[HN Gopher] How to prolong lithium based batteries
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How to prolong lithium based batteries
Author : VHRanger
Score : 101 points
Date : 2024-06-21 16:55 UTC (6 hours ago)
(HTM) web link (batteryuniversity.com)
(TXT) w3m dump (batteryuniversity.com)
| girishso wrote:
| 1. It's ok to keep laptop plugged in, even at 100% battery
|
| 2. Keep temperature as low as possible, maintain airflow
|
| 3. Avoid fast chargers
| ianschmitz wrote:
| I wish more devices offered a way to enable a "slow charge"
| mode.
|
| When I'm plugging my laptop into my dock to work for the next 8
| hours it doesn't need fast charging.
|
| When I'm plugging my phone in before bed to charge for the next
| 8 hours it doesn't need fast charging.
| zuppy wrote:
| i have 2 chargers near my bed, one has 3 amps, the other one
| has 1. i use one on another depending on how fast i need it
| charged. not the best solution, but it works.
| mtlmtlmtlmtl wrote:
| At least on Android it's possible to disable fast charging.
| It's in the battery settings on my phone.
| zimpenfish wrote:
| > When I'm plugging my phone in before bed to charge for the
| next 8 hours it doesn't need fast charging.
|
| iPhones do this with "Optimised Battery Charging" turned on
| (which I believe is the default setting) - "allow iPhone to
| wait to finish charging past 80% until the time you need to
| use it" (which it learns over time.)
| delecti wrote:
| Android has something similar. A notification pops up when
| I plug in at night, letting me know that it's charging
| slowly because I usually leave it plugged in overnight, and
| that I can disable it (once or permanently) to switch to
| fast charging.
| dsp_person wrote:
| On my laptop I have a script to set
| /sys/class/power_supply/BAT0/charge_control_end_threshold
|
| I could imagine automating this to set the threshold to the
| current battery level, and incrementing the threshold by 1%
| every N minutes to control charge speed.
|
| Right now I try to keep it at 50% max charge like this while
| plugged in at home.
| kube-system wrote:
| As others have mentioned, many phones do this in software,
| but I find the easiest solution is simply to use a charger
| incapable of fast charging.
| gruez wrote:
| >1. It's ok to keep laptop plugged in, even at 100% battery
|
| It might be "ok" to keep it plugged in at 100%, but if your
| laptop has a "battery conservation" mode that limits the charge
| to 80% (or similar), that's even better.
| crazygringo wrote:
| If you're on a Mac, you can install the free version of
| AlDente:
|
| https://github.com/AppHouseKitchen/AlDente-Charge-Limiter
|
| I keep my MBA at 60% since it basically never goes for more
| than a couple hours within being plugged in.
| oidar wrote:
| Also batfi - https://github.com/rurza/BatFi
| crazygringo wrote:
| Oh wow, looks like that's brand-new (from March?) as
| opposed to AlDente which is about 4.5 years old at this
| point, at least according to GitHub releases.
|
| It looks really really sharp, the UX is definitely much
| more visually appealing than AlDente. I might have to
| check it out.
| ein0p wrote:
| I think (though I might be wrong) charging of Apple
| hardware detects usage patterns and it would already not
| charge the battery to 100% if you're frequently plugged in.
| crazygringo wrote:
| Kind of, it's described here [1].
|
| But that only applies if you have a "charging routine",
| e.g. you always charge overnight and use it on battery
| all day long starting at 9:15 am:
|
| "When the feature is enabled, your Mac will delay
| charging past 80% in certain situations. Your Mac learns
| your charging routine and aims to ensure that your Mac is
| fully charged when unplugged."
|
| But in my experience, the feature doesn't do anything if
| your Mac is just usually plugged in. It simply stays at
| 100% because there's no routine for it to learn for when
| you tend to unplug it.
|
| [1] https://support.apple.com/en-us/102338
| ein0p wrote:
| Useful info, thanks. There's really no reason for my MBP
| to be charged 100% - I rarely unplug it
| user_7832 wrote:
| > 3. Avoid fast chargers
|
| Isn't this primarily due to heat produced? Aka cool fast
| charging is better than warm slow charging.
