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#1
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Stop dischargie of laptop battery by disconnecting?
I pretty much only use my laptop when I go out of town, so that means
I don't use it for months at a time sometimes, and even if it was 100% charged last time I used it, it's as little as 1% (or 0%?) charged after 4 months. That's bad for me and the battery too, I think. Can I stop the discharge of laptop battery by disconnecting it? It's easy to do since the battery is not under a cover, its at the edge, above the keyboard, and two plastic sliders release it, and it plugs back in even more quickly. It's an ACER Aspire. Thanks. |
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#2
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Stop dischargie of laptop battery by disconnecting?
Not all, but as far as I know, most laptop batteries have
protection circuitry in the battery itself that slowly drains the charge. The effect this has depends heavily on the condition of the battery and the the individual design and specs. At the end of the day, batteries always loose charge over long periods of time (whether used or not), and it gets worse as they get older. Perhaps get a new battery, or leave the laptop plugged into a power point timer set to turn on the power supply and give the battery a little charge for half an hour a day (or week etc.). -- __ __ #_ |\| | _# |
#3
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Stop dischargie of laptop battery by disconnecting?
On 11/14/2013 4:53 PM, micky wrote:
I pretty much only use my laptop when I go out of town, so that means I don't use it for months at a time sometimes, and even if it was 100% charged last time I used it, it's as little as 1% (or 0%?) charged after 4 months. That's bad for me and the battery too, I think. Can I stop the discharge of laptop battery by disconnecting it? It's easy to do since the battery is not under a cover, its at the edge, above the keyboard, and two plastic sliders release it, and it plugs back in even more quickly. It's an ACER Aspire. Thanks. Executive summary: If you expect to get on a plane and write a memo after 4 months of disuse, you're likely to be disappointed. I'd charge it, run it down and charge it again before the trip, no matter what the battery gauge says. YMMV. You'd have to give the exact model number to get much relevant help. Battery management is a crap shoot. I've got a Toshiba that cautions do not leave the charger connected when you're not using the laptop. That's a BAD design. One school of thought says charge it every week whether you use it or not. Some laptops put way more load on the battery than others when off. In general, if it's lithium, the battery power management IC won't drain it fast, but it will discharge over long periods. You can improve the self discharge of the cells by storing it in the fridge...NOT THE FREEZER". But that won't help the tiny drain of the battery management computer. But that's not the only issue. There's a battery or capacitor or something in the laptop that maintains the clock when you remove the battery. Leave the battery out too long, (too long varies from minutes to months) the clock and cmos configuration info get lost. A minor annoyance if that internal battery is rechargeable. Major annoyance if it's a coin cell that requires laptop disassembly to replace. |
#4
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Stop dischargie of laptop battery by disconnecting?
Computer Nerd Kev wrote:
Not all, but as far as I know, most laptop batteries have protection circuitry in the battery itself that slowly drains the charge. The effect this has depends heavily on the condition of the battery and the the individual design and specs. Reference???? What "battery protection circuitry" IN a battery? |
#5
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Stop dischargie of laptop battery by disconnecting?
On 15 Nov 2013, Bill in Co wrote:
Computer Nerd Kev wrote: Not all, but as far as I know, most laptop batteries have protection circuitry in the battery itself that slowly drains the charge. The effect this has depends heavily on the condition of the battery and the the individual design and specs. Reference???? What "battery protection circuitry" IN a battery? Lithium Ion batteries like to get hot and catch fire if they are charged when the voltage if too low. So there is some small circuitry to monitor this voltage and prevent charging when it is below a set threshold (and discharging below it, although the circuitry itself drains a small amount of current and thus over time self-sabotages this function (lesson of the day: keep your Li-Ion batteries charged (actually applies to a lot of batteries))). In addition, some also protect against excessive current draw or heating by disabling the voltage output when sensor readings exceed pre-set values. References? Oh all right: http://batteryuniversity.com/learn/a...y_circuits_for _modern_batteries Why I say not all laptop Li-Ion batteries have this circuitry: http://www.fonerbooks.com/laptop_3.htm http://www.thinkwiki.org/wiki/Batteries -- __ __ #_ |\| | _# |
#6
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Stop dischargie of laptop battery by disconnecting?
