Comment by bbarnett
Comment by bbarnett 4 days ago
[flagged]
Comment by bbarnett 4 days ago
[flagged]
Three times I've been lazy and set up an old phone or tablet as an always-plugged-in stationary device without excising the battery, and that has produced two spicy pillows and one completely dead battery (phone wouldn't even boot when plugged in, until I replaced the battery). Granted, these were all 5-10 years ago, but I do not trust the batteries and their controllers in these devices.
Nowadays if I want to leave a device plugged in I crack it open, remove the battery cell, solder on a power supply and capacitor, and then do the nonsense with rooted Android to keep it from shutting itself down.
The fact that they can doesn't mean they will.
On older devices the controller might make some assumptions that holds true with a new battery, but very much doesn't with an old and worn one.
My Macs have all been sensible about it, but I've seen Windows machines with batteries that just died from being plugged in all the time not even 10 years ago. Even if that specific instance was just a bad battery and not due to a charge controller, I have no faith in Random Windows or Android OEM Number 582 doing this correctly.
For devices that are fixed, I'd prefer to eliminate the potential of there even being a problem in the first place.
There’s basically zero risk for these cell phone batteries outside of freak accidents, speaking as someone who who’s been building packs since pouch cell Lipos first started coming out for model airplanes back in 2008/2009.. That’s because in a single cell configuration, there’s no way for the charge controller to run up an imbalance and overcharge one of the cells.
I somewhat agree with you. As my last comment suggests, I have a lot of experience running phones as AP’s including phones with dual cell configurations.
Where things go off the rails is situations where extreme heat can be present (shoving phone in direct sunlight in window with hot climate is a bad move) another thing they don’t tolerate well and people don’t talk enough about this is deep discharging the batteries frequently. This causes a breakdown of the SEI membrane and makes it so future recharging generates more heat and gas. This will cause expansion and might cause a short/failure if poorly designed (galaxy note 7).
fwiw I’ve used 24/7/365 plugged in phones as AP’s in multiple locations for a decade or so now, never had an issue. Past few years I use the battery threshold to set them to 70% charge and they don’t move from this for months at a time.
What roasts the lifetime of my laptop batteries is compiling with gentoo, but again never an issue with catastrophic failure and I have 20+ years of experience with that as well.
I've gone through a dozen or so LiPo-utilizing portable devices at my property in the Mojave desert. All it takes is a single season for many of these batteries to swell up to such an extent the enclosures split open.
Ostensibly they contain charge controllers and temperature sensors, yet they're unable to prevent this outcome when the ambient temperature exceeds 110F day after day while the device stays on in a hot attic w/usb-c pd connected.
Fortunately I haven't had any burst into flames yet, but after a few years of seeing this pattern repeatedly I stopped deploying anything containing LiPo batteries at the property.
YMMV - but IMHO it's prudent to exclude these batteries from such unattended, powered 24x7 devices.
Leaving such devices plugged in 24x7 unattended creates opportunities for such ambient conditions to develop unnoticed.
These mobile LiPo-using rechargeable devices simply aren't ideal for being left powered while unattended, day after day, year after year. All it takes are some sunny days with normally closed blinds left open and you may slowly be cooking that device you forgot about that Just Works but is a ticking time bomb after the 10th day it spent an hour in direct sunlight while charging.
AIUI the high temperatures are particularly damaging to the SEI (Solid Electrolyte Interface) layer, which is the layer preventing dendrite growth. If that layer breaks down enough for dendrites to grow, you're in internal short / fire-risk land.
Excellent advice. Did you swap any of the cells with a different chemistry?
Not really, there was a brief excursion in kludging a ZTE MiFi device to use a DIY NiMh pack of AA cells when it refused to stop self-destructing its OEM LiPo batteries every summer. (I use a MiFi hotspot for a cheap security camera network)
It worked as a stop-gap but I've since replaced it with a GL.Inet X300b ruggedized hotspot without any batteries.
There's no UPS for now... if I went the route of wanting uninterrupted power at the property I'd probably put a battery bank underground outside to power the entire building. It's not worth risking anything rechargeable inside the place given how hot it can get, and how long I sometimes go without visiting.
I'm not sure how generally applicable it is. When you have several acres of undeveloped land full of sand at your disposal it's relatively trivial to dig a pit, mix some concrete from the sand you excavated, and pour a subterranean cellar to house a battery bank and other hazardous infrastructure. Nobody would even notice it happened/exists.
The situation is far more complicated for folks in apartments or high density housing.
That's silly. Batteries don't like to be kept at 100% all the time, not unlike your lungs which doesn't want to stay filled all the time (which is uncomfortable for your muscles even if you ignore the carbon dioxide).
e.g.: MacBooks discharge the battery down to 80% by using the battery even if it's plugged in by citing "Rarely used battery", and keep the battery at 80% for at least half a day, then charge it again.
Li-ion is an adversarial chemistry. You need to take care of it or the battery bites back by puffing up or losing capacity very fast, or becoming an indoor firework.
I've been using an old Pixelbook for 3 years that I had laying around for an always on Home Assistant control panel (but with adaptive dimming that defaults so extremely low brightness to reduce heat until approaching it).
I noticed a few months ago that the battery has started to significantly swell pushing the back panel apart, but I haven't worked up the motivation to try removing it yet. From what I can ascertain from user experiences, it actually does boot sans battery but haven't confirmed, it would be awesome if that worked and would probably give me 5+ more years of usage.
So in my case, data point is that 3 years of 24/7 use/charging of an old laptop/tablet was enough to push it over the edge and finally swell. It's really a shame how so many otherwise usable devices that could be wall mounted turn into e-waste because they won't run without a battery. With USB-C PD a well-designed device should be able to get whatever power is needed on demand but manufacturers don't really have any incentive to future proof for the .01% of users like me who would benefit.
Right, but, this is just a single data point anecdote, right? Let’s say for same of argument that there is a 5% chance of overheating in five years - and another sub-percentage where this causes a fire, depending on where it is plugged in.
95%+ of people would report “zero problems here, all concern is overblown”.
Safety doesn’t work that way?
I have a Samsung tablet in a non-flammable container waiting to be disposed of after being mostly plugged in for 3 years then suddenly swelling quite alarmingly. YMMV.
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