Phone LiPo that has reached ~5% charge over 8 mo storage

[ASK1]

I have an old Droid Mini phone (w/ integrated LiPo battery) that has been collecting dust for 8 months & that I was considering reviving temporarily for a friend whose phone broke. Unfortunately, I have let the battery waste away to 5% charge. Could it potentially be dangerous to charge/use this battery? Or is it just a matter of lost capacity? Thanks.

(And had I not started reading this forum a couple of months ago, I wouldn't have even thought twice about going on with charging and using this phone.)

 

[dnmun]

how do you know it is 5% SOC? it should charge right up and work fine if it is still in the phone.

 

[amberwolf]

Assuming that like most such commercial products it has a proper BMS in there to monitor the battery and control it's charge and discharge, and you're just using it's normal charge/discharge process, there's no reason to worry about it.

If it's badly designed, then stuff coudl happen, but that's true of even just it's normal usage.


If by 5% you mean that according to it's own screen it only has 5% of it's charge left right now, and you haven't tried recharging it, then you mgiht as well let it charge normally.

If by 5% you mean that even after charging normally it still only has 5%, well, that may mean the battery is simply dying and needs replacement. (it could also mean there's a bug in the software and it might need a hard reset, or something else, but that you'd have to check with the manufacturer to find out, and it's unlikely).

 

[ASK1]

That information is just based on the battery charge indicator the phone shows when plugged in.

I'm sure it has a BMS, being a not-terribly-old Motorola phone.

I wanted to be cautious because I don't know how battery damage due to time spent at low SoC works, or if passive discharge can happen (& damage the battery) regardless of a BMS being there (which I would, maybe incorrectly, assume).

Going to proceed with charging, thanks guys.

 

[dnmun]

storage at low SOC is the best way to store lipo. keeping it charged all that time would have eaten up cycle life.

 

[ASK1]

storage at low SOC is the best way to store lipo. keeping it charged all that time would have eaten up cycle life.

I thought storage at 40-80% SOC was ideal, and that going outside of that in either direction caused problems (that accumulate over time). I guess I need to read more.

 

[dnmun]

there really is nothing but misinformation about charging lipo and SOC available in the common knowledge.

i have read that the cathodic matrix of the cobalt oxide suffers structural changes and shrinks as the SOC drops below 50% SOC so every time the cell is discharged below 50% SOC there is that effect to the integrity of the cathode. it obviously is a small effect, but it also is part of what causes the aging of the lipo. this may be why the chemistries that include the Mn, and Al in the eutectic show better long term cycle life, but i am not knowledgeable on that.

so leaving it in the one low SOC for that entire period of time would have been your best option, and the lower voltage means that the oxidation of the electrolyte at the SEI would be minimal so there was minimal aging to reduce cycle life. all in my own slightly informed opinion.

 

[ASK1]

I've fully charged & discharged it without any issues (which I'm sure is of no surprise to anyone, I just wanted to conclude this thread). The battery capacity is meager, but it always was.