Laptop Battery.

[Flying Torquewrench]

Hello all,

Just bought a HP DV6174EA laptop and i have got a question about its battery.

99% of the time i use this laptop at home and it will be hooked up to the mains supply. When connected to the mains i can remove the battery while the laptop keeps working.

Whats the best thing to do to keep the battery in the best state?

1) Keep laptop connected to mains and remove the battery.

2) Run laptop on battery till the battery is empty than switch over to mains. Keep on mains till the battery is fully recharged and than go back to battery. Repaet the above cyclus over and over.

3) Keep laptop connected to mains and leave the battery in its place.
(dont run on battery even when battery is fully charged)

I ask this question as i ruined :{ the battery of my previous laptop by running the laptop on mains power with the battery installed. But that laptop was bought in jan 2002 so there might have been a great improvement in battery's

Thanks, FT

[bladewashout]

The batteries have finite life, usually measured in cycles of use. Lithium Ion is not as susceptible to memory as the old NiCd/NiMh.

If it's not a pain, I would suggest removing the battery once charged and using on the mains without a battery, slip the battery in if you're using it without mains. If you usage pattern makes this easy, it will prolong battery life.

You should use the battery occasionally, at least once a month, and let it fully discharge then charge again, possibly twice, for conditioning.

Or (like me) you can just live with the fact that leaving it in all the time means it wears out quicker (holds less charge) and hope the laptop dies before the battery - my laptops rarely last much over 3 years, I now buy IBMs with a 3 year warranty, then buy another one. By the end the battery only lasts about an hour. Good incentive to buy a new one, give the old one to the kids!

Hope this helps.

BW

[Flying Torquewrench]

Bladewashout,

Thanks for your reply. I have removed the battery now and just operate the laptop on mains only. As you said once a month i will use the battery to keep it in a good condition.

Thanks again and my apologies for the late reply.

FT.

[Keef]

Actually, it's a little bit more complex than that.


If the battery is NiCd, it's important to run it completely flat before you recharge it. Battery life is generally around 500 charge/discharge cycles before it refuses to play. NiCd are almost extinct now, but do check.

If it's NiMH it's not so fussy, and you can recharge as you wish. Battery life is still around 500 cycles.

Lithium Ion (LiIon) is different. Battery life isn't much dependent on number of cycles, but entirely on time elapsed since the battery was made. Some last longer than others, but if you buy three out of the same batch made on the same day, they will all start to lose capacity around the same time - regardless of whether they are used or not. Don't buy "old stock", and if you buy a new one, check the "manufactured date" on it.


Meanwhile - check the owner's manual very carefully indeed before you run your laptop with the battery "out". You could damage it. In some (not all) it's the battery that stabilises the power supply voltage to whatever the computer is designed to. If you run it without a battery in those circumstances, the voltage may be significantly over "nominal" and the machine may be damaged. The manufacturer would probably know what you'd done (from the nature of the damage inside) and refuse to honour the warranty.

Not all laptops are like that - but even so, I would never run one without the battery. A new battery is a lot cheaper than a new laptop.

[planecrazy.eu]

Well cant speak for your laptop(s) but mine, and others i have had in the past have no issues...

Case One # Leaving the Batt in whilst always on mains = There is chargeing circuit, once the batt is at top capaicty it doesnt charge the batt no longer and the power is supplied directly to the laptop without going through the battery, the second the direct voltage goes, the batt kicks in

Case Two # Leaving the batt out = makes no difference, but leaving the batt in is great for when the power goes, if some one turns the plug off by "accident", power cuts and so you can just get up and park ya self where you want

As i say, cant speak for others, but the laptop i have works like that, i have an acer, we used to sell acers where i used to work, and the acer guy recomended that we dont use the batterys whilst on display as it will make the laptop easier to sell if the battery is brand new when we take it off display. He said however, if its left on charge all the time nothing will happen as the charge is designed to shut off when at full capacity. This maybe true of false but i usually have mine on charge most the time and have done for well over a year and cant see no drop in battery life, i use my laptop for work (7hrs a day) and for games (1hrs a day) and study (2-3hrs a day) and then others use it for bits and bobs. so my laptop is on more or less all day if its been used or not...

Good advice keef with the types of battery, i didnt know that about liIon batteries, and agree that the manual should always be consulted to stay within those tight warrenty terms and conditions...

[bladewashout]

As you say, best consult the manual.

I live with the fact that the battery will die. My current cycle count is 236 and charge capacity is below half the design capacity (battery info report).

It is handy that the machine stays up when the power goes down, we lose power out here in the sticks fairly regularly. The elapsed time life thing is news to me, I'm off to browse the internet to look into that one, and perhaps revisit my opinions if its true.

The batteries do naturally lose charge, so if you are permanently on the mains, I would expect there to be a small amount of recharging going on from time to time.

I happened to be looking on the internet for a new battery the other day, batteries from china seem amazingly cheap. I bought a li-Ion replacement for an ipod for 1.99 + 3.50 postage, it really does seem to work as described, and very cheap. At the price, (£35) perhaps I would not care as much as when I was looking at £145 from IBM.

I would just worry that they might have less than perfect quality control and start exploding....

BW

[under_exposed]

You may wish to look at http://dansdata.com/gz011.htm

[planecrazy.eu]

bladewashout, how do you know how many cycles you battery has done, and its current capacity?

I am currious now what state my battery is in =)

[bladewashout]

My thinkpad T40 has a 'Battery Maximiser' wizard which interrogates the battery, giving a whole pile of real-time information about the current draw (or charge), cycle count, actual capacity vs design capacity, battery serial number, manufacturer etc. etc.

Part of the thinkpad battery design must include data storage and retrieval, plus some non-volatile RAM.

BW