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Laptop power question 2: dead battery
Hi again,
If a laptop battery is dead, like mine which holds about 45 seconds of power, are there power advantages to running the laptop without the battery installed? For example: Will it draw less power; be more stable? I suppose indirectly I'm asking how does a laptop treat a diminished capacity battery: will it treat it as simply a lower capacity and once it's been filled with charge just leave it or will in constantly be trying to charge it to somewhere near it's original capacity? Thanks |
#2
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Laptop power question 2: dead battery
Keiron wrote:
Hi again, If a laptop battery is dead, like mine which holds about 45 seconds of power, are there power advantages to running the laptop without the battery installed? For example: Will it draw less power; be more stable? I suppose indirectly I'm asking how does a laptop treat a diminished capacity battery: will it treat it as simply a lower capacity and once it's been filled with charge just leave it or will in constantly be trying to charge it to somewhere near it's original capacity? Thanks Some charging circuits are intelligent enough, to not attempt to charge a flat battery. http://www.batteryuniversity.com/partone-12.htm "The safety circuit is designed to cut off the current path if the battery is inadvertently discharged below 2.50V/cell. At this voltage, most circuits render the battery unserviceable and a recharge on a regular charger is not possible." I have no idea what a laptop uses for charging, but it does have to be careful with that kind of battery. Paul |
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Laptop power question 2: dead battery
"Paul" wrote in message
... Keiron wrote: Hi again, If a laptop battery is dead, like mine which holds about 45 seconds of power, are there power advantages to running the laptop without the battery installed? For example: Will it draw less power; be more stable? I suppose indirectly I'm asking how does a laptop treat a diminished capacity battery: will it treat it as simply a lower capacity and once it's been filled with charge just leave it or will in constantly be trying to charge it to somewhere near it's original capacity? Thanks Some charging circuits are intelligent enough, to not attempt to charge a flat battery. http://www.batteryuniversity.com/partone-12.htm "The safety circuit is designed to cut off the current path if the battery is inadvertently discharged below 2.50V/cell. At this voltage, most circuits render the battery unserviceable and a recharge on a regular charger is not possible." I have no idea what a laptop uses for charging, but it does have to be careful with that kind of battery. Presumably if in doubt then its better to take the battery out? -- Brian Cryer http://www.cryer.co.uk/brian |
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Laptop power question 2: dead battery
On 09/28/2010 03:33 AM, Keiron wrote:
Hi again, If a laptop battery is dead, like mine which holds about 45 seconds of power, are there power advantages to running the laptop without the battery installed? For example: Will it draw less power; be more stable? I suppose indirectly I'm asking how does a laptop treat a diminished capacity battery: will it treat it as simply a lower capacity and once it's been filled with charge just leave it or will in constantly be trying to charge it to somewhere near it's original capacity? Thanks I also have a laptop with a very weak battery but just leave it in. In the event of a short power failure... the laptop at least will not cut out. When I'm done using it...it just turn off the power at the strip |
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Laptop power question 2: dead battery
On Tue, 28 Sep 2010 05:01:12 -0400, Paul wrote:
Keiron wrote: Hi again, If a laptop battery is dead, like mine which holds about 45 seconds of power, are there power advantages to running the laptop without the battery installed? For example: Will it draw less power; be more stable? I suppose indirectly I'm asking how does a laptop treat a diminished capacity battery: will it treat it as simply a lower capacity and once it's been filled with charge just leave it or will in constantly be trying to charge it to somewhere near it's original capacity? Thanks Some charging circuits are intelligent enough, to not attempt to charge a flat battery. http://www.batteryuniversity.com/partone-12.htm "The safety circuit is designed to cut off the current path if the battery is inadvertently discharged below 2.50V/cell. At this voltage, most circuits render the battery unserviceable and a recharge on a regular charger is not possible." This has to be for a battery charger that is doing nothing but charging a battery. I have no idea what a laptop uses for charging, but it does have to be careful with that kind of battery. Paul But a laptop power supply isn't just charging the battery, it's powering the computer, and for sure it's doing so when the output voltage of the battery would be very low. So it can't turn off or the computer would not work. Some circuit might interrupt battery charging, but the circuit would have to be in the laptop, and I don't think it would be practical, since most people have no other way to charge their laptop battery except in the laptop, and if the the charger wouldnt' work at very low battery voltage, what would the user do. And at least there should be warnings about this. My IBM Thinkpad battery would only power the computer for 30 seconds iirc, but it still needed to be recharged, or it wouldn't do that. 30 seconds was enough to unplug the cord and move to another nearby electrical outlet, so I valued those 30 seconds (later 15 iirc.) I'll go back to asking questions and lurking now. |
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Laptop power question 2: dead battery
mm wrote:
On Tue, 28 Sep 2010 05:01:12 -0400, Paul wrote: Keiron wrote: Hi again, If a laptop battery is dead, like mine which holds about 45 seconds of power, are there power advantages to running the laptop without the battery installed? For example: Will it draw less power; be more stable? I suppose indirectly I'm asking how does a laptop treat a diminished capacity battery: will it treat it as simply a lower capacity and once it's been filled with charge just leave it or will in constantly be trying to charge it to somewhere near it's original capacity? Thanks Some charging circuits are intelligent enough, to not attempt to charge a flat battery. http://www.batteryuniversity.com/partone-12.htm "The safety circuit is designed to cut off the current path if the battery is inadvertently discharged below 2.50V/cell. At this voltage, most circuits render the battery unserviceable and a recharge on a regular charger is not possible." This has to be for a battery charger that is doing nothing but charging a battery. I have no idea what a laptop uses for charging, but it does have to be careful with that kind of battery. Paul But a laptop power supply isn't just charging the battery, it's powering the computer, and for sure it's doing so when the output voltage of the battery would be very low. So it can't turn off or the computer would not work. Some circuit might interrupt battery charging, but the circuit would have to be in the laptop, and I don't think it would be practical, since most people have no other way to charge their laptop battery except in the laptop, and if the the charger wouldnt' work at very low battery voltage, what would the user do. And at least there should be warnings about this. My IBM Thinkpad battery would only power the computer for 30 seconds iirc, but it still needed to be recharged, or it wouldn't do that. 30 seconds was enough to unplug the cord and move to another nearby electrical outlet, so I valued those 30 seconds (later 15 iirc.) I'll go back to asking questions and lurking now. I don't know anything about the charging policy. I have a grand total so far, of one laptop schematic here, and it's a joke of a schematic. So I'm no further ahead on getting info on the topic. The charging circuit has to follow safe practice, whatever that is. On some battery types, you could dump charging current into them (in vain), for as long as you want. A NiCD with a dead short inside, probably doesn't care that you're trying to charge it. Lithium chemistry could be different, and that's why I selected the batteryuniversity article as an example. The laptop does have sophisticated power management in it, and it isn't a dumb charger like the one on my cordless screwdriver. The dumb chargers definitely damage batteries, but the battery type is such there are no safety issues, only cost of replacement as an issue. Paul |
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