 3: 35 and 202 series ‘smart’ batteries featuring SMBus.Available in nickel-cadmium, nickel-metal-hydride and lithium-ion chemistries, these batteries are used for laptops, biomedical instruments and survey equipment. A non-SMBus (‘dumb’) version with same footprint is also available.
In spite of the agreed standard and given form factors, many computer manufacturers have retained their proprietary batteries. Safety, performance and form factor are the reasons. They argue that enduring performance can only be guaranteed if their own brand battery is used. This makes common sense but the leading motive may be pricing. In the absence of competition, these batteries can be sold for a premium price.
Negatives of the ‘smart’ battery
The ‘smart’ battery has some notable downsides, one of which is price. An SMBus battery costs about 25% more than the ‘dumb’ equivalent. In addition, the ‘smart’ battery was intended to simplify the charger but a full-fledged Level 3 charger costs substantially more than a regular model.
A more serious drawback is the requirements for periodic calibration or capacity re-learning. The Engineering Manager of Moli Energy, a manufacturer of lithium-ion cell commented, “With lithium-ion we have eliminated the memory effect; but is the SMBus battery introducing digital memory?”
Why is calibration needed? The calibration corrects the tracking errors that occur between the battery and the digital sensing circuit while charging and discharging. The most ideal battery application, as far as fuel-gauge accuracy is concerned, would be a full charge followed by a full discharge at a constant current. In such a case, the tracking error would be less than 1% per cycle. In real life, however, a battery may be discharged for only a few minutes and the load pulses may be very short. Long storage also contributes to errors because the circuit cannot accurately compensate for self-discharge. Eventually, the true capacity of the battery no longer synchronizes with the fuel gauge and a full charge and discharge is needed to ‘re-learn’ the battery.
How often is calibration needed? The answer lies in the battery application. For practical purposes, a calibration is recommended once every three months or after every 40 short cycles. Many batteries undergo periodic full discharges as part of regular use. If the portable device allows a deep enough discharge to reset the battery and this is done regularly, no additional calibration is needed. However, if no discharge reset has occurred for a few months, a deliberate full discharge is needed. This can be done on a charger with discharge function or a battery analyzer.
What happens if the battery is not calibrated regularly? Can such a battery be used in confidence? Most ‘smart’ battery chargers obey the dictates of the chemical cells rather than the electronic circuit. In this case, the battery will fully charge regardless of the fuel gauge setting and function normally, but the digital readout will become inaccurate. If not corrected, the fuel gauge simply becomes a nuisance.
An addition problem with the SMBus battery is non-compliance. Unlike other tightly regulated standards, the SMBus protocol allows some variations. This may cause problems with existing chargers and the SMBus battery should be checked for compatibility before use. The need to test and approve the marriage between a specific battery and charger is unfortunate, given the assurance that the SMBus battery is intended to be universal. Ironically, the more features offered on the SMBus charger and the battery, the higher the likelihood of incompatibilities.
more hight quality Sony VGP-BPS2, VGP-BPS2A, VGP-BPS2B, VGP-BPS2C batteries.
pls visit our website: www.ok-battery.co.uk
About the Author
www.ok-battery.co.uk are a manufacturing representative and distributor of sony batteries, sony battery chargers, sony Auto(DC) adapters and sony laptop AC adapters. We specialize in the distribution of leading edge technology sony battery packs for sony notebook computers, sony camcorders, sony digital cameras, sony mobile phone battery, sony PDA battery and sony battery charger.