|
| I seem to remember a tweet I think by Mishaal Rahman (or
| another android journalist) on this.
| kccqzy wrote:
| Yes that's absolutely the case. So it just depends on how
| good the cooling system is. For a phone, it has no active
| cooling system. For an electric vehicle, almost all
| manufacturers (except Nissan Leaf) have adopted active
| cooling and you can expect them to do a good job activating
| adequate cooling for the battery.
| ssl-3 wrote:
| In absolute terms, cooler isn't always better.
|
| For example, Tesla has a pre- _heat_ function for their
| cars ' batteries that can be used prior to charging.
|
| https://www.tesla.com/ownersmanual/model3/en_us/GUID-F90720
| 0...
| kccqzy wrote:
| That affects charging speed, not battery longevity.
| VygmraMGVl wrote:
| It can affect battery longevity. If you charge lithium
| ion at cold enough temperatures, you get lithium plating
| which rapidly degrades capacity and can lead to internal
| shorts and fires.
| VygmraMGVl wrote:
| It's due to heat produced, gas generated from overvolting the
| battery, and stress gradients from different levels of charge
| across the battery.
| sopchi wrote:
| I disagree with your point #2 as it is written. You want to
| keep you battery close to the temperature at which it is rated.
| Cycling below that also harms batteries and shortens their
| life. If you really want to geek out about that, I can
| recommend for example a talk [1] that was given last week (you
| can jump to slide 15). The presentation has nice electron
| microscopy images of the cracking this type of abuse causes in
| batteries.
|
| [1] https://academy.covalentmetrology.com/wp-
| content/uploads/Bat...
| Filligree wrote:
| I wish I could find this information for LFP batteries. There's a
| lot out there, but it's all mixed with advice for LiPo; I can't
| find anything I trust to tell me the optimal voltages for maximum
| lifetime.
| user_7832 wrote:
| Is it possible to reach out to the manufacturer, or the place
| you;re buying your batteries from?
| speedgoose wrote:
| I was told that LFP is difficult because the battery management
| system (BMS) cannot reliably guess the state of charge using
| the voltage. The voltage is a mess on LFP.
|
| Even though a lower voltage prolongs the battery, you have to
| charge to 100% regularly to help the BMS. Thankfully the LFP
| chemistry doesn't seem to mind high state of charge as much.
|
| As a popular source, Tesla recommends to daily charge the LFP
| batteries to 100%.
| andruby wrote:
| > The voltage is a mess on LFP
|
| That's a weird statement. The voltage curve for LFP [0] is
| just a lot flatter. That's nice for your electronics, but
| makes it hard to estimate state of charge based on the
| voltage alone. So the BMS needs to keep track of total energy
| used to calculate state-of-charge.
|
| [0] https://www.jackery.com/blogs/knowledge/ultimate-guide-
| to-li...
| Filligree wrote:
| Excellent link, thank you!
| speedgoose wrote:
| True, it's very flat. And If you add some major temperature
| changes over many days and a descent amount of non full
| charging cycles, it's more challenging. Maybe I wasn't told
| it was a mess, but it's how I remembered it.
| fy20 wrote:
| The 100% charge thing is also for balancing, as most BMSs are
| pretty dumb and only use passive balancing.
|
| When an individual cell reaches a set voltage, a resistor is
| turned on which bleeds the excess power preventing that cell
| from overcharging. When the pack reaches 100% theoretically
| every cell should then be at the same voltage.
| Filligree wrote:
| If that's the case, then if you don't regularly charge to
| 100% you can end up depleting any cell that's out of
| balance. Good to know.
| serpix wrote:
| Lfp voltages are all over the place and even after charging to
| 90% the voltage drops back down. They might not care much at
| all being charged to high percentages. There is no reliable way
| to know the SoC other than coulomb counting and regular 100%
| top balancing.
| 8xeh wrote:
| LFPs are indestructible and last forever.
|
| For general advice, they like it cooler[1] than other kinds of
| lithium batteries. Try to keep them between 15-25degC. Other
| than that, charge LFP batteries to whatever percentage you want
| whenever you want.
