Lipos the storage of

[TAIL DRAGGER]

I have an electric Cessna  ,i will not be flying it  until spring or summer , so what is the best way to store the lipos ,charged or not ? would appreciate some help . cheers TD

Edited By TAIL DRAGGER on 18/01/2010 17:34:55

[birdy]

Half charged. I think the recomended voltage is around 3.6 but I couldn't say.

[BB]

Hi Taildragger.  Theres a link below, But it may no work.  I would suggest you PM Timbo.  My understanding is don't 'fully' discharge.  It causes internal cell damage, not recoverable.  2/3 rds discharge seems to be the very 'rule of thumb'.  PM Timbo.

Link

 

BB

[Tim Mackey]

HERE

[TAIL DRAGGER]

Thanks ,that's very helpfull.

[Tim Mackey]

We try to please

[Zflyer]

I like others, i am sure, keep mine in ammo boxes. I recall seeing a posting, not sure if it was on this site, that to prevent the box from exploding in the event of a fire to remove the rubber seal. This has a tendency to make it rattle.

I have found that if you drill a couple of holes in the sides, one towards the front the other to the rear, then plug them using rubber grommets, you loose the rattle and also keep the box water and air tight.. In the event of anything untoward happening the grommets blow out releasing the expanding gas.

[leccyflyer]

Posted by TAIL DRAGGER on 18/01/2010 17:31:28:

I have an electric Cessna ,i will not be flying it until spring or summer , so what is the best way to store the lipos ,charged or not ? would appreciate some help . cheers TD

Edited By TAIL DRAGGER on 18/01/2010 17:34:55

Storage voltage = 3.8 -3.85v/cell. Your charger might well have a storage voltage function and, for long term storage, that voltage range is generally reckoned to be about right. Try not to store fully charged, it reduces overall battery life and it is more dangerous in case of a mishap to have the battery fully charged.

[GrumpyGnome]

Hopefully, the OP did not leave his LiPos charged for the 10 years since the thread was started 😁

These seems to have been a few threads resurrected lately - another unexpected lockdown result perhaps!

GG

[MattyB]

The OP's thread was posted in 2010, I suspect he has his answer at this point...

[Phil McCavity]

Posted by Zflyer on 31/01/2021 11:08:20:

I like others, i am sure, keep mine in ammo boxes. I recall seeing a posting, not sure if it was on this site, that to prevent the box from exploding in the event of a fire to remove the rubber seal. This has a tendency to make it rattle.

An ammo box with the seal in place won't explode in these circumstances, there are plenty of filmed experiments to prove this. It will distort but the seal will be forced and incinerated by the heat and pressure, saying that and having seen the films the (debatable) conclusion is not to leave the seal in place.

Lipos don't explode, they rapidly combust, there is a dfference. There's enough Lipo myth to frighten people without throwing explosions into the equaution:

Combustion is when a substance burns to produce heat and light.
Example: Petrol when ignited burns to produce steady, prolonged heat and light.
Combustion in which a sudden reaction takes place on ignition of substances to produce heat, light and sound is called an explosion. Explosion requires expansion of volume while this is not necessary in the case of combustion.
Example: A Firecracker when ignited burns to produce instantaneous heat, light, sound and rapid expansion.

 

 

Edited By Phil McCavity on 31/01/2021 12:06:49

[Phil McCavity]

Posted by MattyB on 31/01/2021 11:41:41:

The OP's thread was posted in 2010, I suspect he has his answer at this point...

It's still an often asked question as relevant now as it was then so well worth resurrecting rather than clutering the forum with the same rotation of questions, Zflyer has actually done a search of the forum and found something to add to as suggested many times on here rather than generate posts with links to past questions. It seems you're damned if you do and damned if you dont.

Picking up posters for continuing old threads seems to be the latest forum game.

 

 

 

Edited By Phil McCavity on 31/01/2021 12:22:44

[Richard Wills 2]

Lipos don't explode, they rapidly combust, there is a dfference. There's enough Lipo myth to frighten people without throwing explosions into the equaution:

Gunpowder also does not explode it rapidly combusts. The explosion in a firecracker happens when the expanding gases are trapped by a container (cardboard casing) and the build up of pressure causes it to fail. Another reason to vent your box is the gases released by the failed lipo will displace the air in the box rapidly, once thats gone no oxygen remains and combustion cannot continue.