|
|
Oakton EcoTestr pH 2 Waterproof pH Tester, -1.0 to 15.0 pH Range $57.95 Simply dip and read— the orientation of the display means no need to turn your head or tilt the tester. This low-cost meter is perfect for most applications. The single-junction electrode is recessed to protect against breakage. The unit offers up to three-point calibration with auto-buffer recognition for quick calibrations, automatic temperature compensation for accurate reading under chang… |
|
|
Adam Equipment WBW Washdown Bench Scale The Adam Equipment WBW is designed for food, agriculture, and other wash down applications. Ideal for food preparation, food processing plants, agricultural facilities, and more, WBW scales feature an IP65 rated wash down housing and a large stainless steel weighing pan. Color indicators for Under, Ok, and Over limits make check weighing fast and easy, and a brilliant backlit LCD with capacity tra… |
|
|
DEWALT DC970K-2 18-Volt Drill/Driver Kit $118.99 DEWALT’s DC970K-2 18-volt cordless 1/2-inch compact drill driver kit is perfect for anyone looking for a compact tool capable of drilling and driving in tight spaces that other tools cannot reach. The lightweight design of the DC970K-2 makes it extremely comfortable to use. Despite the compact design, this drill/driver makes no sacrifice of power and also features a 1/2-inch single-sleeve keyles… |
|
|
DEWALT Bare-Tool DC825B 1/4-Inch 18-Volt Cordless Impact Driver $197.00 DC825B – 3/4″ (6.4mm) 18V Cordless Impact Driver (Tool Only). Frameless motor for extended tool durability and life. Compact size and weight allow access into tighter areas and reduces user fatigue. 1,330 in-lbs of torque to perform a wide range of fastening applications. 0-2,400 rpm/0-2,700 ipm for faster application speed. Replaceable brushes for increased serviceability. Textured anti-sli… |
|
|
Compaq Laptop AC Adapter 163444-001, 179725-003, PPP005L $1.06 [Compatible Compaq Model Number:] ** Compaq Armada Series: 110, 110S, E500, E500s, E700, M300, M700, V300 ** Compaq Business Notebook Series: 2510p, NC2400, NC4000, NC4010, NC4200, NC4400, NC6000, NC6110, NC6120, NC6125, NC6140, NC6220, NC6230, NC6320, NC6320, NC6325, NC6400, NC8000, NC8230, NW8000, NW8200, NW8440, NX4800, NX5000, NX6110, NX6120, NX6125, NX6310, NX6315, NX6320, NX6325, NX7000, Se… |
|
|
Philips Sonicare HX6311/02 Sonicare for Kids Rechargeable Electric Toothbrush $39.99 Finally a Sonicare for your kids! Philips Sonicare, makers of the #1 recommended power toothbrush brand by dental professionals, introduces Sonicare For Kids! Using the same patented sonic technology that Sonicare is famous for, Sonicare For Kids is designed especially to encourage healthy brushing habits in growing kids while delivering outstanding results- even when they are brushing on their ow… |
|
|
DURACELL 9 Volt PROCELL Professional Alkaline Battery, Pack of 12 $14.39 Duracell ProCell alkaline batteries…. |
|
|
Swiffer WetJet Spray, Mop Floor Cleaner Starter Kit (Packaging May Vary) $18.00 Swiffer WetJet Starter Kit includes 1 power mop, 2 absorbent pads and multi-purpose cleaning solution. Features new & improved dual nozzle sprayer…. |
|
|
Jabra CRUISER2 Bluetooth In-Car Speakerphone $50.57 JABRA 100-47200000-02 CRUISER2 SPEAKERPHONECALLER ID ANNOUNCED CALLER’S NAME; SUPERIOR SOUND WITH DUAL MICROPHONE TECHNOLOGY ; SIMPLE SETUP WITH NO INSTALLATION NEEDED; MULTI USE… |
|
|
Battery Tender Waterproof Jr. Motorcycle Battery Charger $52.95 12V-800mA charger is 100% waterproof, lightweight and compactThree-step constant current charge program with SuperSmart technologySpark-proofShort circuit and reverse polarity protectedWeighs just 1 lb…. |
|
|
