How do you store devices with Lithium-Ion batteries for long-term?
I'm curious about how everyone stores old smartphones and other lithium-ion battery-dependent devices while preserving battery life. Especially when they might want the device to keep working over several years.
I've tried charging my backup devices to 50% and storing them in a cool, dry place, but I often forget to do so, resulting in a drained battery by the time I recharge them. I am worried this might be affecting the battery's longevity.
Does anyone have a better method, such as an automated charging system, for managing this?
No idea about anything automated for it but my understanding is that you really can't prevent the problems. I think I read that 70% is more ideal thoguh, because it will keep a charge longer in the better range for the chemistry. The real problem is that the chemistry itaelf of the batteries will slowly and irreversibly break down over time whixh is why once it discharges past a certain point it may not be safe ever again to charge the battery without reprocessing the materials into a new battery. The safest way is really to remove the battery entirely and replace it once you're wanting to use it again. This might also make it easier to keep the battery at a safe charge level if you can find something else to handle it.
I don't think you want an automated charging system. Maybe make a calendar invite for yourself on the first Saturday of every month to check them. Probably takes at most 10 minutes of your weekend.
in a dedicated concrete structure at least fifty feet from neighboring structures
If you're using the device that infrequently, recycle it and stop worrying about it.
In a freezer I’ve been storing detachable batteries of a laptop that was mainly used at a desktop. They came out fine after some five years, didn’t do tests before and after though.
I was going to ask if it was even safe to keep those batteries in device long term, but the answer is already out: https://news.ycombinator.com/item?id=37684415
Those warning stickers asking you to remove the batteries when the device won't be used for a long time were not just decorative.
NMC chemistries: 70-80% charge, minimal humidity (corrosion of electronics is always a concern), very cold, and in a fire-proof container.
Pb chemistries (automotive, boat, etc.): trickle charge with periodic desulphation.
Whenever I go on vacation for more than 2 weeks, I have this irrational fear that one of those neglected devices in a drawer somewhere would become a spicy pillow and self combust and burn my house down. Sometimes I keep them in those thin metal cookie boxes with a lid, so it could have some level of isolation. Never validated though.
I do nothing and surprisingly nothing is broken. I.e. I found 6 years not used Xperia phone, I charged it and it just works, without any visible battery degradation issues. I have few other battery powered devices and none is giving me any issues after years of storage.
Last time I've seen swollen battery was in the Nokia dumbphones era.
So while it might not be the best idea - I will keep doing nothing special.
Modern smartphones have sophisticated battery management systems that could theoretically be programmed to optimize long term battery longevity but unfortunately those systems tend to be off limits to third party developers.
I just make sure to never store them fully charged, or fully discharged. Some neutral state of charge tends to work fine.
There are inexpensive timers you can plug into an outlet and attach one or more devices to (power-strip style). Just choose some cycle (half an hour once per week, for example) and attach all your devices you want to keep the batteries from draining to zero.
I don’t know the best timing approach to maximize battery longevity, but draining to zero for a longer time can definitely kill a battery.
If you are going to need that device in not nearest future (1 year+), probably you should buy an original spare battery. There are maybe a million of Lithium battery designs on the Earth, do not expect you can easily buy a battery to your device. Especially if this is a Blackberry/GoPro/proprietary device with a sophisticated battery connection which refuses to just use 4.2V from any source.