Laptop Battery

HP clocks up 24-hour laptop battery life

2008-10-30T08:57:00.000-07:00

HP has beaten Dell - in the laptop battery longevity hype stakes, that is. It's produced a notebook with a full-day runtime, it claims - five hours longer than Dell's most recent battery life boast.

Register Hardware readers will not be surprised to learn there's a catch. Several catches, in point of fact.

First, you need to add an optional-extra secondary battery to the EliteBook 6930p to come within striking range of the claimed duration.

Punters will also need to make sure their 6930p uses not only one of Intel's new 80GB solid-state drives but also an "HP Illumi-Lite LED display". They'll have to run Windows XP - not Vista, you'll note; so much for the latest technology.

HP's EliteBook 6930p: all day runtime?

They'll also have to install new Intel graphics drivers - which presumably is pre-set to reduce the backlight and to perform other power-saving integrated GPU tweaks - and a new Bios from HP.

Do all that, and you might get you 24 hours of battery life. But not yet - HP's miracle screen, which "boosts battery run time by up to 4 hours compared to traditional LCD displays", won't be available as a system-configuration option until October.

HP also noted that "battery life will vary depending on the product model, configuration, loaded applications, features, and power management settings", so it's entirely possible you have to max out the laptop's power-conservation settings and turn the display down to its minimum brightness level to get the claimed runtime.

HP - as per all other laptop makers with the exception of Dell - didn't say how it had tested its machine to get the claimed battery life.

When Dell unveiled its 19-hour laptop - again, that's with an extra battery on board - it said it used the MobileMark benchmark to come up with that figure.

HP didn't say how much the suitably specced EliteBook will cost, but given the price of the Intel SSD, it's likely to be at least $600 on top of any given currently available 6930p HDD configuration.

By Tony Smith - reghardware.co.uk

Sharing battery knowledge

2008-10-30T08:54:00.002-07:00

It is my pleasure bringing to you Battery University, the institution for Learning the basics about batteries. In each of the short commentaries you will read about the best battery choices, new battery technologies and ways to make your batteries last longer. Practical, down-to-earth battery information is sometimes hard to find. Battery manufacturers are often too optimistic with their promises and only emphasize positive features.

I have a background in radio communications and studied the behavior of rechargeable batteries in practical, everyday applications for several decades. In desiring to share this battery knowledge with you; I wrote several articles addressing the strength and limitations of the battery. These articles have been published in various trade magazines in the USA, Canada and Europe. I later compiled the material and wrote my first book entitled Batteries in a Portable World - A Handbook on Rechargeable Batteries for Non-Engineers.

The 88-page first edition appeared in 1997 and covered such topics as the memory effect of nickel-cadmium batteries and how to restore them. Some readers commented that I favored nickel-cadmium over nickel-metal-hydride. Perhaps this observation is valid and I have taken note. Having been active in the mobile radio industry for many years, much emphasis is placed on battery longevity, a quality that is true of nickel-cadmium. Today's battery users prefer small size and want maximum runtime. Longevity may be less important, especially in the fast-moving consumer market.

The second edition of Batteries in a Portable World was published in 2001. With 18 Chapters and 300 pages, this book has been extended to include new battery technologies and various field applications.
In May 2001, the Battery Information Website www.buchmann.ca was launched, making the contents of the book available to the world at large. Battery articles have been added to complement the book and serve readers of non-English languages. A search engine was installed to help you find topics of interest. The Battery Information Website is sponsored by Cadex Electronics Inc., the manufacturer of advanced battery analyzers chargers and PC software.

Getting the Most from your Batteries has consistently been first choice. People want to know how to care for their batteries to get maximum runtime and dependable service. Proper Charge Methods is also very much in the hearts of the battery users. A surprise was Internal Battery Resistance in third position. This subject is of growing concern with digital equipment that puts high demands on the battery. A seemingly good battery often fails to deliver the heavy current bursts because of elevated internal resistance caused by aging batteries.

Battery University is based on the book Batteries in a Portable World and will address such issues as the choice of battery chemistries, physical battery packs, charge and discharge methods, runtime concerns, the 'smart' battery, internal battery resistance, getting the most of your batteries and much more.

Batteries in a Portable World is written for the non-engineer. It addresses the use of the battery in the hands of the general public, far removed from protected lab environments of the manufacturer. Some information contained in this book was obtained through tests performed in Cadex laboratories; other knowledge was gathered by simply talking to diverse groups of battery users. Not all views and opinions expressed in the book are based on scientific facts. Rather, they follow opinions of the general public, who use batteries. Some difference of opinion with the reader cannot be avoided. I am prepared to accept the blame for any discrepancies. The book is available from www.buchmann.ca at $29.50US
I would like to hear your comments on Battery University. After all, battery technology is not black and white but has many shades of gray. I hope you will find these lessons interesting and helpful.