|
| They are simply better than every other kind of lithium
| chemistry. Their practical downside is lower cell voltage (3.2
| vs 3.8), and slightly lower energy density. I've spent the last
| 7 years building LFP-powered lawnmower-sized robots, and in
| practice, the lower voltage and doesn't matter. And, unlike
| other chemistries, they don't catch fire when you stab them.
|
| For other kinds of lithium batteries, to maximize lifetime,
| keep them between 40-60%, avoid big charge swings (10-90%), and
| keep them warm (above 25degC).
|
| [1]: At 35degC, tests show they lose about 5% more capacity
| after 2,000 cycles compared with 25degC. But even that isn't
| really a problem, because they don't get to 20% capacity loss
| until 4,000 cycles. See:
| https://iopscience.iop.org/article/10.1149/1945-7111/abae37,
| fig 3.
| Filligree wrote:
| A practical concern is that the batteries in question will be
| powering our cottage, which is entirely off-grid.
|
| It's also unused for half the year, and for much of that half
| the solar input is effectively zero; for part it's literally
| zero. Not enough to even run the Victron gear, never mind a
| heater. Spring temperatures often drop below -5C.
|
| So we'll winterise it by shutting everything off, BMS
| included to the degree it'll let us, and the question is what
| SoC they sold be at for that to work.
| speedgoose wrote:
| I'm not a battery expert but some coworkers from the battery lab
| at work are, and they say that charging more often is better than
| doing big cycles. On most chemistries.
|
| In more concrete terms, it's better to keep the state of charge
| between for example 60 to 30% compared to for example 80% to 15%.
| Big cycles like 100% to 5% are the most damaging over time.
| izzydata wrote:
| Do you know if it is true that a battery reporting 100% is
| really only 80% and 0% is really about 20%? I heard that
| somewhere, but have had trouble confirming it. At least for
| something like a common smartphone.
| SubiculumCode wrote:
| Probably depends on the device,but I bet that marketing
| incentives suggest most won't. I mean do you buy the device
| that says10 hours battery live or 8 hours battery life?
| plonk wrote:
| "The battery is messed up after 2 years" is a complaint
| I've seen and it was pretty damaging to my buying
| intentions. Just one data point
| radomir_cernoch wrote:
| I think it's hard to define "the true 100%". It's always a
| matter of finding a tradeoff between capacity and lifespan -
| by defining a voltage range.
| aidenn0 wrote:
| True 100% seems easy for LiPo; it's the point at which it
| spontaneously catches fire.
| layer8 wrote:
| "Spontaneously" seems to imply that it's not actually a
| deterministic point.
| speedgoose wrote:
| It depends on the BMS. Some have big buffers, some don't. One
| simple clue is how fast it charges relative to the state of
| charge. If the battery takes a while to go from 95 to 100%,
| it more likely goes to a full state of charge. If the battery
| charges very fast to 100%, it probably has some buffer.
|
| In my experience, vacuum cleaners and smartphones are
| designed to destroy the battery as fast as possible, while
| most car manufacturers will have a big buffer and lie about
| the true 100%. With some notable exceptions though, like
| Tesla that allows to charge to 100% with some scary warnings
| or Nissan that designed some early Leafs battery pack without
| longevity in mind.
| 1970-01-01 wrote:
| This % all depends on how the battery management system (BMS)
| was designed to manage the state of charge (SOC). Some BMS may
| set 100% SOC to 80% capacity to prolong the cell and pack
| lifetime. Additionally, 0% SOC may be set as high as 20%
| capacity.
| tooltalk wrote:
| >> Additionally, 0% SOC may be set as high as 20% capacity.
| <<
|
| I think that was the case for GM Bolt years ago, but
| batteries cost a lot of $$ and you won't see more than 5%
| reserved for buffer these days -- or 95% usuable capacity.
|
| Tesla also had software lock limiting access to extra battery
| capacity on the Model S -- 70KWh instead of 75KW, or about
| (7%?). No point in carrying around extra weight that costs
| $3,000 to unlock, but it probably helped prolong battery
| life.
