Laptop Battery Saving Scheme

[TromboneAl]

My 17" laptop sits on my desk, and I expect I will never take it on the road (I use my Nexus 7 for that), or need to use it on the battery.

However, my understanding is the having the battery almost always at near 100% charged degrades its lifetime (I'm using "lifetime" to refer to the number of years that a battery will remain viable rather than the "life" in terms of hours of charge). From what I've read, a battery that stays between 40% and 70% charge might last twice as long.

The obvious solution would be to have the computer manage this. Have it stop charging when it reaches 70% and start again at 40% (if you choose this option). Of course the computer companies have no incentive for this--they'd rather sell new batteries.

Another solution would be to have a hardware device. You plug your computer into it, and it monitors charge and effectively unplugs or plugs in the laptop at the appropriate times. Probably not a viable product.

I once downloaded an app that would display a warning when the battery got below one level or above another, manually removing or reinstalling plug when needed. That was not convenient, and didn't work when I wasn't at the computer.

So now I have a new scheme: I will plug my laptop into a timer:

And estimate how many hours per day to keep it between 40% and 70% charge. Since it is always in sleep mode overnight, I will have the timer shut it off during those hours.

What do you think?

 

[REWahoo]

Can you purchase software rather than using a timer? My Lenovo laptop came with a 'power management system' that defaults to the 50% charge range unless you override it.

 

[GrayHare]

My understanding of typical rechargeable science is that it's not the 100% charge that's the problem, it's a lack of exercise of the battery. The portions that never get discharged tend to develop a "memory", that is, over time they become more reluctant to yield their stored energy.

 

[TromboneAl]

Can you purchase software rather than using a timer? My Lenovo laptop came with a 'power management system' that defaults to the 50% charge range unless you override it.

It looks like Lenovo and Samsung laptops come with this. Good for them.

Maximizing the lifespan of a laptop battery | Computerworld Blogs

but last time I looked I didn't find any general software. One problem is that if you search for battery life or lifetime, you get articles about making the battery last for more hours per charge.

 

[meierlde]

It looks like Lenovo and Samsung laptops come with this. Good for them.

Maximizing the lifespan of a laptop battery | Computerworld Blogs

but last time I looked I didn't find any general software. One problem is that if you search for battery life or lifetime, you get articles about making the battery last for more hours per charge.

As do Dell laptops with windows 8 as well.

 

[Lakewood90712]

It's my understanding , that LI-ION batteries get the longest life by charging to 80% and not drawing down below 40%. It would take power management software to do this effectively. My acer laptop is stationary 75% of the time and plugged in. It has no options in the software to chose a charging profile. I'm sure I'l be buying a new battery someday because of this.

The ni-cads were the ones that developed a memory and needed a full draw down occasionally. This is bad for lithium ion batteries, IIRC.

 

[TromboneAl]

From this article:

Four essential tips for extending the battery life of your computer, cell phone, and every other gadget.

Ideally, Buchmann says, you should try to keep your battery charged from 20 percent to 80 percent. Keep in mind that these are guidelines for ideal use—it's generally inconvenient to unplug your machine before it goes all the way to 100. But even if you're not on constant guard, be mindful of charging your machine constantly, well past when you know it's full. You also should be conscious of letting your battery run all the way to zero.

​

In addition to my timer system, I can set Windows to warn me when the charge gets below 20%.

 

[TromboneAl]

And you can get an EXCELLENT battery report in Windows 8 like this:

Battery Usage Report - Generate in Windows 8

I guess I will have to figure out the color coding, since there's no key.

 

[TromboneAl]

Also, I've found that the fan is on more soon after I start it up from sleeping, so perhaps it builds up some heat when it is being charged when sleeping??

 

[bjorn2bwild]

My simple solution is to remove the battery at ~ 70% charge. It is very easy to pop it back in when I need a portable computer.

 

[TromboneAl]

My simple solution is to remove the battery at ~ 70% charge. It is very easy to pop it back in when I need a portable computer.

The problem with that, for me, is that if the power goes out, or it gets unplugged for any reason, I could lose my work. Your power is probably more reliable than ours, but one thing I like about laptops is the free UPS. I estimate that we have ten power outages a year, although most only last for a few seconds.

Another option I've considered is to buy a super-cheap replacement battery, and use that in the computer, and store the Original. But I never need a portable computer.

