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Comment by LeonenTheDK | Hacker News Reader

No sign of battery issues is huge, I'm still rocking my 3 year old Pixel 3a and recently replaced the battery, it was a night and day difference. General slowness/lack of responsiveness, half day battery life. Been like that with all my other smart phones since 2013. Would love my next phone to go on year 4 with no sign of battery degradation (although in lieu of that I'll take an easy to replace battery).

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> night and day difference

> slowness / lack of responsiveness

Are you saying that replacing the battery improved your phone's responsiveness? I knew there was a throttling thing with iPhones but hadn't heard of anything outside of that.

Samsung, OnePlus, and other phone manufacturers have all been accused of throttling phones and have acknowledged the throttling and/or released patches to give more user control. You can google "<manfacturer name> throttling" and get new reports of throttling as recently as last year for Samsung.

> Samsung, OnePlus,

Blame bad Samsung fab. Things like the Qualcomm 888 chipset were notorious for overheating like crazy requiring throttling (used in both Samsung and some Oneplus devices). Need TSMC. Apple had issues all the way back to like 6S era when they sourced from both and the TSMC ones just ran better.

You can override it with a custom rom and messing with EFS on those devices but it's already flirting with battery dangerous temps doing gaming. Better to buy TSMC or strap an icepack to the phone lol.

My wife's Nexus 6 would only play games at what appeared to be 2 fps unless hooked to a charger after three years. And those were just some 2D puzzle games, not COD, so I imagine other 2D apps were not running at full speed too but it was extremely apparent on games.

A degraded battery can't deliver as much power as a new battery and for your phone to feel fast you have big cores to boost to over 3 GHz which requires a relatively high voltage. These voltages aren't possible with a degraded battery and that's why your phone feels slower.

The voltage range of aged batteries is the same as the day they leave the factory. Or it could be even larger if the BMS is set up to sacrifice a little nominal capacity für lower wear when new, slowly widening the range as capacity decays. The temporary voltage drop while drawing a large current will be bigger on an older battery, that much is true. But that would still be a smaller delta than the one between fully charged and not at any age. If there's performance difference, I'd expect it to be from deliberately yearning performance/runtime trade-offs (which arguably are better to have than not have)

Why don't you actually take some lithium ion batteries and keep checking the voltage? Because mine have dropped to 1.3V

now, I noticed they weren't 1.5V to start, so they are crap, but it seems it just only goes lower as they age

If your Lithium Ion batteries are at 1.3V they are way beyond their service life.

Normal voltage range for Li Ion is 2.5 to 4.2V, nominal voltage is 3.7V, some manufacturers recommend you never discharge them lower than 3V. So something is off or you have your battery chemistries mixed up.

See https://docs.rs-online.com/3f21/0900766b816d9301.pdf

This is typically specified in open circuit voltage. Under load, lithium ion batteries can get to VERY low voltages due to internal resistance. 2.0V is not uncommon.

I've built a bunch of Lithium Ion packs (nothing huge, the largest was 10 KWh, but still you don't want to mess that up, that's 1000 cells in a 40S25P arrangement), none of them go that low under load. If your cells drop down to 2.0V under load that's not a normal condition, either you are discharging your cell at more than the 2C or so that is normally specc'd (which you are welcome to do but it will cost you in lifespan) or the cell is on the way out. The normal arrangement for high current discharge is to simply set up more cells in parallel so they all carry only a fraction of the current and stay well below the maximum permissible current.

One application where cells are loaded up really heavily is in RC toys and drones, there lifespan is secondary to performance. But a normal, long-life application for a Lithium Ion battery pack will ensure that batteries are not overloaded (either during charge or discharge).

There are also special cells that can gracefully handle high discharge current (and usually correspondingly high charge currents) typically at the price of some capacity for a given volume.

You'd be surprised the peak current demand of modern smartphones. AVERAGE current demand (not peak) of a Snapdragon 8 Gen 2 can hit 16W for short periods of time. At 3V, that's 5+ amps out of the battery. Worse if you account for efficiency, and even worse if you account for other power draws such as camera, display, etc etc. Running at 3-4C for short bursts is not out of the question.

That I readily believe. But in a well designed system (designed for longevity) you'd never see such discharge currents in a sustained manner and even short bursts are better served by capacitors (charged at a lower constant current) close to the consumer than by batteries. And that's why you'll see voltage regulators and large banks of capacitors right next to the CPU (besides compensation for line losses and stability of the supply, which with rapid wide load variations would cause all kinds of problems for the logic).

But in for instance a vehicle or an e-bike you'd rarely see batteries drained faster than the spec, not if you want to use your expensive device for a while.

