Kitz Forum

Computers & Hardware => Other Technologies & Hardware => Topic started by: tickmike on January 10, 2013, 12:15:32 AM

Title: Laptop Batteries.
Post by: tickmike on January 10, 2013, 12:15:32 AM

Acer 5738Z battery, With me taking over my daughters old laptop I find it needs a new Battery.
There seem to be lots on the internet from £13 to £40 . :hmm:
Has anyone any advice about which one to get .?

Title: Re: Laptop Batteries.
Post by: oldfogy on January 10, 2013, 04:25:29 AM

Not much help I'm afraid, but with the like from this search some as showing the batter as '6 Cell at £15.99' and some as being '12 Cell at £14.89'

Sorry to confuse it further, but I did read something some time ago which was with some of them basically they were reducing the number of cells, there fore the charge did not last very long.

http://www.google.co.uk/products/catalog?q=acer+5738z+battery+price&hl=en&client=firefox-a&hs=ns&rls=org.mozilla:en-US:official&bav=on.2,or.r_gc.r_pw.r_qf.&bvm=bv.1357700187,d.d2k&biw=1366&bih=587&um=1&ie=UTF-8&cid=16905986564495543254&sa=X&ei=WEDuUJO9B63Y0QWB-YA4&ved=0CGQQ8wIwAA#freeship=1

Not looked yet, but how much are they from Acer?


****************
Just another thought, have you tried 'Calibrating' the battery.
Basically totally flatten the battery, but this clip gives us a good reminder of what settings to disable first.
Not forgetting that some computers have this 'Calibrate' setting in the BIOS which is best to use if available.

[youtube]http://www.youtube.com/watch?v=S8hXlavoXAw[/youtube]

Title: Re: Laptop Batteries.
Post by: tickmike on January 10, 2013, 11:32:43 AM

re "Not looked yet, but how much are they from Acer?" = £84  :o

Title: Re: Laptop Batteries.
Post by: tonyappuk on January 10, 2013, 11:53:44 AM

From my limited experience buy the cheapest one with the highest capacity (Amp Hours). If you do it through Ebay make sure his approval rating (?) is near 100 %. I have just bought a battery for my daughters laptop (Compaq) from Amazon where they had a selection for her model from £40 to £13 (maybe the same one you've seen!). Having read the reviews/comments we opted for the £13 job but it's not been fitted yet and in any case the main criterion we're looking for is longevity, that remains to be established. I would not spend loads of cash on a "genuine" makers battery because you're almost certain to use it plugged into the charger most of the time arn't you? The pictures you see of someone using their lappy in the garden always strike me as a bit unreal as even new a laptop battery only lasts a couple of hours before it needs recharging and you can't see the screen in sunlight anyway.. If you want longer "unplugged" you have to use a newer tablet or maybe netbook or even one of the infamous (to me) Apple products!
Tony

Title: Re: Laptop Batteries.
Post by: tickmike on January 10, 2013, 12:50:18 PM

Just been reading this about battery life.

http://batterycare.net/en/guide.html

http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries

http://batteryuniversity.com/learn/article/do_and_dont_battery_table

http://www.apple.com/pt/batteries/

Title: Re: Laptop Batteries.
Post by: burakkucat on January 10, 2013, 09:07:46 PM

Well, I have just learnt something. There is no 'memory' effect with a Lithium Ion battery pack.  :)

Title: Re: Laptop Batteries.
Post by: silversurfer44 on January 11, 2013, 09:01:07 AM

Very interesting reading Tickmike. I had heard many times that Lithium Ion batteries did not suffer from the 'memory effect'.
I remember a guy at NASA explaining how they calculate their batteries on the Hubble telescope, which went something like this. They aim for a zero balance between charge and discharge of the batteries. Now the batteries are charging whilst the telescope is in sunlight and discharging in the dark. If the the amount of charge in the sunlight is used in the dark then they have a zero balance. This doesn't mean the batteries are fully discharged. In fact when the get anywhere near something like 25% of total capacity then the battery pack is said to be worn out. Of course they cannot just go replace the batteries, so they bring into service another set. I forget how many sets they have. When all the sets have been used this time around then that is it, then end of the Hubble. Unless by some miracle there is another mission of some sort to service the telescope.
Now, if NASA can charge and discharge their batteries in such a manner for 15 years or so then surely us earthlings can do the same, and the people in the know must be right. 'No Memory Effect'. Carry on folks, charge and discharge at will, so to speak. :)

Title: Re: Laptop Batteries.
Post by: roseway on January 11, 2013, 10:05:34 AM

This is a subject which comes up from time to time in photographic circles, because most cameras these days use lithium-ion batteries. I remember a while back reading a posting from a chap who had devised a little gadget to connect his camera battery to, which had the purpose of fully discharging the battery at a controlled rate. He seemed quite surprised when it was explained to him that use of his gadget could make the battery impossible to recharge.

Most electronic equipment using this type of battery will have circuitry to protect the battery against the possibility of over-discharge, by powering down the equipment before that point is reached. Again in photographic circles I've seen people complaining about the fact that their camera switches off before the battery is exhausted, and thinking that it's a fault. :)

Title: Re: Laptop Batteries.
Post by: tickmike on January 11, 2013, 10:37:03 AM

I spent some time yesterday re-calibrating the battery/laptop and now may be I do not need a new battery yet, it was showing 18% when I booted it up and lasted 20 min,  and now after doing the re-cal (as in links above  ;) ) it is showing 45% and lasting 2 hrs  :).

Title: Re: Laptop Batteries.
Post by: JGO on January 11, 2013, 12:01:45 PM

An associated point.

Battery charging, like electroplating, works better with a strong AC component in the charging DC, since metal deposited with pure DC is porous. This is bad for plating finish and the battery can may leak in time. With a 50Hz charger the recommendation  is half wave rectified with a resistor shunting the rectifier.  Information direct from a manufacturer.
I don't know the internals of all chargers, but a switching regulator won't provide the optimum waveform.   

Title: Re: Laptop Batteries.
Post by: burakkucat on January 11, 2013, 05:22:36 PM

Ah, yes. Thank you for reminding me, JGO. When I first read about that charging method in the late 1960s it was described as 'dirty DC charging'.

Title: Re: Laptop Batteries.
Post by: roseway on January 11, 2013, 06:34:49 PM

I don't think that applies to lithium-ion batteries though, because Li-Ion charging doesn't depend on metal deposition. A significant AC component in a Li-Ion charger would potentially be quite dangerous.

Title: Re: Laptop Batteries.
Post by: JGO on January 11, 2013, 09:22:54 PM

Fair enough I stand corrected, I was thinking of NiCads although I don't see how one can connect without any metal electrodes at all.

Title: Re: Laptop Batteries.
Post by: burakkucat on January 11, 2013, 10:06:48 PM

Quote

. . . although I don't see how one can connect without any metal electrodes at all.

Organic polymers.  ;)

And when I first read about 'dirty DC charging' it was in conjunction with that reliable heavy-weight, the lead-acid cell.

Title: Re: Laptop Batteries.
Post by: tickmike on January 12, 2013, 11:49:25 AM

@  jgo,  Also it will make the battery get hot which is not good for these type of battery.

Title: Re: Laptop Batteries.
Post by: JGO on January 12, 2013, 12:13:57 PM

"Dirty DC" charging was recommended for NiCads too,  by DEAC from memory.  As I said it should be beneficial for any secondary cell with a metal can, but yes the gain might be offset by overheating.
Re Lead-Acid cells as the electrodes are not solid anyway I'm surprised it does much good, but car batteries in particular get a brutal life anyway.