 

[Alan]

Good thread. I have long been in the habit of unplugging the cable from the back of the laptop and working on battery until I get the low battery warning, but have never tried to unplug it when it gets to 80%. (I have the low battery warning on my Dell laptop set to <20%).

It would be nice, in the absence of good battery management software, to be able to set a warning for >80% charge.

 

[heeyy_joe]

Energous has developed a wireless charging approach that works at a distance, using base stations to charge mobile devices without plugging them in or halting the use of the device. So far, Energous has managed to send energy up to 30 feet from its transmitters, which are similar in size and shape to a Wi-Fi router, to receivers meant to mimic mobile devices, which CEO Stephen Rizzone termed "a game-changing technology."

"Our technology has the key components that we believe the consumer wants in a wire-free solution: It has power, it has distance and it has mobility," Rizzone said Friday. "You have the ability to charge your phone when you're walking around your office, when your cellphone is lying on the desktop, or when you're at Starbucks getting a cup of coffee."

Energous IPO: Smartphone charging from a distance gets a boost - San Jose Mercury News

 

[ERD50]

I've also thought about this, and I have not found any general purpose SW either. I think I mentioned in another thread, this is controlled by the charger's firmware, which is obvious if you think about it, as the charger works with the computer shutdown. So I think it becomes very vendor specific, they need to make their SW work with their FW.

At first, I thought there was little value to your timer idea, because you are forcing it to go through more charge/discharge cycles. I'm not sure which is worse, being at 100% all the time, or doing a partial cycle each day - might be a wash? From what I recall, for a rechargeable Lithium, going through ten 10% cycles is about the same as going through one 100% cycle.

But this might work OK (maybe a slight variation of your idea?): Have the timer shut off an hour or two before your expected 'sleep time'. So the battery is at maybe 70% when you sleep it, and it stays near 70% all night since sleep uses so little power. Then set a duty cycle that just maintains ~ 30% to 70% throughout the day. You can get cheap timers with thos pins for each hour, that might get you close.

But I don't know - this is still charging/discharging. When it is topped off @ 100%, it just charges when it has dropped a few % - which isn't often when it is running off the main power line. You are only charging it up to make up for 'self-discharge', not because the battery was drained by using it. I think this could do more harm than good, it will be charging and discharging because you are now draining the battery with the computer, rather than just topping off the 'self-discharge' losses. I have a feeling the firmware changes to make it stop charging at 70-80%, without then drawing from the battery (draw from the mains) is the only real answer.

But I do not know for sure.

-ERD50

 

[pb4uski]

I am having something interesting happening. A little over a year and a half ago my laptop battery was not keeping a charge so I bought a replacement for ~$30 and threw the old one in a drawer. Recently the newer on wasn't keeping a charge and I was about to buy another replacements.

As part of deciding the replacement I found the old original batter and put it back in the laptop. It took a full charge and seems to be holding it and working fine. Perhaps it just needed a sabbatical.

 

[TromboneAl]

But this might work OK (maybe a slight variation of your idea?): Have the timer shut off an hour or two before your expected 'sleep time'. So the battery is at maybe 70% when you sleep it, and it stays near 70% all night since sleep uses so little power. Then set a duty cycle that just maintains ~ 30% to 70% throughout the day. You can get cheap timers with thos pins for each hour, that might get you close.

I have the Ingraham version of the timer in the above picture and it's much better than the physical types. You can set up to 20 on off periods for each day--a feature I never used until today.

I currently have it charge from 5 to 6 AM, 8 to 9, 1 to 2 PM, and 5 to 6 PM.

I'll be able to tell from the battery reports whether that's about right. Perhaps I can get by with fewer charges.

 

[NW-Bound]

My 17" laptop sits on my desk, and I expect I will never take it on the road (I use my Nexus 7 for that), or need to use it on the battery...

Then, the battery only serves to prevent a crash if the power cord is accidentally detached, or the power line is intermittent. Even a sub-optimized and worn-out battery will work for that purpose.

I would not bother doing anything.

 

[TromboneAl]

Energous has developed a wireless charging approach that works at a distancehttp://www.mercurynews.com/business...-smartphone-charging-from-distance-gets-boost

Speaking of which, I use a wireless charger for my Nexus 7, and it's really nice. You might think "How fat and lazy are we getting that we can't even take the time to plug in the tablet? Oh, it's so hard!"

But in practice, it's great to just put your tablet down on the stand and have it charge. I made a stand so that it can be charging while I use it.