On 11/14/2013 6:08 PM, Bill in Co wrote:
Computer Nerd Kev wrote: Not all, but as far as I know, most laptop batteries have protection circuitry in the battery itself that slowly drains the charge. The effect this has depends heavily on the condition of the battery and the the individual design and specs. Reference???? What "battery protection circuitry" IN a battery? Like virtually every lithium battery made? google bq29311 for an example. Or pop the battery out of your cellphone. You're holding one in your hand. |
#7
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Stop dischargie of laptop battery by disconnecting?
micky wrote:
I pretty much only use my laptop when I go out of town, so that means I don't use it for months at a time sometimes, and even if it was 100% charged last time I used it, it's as little as 1% (or 0%?) charged after 4 months. That's bad for me and the battery too, I think. Can I stop the discharge of laptop battery by disconnecting it? It's easy to do since the battery is not under a cover, its at the edge, above the keyboard, and two plastic sliders release it, and it plugs back in even more quickly. It's an ACER Aspire. My guess is your battery is old, like 3 years, or more. It isn't retaining a charge plus being old means it can't store as much a charge. The older the rechargeable battery then the less it will hold. Also, there is reduction/degradation with an increased number of charge cycles, so the more often you recharge the weaker (less total charge) the battery becomes. Laptop batteries have a lifetime of around 400 charge cycles. Over time, capacity wanes. With recharging, capacity wanes. Consider the battery a physical component that encounters wear (chemical instead of abrasive). Expect to replace the battery after 3 years (sometimes only 2 for less quality units). The battery won't last forever. Don't believe me? Then go read what others state, like: http://www.dell.com/content/topics/g...=en&cs=04#faq1 http://www.ehow.com/decision_7231941...ies-last_.html http://www.maximumpc.com/article/fea...able_batteries (sorry, don't remember the white paper that delved deeply into how these batteries operate, that lithiums do have a memory but not like nicads, why recharging reduces capacity, why age reduces capacity, and why 3% is considered the bottommost charge level at which a lithium should be stored). Do not allow lithium batteries to go under 3% charge. Add a reminder to your calendar to check the charge of your rechargeable batteries. If the charge remaining is above 3% then change the reminder's recurrence to every 2 months. Keep increasing the recurrence interval for the reminder until the battery approaches 3%. I'd probably not go under 10%. Then shorten the recurrence by a month and thereafter recharge the battery to full charge. Unlike nicads, there is no point in discharging (to 3%, not a full discharge) and then recharging (i.e., don't cycle the battery) since lithiums don't have a memory like nicads, plus you want to minimize how many times you recharge. That's why, for example, you don't discharge your cell phone to charge it up. You just charge it up from whatever state it is currently. The only reason to do a cycle charge (discharge to 3% and then recharge) to recalibrate the power level monitor, if and when needed. The cycle charge is for the logic, not the battery itself. If it's an old battery (over 2 years and especially over 3 years) then start hunting around for a replacement. |
#8
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Stop dischargie of laptop battery by disconnecting?
Bill in Co wrote:
Computer Nerd Kev wrote: Not all, but as far as I know, most laptop batteries have protection circuitry in the battery itself that slowly drains the charge. The effect this has depends heavily on the condition of the battery and the the individual design and specs. Reference???? What "battery protection circuitry" IN a battery? How many contacts are on the battery interface ? Only two would be needed, if it was "just a battery". There are multiple pins on the connector, implying it is "smart". Only an older battery technology, one that doesn't catch fire, could be more careless. Like NiCD batteries that swell or leak, nothing bad could happen there :-) Lithium on the other hand, is nothing to be toyed with. In this example, there are connections for the current carrying part of the battery, plus digital connections for SMBus. The laptop can talk to the battery, and get status information. And the status information could say "too low for safety". It's not like the chip in the battery necessarily breaks a connection with a series pass transistor or anything. But the pinout here suggests the laptop can query information from the battery monitor chip. http://www.allpinouts.org/index.php/...0_D600_battery The battery monitor chip really doesn't need to do anything when it is not running. But as soon as a clock signal appears, then the logic inside can be used to do stuff. Such as measure the overall battery voltage or temperature or whatever. The battery does have "dumb" physical features, to protect the battery. But once activated, the battery is toast. http://batteryuniversity.com/learn/a...dern_batteries "a circuit interrupt device (CID) that opens the electrical path if an over-charge raises the internal cell pressure to 1000 kPa (145psi)" The CID inside the battery, is shown here. http://www.ntsb.gov/investigations/f.../HZB0501_6.JPG "Figure 6. Lithium-ion cell with safety devices. A: The disc is a temperature-sensitive polymer that resists electron flow as the temperature increases. [PTC ???] B: The CID opens with internal pressure breaking the cell circuit. C: Increased pressure causes the CID to vent to the cap. D: A polymer sheet between the anodic and cathodic foils melts at a given temperature, stopping the electron flow " HTH, Paul |
#9
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Stop dischargie of laptop battery by disconnecting?
