Laptop Battery Life Span

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ZeeOSix

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The new Dell laptop I bought shows in the operating manual that the battery is specified as: "3-cell "smart" lithium-ion (42 WHr)".

Also shows that the approximate battery "Life Span" is "300 discharge/charge cycles". 300 charge cycles don't seem like that many considering some users could potentially charge it almost every day so 300 cycles could be burned in a year. Andmaybe they mean full discharge and recharge cycles? They don't clarify exactly what constitutes a "discharge/charge cycle".

Would it be better to leave the laptop plugged into the wall and keep the battery at 100% charge as much as possible? Maybe that would help prolong the Life Span of the lithium-ion battery ... ??
 
Yes, that 300 cycles is the full recharge and discharge of the pack, per the Li-Ion cell manufacturer's data if the cells are charged to the expected 4.20V (usually, ID the cells and check the datasheet in case of an unusually, different voltage spec), from the fully discharged voltage level, whatever that might be based on the threshold set by the battery protection board included, or integrated onto the laptop mainboard. For example that discharge voltage could be around 2.5V (again per cell, not the sum of all 3 cells' voltage in series), but an OEM laptop manufacturer may build in a little voltage buffer to allow the laptop to gracefully shut down when it reaches the software reported 0%.

Topping off will not count as an entire charge, just that % put back into it, however Li-Ion battery lifespan is greatly increased if you terminate charge slightly under 4.20V, and yet few manufacturer do this because it is a competitive market, how long their product will run per change while being reviewed and tested... not so much how long the battery lasts, much later. Anyway it is not always convenient to try to terminate charge slightly before 4.2V so the most practical advice is, don't fully recharge it if you don't need it topped off, OR just forget I wrote anything since a 3 cell battery shouldn't be all that expensive from aftermarket sources, once the laptop model has been relased long enough ago that 3rd parties have time to produce batteries for it. Some will suggest to only buy OEM batteries and that too is a good idea if runtime matters more than price.

I sort of answered your second question without trying. No, it would not necessarily be better to keep that battery at 100% charge. It would be better to take the battery out of the laptop while operating it from the AC/DC adapter, as long as it has enough charge to last longer than needed for your next portable (off-grid) use.
 
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Constantly charging Lithium batteries to 100% is a great way to reduce their life span most damage to lithium cells occurs when they are fully discharged and as they reach termination during a full recharge, I mostly use my Laptop plugged in and my last dell had a power management app that let me set a maximum charge, I think I had it sat at 70 or 80% and then it had another option for at what minimum percentage to start charging it again if you let it discharge I had it sat at 40% or 50% so pretty much it never cycled the battery. The 300 cycles rating should be referring to a complete discharge to full recharge cycle.
 
You'll damage the battery faster with deeper discharges.

Most Dell laptops I'm familiar with have a few options in the BIOS, also typically available as a Windows app, where power charging settings can be tweaked.

There's a setting that will maximize battery life for your particular situation, and other settings that are available if you need, for example, rapid charging because you're a business traveller and may only have limited time to plug the laptop in at an airport.

The setting in the software that is for "mostly plugged-in computer" actually won't charge to 100% most of the time, as long-term charging of a Li-Ion battery to 100% is damaging.

Fortunately the newer Dells are smart enough to recognize that very low temperatures and attempting discharge can be incredibly harmful. And refuse to start up accordingly.

There are some battery users that burn their batteries up in a year. That's just a cost of doing business. Tesla can probably be single-handedly credited with creating so much demand for Li-Ion cells that prices have crashed on replacement units. Even 10 years ago I was easily spending $150 every year or two on a new battery for a laptop at the time. By the time I put the final battery in that laptop, they were down to $25.
 
Deep discharge is in the hundreds. Very shallow discharges in the middle 50% of the charge range can be millions.

Charging to max can accelerate electrolyte oxidation, plating, etc.

Best to not fully charge li-ion if possible, but also to indeed full cycle every now and again to ensure calibration drift of the charge algorithm isn't an issue.
 
Originally Posted by ZeeOSix
The new Dell laptop I bought shows in the operating manual that the battery is specified as: "3-cell "smart" lithium-ion (42 WHr)".

Also shows that the approximate battery "Life Span" is "300 discharge/charge cycles". 300 charge cycles don't seem like that many considering some users could potentially charge it almost every day so 300 cycles could be burned in a year. Andmaybe they mean full discharge and recharge cycles? They don't clarify exactly what constitutes a "discharge/charge cycle".

Would it be better to leave the laptop plugged into the wall and keep the battery at 100% charge as much as possible? Maybe that would help prolong the Life Span of the lithium-ion battery ... ??



I got a free 2013-2014 Lenovo Thinkpad t530 from my employer late last year. It spent most of its life plugged into the wall and I expected the battery to be garbage. When I first got it, it would run for over 6 hours of steady usage. I upgraded to windows 10 and have used it quite a bit for the past 5 months or more. It has probably degraded a little bit still lasts me 4+ maybe 5+ hours. I'm not sure how to figure out how many cycles it has, but I assume that the Lenovo battery management kept it running on the cord and saved the battery all those years.
 
