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View Full Version : Keeping laptop plugged in or not...



Sisk
06-22-2011, 06:51 PM
Ok, I've heard conflicting opinions on this for years and what to know ST's opinion. I use to keep it plugged in all the time and it worked fine (obviously). Then, I bought an HP a little over a year ago and only used the charger to recharge then used the battery until it needed a charge again... the battery lasted about 10 months.

Anyways, what's the proper thing to do with these batteries?

Drachen
06-22-2011, 07:14 PM
Ok, I've heard conflicting opinions on this for years and what to know ST's opinion. I use to keep it plugged in all the time and it worked fine (obviously). Then, I bought an HP a little over a year ago and only used the charger to recharge then used the battery until it needed a charge again... the battery lasted about 10 months.

Anyways, what's the proper thing to do with these batteries?

The fewer amount of cycles that the battery goes through, the longer it should last. I have read (about my laptop specifically) that it doesn't count as a cycle unless it has reached 95% or less (i.e. if I use it unplugged for less than 5% of the battery, then it doesn't affect the longevity). Your laptop may differ. My general rule is that if I am anywhere that a plug is readily available, my computer is usually plugged in (home, work, school). My laptop is 3 years old and still lasts as long on battery as it did the first day.

Sisk
06-22-2011, 08:54 PM
Well, then that's what I'll do. I tried the whole unplug it whenever it was a full charge and it destroyed my battery. Thank you.

objective
06-22-2011, 08:58 PM
i always keep it plugged as I find it too dim otherwise.

Battery and charger have been fine for 4+ years now.

jacobdrj
06-22-2011, 10:23 PM
i always keep it plugged as I find it too dim otherwise.

Battery and charger have been fine for 4+ years now.

The dimness is a property of the operating system's power plan settings 99/100 times. You can tell the computer to have full brightness even on battery. In fact, you might not be running on full brightness even plugged in. Make sure, if you are in Windows Vista, for example, to click on the battery icon next to the clock on your task bar, and set the power plan radio-button to 'High Performance'.

Back to the topic:

Lenovo has implemented a feature in their newer laptops where if you are in an office enviroment, and rarely take your laptop off the charger, the battery is allowed to discharge down to 80% so that the heat is lower in the battery. This is supposed to increase the longevity. Charging to 100% creates more heat. A fully discharged Li-on chemistry battery (probably your battery if your laptop is less than 7 years old) should NEVER EVER EVER be allowed to fully DIScharge! If it does, the battery will cease to be able to hold a charge. Your power plan for your OS should force you to shut down if you reach 7% (which gives your battery some buffer leeway to allow you to have time to plug in your laptop).

All Li-on batteries degrade when charged. There will be a point in the life of every battery when it will degrade to the point where it isn't worth it to lug it around with you anymore. Battery life-cycle charges can vary from 200 to 1200 charges (give or take) depending on the type and amount charged.

In summary: Keep your battery charged. Keep your battery cool. Never discharge your battery 100%, and it will last you a couple of years...

Sense
06-22-2011, 11:55 PM
I've had my laptop for about a year.. and about a week ago or so, my battery died....

I disconnected it, and it turned off by itself way before it reached 0%...

I was a bit confused, when I turned it on though.. my laptop is telling me that I need to replace it..

This had never happened to me with my other HP laptop..

ElNono
06-23-2011, 01:42 AM
Depends on the battery type...

If it's NiMH (Nickel Metal Hydride), then interrupted cycles don't matter much, but eventually your battery can develop what's called 'voltage depression', where the battery drains current faster than it should, and the laptop's sensing circuitry sometimes detects this as a failing battery. The way to cure 'voltage depression' is to let the battery discharge to about 1v (basically almost dead), then fully charge it.
These types of batteries can last for as much as 10 years if you're lucky. They're heavier than their Li-ion cousins listed below.

If it's Li-ion, interrupted cycles do not matter at all, and is a kind of battery that does not suffer from 'voltage depression'. Charge capacity does decrease progressively as time goes by (regardless of the amount of charge/discharge cycles) due to the electrolyte wearing out. Temperature can accelerate (hot) or slow down (cold) the battery's degradation. Average peak lifetime of a Li-ion battery in normal temperate conditions is 3 years from manufacturing date. Notice that even if the battery was stored and never used, it still degrades over time (can be slowed down by storing at cold temperature). So if you're buying replacement Li-ion batteries, make sure to look at manufacturing date.

Older laptops used mostly NiMH. Relatively newer laptops and hand-held devices normally use Li-ion. Some manufacturers still prefer to use NiMH for laptops.

Hope it helps.

Sisk
06-23-2011, 04:00 AM
Wow. A lot more information than I expected. Thanks a lot everyone - good stuff :tu

Dex
06-23-2011, 11:34 AM
Leave your laptop/portable plugged in whenever possible. Once the battery is fully charged, it will switch into AC only mode and run strictly off the AC-adapter, so you don't have to worry about "over-charging" your battery.

However, the more you use your battery, the quicker it degrades. Batteries are rechargeable, but they are still depletable resources that will stop working over time. People already talked about how depleting your battery completely from 100% to 0% counts as 1 "cycle". Draining your battery from 100% to 50% twice also counts as 1 cycle. After you reach a certain cycle count (like jacob said, can be anywhere from like 200-1000), the battery will either not last very long, or stop functioning altogether.

Thus, the goal is to avoid burning cycles if you can help it. The easiest way to do that is to leave it plugged in.

It's also good to occasionally recondition your battery by letting it get completely depleted (this can be through normal use), then charge it all the way back up.

Viva Las Espuelas
06-23-2011, 01:55 PM
Wow. A lot more information than I expected. Thanks a lot everyone - good stuff :tu

GoodOdor
06-23-2011, 09:58 PM
I've had my laptop for almost a year now, and basically I never used the battery, it's always been plugged. However, just a week ago I had to use the battery, and I got about 2 hours out of it. Pretty damn sure it should be about 3-4 hours if I remember the details correctly, so I was kinda bummed. Maybe it's because I had a lot of shit running on it?

lefty
06-23-2011, 11:11 PM
Is it ok to leave a laptop turned on (plugged of course) for consecutive days?


Or is it OK only for desktop computers?

(looks like laptops can get hot easily)

resistanze
06-24-2011, 07:52 AM
I've had my laptop for almost a year now, and basically I never used the battery, it's always been plugged. However, just a week ago I had to use the battery, and I got about 2 hours out of it. Pretty damn sure it should be about 3-4 hours if I remember the details correctly, so I was kinda bummed. Maybe it's because I had a lot of shit running on it?

Capacity of your battery will be reduced if you don't cycle the battery occasonally. You can do a battery calibration (either your BIOS will have a tool or you can do it manually). Bascially drain your battery and recharge.

ElNono
06-24-2011, 02:18 PM
Is it ok to leave a laptop turned on (plugged of course) for consecutive days?

Or is it OK only for desktop computers?

(looks like laptops can get hot easily)

Heat is a concern. If you already know you're going to do this, and your battery is Li-Ion, you should consider popping the battery out and run the laptop on AC only.

lefty
06-24-2011, 04:30 PM
Heat is a concern. If you already know you're going to do this, and your battery is Li-Ion, you should consider popping the battery out and run the laptop on AC only.
Ok
Thanks :tu

jman3000
06-25-2011, 10:13 PM
I received a laptop as a gift a few years ago and that thing had bad battery life out of the gates. The 17 inch screen was too much of a drain and I could barely finish one class before it would need to be plugged in. It's pretty much immobile.