In Computer Nerd Kev
wrote: Not all, but as far as I know, most laptop batteries have protection circuitry in the battery itself that slowly drains the charge. All chemical batteries, LiIon or otherwise, self-discharge without the help of any external circuitry. If you choose to believe Wikipedia, it says "Li+ batteries have a self-discharge rate of approximately 5–10% per month" https://en.wikipedia.org/wiki/Lithium-ion_battery -- St. Paul, MN |
#10
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Stop dischargie of laptop battery by disconnecting?
Paul wrote:
Only an older battery technology, one that doesn't catch fire, could be more careless. Like NiCD batteries that swell or leak, nothing bad could happen there :-) Lithium on the other hand, is nothing to be toyed with. Yep, lithiums can cause a fire. http://www.youtube.com/watch?v=vS6KA_Si-m8 The first was a recorded fire at LAX. I can't tell for sure if the cord from the laptop was for charging. The other fires shown were induced but show that Li packs will not only catch fire when overheated but sustain a fire and are explosive. http://www.youtube.com/watch?v=pizFsY0yjss Anything that overheats the Li battery causes it to go aflame. That includes trying to charge a bad Li battery assuming the protection circuitry doesn't prevent the problem of overheating. http://www.youtube.com/watch?v=fG_UuPmLO1c More than just physical damage can result if your laptop gets ran over. http://www.youtube.com/watch?v=-DcpANRFrI4 Fire from overcharging a Li battery pack. http://www.youtube.com/watch?v=jX51jVVPCSA And you thought buying fireworks in your state was illegal. |
#11
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Stop dischargie of laptop battery by disconnecting?
mike wrote:
On 11/14/2013 6:08 PM, Bill in Co wrote: Computer Nerd Kev wrote: Not all, but as far as I know, most laptop batteries have protection circuitry in the battery itself that slowly drains the charge. The effect this has depends heavily on the condition of the battery and the the individual design and specs. Reference???? What "battery protection circuitry" IN a battery? Like virtually every lithium battery made? google bq29311 for an example. Or pop the battery out of your cellphone. You're holding one in your hand. I think that bq29311 is a battery protection IC, and is not inside the battery, no? |
#12
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Stop dischargie of laptop battery by disconnecting?
Computer Nerd Kev wrote:
On 15 Nov 2013, Bill in Co wrote: Computer Nerd Kev wrote: Not all, but as far as I know, most laptop batteries have protection circuitry in the battery itself that slowly drains the charge. The effect this has depends heavily on the condition of the battery and the the individual design and specs. Reference???? What "battery protection circuitry" IN a battery? Lithium Ion batteries like to get hot and catch fire if they are charged when the voltage if too low. So there is some small circuitry to monitor this voltage and prevent charging when it is below a set threshold (and discharging below it, although the circuitry itself drains a small amount of current and thus over time self-sabotages this function (lesson of the day: keep your Li-Ion batteries charged (actually applies to a lot of batteries))). In addition, some also protect against excessive current draw or heating by disabling the voltage output when sensor readings exceed pre-set values. References? Oh all right: http://batteryuniversity.com/learn/a...y_circuits_for _modern_batteries Why I say not all laptop Li-Ion batteries have this circuitry: http://www.fonerbooks.com/laptop_3.htm http://www.thinkwiki.org/wiki/Batteries The idea of a "smart battery" was new to me. Having external circuitry to monitor it is one thing, and is something quite different. But actually having ANY circuitry built into tthe battery itself, per se, is something else, and was something I wasn't aware of. Up to this point I thought all batteries were just chemical sources of power, and that's all. |
#13
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Stop dischargie of laptop battery by disconnecting?
