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Comment by vigneshv_psg | Hacker News Reader

Isn't it an inherent problem with phones that if they are left on charge forever that their battery will explode? I've had test devices that I left connected for months together and inevitably the battery has exploded on every single one of them.

Perhaps, it can be hooked up to a smart plug and charged up whenever battery goes down below a certain percentage and shut it off when it's full.

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> Isn't it an inherent problem with phones that if they are left on charge forever that their battery will explode?

Not necessarily, it depends on how much care went into making the phone.

Ever since Samsung had the unfortunate experience of having every airline announce that their phone wasn’t allowed on board (even when switched off), battery management has received as much attention as is possible. Most implementations today have multiple fail safes in place to prevent the chances of a battery exploding.

Today, several extremely improbable events must happen in a row to make a battery explode from just being connected to a charger 24x7.

Source: Implemented battery charging on a different Lithium Ion battery bearing consumer product.

dont forget that Samsung followed that up with batteries that swelled while just sitting on a shelf as well.

https://youtu.be/OfM0GqsIB6c

Do a lot of phones have faulty charge termination circuits or something? I can't see any logical reason for this. Plenty of people leave laptops plugged in constantly for months without that happening.

I have a 2011 Macbook Pro that I have left on a charger for 5 years with no issue. Only runs for about 40-50 minutes off the charger nowadays.

That’s basically what I did for a android tablet mounted to a wall for home assistant control panel. Had a shelly smart plug that could be controlled via a simple http get request. I used tasker to monitor the charge state. When it reached specific state value, it would then make an http request to the shelly plug to turn off. Same when battery level dropped below a certain percentage.

Just watch out for battery degradation, at some point the % shown will not mean anything.

Even at 100% the battery won't be able to give enough power to even stay ON unless plugged in all the time. This is why we need removable and easily replaceable batteries as most devices are 2-3 years of regular use will have a degraded battery.

Yes - you're absolutely right. Eventually I'm going to see degradation in capacity. Fortunately, the tablet is a Amazon fire 10 tablet (rooted) and relatively cheap to replace. I paid $100 for it 3 years ago.

That's actually a really clever hack.

Lenovo's tablets are designed to be aware of this - after they've been plugged in for extra long (afaik 24H) they switch to battery-protector mode where they hover from 40%-60%. Hopefully somebody could steal this feature and add it to LineageOS or something. Edit: apparently you can do this on stock android with root[1]

[1]https://f-droid.org/en/packages/mattecarra.accapp/

There is BatteryBot Pro on https://f-droid.org where can set an alarm for charging the phone you use till 80%.

Yeah, this is a concern for me too. I'd be more comfortable if I could replace the batteries in repurposed Android devices with a dummy passthrough that pulls power straight from USB-C.

Becoming a spicy pillow is the inevitable fate of almost all small lithium electronics batteries. Keeping them in the 60-80% range will slightly help extend life, but that's about it, unfortunately.

I've been using "al dente" on my new laptop to keep the battery charge maxed out at 80% and hopefully extend the life of my battery.

For anyone who's interested, it's written as AlDente, one word:

Free version: https://github.com/davidwernhart/AlDente-Charge-Limiter

Pro version: https://apphousekitchen.com/

If you have root, that's easy to do on Android as well. Honestly, it's one of the like three things that I root for these days

My Samsung has this option, it's called Protect Battery, but I still need to turn it off to get through flights and other fun events.

Thank you. I've never heard of this option, I just enabled it.

Thanks, didn't realize I could do that

> spicy pillow

British English speaker here. I've not come across that expression before. The "pillow" part seems obvious, but not "spicy". What am I missing?

https://www.reddit.com/r/spicypillows/

Thanks. I suspect my brain is just too old to ever grok meme formation.

Battery fires are a genuine danger if a lithium ion battery at a high state of charge suffers physical damage.

https://www.youtube.com/watch?v=jGUkKi7cfK4#t=2m36s

For fully stationary use, you could replace the battery with a voltage regulator + supercap combo like in this video: https://youtu.be/YfvTjQ9MCwY?t=856

This ensures that the phone does not get confused when powered straight from the adapter with the battery removed (provided it is even possible to do so).

My old Nexus One has been serving me as an alarm clock for over 10 years now and it hasn't exploded yet.

Didn't they have removable batteries? One of my old nexi did at least.

The dative plural of nexus is nexui (and the nominative plural is nexus, with long u) :)

Nobody expects the fourth declension.

If you don't need the "UPS" capability, you should be able to run them without a battery.

Not necessarily; laying aside the issue of whether the battery is even removable, a lot of devices expect to be able to lean on the battery for temporary spikes in power consumption. I don't specifically know that this affects phones, but I'd be surprised if it didn't

yes, and typically at the very least a protection circuit that needs to be implemented or faked, or whatever.

i replaced a swollen battery on a cheapo hotspot with an 18650, but i had to remove the protection chip from the old battery and wire that up with my battery holder. if i was more industrious/desperate i probably could have used the one in the 18650, but that was more fiddling than i wanted

Some phones refuse to boot without a battery. It was the case for my Lenovo P2.

The PinePhone boots without a battery but it's modem won't.

I've not used these myself but they seem to be designed to solve this problem:

https://chargie.org/

one way to defeat this problem is to connect the charger to a timer plug so that the charger can turn off at night. I use this approach to keep some lesser-used laptops connected and charged (edited) without so far running into the spicy pillow problem.

can laptop batteries explode as well in that condition? I have an old lenovo running ubuntu 24/7.

I and an acquaintance got identical Onn i3/4gb laptops (clearanced for 100usd). They left theirs plugged in constantly while I used the mechanism above. Three months later, theirs was suffering from spicy pillow, bad enough to rip the screw holders for the case, while mine is ok so far. I think the mechanism above is reasonable for shady hardware like the Onn laptop but I hope your Lenovo might do better.

If fits plugged in and running 24/7 and is old enough most laptops can run without a battery.

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