Keep in mind, when I say 'short bursts', I mean on the time scale of seconds. No capacitor bank is going to be capable of supplying current for that long; especially not one put in a phone. In most cases, the restriction is inevitably heat based (how long can I run this before thermals cause me to need to throttle) and the power supply is pushed to be able to handle it.

EV batteries and e-bikes are a whole different animal than what is used in cell phone battery tech.

Also, is 2.0V bad for the battery? It's not great, but it's not Voc of 2.0V. It's Vsc, essentially. Which is a very different quantity.

What's the airspeed velocity of an unladen ion? A lithium ion cell at 1.5V is in deep discharge.

How do you feel about the lack of security updates? I miss the smaller size of the 3a bit upgraded since they stopped shipping software updates. I'm hoping you can talk me in to resurrecting it.

I believe you can install LineageOS on any old Pixel and still get updates. Though the type of updates will be limited. https://www.lineageos.org/

YMMV may vary a lot with LineageOS, unfortunately.

I was a big fan, but:

- Nexus 5X support was terminated

- Pixel 1 support is broken; the device used to reset daily (works fine with the original OS)

- They have at least one serious open issue (GPS not functioning, although it can be worked around)

In the end, I had to buy a new phone, that is officially supported. I still donate, but I don't hold my hopes high anymore, anytime that a device gets out of official support.

Only charge up to 80% battery unless you need the full charge and the battery generally lasts much longer

Is there a place that has empirical data on this stuff? Like what battery factoids are still true with the latest devices or not?

I would honestly love for phone manufacturers to outright build in some software to build in best practices if they actually exist. Don't let me charge to 100% at first or something!

AccuBattery is an Android app that gives battery usage statistics and more detailed readouts from the OS w/r/t battery condition and charge/discharge behavior.

Their help portal has a research summary explaining their sources (the most recent of which is from 2010, so battery tech has likely improved in some respects but it's still a useful reference point): https://accubattery.zendesk.com/hc/en-us/articles/210224725-...

Chargie is another solution for the problem and links to researches https://chargie.org/

I don't believe Apple has released empirical data, but Apple has optimized phone charging built into recent versions of iOS (Settings > Battery > Battery Health and Charging). It will stop at 80% and then resume charging to 100% about an hour before you start using your phone every day. iOS tracks your daily habits to determine the start of your day.

In the most recent iOS versions, if it can determine when "clean energy" is available near your location, it will also try to charge only during those time periods. I don't think any 3rd party has determined if it is effective.

This feature exists in Macbooks too, but it's useless to me - it never works because apparently my usage pattern doesn't convince the smart system to limit charging, and it gives me no manual control whatsoever. I think I'd have to always keep charging the laptop for it to kick in.

Just gimme a slider that lets me tell it to only charge to 80% and be done with it.

At least some Android devices have the same, it keys off your alarm if you have one set. My Pixel 6 Pro will also take advantage of chargers' ability to supply different amounts of power to not charge as quickly as it's physically capable of doing if it thinks I've put it on charge for the night.

My iPhone 12 mini spends 95% of its life on a MagSafe charger and has never charged to 80% after a year with this setting enabled. I wish Apple would add an explicit option like "Protect Battery" on Samsung devices.

Get into the quadcopter hobbyspace, you will learn more than you ever wanted about battery chemistries.

I just want to know how much of this stuff is “batteries in the fridge” stuff

One way to slow down the aging of batteries is to charge them only up to 80%, but this is not the only factor that affects their lifespan. Other factors include the temperature of the environment, the power consumption, and the quality of the battery materials and manufacturing process, which may be hard or impossible to know before buying.

https://www.nrel.gov/transportation/battery-lifespan.html

You'd be better served by leaving power save mode on all the time (No haptic touch or animated UI) and minimize brightness to extend the intervals between charging.

I’m pretty sure you should be able to find data. Only a handful of battery manufacturers used.

Phones typically are geared to use the full capacity of the battery.

The demand towards the thinnest phones possible leaves smaller tolerances towards cramming in the biggest battery possible.

I think the galaxy note 4 was the last one with a removable battery therefore something that could run a long time.

An external battery case depending on how you use it can extend the lifespan of an internal battery too.

I've seen the longevity graphs for lithium ion (don't know about other chemistries, but there's still a lot of lithium ion around). Ability to retain charge drops off faster if the battery is kept fully charged, especially in warm temperatures.

My electric car by default only charges to 80% unless you tell it you're planning a long drive in order to conserve battery life.

My Note10 has this. You can switch on battery protection and it will stop charging at 85%

The quadcopter community has dig up research on the longevity of lipo batteries under different charge levels. Note that they do push their batteries really hard. Their findings apply as long as the latest devices still set 4.2V as 100%.

Mind if I ask what battery you purchased?

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