[john davidson 1]

Richard, lipos dont need oxygen to burn, they will even continue to combust merrily in a bucket of water, which might be one of the safer ways to dispose of them

[Brian Lambert]

Richard, Wikipedia seems to think gunpowder is an explosive!

[Roger Jones 3]

An old thread. Some of my lipos, stored at roughly half charge, are as old as the thread and still fine.

Myths? We had them when NiCads came out too. Not so much with NiMH.

[Phil McCavity]

Posted by Richard Wills 2 on 31/01/2021 16:31:12:

Lipos don't explode, they rapidly combust, there is a dfference. There's enough Lipo myth to frighten people without throwing explosions into the equaution:

Gunpowder also does not explode it rapidly combusts.

I'm afraid it does, it's a low explosive. The speed of combustion is close to the speed of sound and defined as deflagration, low explosive combusts beyond the speed of what is defined as rapid combustion whereas as high explosive detonates.

[Richard Wills 2]

A burning log on your fire is also a deflagration.  Gunpowder does not explode unless confined, however slight, in some way.

Edited By Richard Wills 2 on 31/01/2021 20:27:43

[Phil McCavity]

Posted by Richard Wills 2 on 31/01/2021 20:26:38:

A burning log on your fire is also a deflagration. Gunpowder does not explode unless confined, however slight, in some way.

Edited By Richard Wills 2 on 31/01/2021 20:27:43

It does, it is classed as a low explosive because of the speed it combusts. That is what defines an explosive.

[Julian Murch]

Forgive me if this has already been covered here but is it OK to store Lipo batteries in a metal shed outside bearing in mind likely winter temperatures. I have a fireproof briefcase/box made by Brinks Home Security and will not lock the lid so hopefully if it does go up gas can escape.

[MattyB]

Posted by Julian Murch on 01/02/2021 13:10:54:

Forgive me if this has already been covered here but is it OK to store Lipo batteries in a metal shed outside bearing in mind likely winter temperatures. I have a fireproof briefcase/box made by Brinks Home Security and will not lock the lid so hopefully if it does go up gas can escape.

The optimum storage temp is said to be ~15 degrees C, but if it stays above zero and the packs are stored at ~3.7-3.8V/cell, you should be ok. Any colder than that though and they are really better indoors.Read the section on Battery University about prolonging Li-ion packs life for more info (Lipos are a subset of the overall class, Li-ion).

[Christopher Wolfe]

Today I just checked and storage charged some 6S 5000 packs that are over 5 years old and seldom used.

Stored in an ammo box (minus seals) at about 4°C in my workshop fridge the annual check (last one 19 Dec 2019) revealed that cell voltages were about 3.76V, down 0.04V from the original storage voltage of 3.80V over 12 months ago. Packs were allowed to warm to ambient temperature (about 28°C) for 24 hours before testing and balance charging to storage voltage of 3.80V per cell.

Dunno if I should have even bothered as 3.76V per cell is adequate for storage IMHO.

As with most chemical reactions, I believe that low temperatures slow them down, including the degradation of batteries.

I decided to use the fridge as summer temperatures here can exceed 41°C

skippy

[Danny Fenton]

Hi Christopher, interesting that you have used a fridge. In the April RCM&E I will be showing that I have done the same to store my batts, except my fridge also has a heater element to hold the cells at around 15 degrees C.

Glad I did it just before Christmas and the packs have been protected from the frost.

Cheers

Danny

[Phil McCavity]

As an alternative to an ammo box for strorage also consider the metal petty cash boxes, they are seamless, made of decent gauge steel, don't have a waterproof seal and are lockable, they're also cheaper in many cases and take up less room. The cost of buying a few of these rather than a single ammo box will be recouped if it all goes tits up because rather than storing a stack of Lipos in the same container and losing them all you can split your collection into different containers. Lipos aren't cheap.

Mods.note:

Changed wording at poster's request as he wished to use more emphatic language which has been adjudged to be marginally acceptable within the forum CoC.

Edited By Martin Harris - Moderator on 03/02/2021 15:52:07

[Capt Kremen]

Assuming storage outside in a shed, garage, etc., a greenhouse max/min thermometer will give you a rough idea of the extremes of temperature your precious LiPo have experienced. You can then decide if heating or insulation from extreme heat e.g. in summer, is required. Plastic clip lid 'pencil' boxes from pound-shops then stored in Ammo box has worked for me. Touch wood, no serious issues and good LiPo longevity.