How long does your battery last?

Discussion in 'Asus' started by Righi, Feb 7, 2008.

  1. mattj

    mattj Scribbler - Standard Member

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    i think the more u guys try to test it by running it all the way down, the more the batteries seem to be degrading.

    just tried batterymon n it was reporting the same info as NHC. I'm still at 3% from when this thread started. but i have only used the battery for up to 20 mins at a time and since i've had it, it's probably only been run completely down once.

    all the other times i had at least 30 mins - 1 hour left.

    but everywhere i go i look for a power plug.

    start looking for powerplugs. sit in the back of the lecture room or bring an extension cord lol.
     
  2. zun

    zun Pen Pal - Newbie

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    There's definitely a problem with the wear of the 6-cell main battery. I've had my tablet since end of Sept only using it a couple times a week. My battery is down to a little less than 2 hrs of life with screen at 73% doing wireless web browsing. According to NHC, the battery is at a wear level of 37%.

    I recently got the modular bay battery, which is rated less than the main battery (3600 vs 5200 mAh), and my battery life has doubled to 4 hours. I was hoping to get 5-6 hours total with both batteries but that's not happening with the degradation of the main battery. Looks like I'll have to try sending it in under warranty.

    (NHC is measuring my main battery at 2783 mAh and my modular bay at 2950 mAh)
     
  3. mattj

    mattj Scribbler - Standard Member

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    Tsukiyomi - completely discharging lithium batteries to improve them is only a very recent thing. all the old lithiums would die very quickly if u did this.

    what if the battery we have is using the old tech?

    both my old samsung n new sony ericsson cellphones have suffered from being fully discharged a lot.

    the samsung was horrible cause i used to let it go all the way down all the time. so when i got the sony i have made an effort to keep recharging it everyday. and the sony has only been fully discharged about 3 times and since then I can see a small amount of performance loss on the battery.

    I have great trouble in believing the statements by lithium-ion manufacturers.

    they work nothing like Ni-MH does. Now those are the most versatile batteries out there. charge em up. charge em down. charge em but don't use them for a whole year. no problems.

    but lithium. treat it like royalty or pay the price.
     
  4. Tsukiyomi

    Tsukiyomi Scribbler - Standard Member

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    mattj, that's good advice, I suspect that the more I use this battery close to zero, the more it is wearing down. I've essentially decided to use it only until 30% or so and recharge it, hoping that it will not deteriorate from that. I read somewhere that lithiums have a certain number of charge cycles for its lifetime, and it only counts as a cycle if it is fully charged and then discharged. Now that I've "calibrated" it, the battery will be left never fully discharged.

    With the Ni-MH, why don't laptop manufacturers use them? Is it because they do not have as much voltage/current/whatnot? My BT devices are all on Ni-MHs and they literally last forever, from getting it to now, the Asus mouse that came with my R1F has never been charged at all. And I got this computer the first week it came out too.
     
  5. mattj

    mattj Scribbler - Standard Member

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    yeh i know. also Ni-MH is much heavier and has less power output, but strangely they use them in electric cars. :p

    I'm hoping that the Ovshinsky's (the husband n wife who invented Ni-MH) will get their H-MH (Hydrogen Metal Hydride) batteries onto the market soon. It's been years. http://www.ovonic.com/
     
  6. Fido

    Fido Scribbler - Standard Member

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    I don't know. I get about 3 hours and I accept it for what it is. If I need more battery life I'll get the extended battery. I think you guys are obsessing way too much about this. And yes, discharging the battery all the way does increase deterioration. Please read the link to BatteryUniversity that I posted as it covers all the effects.

    Some tips from BatteryUniversity

    * Avoid frequent full discharges because this puts additional strain on the battery. Several partial discharges with frequent recharges are better for lithium-ion than one deep one. Recharging a partially charged lithium-ion does not cause harm because there is no memory. (In this respect, lithium-ion differs from nickel-based batteries.) Short battery life in a laptop is mainly cause by heat rather than charge / discharge patterns.

    * Batteries with fuel gauge (laptops) should be calibrated by applying a deliberate full discharge once every 30 charges. Running the pack down in the equipment does this. If ignored, the fuel gauge will become increasingly less accurate and in some cases cut off the device prematurely.

    * Keep the lithium-ion battery cool. Avoid a hot car. For prolonged storage, keep the battery at a 40% charge level.

    * Consider removing the battery from a laptop when running on fixed power. (Some laptop manufacturers are concerned about dust and moisture accumulating inside the battery casing.)

    * Avoid purchasing spare lithium-ion batteries for later use. Observe manufacturing dates. Do not buy old stock, even if sold at clearance prices.

    * If you have a spare lithium-ion battery, use one to the fullest and keep the other cool by placing it in the refrigerator. Do not freeze the battery. For best results, store the battery at 40% state-of-charge.
     
  7. mattj

    mattj Scribbler - Standard Member

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    hey that better be a "frost free" fridge. none of those old jobs, cause theirs too much moisture in them.

    and considering i've only fully drained mine once n it's still sitting on 3% i don't think i want to risk draining it at all. let alone 30 charges.

    either way, i emailed asus about it last week, n hopefully they will look into it sometime soon.
     
  8. Tsukiyomi

    Tsukiyomi Scribbler - Standard Member

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    Sometimes though, avoiding deep discharges is impossible - for instance, a few of my lecture halls do not have power outlets available and the lectures themselves last an hour and a half to two hours. If this battery deteriorates at the same rate as the first one (it seems to be going downhill faster), then in two months, I would run out of battery before the end of lecture, finding a place that sells the extended battery notwithstanding.

    I guess it just irks me that the R1F ends up getting poor battery life, my 3 year old Powerbook gets 3 hours with higher screen brightness and with wireless on as well, my brother's Fujitsu T4210 gets four hours with half brightness and wireless off...and for the same settings, I get 1.5 hours.
     
  9. mattj

    mattj Scribbler - Standard Member

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    yeh these battery problems just shouldn't be happening. u should try emailing tech support in taiwan. i've already mentioned it to them, but i've annoyed them enough already.
     
  10. alanpark

    alanpark Pen Pal - Newbie

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    Im with Fido and Mattj on the discharging issue. It might be better for those who got replacements to not discharge it whatsoever, either to calibrate it or test wear.

    My old cellphone was relegated to one call per charge in less than a year due to discharging. My "new" one still goes for days before recharging for the last 2 years, and has never been discharged. My old ASUS battery suffered horribly after a couple discharges. But in the end this is all anecdotal...

    I for one, have never fully discharged it, or even put it within a 10% threshold..Ill let you all know how my battery is faring in a couple months (right now my R1F is too new to tell)

    amen on the H-MH battery mattj
     
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