Laptop batteries can be one of the most frustrating parts of an older laptop. They only last 15 minutes, or maybe only 2 seconds, perhaps explode, etc. I created this site to try to document and analyze these problems.
How notebook batteries work
The battery consists of a plastic outer case, metal electrical contacts, an inner metal case filled with a chemical and special electrical contacts called electrodes, and lastly, perhaps some control circuitry.
Note that the actual charging circuit is usually part of the laptop main board.
Battery chemistry
• Lithium Ion (LIon)
• Nickel Metal Hydride (NiMH)
• Others...
Control circuitryDifferent batteries may have none, some, or all of these circuits.
Overheat protection:
A thermal sensor and circuit cuts off charging and/or usage if the battery gets too hot.
Over-current / short-circuit protection:
Like a circuit breaker, if the current is too high this will cut off the electricity coming from the battery to prevent explosion or fire.
Over-discharge protection:
Certain battery chemistry, such as Lithium Ion, will break down if the battery gets discharged below a certain point. This circuit cuts off usage just before this point is reached.
Status meter / battery tester: Many modern battery have a button you can push, and a meter of LEDs will show you how charged the battery is.
Reconditioning: Battery performance can be improved through a process called reconditioning. This is usually a special pattern of charges and discharges designed to get the chemicals back to their original state. I suppose shaking might also be involved, as certain substances may build up near the electrodes inside.Case Studies & Anecdotes
Gataway Solo :
Fully charged, the charging circuit will not reactivate until after you have used the laptop under battery power. However, the battery slowly drains itself over time. The result is that if you have had the laptop plugged in to the AC for too long, the result will be a dead battery. The solution? Unplug the laptop from the AC for just a minute, and then reconnect. The battery will recharge.Additionally, when using the battery, the power level detected by Windows when the computer first comes on sometimes is very low, such as 5%, causing Windows to automatically go back into standby. However, by turning it on again, you discover that now the battery is almost fully changed.
HP Pavilion N5000 series (N5430)
By the end of the first year of use, the battery charge ended up only being good enough for 30 seconds of operation. :-/ Warranty service would have been a good idea.
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