 

[photoguy]

At first, I thought there was little value to your timer idea, because you are forcing it to go through more charge/discharge cycles. I'm not sure which is worse, being at 100% all the time, or doing a partial cycle each day - might be a wash? From what I recall, for a rechargeable Lithium, going through ten 10% cycles is about the same as going through one 100% cycle.

I've read so much different and conflicting advice about this with only anecdotal support. For my last last laptop I I did the partial cycle all day but for my new one, I'm going to try to keep it mostly full charged and then maybe once a month drop down to 20-30%.

I've been tracking my battery life with an app but it's too early to tell if this new approach is going to be better. Unfortunately I didn't save the data from my old laptop (cycle every day) but it was definitely better than the average reported.

Note: I have no idea what the measurement error is on the battery capacity.

 

[M Paquette]

I recommend taking a look at:

Battery Information Table of Contents, Basic to Advanced

The site was written by Isidor Buchmann, the founder of Cadex Electronics. This company builds battery analyzers, test systems, and chargers. My former employer used these gadgets in the design, test, and evaluation of batteries for a variety of products, including photoguy's battery...

The site has a LOT of information on the very different ways that different types of batteries need to be handled to maximize life, oriented towards non-engineering folks. It's well worth a look.

 

[springnr]

My Lenovo power manager settings are set to start charging at 25% and stop charging at 40%. I try to remember and cycle the battery every month or two. This way the lithium cells are standing by in storage mode at a partial charge of 40%. There is a button to select full charge if you are going to be using the laptop on battery power.

 

[ERD50]

I recommend taking a look at:

Battery Information Table of Contents, Basic to Advanced

The site was written by Isidor Buchmann, the founder of Cadex Electronics. This company builds battery analyzers, test systems, and chargers. My former employer used these gadgets in the design, test, and evaluation of batteries for a variety of products, including photoguy's battery...

The site has a LOT of information on the very different ways that different types of batteries need to be handled to maximize life, oriented towards non-engineering folks. It's well worth a look.

Thanks, I've been looking through that. A couple pertinent bits:

How to Prolong Lithium-based Batteries - Battery University

Most Li-ions are charged to 4.20V/cell and every reduction of 0.10V/cell is said to double cycle life. For example, a lithium-ion cell charged to 4.20V/cell typically delivers 300–500 cycles. If charged to only 4.10V/cell, the life can be prolonged to 600–1,000 cycles;

Charging to 4.10V/cell the battery holds about 10 percent less capacity than going all the way to 4.20V. In terms of optimal longevity, a voltage limit of 3.92V/cell works best but the capacity would only be about half compared to a 4.20V/cell charge (3.92V/cell is said to eliminate all voltage-related stresses).

So double the lifetime of the battery by accepting 10% lower capacity seems like a good tradeoff for me (maybe not the mfg, who wants to advertise max battery hours/charge).

After unplugging for a few minutes, my Power Manager reports 96% and 11.9 V. I assume that there must be three cells in series, so 3.97 V per cell? But there may be some other small voltage drops in that reading?

Anyhow, I'm going to go through a few cycles and record these voltages to get some ideas.

-ERD50

 

[Lsbcal]

I've had my wife's laptop battery out of her system for months. She uses it basically as a desktop PC so no need for the battery. Pulled it out when it was at 100% charge (I think). I've been feeling guilty about it because I had read (as others posted here) that I should get it down to 70% or so before storing.

Just checked this battery now and it's now at 77%. So maybe after months a battery looses some when stored out of the laptop?

I've put a post-it on the stored battery now with the charge state and date.

I too have a Nexus 7 for mobile web surfing. Just bought the minisuit bluetooth keyboard recommended by Al and it works nicely. Technology moves on.

 

[Totoro]

So maybe after months a battery looses some when stored out of the laptop?

All batteries lose charge slowly, even when you are not using them. Rechargable batteries lose charge faster.

 

[pb4uski]

Update - the original battery, which had not been keeping a charge and was then replaced and stored for about 18 months seems to be working fine now. Fine enough that I'm not planning to buy another replacement right away.

I am having something interesting happening. A little over a year and a half ago my laptop battery was not keeping a charge so I bought a replacement for ~$30 and threw the old one in a drawer. Recently the newer on wasn't keeping a charge and I was about to buy another replacements.

As part of deciding the replacement I found the old original batter and put it back in the laptop. It took a full charge and seems to be holding it and working fine. Perhaps it just needed a sabbatical.