BlueAnt Supertooth 3 Bluetooth Hands-Free Speakerphone (Black) $47.99 Keeping your hands on the wheel & your eyes on the roadThe BlueAnt Supertooth 3 handsfree speakerphone provides a safer, legal alternative to talking on your cell phone while you drive. Voice prompts provide assistance to help you connect the device with your phone and upload your address book. The Supertooth 3 announces the name or ID of the caller when the phone rings – just say ‘OK’ to accept t… |
|
|
Ear Force X12 Gaming Headset and Amplified Stereo Sound $43.99 The definitive headset for gamers seeking amazing game sound crystal-clear munication and enhanced fort all at an unmatched valueFeatures massive 50mm speakers delivering superior audio quality with crisp highs and deep rumbling lowsEnhances game sounds for a more immersive gaming experienceIndependent controls allow for quick adjustments to game audio and chat volumesUSB powered: no AC adapters o… |
|
|
CTA Digital Nintendo 3Ds External Power Supply and Charging Dock $19.46 LED CHARGE INDICATOR LIGHTSDOCK’S INTERNAL BATTERY TO POWER 3DS ALLOWS USERS TO RECHARGE 3DS WHEN ON THE GOGIVES EXTRA POWER FOR 3DS WHEN NOT NEAR A POWER SOURCEINTEGRATED STAND TO ADJUST VIEWING ANGLEUPC : 656777011789Shipping Dimensions : 6.15in X 4.15in X 1.55inEstimated Shipping Weight : 0.35… |
|
|
Wii Remote Quadruple Charge Station with 4 Rechargeable Batteries $14.99 Recharge four Wii Remotes simultaneously with the Quadruple Remote Charging Cradle from CTA Digital. This charge station contains a four-space cradle that allows you to charge and rest four remotes in an upright position…. |
|
|
Great American Battles Of The Civil War $42.19 Re-create the tactics of the great Civil War generals at Gettysburg and Shiloh with the Great American Battles Of The Civil War two-disk set from Mindscape. The software loads easily, providing intuitive game controls. Though the manual is a bit skimpy, you’ll pick up the rules quickly, finding yourself maneuvering units just like Grant and Lee. The emphasis here is on small-scale tactical combat,… |
|
|
Techno Earth® NEW Apple 13 Macbook Rechargeable Battery A1185 White (equivalent) $32.46 Products trademarked Techno Earth are marketed and sold exclusively by Techno Earth. High Quality. Specially for more convenient and safe work.Also compatible with Techno Earth® Newly listedNEW Apple 13″ Macbook Rechargeable Battery A1185 White (equivalent)… |
|
|
AC Adapter Charger A1021 for Apple, iBook G4, PowerBook G4, 12 15 17 14 (24.5V, 2.65A, 65W) $1.34 Important: Compatible with PowerBook G4 (Aluminum or Titanium models) or dual-USB iBook (500Mhz Power PC G3 or higher)…. |
|
|
Microsoft 39303 Laptop Backpack – Everest (Black/Gray) $58.99 Everest Laptop Backpack is constructed of 1680D poly with vinyl accents. This backpack features a padded sleeve to hold laptops up to 15.4″ and a zipper pocket for cord and battery storage. Front zipper pocket with digital accessory pocket. Outside mesh pockets and back zipper security pocket. Large center compartment with mesh pocket holds books, files, clothes. Also includes a drop pocket for ke… |
|
|
Timex Ironman Triathlon Sleek TapScreen 150 Lap Watch This cutting-edge performance watch allows you to access information without breaking your stride, giving you the edge when every second counts. TapScreen Technology logs split times with one firm tap on the watch face. Glancing at the oversized display, or listening to the audible alarms then provides real-time performance feedback. Features – INDIGLO Night-Light with Night-Mode – TapScreen Tec… |
|
|
Black carrying case for The OK Electronic Cigarette Decorative Leather Bound Carrying Case for The OK Super Mini Cigarette makes it easy to carry The OK Super Miini Cigarette in your pocket or purse. Available in Red or Black. *Cigarette and Battery Sold Separately*… |
|
|