Bill in Co wrote:
mike wrote: On 11/14/2013 6:08 PM, Bill in Co wrote: Computer Nerd Kev wrote: Not all, but as far as I know, most laptop batteries have protection circuitry in the battery itself that slowly drains the charge. The effect this has depends heavily on the condition of the battery and the the individual design and specs. Reference???? What "battery protection circuitry" IN a battery? Like virtually every lithium battery made? google bq29311 for an example. Or pop the battery out of your cellphone. You're holding one in your hand. I think that bq29311 is a battery protection IC, and is not inside the battery, no? It's inside the battery pack. http://www.ti.com/product/bq29311 http://www.ti.com/lit/ds/slus487d/slus487d.pdf "...the bq29311 can activate the FET drive as a secondary protection level." "APPLICATIONS Notebook computer battery packs" The schematic on page 9, hints at what it does, but you need to look at page 6 to interpret it. The "X" connections on the left, are to the individual lithium cells. And the FETs at the top of the schematic, are series pass during charge and discharge. I'm not going to try and figure out, which features are local and purely hardware, and which ones require the laptop processor in order to work. The S-8244 is here. http://www.sii-ic.com/en/semicon/dat...ion-ic/s-8244/ http://datasheet.sii-ic.com/en/batte...on/S8244_E.pdf It looks like Q3 (2N7002) is there for series disconnection of the pack. And the S-8244 provides a second opinion on opening the circuit. Something like that. I didn't read the whole thing. But it looks like all that crap is hiding inside the battery pack. No wonder it's so big and the shape is so weird looking. HTH, Paul |
#14
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Stop dischargie of laptop battery by disconnecting?
On 11/15/2013 4:34 PM, Bill in Co wrote:
mike wrote: On 11/14/2013 6:08 PM, Bill in Co wrote: Computer Nerd Kev wrote: Not all, but as far as I know, most laptop batteries have protection circuitry in the battery itself that slowly drains the charge. The effect this has depends heavily on the condition of the battery and the the individual design and specs. Reference???? What "battery protection circuitry" IN a battery? Like virtually every lithium battery made? google bq29311 for an example. Or pop the battery out of your cellphone. You're holding one in your hand. I think that bq29311 is a battery protection IC, and is not inside the battery, no? If you're talking about being inside a CELL, not usually. Although there are "CELLS" with electronics attached to the end and shrink-wrapped so that they look like a bare cell. This is one such attachment. http://dx.com/p/charge-discharge-pro...mm-1-9mm-26112 Same site has "cells" with the attachment already installed. Typically, a group of cells is called a battery. You could argue that one cell does not a battery make. If you just want to nit-pick, that's your right. The rest of us try to discuss the issue in context. |
#15
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Stop dischargie of laptop battery by disconnecting?
Bill in Co wrote:
Computer Nerd Kev wrote: On 15 Nov 2013, Bill in Co wrote: Computer Nerd Kev wrote: Not all, but as far as I know, most laptop batteries have protection circuitry in the battery itself that slowly drains the charge. The effect this has depends heavily on the condition of the battery and the the individual design and specs. Reference???? What "battery protection circuitry" IN a battery? Lithium Ion batteries like to get hot and catch fire if they are charged when the voltage if too low. So there is some small circuitry to monitor this voltage and prevent charging when it is below a set threshold (and discharging below it, although the circuitry itself drains a small amount of current and thus over time self-sabotages this function (lesson of the day: keep your Li-Ion batteries charged (actually applies to a lot of batteries))). In addition, some also protect against excessive current draw or heating by disabling the voltage output when sensor readings exceed pre-set values. References? Oh all right: http://batteryuniversity.com/learn/a...y_circuits_for _modern_batteries Why I say not all laptop Li-Ion batteries have this circuitry: http://www.fonerbooks.com/laptop_3.htm http://www.thinkwiki.org/wiki/Batteries The idea of a "smart battery" was new to me. Having external circuitry to monitor it is one thing, and is something quite different. But actually having ANY circuitry built into tthe battery itself, per se, is something else, and was something I wasn't aware of. Up to this point I thought all batteries were just chemical sources of power, and that's all. Many cameras not only have regulator circuitry built into the battery pack but also have ID chips built in as well. If the camera does not confirm the battery ID as factory oem, it will not work. May be the same for most other devices as well. |
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