About the Author
Isidor Buchmann is the founder and CEO of Cadex Electronics Inc., in Vancouver BC. Mr. Buchmann has a background in radio communications and has studied the behavior of rechargeable batteries in practical, everyday applications for two decades. Award winning author of many articles and books on batteries, Mr. Buchmann has delivered technical papers around the world.
Cadex Electronics is a manufacturer of advanced battery chargers, battery analyzers and PC software. For product information please visit www.cadex.com.

Zapping

2008-10-30T08:54:00.001-07:00

Zapping:
The process of applying a momentary high current pulse to a battery to improve performance. Zapping is said to improve new NiCd batteries but does not restore weak packs.

Voltage-limiting charger

2008-10-30T08:53:00.005-07:00

Voltage-limiting charger:
A charger that limits the maximum voltage to a battery but allows the current to drop towards the end of charge. A voltage-limiting charge may also include current-limiting. (Typically used on lead acid and Li?ion battery chargers).

Voltage limit

2008-10-30T08:53:00.003-07:00

Voltage limit:
The voltage value beyond which a battery is not permitted to rise on charge or fall on discharge.

Voltage delay

2008-10-30T08:53:00.001-07:00

Voltage delay:
During open circuit storage, some battery systems develop a passivation film on the surface of the active material. On the initial discharge, these batteries demonstrate a momentarily lower than normal voltage until this film is removed by the discharge.

Topping Charge

2008-10-30T08:52:00.005-07:00

Topping Charge:
To complete the fast charge, a topping charge is applied that continues charging the battery for 30 minutes or longer at a lower current. Typically used for nickel-based batteries.

Trickle charge

2008-10-30T08:52:00.003-07:00

Trickle charge:
Maintenance charge to compensate for the battery's self-discharge.

Thermal runaway

2008-10-30T08:52:00.001-07:00

Thermal runaway:
A condition whereby an electrochemical cell will overheat and destroy itself through internal heat generation. This may be caused by overcharge or high current discharge and other abusive conditions.

Thermal battery voltage

2008-10-30T08:51:00.004-07:00

Thermal battery voltage:
Batteries are non-linear systems. The equations, which govern the battery's response, becomes linear below 25mV/cell at 25°C. This voltage is called the battery thermal voltage.

System Management Bus (SMBus)

2008-10-30T08:51:00.003-07:00

System Management Bus (SMBus):
A commonly used protocol for the 'smart' battery.

Supercapacitor

2008-10-30T08:51:00.001-07:00

Supercapacitor:
A capacitor that can store a high amount of energy. Supercapacitors hold about one tenth the energy of a nickel or lithium-based battery.

Sulfation

2008-10-30T08:50:00.004-07:00

Sulfation:
The growth of lead sulfate crystals in lead acid batteries, which inhibits current flow. Sulfation is caused by storage at low state-of-charge.

State-of-Health (SoH)

2008-10-30T08:50:00.003-07:00

State-of-Health (SoH):
A measurement that reflects the state-of-health of a battery, taking into account charge acceptance, internal resistance, voltage and self-discharge.

State-of-Charge (SoC)

2008-10-30T08:50:00.001-07:00

State-of-Charge (SoC):
A measurement that reflects the state-of-charge of a battery. The SoC alone is not a valid indicator of the battery's runtime. The SoC readings will indicate 100 percent, even if a battery whose acceptance has dropped to 50 percent is fully charged.

Spinel

2008-10-30T08:49:00.004-07:00

Spinel:
A family of compounds that have a specific chemical structure. In lithium-ion batteries, the structure is manganese-based.

Spectroscopy

2008-10-30T08:49:00.003-07:00

Spectroscopy:
Same terminology as Electrochemical Impedance Spectroscopy.

Soft cell

2008-10-30T08:49:00.001-07:00

Soft cell:
A cell whose voltage rises above its defined boundaries during charging. This voltage rise may be caused by high cell impedance, cold battery temperature or lack of electrolyte.

'Smart' battery

2008-10-30T08:48:00.005-07:00

'Smart' battery:
Also known as an 'intelligent battery.' A battery pack containing internal circuitry that enables communication between the battery and the user.

Slow charge

2008-10-30T08:48:00.003-07:00

Slow charge:
Typically an over-night charge lasting 10 to 16 hours at a charge current of 0.1C. A battery does not require instant removal when fully charged.

Single wire bus

2008-10-30T08:48:00.001-07:00

Single wire bus:
Simplified 'smart' battery using only one wire for digital communications to the outside world.

Self-discharge

2008-10-30T08:47:00.003-07:00

Self-discharge:
Capacity loss during storage due to the internal leakage between the positive and negative cell plates.

Secondary battery

2008-10-30T08:47:00.001-07:00

Secondary battery:
A battery that is rechargeable by reversing its chemical reaction.

Reverse load charge

2008-10-30T08:46:00.004-07:00

Reverse load charge:
A charge method that intersperses discharge pulses between charge pulses to promote the recombination of gases generated during fast charge. Reverse load charge also helps to reduce memory.

Residual capacity

2008-10-30T08:46:00.003-07:00

Residual capacity:
The charge capacity remaining in a battery prior to charge.