Storing an unused Astro Slide without damaging the battery?

[slide]

How do I store a spare Astro Slide without damaging the battery? If I charge it to, say, 90% and check the battery once a week, I get, say, 90%, 90%, 90%, 90%, 0%. This looks quite dangerous for the battery. I can't really check the battery daily and I don't want to keep the charger plugged in all the time.

[ZimbiX]

I believe manufacturers charge batteries to 40% to make them able to sit in the box for the longest period with as little degradation as possible

[slide]

Well, the battery must have went through 40% on the way from 90% to 0%. I don't think charging to 40% will help prevent the sudden drop. Maybe I should fully boot Android to check the battery rather than booting to the charger animation.

[Zarhan]

The problem I've had that even with root, there doesn't seem to be a way to set charging limits.  Yes, you can raise an alert when charge reaches e.g. 85%, but then you need to unplug and battery state starts going down again.

I'd like to set something like "do not charge if > 40%, stop charging when reaching 85%", like I have on my laptop, to avoid all those cycles...

[Robsno5]

The attached table is from battery university showing how much capacity is lost at different storage temperatures and you can see the benefits of storing at 40% charge and a cool temperature.😊

[slide]

That table is probably for batteries stored outside devices, without a BMS or RTC or whatever draining them.

My problem is this:

2023-10-07 89%
2023-10-15 88%
2023-10-18 88%
2023-10-20 87%
2023-10-26 85%
2023-10-30   0%  <---

The problem is the sudden drop from 85% to 0%. This time I booted Android to read the battery level (except for the last line because Android doesn't boot with a completely drained battery). I don't think charging to 40% would make a difference.

[Robsno5]

I experienced something similar with my Cosmo as I use an Astro as my main machine and just boot up the Cosmo every 3 Weeks to top up the battery which was changed earlier this year and allow it to sync as a standby. initially I left it at 50 percent put it in airplane mode, powered it down and checked it every week, like you it hardly changed and then suddenly went flat. It looks to me like either something causes it to wake up like possibly an update routine or it ceases to be able to monitor battery charge after a while. It is most odd and I wish I knew what was going on. I have an iPad from the first release and shut that down for months on end but when powered on the battery has hardly altered, the Astro should be capable of  being powered down for ages. Rob

[Robsno5]

I think the best way is to put it in the same state as a new one ie factory reset and power down then power per engage will hardly alter after months switched off.

[slide]

Have you actually tried that? Do I have to factory-reset the device each time I check the battery level?

[Robsno5]

Yes I factory reset and a month later booted up set the language and the battery had the same percentage as  a month ago, then factory reset and power off. Two months wait next time and 1% less so now just boot up every couple of months to check still around 40-50% and if below top up. But so it should be, given that is how it would sit in a box until sold initially.

[slide]

A factory reset didn't improve things for me: the battery is completely depleted a month after the factory reset.