Do Li-On batteries build a memory?

[DarkManX]

Do lithium Ion batteries used in cell phones build a memory? or can get overcharged? I thought that all modern phones/chargers keep the battery from getting overcharged, so t-mobile told me today that i shouldnt leave the phone on over night, i thought thats no longer a problem with li-on batteries, i coudnt find anything on google about it so maybe someone here knows?

 

[WayneTeK]

I know Lithium Polymer (iPOD batteries) don't build memory. For Li-ION, i heard that it doesn't build memory like Nickel Cadium, but it does build some sort of memory. Not that big of a deal, but it does build small memory over time.

 

[Lynx516]

Li Ion batteries do crystalise slightly if not discharged so they do degrade over time. The phones should stop them from over charging because if they are overcharged Hydrogen gas is produced causing the battery to explode

 

[DarkManX]

so whatever t-mobile is telling me about leaving it in plugged in is BS right?

 

[DarkManX]

so whatever t-mobile is telling me about leaving it in plugged in is BS right?

 

[WobbleWobble]

All the phones I've used (Nokia, Ericcson, Motorola) stop charging when the battery is full. Although I have heard it's bad to talk with your phone plugged in to the charger, but I'm not sure why.

So I'm going to call BS.

As far as I know, Li-Ions don't go through the memory effect, though they do have a cycle count. There's a max number of times a Li-Ion can be charged and it's lower than Nicad.

 

[rowcroft]

I have a V60t and I've noticed my battery drains much quicker then it used two (like half). This could be a function of it having some sort of a memory since it follows the normal progression of full charge to no charge, just at a much faster rate.

 

[Mark R]

Li-ion batteries don't have memory in the same way as NiCd or NiMH batteries are purported to exhibit it. It is reasonable to top-up charge whenever required

Li-ion batteries do have a relatively short life - you are likely to notice a significant reduction in capacity after only 150-200 charges (Compared to NiMH or NiCd which should do close to 1000).

Having said that, Li-ions do degrade faster if left fully charged. In particular, if you are not going to be using the phone then you should allow the battery to discharge before storing the phone (a sensible safety precaution as well - a fully charged Li-ion battery can explode violently if damaged, whereas a discharged one is harmless).