Computers & Electronics

47Wh vs 55 Wh for laptop battery?

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  • Mar 13th, 2013 6:53 pm
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Deal Addict
Mar 16, 2010
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m4r 1k8

47Wh vs 55 Wh for laptop battery?

hey guys so i bought my laptop two years ago and its still going strong :p HP-dm4 1275CA buuuut the battery is dying (barley lasting me 2 hours from when i first purcahsed i could watch movies for up to 5 hours, and battery would last all day if i did just browsing :p)

now im thinking of buying a replacement battery ... looking on ebay is the cheapest chocie for me (some claim to be original) and yeah for ~$30 why not .. now my question is which one would provide me with the best battery life? 55wh or 47wh? my original one is rated at 55wh / 5200 mah ... should i go for 9cell non-oems? just maybe they will make a big bump on my laptop at the bottom .... so any info would be nice :) thanks guys!
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Feb 15, 2008
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Calgary
I personally find the "Chinese" watt-hour specs to be a little bit suspect on the cheapie batteries off of eBay. Theoretically, they use cells (ie: 18450 Li-Ion cells) that are rated for so "x" number of amp hours at a given voltage, but the Chinese cells tend to be slightly exaggerated in terms of capacity, hence, a completed battery pack is also exaggerated as to its rating.

However, if you're priced out an OEM HP battery, you'd realize that putting up with a little bit of dishonesty in the ratings, is a small price to pay for the very large amount of money you're saving.

55Wh obviously is a higher rating than a 47Whour battery. But what you actually are delivered is anyone's guess. If you want better battery life, take the $80 you're going to save over buying OEM, and throw a SSD in that laptop in addition to the battery. You will not be displeased.
TodayHello wrote: ...The Banks are smarter than you - they have floors full of people whose job it is to read Mark77 posts...
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Sep 13, 2012
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Your signature is self-satisfied. Your insights come from a modicum of reflection, nothing special except in this sea of mediocrity.

Your advice to this chap is however sound.
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Oct 31, 2012
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peteryorkuca wrote: Try calibrating your laptop battery by draining it all the way and letting it cool down for awhile and charging it. Might work out.

http://www.ghacks.net/2011/09/14/how-to ... p-battery/
It might, but Li-Ion batteries have an average lifespan of 2-3 years before they drop in capacity by 80% in any case...so it's about right. I've also found that HP laptops (among other failures) tend to have batteries that fail quite soon, around the 2 year mark.

But for OP, yes, the higher wh will last you longer.
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Feb 15, 2008
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peteryorkuca wrote: Try calibrating your laptop battery by draining it all the way and letting it cool down for awhile and charging it. Might work out.

http://www.ghacks.net/2011/09/14/how-to ... p-battery/
Deep cycling is the absolute worst for Li-Ion batteries and should be avoided. You don't need to do a full deep cycle to get a reasonable recalibration of a Li Ion battery meter.
TodayHello wrote: ...The Banks are smarter than you - they have floors full of people whose job it is to read Mark77 posts...
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Nov 14, 2010
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You do need to deep cycle a Li-Ion battery to recalibrate the meter. Best thing is to leave it on the BIOS screen till it powers down. That avoids an improper OS shutdown. However never leave a Li-Ion battery deep discharged, recharge it immediately. You don't need to do it monthly, or even ever. Only if the gauge is inaccurate for your uses.

In the case of the cheap batteries, I have little experience with laptop batteries, but I know with camera batteries, they exaggerate the capacity by 40% with lighter cells. However even if they are HALF as good as the original they are a good bargain, especially as a spare. $40 for an OEM battery, vs. $6 for 2x no name batteries.

Only thing is the no-names are more likely to explode. I never charge them unattended.

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