How long will a battery hold its charge for?

Assuming I am buying brand new official batteries and charge them up fully, then remove them from the laptop, how long can I expect them to hold a full charge for?

Do they start draining as soon as they're removed from the computer?

My time limit is a week, so if they can hold full charge for a week, that's fine.

At the moment I will have one battery (my current one) IN the laptop, plus up to three batteries that will be charged up the day before I leave. I'm trying to establish whether or not the batteries NOT in the laptop will retain their charge or if a battery needs to be in the laptop to hold its charge.

(I usually disable battery charging using Dell QuickSet if I know I'm not going to be moving the laptop around, so I know a battery IN the laptop can hold its charge even when not being charged up continually by the power supply.)

The battery technology. For example we peg NiMH batteries to lose about 2 per cent a day with no load. You can google up what each battery tech looses per day.
Bob

It's a Li-Ion battery. The current one is a 6-cell but apparently 8-cell "extended life" ones are available.

Just tried Googling "li-ion loses charge" and Firefox promptly crashed. I'm using the 3.6 Beta 3, which appears to have the same problem as the Beta 1 and Beta 2 - the entire browser will crash whenever I Google search. I did get a glimpse of the first search result in the 2 seconds or so before it went down and it appears that NiMH and Li-Ion batteries lose the most holding charge, which is annoying.
Unfortunately, I can't buy a laptop battery of a different battery technology because they don't make them.

But batteries can be external. For example this LEAD ACID powers a laptop -> http://www.viddler.com/explore/karosa/videos/2/

So it is possible to use other battery technologies.
Bob

Battery run-time on a laptop is difficult to determine.
Actual battery running time depends upon the power demands made by the equipment. The use of the screen, the hard drive and other laptop accessories results in an additional drain upon the battery, effectively reducing its running time. The total run-time of the battery is also dependent upon the design of the equipment. Generally, a Hi-Capacity battery will run 30% to 50% longer than the old battery did when it was new.

Looks like it would be worth getting a high-capacity battery, then. Hopefully charging as late as possible before use, not using any programs except necessary ones and keeping the screen as dim as it will go might give me enough time to finish my typing.

Laptop batteries typically last 1 - 2 hours, but it is difficult to be precise because much will depend on what you're actually doing. For example, graphics-heavy usage will drain quicker than using Word.

You probably need extra batteries, but remember how heavy they are - I have three for my Mac, and that's enough wight-wise when I'm travelling, I can tell you!

Most likely only Word, possibly Excel and maybe a couple of other programs. I saw the media players eat battery power so I won't be using them.

I acquired it from my brother when it was about a year old and I've had it roughly a year now.

The battery never ran for more than 2 1/2 hours. If a 12-hour battery was made for the Dell Vostro 1710, I'd buy it like a shot.

I've found by switching off the sound, reducing screen brightness to minimal and turning off Bluetooth and the wireless, I can maximise the length of time it'll run. But I still won't get more than a bit over 2 hours - it's programmed to hibernate at 3% battery. I usually close everything anyway just before it shuts down.

All the dells back then came with 300 CYCLE batteries and you have a 2 year old battery. Count it luck you get over a hour.

Nothing seems wrong here.
Bob

It isn't as old as I thought. When I got it from my brother, he gave me the paperwork and it says he got it September 2008 - so it's actually about 18 months old.

Maybe I should just make off with my dad's netbook for the duration. He reckons he gets 8 hours' battery life.

That 8 hours is usually good for about 300 times. So in a year another dead or not so good battery.

I'm unsure if the lesson is being lost here. Don't use the battery unless you have no other choice.
Bob

I sometimes use the battery to "hold" while I'm moving the computer from one power-point to another.

I've heard that the battery will drain to some extent if left in the laptop while it's plugged into the mains. I tend to disable the battery charging in Dell QuickSet (it has an option for that) except when I've been using it and need to recharge it.

How fast does hibernation drain the battery? I use it quite a lot.

I'm going to share one and only one example. My dv6310us was in storage for over a month. It was not in sleep but hibernation. I didn't connect the AC because I wanted to answer this question again.

It booted from hibernation and showed 99% full on the battery.

Be aware that I used the battery sparingly over 2 years. I know it's a limited resource. I never bothered to turn off charging. It sat on the desktop with AC for years.
Bob

The salesman at the computer store that I buy from told me that when I am at home, always use the AC and pull the battery completely out. In addition, when you do run down the battery, keep it plugged in for several hours, so it can get a FULL charge.

My daughter refuses to listen to me and plugs it in for only 45 minutes - 1 hour, and then she wonders why it drains in a matter of 15-20 minutes or so. I bought her a brand new Acer laptop in June and told her to ALWAYS charge it for at LEAST 5-6 hours (while she is sleeping), but again, she didn't listen. She had the battery useless in only 3 months.

~ Barry

Because it doubles as my uninterruptable power supply. I also never bothered to drain it since that counts as ONE cycle. These HP, Dell and most are 300 Cycle batteries. The advice I read, reads like what battery sales folk would hand out (sorry if that offends anyone.)

Back in the bad old days of NiCad and bad designs we did pull the battery but since about 2000, never bothered.
Bob

Do you mean to say that if you take out a fully charged battery and put it back in when you need it, even though you have not charged it up again, that counts as another cycle? If that IS what you are saying, that makes perfect sense to always keep it in and never let it drain. Maybe the salesman I talked to didn't know about those new batteries.

Which you can digest all this.

My personal best is an even older laptop. A Compaq R3000 which the office acquired in late 2004. It's battery shared the same fate as most of our desktop bound laptops. It's 5 years old and again it seems fine but we don't run it on battery power, didn't remove the battery and it just runs and runs on AC.

All that advice about removing the battery seems silly at times.

I had a on site update to some software which is hosted on this machine and took it out. There was no power there and I ran for over an hour on the 5+ year old battery. I think that explains it.

Cycles count.
Bob