Fairphone 4 battery lifetime?

Hello, I’ve bought FP4 last year but didn’t have time for linux development so the phone was in my drawer all the time. I usually try to be sure to “store” batteries half charged (but I can’t be sure I charged it before turning off).

Fast forward, when I took out the phone out of the drawer the battery was completely dead. It charged back to 100%, however I’m shocked how weak it is. I didn’t start doing anything with it yet. I just updated the Android and played a little bit with it, then left it again on the desk. Next day the batter was already dead.

I repeated a few charging cycles, but the battery doesn’t even survive 24h with an idle phone. This really puzzles me. What if I was using the phone, perhaps the battery would have died within 3-6 months.

Anyone can confirm a nearly no performance loss of the batter after about a year of use, which is my experience with Huaweii and Samsung phones.

But most importantly anyone knows where to buy a solid quality battery for FP4? I don’t have confidence in a stock FP4 battery.

Under normal temperatures a batterie discharges itself by around 0,5% each day.
So, after x days the battery gets exhausted (charge way below the “normal” empty, when the phone usually will shut down forcefully).
This will damage the battery and can result in your situation.
The only thing you can do now is trying to “train” the battery to get some capacity back - or buying a new one.

If you are not using lithium-ion batteries for a long time in the future, I’d suggest you to charge them up to 100% and then put them inside a double plastic bag into the freezer.

Are you sure about this? I’m pretty sure I’ve read studies suggesting it’s terrible to leave them in the freezer at 0 or 100 percent.

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Probably you’re right, the battery got damaged by being left drained. I just wonder, I wouldn’t be surprised if the phone still drained a little current being in OFF state. Well, a thing to remember, remove the battery from the phone for storage…

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0% is always bad.

But what should happen with 100% ?
If you put the warm battery in the freezer and then somehow check the charging level after it got frozen, you probably will see a charging level several % lower than before. (You can charge a cold battery more than a warm one.)
And then in the freezer the battery will discharge itself slowly (but with less than 0,5% each day).

Of course you can play it save by only charging the phone to 80% but I think this defeats the purpose to store the battery for a long time without the battery getting exhausted.

You might try out to use an app like e.g. AkkuBattery during some days for getting an estimation of the remaining battery capacity.

your LiIon battery probably got damaged by the non-charging, buy a new one and properly dispose off the old one. Potentially such batteries can ignite…

The charging circuit is always powered, so yes. (It uses almost no power.)

Self-discharge is a more likely cause of running down – batteries are not magic and ions migrate down the potential gradient on their own, so any battery of any sort is slowly going to lose charge just sitting there. Even high-altitude reservoirs used as large-scale storage lose “charge” if pumping is off and evaporation in the area exceeds rainfall :slight_smile:

I use AccuBattery to monitor my phone battery and it shows that I have dropped from 3905mAh to 3450mAh, around 14% of my battery capacity in almost a year. I make a point of keeping the charge between 15% and 80%.

If you leave a Lion device in a drawer it will slowly lose charge. I didn’t use my Steam Deck for around 4 months to find it had no battery and I know it was tip top fully charged. Thankfully it was only for a short time and the battery doesn’t seem to have suffered. It is holding charge and discharging appropriately.

In your case you may have left it too long and caused some damage in the chemistry in the battery. You say you have no confidence in the stock FP4 battery but there aren’t many options for replacements apart from Fairphone themselves or Amazon. The Fairphone store is temporarily out of stock.

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I’ve changed my mind. However, yeah, I would like to buy a “fat” version for this phone, it’s heavy anyway.

The availability doesn’t bother me as long as new batteries will show up this summer.

The Deck has a storage mode you might find useful. (Turn it off, turn it on while holding down volume-+, Setup → Power → Battery storage mode.)

Of course, it’s not clear exactly what this mode does: the battery will certainly still self-discharge but might do so more slowly. Its principal effect is to turn off the power button: only plugging it into the charger will turn it on again, so that you don’t need to worry about accidental knocks turning the thing on and causing it to overheat in a confined space.


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