LeapFrog My Own Leaptop $18.25 Personalize pretend computer play with My Own Leaptop™! Choose and download songs for a custom playlist, explore 6 learning activity stations and personalize emails for your child to enjoy!Parents can connect to the online LeapFrog® Learning Path for customized learning insights and ideas to expand the learning. Product Measures: 8.98″ x 7″ x 1.45″ Recommended Ages: 2 years – 4 … |
|
|
OK to Wake! Children’s Alarm Clock and Nightlight $29.88 Onaroo OK to Wake! Alarm Clock and Night-LightOK to Wake! glows green when it’s time for young kids to go see mom and dad in the morning! For parents, every extra minute of sleep is a luxury. OK to Wake! really works – kids are excited to wait for the green light while parents get some extra shut-eye…. |
|
|
Oakton EcoTestr pH 2 Waterproof pH Tester, -1.0 to 15.0 pH Range $57.95 Simply dip and read— the orientation of the display means no need to turn your head or tilt the tester. This low-cost meter is perfect for most applications. The single-junction electrode is recessed to protect against breakage. The unit offers up to three-point calibration with auto-buffer recognition for quick calibrations, automatic temperature compensation for accurate reading under chang… |
|
|
Adam Equipment WBW Washdown Bench Scale The Adam Equipment WBW is designed for food, agriculture, and other wash down applications. Ideal for food preparation, food processing plants, agricultural facilities, and more, WBW scales feature an IP65 rated wash down housing and a large stainless steel weighing pan. Color indicators for Under, Ok, and Over limits make check weighing fast and easy, and a brilliant backlit LCD with capacity tra… |
|
|
DEWALT DC970K-2 18-Volt Drill/Driver Kit $118.99 DEWALT’s DC970K-2 18-volt cordless 1/2-inch compact drill driver kit is perfect for anyone looking for a compact tool capable of drilling and driving in tight spaces that other tools cannot reach. The lightweight design of the DC970K-2 makes it extremely comfortable to use. Despite the compact design, this drill/driver makes no sacrifice of power and also features a 1/2-inch single-sleeve keyles… |
|
|
DEWALT Bare-Tool DC825B 1/4-Inch 18-Volt Cordless Impact Driver $197.00 DC825B – 3/4″ (6.4mm) 18V Cordless Impact Driver (Tool Only). Frameless motor for extended tool durability and life. Compact size and weight allow access into tighter areas and reduces user fatigue. 1,330 in-lbs of torque to perform a wide range of fastening applications. 0-2,400 rpm/0-2,700 ipm for faster application speed. Replaceable brushes for increased serviceability. Textured anti-sli… |
|
|
Compaq Laptop AC Adapter 163444-001, 179725-003, PPP005L $1.06 [Compatible Compaq Model Number:] ** Compaq Armada Series: 110, 110S, E500, E500s, E700, M300, M700, V300 ** Compaq Business Notebook Series: 2510p, NC2400, NC4000, NC4010, NC4200, NC4400, NC6000, NC6110, NC6120, NC6125, NC6140, NC6220, NC6230, NC6320, NC6320, NC6325, NC6400, NC8000, NC8230, NW8000, NW8200, NW8440, NX4800, NX5000, NX6110, NX6120, NX6125, NX6310, NX6315, NX6320, NX6325, NX7000, Se… |
|
|
Microsoft 39303 Laptop Backpack – Everest (Black/Gray) $58.99 Everest Laptop Backpack is constructed of 1680D poly with vinyl accents. This backpack features a padded sleeve to hold laptops up to 15.4″ and a zipper pocket for cord and battery storage. Front zipper pocket with digital accessory pocket. Outside mesh pockets and back zipper security pocket. Large center compartment with mesh pocket holds books, files, clothes. Also includes a drop pocket for ke… |
|
|
Timex Ironman Triathlon Sleek TapScreen 150 Lap Watch This cutting-edge performance watch allows you to access information without breaking your stride, giving you the edge when every second counts. TapScreen Technology logs split times with one firm tap on the watch face. Glancing at the oversized display, or listening to the audible alarms then provides real-time performance feedback. Features – INDIGLO Night-Light with Night-Mode – TapScreen Tec… |
