Comment by avidiax | Hacker News Reader

Comment by avidiax | Hacker News Reader

I may be a bit odd, but I store lithium ion battery containing electronics in the vegetable drawer in the fridge. You lose 20% of capacity in a year if you have 100% state of charge but only 6% loss of capacity at refrigerator temperatures. So tool batteries, small electronics and whatever else that isn't used weekly gets put in.

I also try to charge fully only just before use (and only if I need 100%), and store at partial charge. If I am charging for storage, I just set a 30 minute timer. Since 1C charging is the most common, 30 minutes at 1C will be about 50% state of charge from empty, which is useful for items with no state of charge indicator.

I use AlDente[1] on my Apple laptops, and the 80% charge feature on my Pixel phone. My bedside phone charger is a slow charger.

Maybe I'm doing too much to manage my batteries, but I also haven't needed to retire anything for having a bad battery in many years, nor had items with dwindling capacity.

[1] https://github.com/AppHouseKitchen/AlDente-Battery_Care_and_...

>You lose 20% of capacity in a year if you have 100% state of charge but only 6% loss of capacity at refrigerator temperatures.

Source? The common figure for smartphone batteries is "at least 80% capacity after 2 years", and that presumably includes cycles, not just leaving it charged.

From the article, Table 3: 100% SoC @ 25°C leaves only 80% of the original capacity after a year.

It's easy to look at that table and think that it's remaining charge after a year; it's not. It's lost capacity.

This is known in the industry as "calendar aging". So far as I know, stockpiles of lithium ion batteries are stored at a relatively low state of charge and in a cold environment for this reason among others. It's common to order a laptop battery or similar and get a unit that was manufactured a year back. It would be terrible to get a new battery that already had diminished capacity, which is what would happen if you stored them in a non-conditioned warehouse in a hot climate.

Have you ever measured your battery voltages over time storing it this way? Is that 6% capacity loss theoretical or measured data? I'm intrigued. This sounds crazy, but it should technically be fundamentally sound.

I haven't, and it wouldn't be the voltages. You would have to do a rundown test and see what the effective capacity is (watt-hours).

Reply on news.ycombinator.com