Originally Posted by ZeeOSix
Would it be better to leave the laptop plugged into the wall and keep the battery at 100% charge as much as possible? Maybe that would help prolong the Life Span of the lithium-ion battery ... ??


You don't want to keep it at 100% non-stop. That is actually bad for a Li-Ion cell. It's better to keep it at 50-60%. Windows has a setting that allows you to do this.
 
It's varied for me. I had an HP that needed a battery under the 1 yr warranty; the replacement also didn't last long.

I had a bargain-basement Dell that had excellent battery life for 4 yrs.

My current 2 yr old Samsung has had a noticeable drop off recently.
 
My MacBook Pro, which I bought in August of 2018, has about 325 cycles on it, and is still at about 90% "health."
I'm thinking it should be good for 4+ years. (I use it pretty heavily, being in college.) I charge it pretty much every night.
 
I got about 3-4 years of healthy usage out of my 2010 Lenovo entry level laptop. Now I have 2 aftermarket batteries for it, neither of which are good, I can get a couple hours before it needs to be plugged in on the LG battery pack and less than an hour on a Sanyo battery. Both new late last year.

7 years on the OEM Thinkpad battery but it wasn't used steadily for 7 years. Probably equivalent of a couple years of regular use at most.
 
Originally Posted by Cujet
Many laptops now have a selection to limit battery charge to about 80%, with the goal of extending battery life.



That would be an amazing option. I don't see anything like that in the windows settings, maybe its a bios thing?
 
Originally Posted by buck91
Originally Posted by Cujet
Many laptops now have a selection to limit battery charge to about 80%, with the goal of extending battery life.



That would be an amazing option. I don't see anything like that in the windows settings, maybe its a bios thing?


Dell usually has some support software that they either pre-install or you can install for yourself from the support.dell.com website, that allows you to access those settings within the Windows environment (if that's the system you run). But yeah, at least on my Dells, such settings are also available in the BIOS.
 
Originally Posted by pitzel
Originally Posted by buck91
Originally Posted by Cujet
Many laptops now have a selection to limit battery charge to about 80%, with the goal of extending battery life.

That would be an amazing option. I don't see anything like that in the windows settings, maybe its a bios thing?


Dell usually has some support software that they either pre-install or you can install for yourself from the support.dell.com website, that allows you to access those settings within the Windows environment (if that's the system you run). But yeah, at least on my Dells, such settings are also available in the BIOS.


Thanks for that comment pitzel. I searched just now and did find the "Dell Power Manager". Show a couple of screen snap-shots below. I'll have to go through and look at all the settings. It does look like I can set an upper charge percent level, and there's also a pre-canned setting for user's who have the laptop plugged in all the time.

So if I set a lower and upper level in the Custom settings, what would be a good lower and upper battery charge percent to use? Something like start charging at 45~50% and stop at 80~85%?

[Linked Image]


[Linked Image]
 
Originally Posted by madRiver
Cheaper laptop eg sub$500?

As a comparison my MacBook Pro which is $$$$ has about 1000 cycles according to software.


This one ... got it for $525 with the 17% discount and little more company member discount on top of that. Think I'll at an 8GB memory stick down the line for ~$35.

https://www.dell.com/en-us/shop/del.../spd/inspiron-15-5593-laptop/nn5593dssfh
 
So after playing around with the battery "Dell Power Manager" application, I looks like it holds the battery charge level constant when the charger is plugged into the wall.

Example:
If I have the "Start Charging" set to 50% and the "Stop Charging" set to 70% then the battery charge will be held constant at whatever charge level the battery is at when the charger is plugged into the wall.

So if the battery charge level was 63% with the charger unplugged, and I then I plugged in the charger, the Power Manager would keep the battery at a constant 63% no matter how much I use the laptop. It will not discharge to 50% and then recharge it to 70%, then discharge to 50% and recharge to 70% ... and repeat any kind of discharge/recharge cycling.

If I leave the laptop plugged into the wall most of the time while using it, what would be a good constant level of charge to maintain on the battery?
 
Originally Posted by ZeeOSix

If I leave the laptop plugged into the wall most of the time while using it, what would be a good constant level of charge to maintain on the battery?


The setting "Primarily AC Use" is basically built for that scenario. It doesn't charge the battery to 100%, and it doesn't do an aggressive charge either when it is used off AC power.

I'm not sure how it works, but it just does and has kept the battery in my 4-year-old Dell in good shape. First time I've ever had a laptop battery last so long. I use to need a new battery practically yearly on an older generation Dell.
 
Originally Posted by pitzel
Originally Posted by ZeeOSix
If I leave the laptop plugged into the wall most of the time while using it, what would be a good constant level of charge to maintain on the battery?

The setting "Primarily AC Use" is basically built for that scenario. It doesn't charge the battery to 100%, and it doesn't do an aggressive charge either when it is used off AC power.

I'm not sure how it works, but it just does and has kept the battery in my 4-year-old Dell in good shape. First time I've ever had a laptop battery last so long. I use to need a new battery practically yearly on an older generation Dell.


Yes, I see the "Primarily AC Use" setting in the "Dell Power Manager", but it doesn't give any details on what max charge level it uses.

After doing some more reading on Li-Ion batteries, I think for now I'll go with this. When plugged in, it will just hold the max battery charge ot 75%.

[Linked Image]
 
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