How do Lithium-Poly batteries act when they die?

[Toohotruk]

I'm not sure I put this in the right place...it's not about batteries I use in a flashlight. And I did do a search, but after going through several threads in the search, I didn't find what I'm looking for.

The Lithium-Polymer battery in my cell phone no longer takes a charge...at least that's what I think is happening. I plugged it in the other night to charge it, then noticed that it was low the next night. I thought that maybe it wasn't plugged in all the way or something, so I plugged it in overnight and once again, it didn't charge. So, I plugged it in via the car charger, thinking it might be the transformer on the other end of the cord and it still won't charge.

This caused me to wonder how these batteries act when they finally die. Do they die gradually, so you lose runtime until they're useless, or do they simply stop taking a charge? Could it be something that's gone bad in the phone itself?

This battery has seen some fairly heavy use over a 2 year period without a whimper...until now.

I guess I had better get a new phone ordered, I should be eligible for an upgrade at this point.

 

[superjoe83]

its probably just its time, I'm not sure how they charge, i would imagine that the phone itself regulates the charge and terminates it, so it could be the phone, but either way do you take the chance and get a new battery and hope it fixes it or do you spend a little more and get a new phone, i would pick the latter, IMO

 

[Toohotruk]

I just ordered a new phone...can't see spending the money for a new battery, when it's cheaper to upgrade the phone. Even if it means signing up for a new contract.

It just makes me curious about how this type of battery reacts when it's service life is over.

Now I just hope the new phone gets here soon!

 

[Fallingwater]

New batteries can be had on eBay for spare change.

 

[radellaf]

From what I've seen with a phone and a laptop of mine, they die pretty quickly. Within a week or two I went from seemingly normal service to very little.

 

[SilverFox]

Hello Toohotruk,

Lithium chemistry gradually suffers from higher internal resistance. This manifests itself as lower runtime, as you have noticed.

In general, Li-Po and Li-ion cells are considered "dead" when their capacity drops to below 80% of their initial capacity. A quick check is to charge your cell full, let it rest for 15 minutes, then measure the voltage. If your charger initially charged the cell to 4.2 volts, and now you are seeing 4.0 volts or lower, your cell is toast.

Tom

 

[Toohotruk]

Hello Toohotruk,

Lithium chemistry gradually suffers from higher internal resistance. This manifests itself as lower runtime, as you have noticed.

In general, Li-Po and Li-ion cells are considered "dead" when their capacity drops to below 80% of their initial capacity. A quick check is to charge your cell full, let it rest for 15 minutes, then measure the voltage. If your charger initially charged the cell to 4.2 volts, and now you are seeing 4.0 volts or lower, your cell is toast.

Tom

I was hoping you would post here! You probably know more about batteries than anyone else on here. :bow:

I took your advice and charged it up and waited 15 minutes and it tested at 4.03V. And going by the status on the phone itself, it dropped to 85% within an hour and it was just sitting there! so I think it's time has come!

That's OK though...I'm expecting the new phone to show up at anytime.

I think I may get a cheapie battery on ebay (depending on finding one cheap enough) and keep the old phone as a back-up. I can switch the SIM card between the two easy enough.

Thanks to all of you that took the time to try and help me! :thanks:

 

[VidPro]

also they start to self discharge, when bad. and they expend more heat in charging, and they can get puffy from gas.