Who has First Hand experienced a LiPo fire ?

[Phil Green]

This is obviously a serious and hugely upsetting event to witness, and a warning we should all keep in mind.

However...

There have been a few counts of 'Lipo charger failed to cut off', but a Lipo charger is constant current to 4.2v then constant voltage, it doesnt 'cut off' in the way that NiMh or NiCd chargers do.  If the CV stage of a Lipo charge never terminated, the battery would be fine with the charger floating it at 4.2v for as long as you like.   A very long term 4.2v float might shorten its life, which is why they do stop after a period of CV floating, but extended float cant of itself be the cause of a failure.  Perhaps the brand new charger was faulty, or through lack of familiarity the wrong profile was chosen?

Cheers

Phil

 

Edited July 7, 2023 by Phil Green

[aidan mcatamney]

The brand new charger was faulty Phill and the 3 s lipo it was charging was also brand new.  It was indeed a bad experience back then in 2007 but since then I've not had a problem with either lipos or chargers.  The charger I have now is state of the art.  

[KenC]

Aidan do you still  charge in the house ?

[aidan mcatamney]

No more charging in the house Ken,  not since 2007.  

 

 

[KenC]

Having your horrific story and others , I have decided I will not even buy a battery until I have my shed outside sorted , and a bat-safe .   

[aidan mcatamney]

Good stuff Ken.  Very wise.   I charge all my batteries in the garden shed inside a fireproof lipo charging bag.  

[Zflyer]

Charge outzide or in other halfs shed which has concrete floor

[Chris Walby]

Ok so looking at the sales pitch an ammo box will get to 700C and the youtuber advises it should be on a non combustible surface and nothing within 1 meter all the way around it?

 

The Bat-safe did say how hot the case actually got but just advised combustible martials should not be within proximity of the Bat-safe, two points of not being very helpful IMO

 

Question for those that use Bat-Safe's - how do you charge batteries as it says the catch has to be latched on the lid and does this not risk pinching the charging cables?

 

Thanks for constructive  reply's

[leccyflyer]

The charging cables on a Bat Safe are routed through a tightly fitting split rubber bung in the lid and don;t come anywhere near the closing part of the lid. On mine I have dual charging cables with 4mm bullets on and an adapter inside the BatSafe to take a 4mm bullet, into a JST of micro Molex plug to handle those batteries. One Bat Safe has a balance board inside,  which takes 2=6 cells in individual ports, the second has individual balance leads for 2,3,4,5 and 6 cells.

[John Lee]

I've a very similar setup to Leccy's, here's how the cable routing works:

 

 

[John Lee]

[J D 8]

After reading all these posts on lipo fire/cooking off issues I decided to up grade my storage.

My only lipo problem was in the air, [ as noted early in this thread] recon I overworked an unsuitable batt in an EDF.

  I only fly small electrics [ handy for a quick fling in field by the house] largest batt's are 3s 2200's 3 of, and 3 3s 1300's and a few tiddlers.

  50 cal box in the back toilet next to the water supply alkathene pipe which would melt and cool the box. Nothing else to ignite other than the seat.

   Mrs thought I should put it in garage at the side of the house, err no way to many combustible items inc several gallons of glow fuel.

 

 

[Rich Griff]

Methane, lol.....

[Piers Bowlan]

On 03/07/2023 at 12:54, John Lee said:

I went to a talk at the Royal Aeronautical Society a few years ago given by the head of Airbus's electric flight research section.

 

If I recall correctly he said that their opinion is that whilst the will be incremental gains in battery efficiency, they could not see any prospect of a fundamental breakthrough. The reason behind this is that Lithium is number 3 in the Periodic Table (after Hydrogen & Helium) and its top left hand position position means that it has the highest useable negative electrochemical potential of any element, which is what drives battery efficiency.

 

I don't have the knowledge to challenge or prove this assertion, but it does make some sort of sense.

 

Yer cannot change the Laws of Physics (or chemistry), Jim!

 

 

I wonder how often has an eminently qualified and respected expert said something along these lines, ‘…could not see any prospect of a fundamental breakthrough because… ‘ There follows a reasoned explanation why. But,  unforeseen discoveries prove them wrong again and again, (eg. Jet engine, transistor/IC, LCD screens, computers, The Internet!).

Solid state batteries have for some time offered the elusive prospect of a step change in efficiency and charge density. Cycle life has hitherto been a major drawback but perhaps no more?

https://www.anl.gov/article/new-design-for-lithiumair-battery-could-offer-much-longer-driving-range-compared-with-the-lithiumion#:~:text=“With further development%2C we expect,than lithium-ion batteries.”

They are also supposed to be safer and if aluminium is used instead of lithium, a lot cheaper, potentially.

[Andy Stephenson]

1200 Wh/kg is impressive for a rechargeable battery but they don't state the power density i.e. the C rate which is the determining factor for the hobby.

By comparison methanol is 6400 Wh/kg.

[Piers Bowlan]

1 hour ago, Andy Stephenson said:

1200 Wh/kg is impressive for a rechargeable battery but they don't state the power density i.e. the C rate which is the determining factor for the hobby.

By comparison methanol is 6400 Wh/kg.

Yes, unfortunately high impedance between the cathode and anode is another issue with this technology, which they are working on…

If they had solved all the problems we would likely be using them now but they have the potential to be a game changer.

A little light reading 😉

https://www.nature.com/articles/s41467-017-01187-y