| UniverseHacker wrote:
| Some tools I use to actually follow this advice on various
| devices: I use Chargie devices (chargie.org - no affiliation) to
| control maximum charge level, and set thermal limits on
| smartphones and other small devices that can't limit charge
| internally with software. I also use a Peltier cooled phone
| holder and charger in the car (about $50 on Amazon), so it keeps
| the phone cool when charging and processing hard during
| navigation, and in direct sunlight. On Macbooks I use the free Al
| Dente app which lets me manage charge level. When I owned an
| e-Golf EV, I was able to set charge limits through the VW Car-Net
| app.
| ssl-3 wrote:
| I just clip my phone cradle to an AC vent on the dash. I've
| been doing this since [checks calendar] 2014, when I retired
| the last phone I ever had that had a specialized window mount
| accessory available.
|
| It cools when it is hot, and sometimes it warms when it is
| cold. Both things can be useful functions.
|
| (Even on old junk I've had without functioning aircon, turning
| the selector to "Vent," the temperature to "Cold," and the fan
| to some speed other than "Off" works to circulate air around
| the phone.)
| UniverseHacker wrote:
| That works on some cars, but I prefer having the phone up
| high so I can keep my eyes on the road, and I drive a
| convertible with the top usually down, so like to leave the
| HVAC off.
| ortusdux wrote:
| I remember the first time I upgraded android phones and
| logging in triggered 100+ apps to start downloading. The
| phone got to hot to old, so I put it in the freezer. As a
| bonus the metal blocked enough of the wifi signal to meter
| the downloads. Not the best initial user experience!
| ssl-3 wrote:
| Yeah, the Motorola Droid 4 was that way for me sometimes
| long after I began using it.
|
| It wasn't clear what the combination of triggers was, but
| sometimes the Play Store would wake up and start updating
| everything that could be updated -- and do all of these
| updates _in parallel_.
|
| Once or twice, it did this when I got in the car, plugged
| my phone in, and started driving -- sucking down what was
| (at the time) an enormous amount of [thankfully unmetered]
| cellular bandwidth and using enough power that the battery
| either would not charge, or would slowly discharge.
|
| It'd get a pretty toasty.
| locofocos wrote:
| TIL there's a name for this! (Chargie)
|
| I have an old Mac multiport adapter (USB C / USB A / VGA) that
| I use only to limit the current going into my smartphone, for
| the sake of battery health. It effectively downgrades any fast
| charger to a slow charger. This looks nicer, thanks for
| sharing.
| sitkack wrote:
| https://chargie.org/
| clumsysmurf wrote:
| The Chargie looks nice but ~6 of them for your devices gets
| pretty expensive.
|
| I'm looking for some device like a 6-port Chargie... Or a
| 6-port charger like this Anker:
| https://www.anker.com/products/a2123?variant=37436925477014
| that would allow you to control the charge status of each port
| via Zigbee / Wifi. Something like A/C smart plug functionality
| but for each USB port.
|
| Anyone see that?
| UniverseHacker wrote:
| Do you really need one for every device you own? Having it
| just for my phone is mostly fine. It is possible to configure
| a chargie to limit charge level based on current draw on non-
| phone devices, but complex, and usually not worth it in my
| opinion, I only use it for my iPhone.
| SubiculumCode wrote:
| The article mentioned heat. I park my ev in the sun in CA.
| Definitely hotter than 86 degrees. Does the car protect the
| battery somehow with cooling, or do I need to find shade asap.
| 1970-01-01 wrote:
| Varies by EV. The 1st generation Nissan Leaf was famous for
| overcooking its own battery pack because it didn't have the
| capability.
| the-alchemist wrote:
| Also worth pointing out that the original Nissan Leaf is now
| at least 13 years old, a lifetime ago in lithium battery
| tech, and intentionally used very cheap cells to keep the
| cost down.
| Rygian wrote:
| My car will run the AC on the battery whenever it needs to,
| even if I'm away.
