Long term storage of Lithium - Best Stored Fully Charged?

[MitchJi]

Hi,

If Lithium Batteries won't be used for several month's should they be stored fully charged?

Thanks!

Mitch

 

[dogman dan]

Yup.

 

[johnrobholmes]

I say nope. 50% charged, or 3.8vish for Lipo variety.

 

[dogman dan]

I was thinking lifepo4. And I don't know for sure, It's just how I've done my drills for 25 years. Mostly because when i pick it up I want it to run some before I have to charge it.

 

[johnrobholmes]

I don't know about LiFe, it seems to be pretty stable at any charge over time.

 

[dogman dan]

I don't know about LiFe, it seems to be pretty stable at any charge over time.

Hey, I finally figured out how to use the quote thing. Funny how dumb a guy can be with computers.
Anyway, With lifepo4 the big danger is to have one cell get too low and be toast so I would think starting out with a full charge would be best. With most of my drills, they have been nicads, and they would definitely lose a charge pretty quick. Couldn't have had anything to do with permanantly storing them in a truck toolbox that would get to say, 150 degrees F everyday? Even so, I'd still get three years of use out of a makita pack.

 

[PJD]

My experience with my LiFePO4's (Thundersky 40AH) is that their self-discharge rate is very, very low (a few percent per month). So unless you are storing them for a year or more, I wouldn't worry about needing to store them fully charged for that reason - unless your particular cells seems to be noticeably self-discharging.

I am going on the assumption that what is true for other lithium is true for LiFePO4's - which is, for maximum calendar ("shelf") life they should be stored at 50% state of charge as much as is practical. This is how Thundersky ships their cells.

But the truth is, LiFePO4's are a very new product and most of the (Chinese) manufacturers did a very poor job of testing them during development so, we really don't know, and won't know for a good number of years.

 

[dogman dan]

So now the dummy wants to know why they store better at 50%? Of course I won't understand the answer, but others will. I dig it that overcharging is wear and tear, but one normal charge? Im confused now for sure.

 

[Drunkskunk]

So now the dummy wants to know why they store better at 50%? Of course I won't understand the answer, but others will. I dig it that overcharging is wear and tear, but one normal charge? Im confused now for sure.

my Understanding is that for non-LiFE Lithium, ( LiMn, LiCo, LiMnCo, ect) they will oxidize The Anode when fully charged, and oxidize the cathode when discharged. But at 50% charge, not only is it harder for any oxidation to take place, but what does occure is balanced between the poles, so it has less effect.

It also slows way down when cold. Freezers make good storage places for Lithium batteries.

 

[tostino]

So now the dummy wants to know why they store better at 50%? Of course I won't understand the answer, but others will. I dig it that overcharging is wear and tear, but one normal charge? Im confused now for sure.

my Understanding is that for non-LiFE Lithium, ( LiMn, LiCo, LiMnCo, ect) they will oxidize The Anode when fully charged, and oxidize the cathode when discharged. But at 50% charge, not only is it harder for any oxidation to take place, but what does occure is balanced between the poles, so it has less effect.

It also slows way down when cold. Freezers make good storage places for Lithium batteries.

From everywhere i've read, it's been advised to store around 65% for lithium batteries (Li-poly and Cobalt based ones mainly).

Thanks for the info!

 

[MitchJi]

Hi,

I should have included that these are Sony Camcorder batteries, about 12 years old and still seem to work (I use it about once every two or three years). They still seem to work OK. Just trying to decide if I should top them up and put them back in storage or top them up (charger doesn't provide state of charge info) and then partially discharge them. So far the partial discharge sounds best.

Thanks!

Mitch

 

[dogman dan]

Ok that makes sense, if they oxidize more, that's bad. Good thing those power tools in the broiling toolbox were nicad or nimh. Now I keep em in a broiling garage. Along with my Ping. At least it's cool half the year.