| SubiculumCode wrote:
| ill have to check: its a 2023 bolt euv
| ydant wrote:
| Bolt will cool itself, but it does so more aggressively
| when plugged in (even if not actively charging). I always
| leave our EVs plugged in when it's over about 80F and below
| freezing because of that.
|
| My 2021 is complaining loudly (running the cooling system)
| about the heat-wave today.
| sitkack wrote:
| I would avoid charging at high temperatures, or rapid
| acceleration when the pack is hot.
| sitkack wrote:
| Like making _anything_ last, don 't operate at the limits of its
| envelope. * Limit max temperatures *
| Reduce maximum currents in and out * For lithium
| batteries, limit peak charge to 3.92V, do *not* charge to over
| 4.1V or 30degC
|
| I can't find the specific research study, but NASA did a study
| that last I read was going on for over 30 years with a neglible
| drop in capacity by only operating in the flat portion of the
| charge/discharge curve. The result is that properly speccd
| battery packs (probably > 1.5x most battery packs) can last
| indefinitely. For my cordless tools, I get the largest modules I
| can (5Ah). I have a single slim 2Ah module for fitting in tight
| spots.
|
| *edit, when using a cheap intermittent high current device, like
| a hand vacuum, apply a duty cycle, like 30 seconds on, 10-30
| seconds off to prevent the internal battery pack from getting too
| hot. These kinds of consumer goods have the smallest battery pack
| that will outlast the warranty.
|
| I really wish battery charge profiles were codified in QR codes
| on the modules themselves (besides existing on an I2C bus).
|
| Short-Course on Lithium Ion Batteries
| https://ntrs.nasa.gov/api/citations/20190030819/downloads/20...
|
| battery aging dataset (appears dead)
| https://c3.ndc.nasa.gov/dashlink/resources/133/
|
| https://www.nasa.gov/wp-content/uploads/2021/10/3-nasa_batte...
|
| https://ntrs.nasa.gov/api/citations/19990032333/downloads/19...
| hinkley wrote:
| In the mid 00's there was a set ACM papers about how a better
| scheduler in the OS could substantially improve battery
| longevity (lifetime and per charge) based on the observations
| that most batteries do worse the faster you draw current, and
| you're better off load leveling to keep the discharge rate
| steady. So for instance instead of running the disk and CPU at
| saturation, reducing CPU use when disk was saturated and vice
| versa. The apparent speed of the system was affected less than
| the battery life was increased.
|
| About 5 years later Apple bragged about how their new laptops
| without discrete batteries were 2x the run time of the previous
| generation due to the batteries being 1/3 bigger, 1/3 more
| power dense, and the operating system being 1/3 better at
| managing battery life. I'm fairly certain the latter came from
| someone reading those papers and taking them to heart. They had
| an advantage for the next few years.
| muzika wrote:
| 3.92V is very conservative, that is a good voltage for long
| term storage even. It should be safe to charge to 4.05-4.10V
| regularly.
| cubefox wrote:
| I think all systems that allow for fast charging should, after
| plugging in, ask: "Do a slow charge instead?" and perhaps: "Only
| charge to 80%?". These could be two check boxes that are
| unchecked by default. Maybe you could change the default in the
| settings.
|
| Anyway, the way this is currently solved e.g. in Android is
| clearly suboptimal. You can only configure charging in the
| settings, but obviously it depends on your current situation
| whether you want to use your device immediately and need a full
| charge.
| freehorse wrote:
| I actually have a couple of chargers that just do _exactly_
| 5V/1A for this reason.
| cubefox wrote:
| Yeah, but a software solution would be better and actually
| easy to implement.
| hartator wrote:
| Note that in most battery chemistries, the degradation floors at
| around 80% whatever you do.
|
| These advices are to get to that 80% slower. If you are fine with
| having 80% in like 2 years instead of 10 years, you don't have to
| really limit yourself.
|
| A better way will be manufactures to advertised 100% as current
| 80% and allows you to boost you to 120%.
| longstation wrote:
| Check the article, it contains a graph where the capacity is
| reduced to 10%.
| hartator wrote:
| The worst I am seeing is 78% in figure 6.
|
| Obviously, I am not talking about charging your battery at
| higher voltage than advised, but comparing 0-100% (least
| optimal cycles) to 40-60% (most optimal cycles).
| lesinski wrote:
| Two unconventional things I do to improve my iPhone's battery
| health (which follow this article's findings): 1) Don't use a
| case - Otherwise, you are literally wrapping your phone in a
| rubber insulator 24/7, increasing its overall temperature. 2)
| Don't charge at night - Turn off your phone at night. Instead,
| charge it during the day when you're at your desk. This reduces
| the number of cycles over years (because your phone is
| continually draining/recharging all night even when you aren't
| using it)
| Daniel_sk wrote:
| iOS will not fully charge your battery during the night - it
| will top off the battery just before you usually take it off
| the charger in the morning (it learns your usual schedule + it
| probably also makes sure the battery is ready based on your
| alarm settings).
| neves wrote:
| All Galaxy phones have a configuration to limit the charge to 85%
| imp0cat wrote:
| Recent updates have changed that. The limit is now 80%. Also
| some more options (like not staying at 100%, but bouncing
| between 95% - 100% when plugged in to a charger overnight) were
| added.
| mnw21cam wrote:
| I have had my phone for 4.5 years. I charge it every night to 80%
| - I have Accubattery installed, so it pings to tell me to unplug
| it, and it also does a fairly decent job of measuring the
| capacity. I charge on a fast charger (10W) instead of the super-
| fast charger (18W) because that keeps the temperature from rising
| too much. I use the phone a fair amount, so I'm usually charging
| from around 50%. Therefore, the battery has had ~1600 cycles of
| around 30%, or 480 full cycles equivalent. The design capacity of
| the battery is 4000mAh, and Accubattery tells me it currently
| stores 3460mAh, which is 87% of the design capacity.
|
| I therefore approve and recommend the above strategy for treating
| the battery to make it last longer. I also recommend Accubattery
| - it seems to do the job fairly well.
| tooltalk wrote:
| Accubattery pings, but doesn't actually stop charging. Some
| Android, Samsung Galaxy for instance, now has "battery
| protection" mode that stops charging at 80%.
| pkulak wrote:
| I just use the hell out of my phone battery and pay 50 bucks
| every 3 years to replace it.
| clearleaf wrote:
| Me too except my first phone is the only one where I had to
| replace the battery. My 5 year old phone still lasts the
| whole day without going through any of this rigmarole. It's
| mostly superstition and the parts that aren't are such a wash
| that they aren't worth worrying about. Just look at these
| people trying to reach an agreement on whether you should
| stop charging at 80% or not. Your gadgets should work for you
| not the other way around.
| chasil wrote:
| On Android, I use the "Advanced Charging Controller" module for
| Magisk.
|
| If you have some way of rooting your phone and installing
| Magisk:
|
| https://magiskmanager.com/
|
| Then you can download the ACC module and set it to halt
| charging at 80%:
|
| https://github.com/VR-25/acc
|
| This functionality should be native to Android and iOS.
| Yesterday.
| Havoc wrote:
| I've been doing 80% >> 45% for a while on a 14 pro max....on a
| best effort manual basis.
|
| Appears to be working...I'm on 93% battery health today while
| googling suggests others where hitting <90% in mid 2023 already.
|
| So unscientifically it does seem to matter, though whether it is
| worth the hassle is another question
| sghiassy wrote:
| For what it's worth, I don't pay attention to my charging
| habits and my iPhone 14 Pro Max is at 92%
| Zak wrote:
| I've been using ACCA[0] to set limits on battery charging on
| Android devices for years. Note that it requires root.
|
| ACCA can limit charge percentage, allowing the device to operate
| plugged in without charging beyond a certain point. It can also
| pause charging when the temperature exceeds a threshold, limit
| the charge rate, and several other tweaks to charging behavior.
| By default, I use a charge limit of 60% and a charge rate of 500
| mA, increasing those when needed.
|
| [0] https://f-droid.org/packages/mattecarra.accapp/
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(page generated 2024-06-21 23:01 UTC)