A new worry for me- are Lipos safe?

[Rich Griff]

As winter approaches ( it like a good February day here in Snowdonia as the moment ), what effect does cold temperatures have on these batteries please ?

[Nigel R]

3 minutes ago, Cuban8 said:

I wouldn't put very much faith in certain statistics when there is a very motivated and vocal lobby pushing a particular agenda

 

London Fire Brigade seem fairly unbiased on this front.

 

Quote

A Freedom of Information request submitted by Air Quality News revealed that the London Fire Brigade tackled 54 EV fires in 2019, compared with 1898 fires involving petrol or diesel cars. True, there are far more petrol and diesel cars on London roads than EVs, but this still means there were proportionally fewer electric car fires than fires involving ICE cars

 

https://www.whatcar.com/news/how-safe-are-electric-cars/n25839

[Nigel R]

2 minutes ago, Rich Griff said:

what effect does cold temperatures have on these batteries please ?

 

To best of my knowledge, it is advisable to raise the battery temp to around 15deg before you start drawing any serious current or fast charging.

 

Performance is poor at low temperature.

[Jon H]

10 minutes ago, Nigel R said:

 

I seem to remember reading statistics that suggest electric cars now suffer fires less frequently than ICE cars

 

Not wishing to derail the thread too much but even if they catch fire less often (which they should given how few of them there are vs ice) the problem is they cant be put out. If one cheap and nasty chinese e-bike or scooter gives up in an underground car park or multi story that has a smattering of other ev's parked there then the whole thing will go up as there is no stopping it. And while normal car fire smoke is hardly good for your health, ev car fire smoke is another level of bad. 

[Rich Griff]

Thanks Nigel, but what about storage ?

 

Storage outside, in lipo bags In a plaster board lined steel box ( vented ), In a steel bin to keep water out ( condensation In deep winter ? )....

[Nigel R]

1 minute ago, Jon - Laser Engines said:

(which they should given how few of them there are vs ice)

 

the statistic takes that into account.

 

not arguing the other points though - battery fires are really, really bad.

 

and when an ev has been put out, it may still have to be dumped in a container of water for a couple of weeks to make sure it doesn't reignite.

[Nigel R]

Just now, Rich Griff said:

but what about storage ?

 

not, as far as I know, an issue

 

 

[Dickw]

11 minutes ago, Rich Griff said:

As winter approaches ( it like a good February day here in Snowdonia as the moment ), what effect does cold temperatures have on these batteries please ?

Storing Lipos at low temperatures is not a problem and preferably at around "storage charge" level and not fully charged. Bring them back up to room temperature before charging and using.

In winter I take my Lipos to the field in a heated box as they don't like high currents when cold, and the performance will be well down at low temperatures anyway.

 

Dick

[leccyflyer]

Have just ordered one of these and will add some insulation to keep the temperature as stable as possible, without the complication of providing heat or cooling. It'll be sited somewhere out of the way, where, even if it goes off it won't do any harm, I'll also be sure that it's adequately vented.

 

https://www.diy.com/departments/livingandhome-2-3-x-2-ft-anthracite-metal-waterproof-garden-storage-box-200-l/0735940250801_BQ.prd

[Geoff S]

... and yet people seem to be quite happy carrying mobile phones and charging them and laptops unattended indoors and often overnight.

 

During and just after the war (WW2 for youngsters) we (or my father) used to recharge 100s of 2v lead acid batteries overnight and the worst was acid eating into his overalls (and the wooden floor of the Ford van).  They were used to feed the valve heaters in battery radios as many households didn't have mains electricity and coal-gas lights were probably a greater fire risk than LiPos at rest and at storage charge.

[Geoff S]

3 minutes ago, leccyflyer said:

Have just ordered one of these and will add some insulation to keep the temperature as stable as possible, without the complication of providing heat or cooling. It'll be sited somewhere out of the way, where, even if it goes off it won't do any harm, I'll also be sure that it's adequately vented.

 

https://www.diy.com/departments/livingandhome-2-3-x-2-ft-anthracite-metal-waterproof-garden-storage-box-200-l/0735940250801_BQ.prd

 

What a good idea and not outrageously expensive.  How do you propose to vent it?  Is it really necessary to do so?

[leccyflyer]

I'll have a look when it arrives - at the worst It would involve drilling some small holes low down, so the rain can't get in and making them small enough so the critters cannot get in. The idea has been hatching for a while - we've got the builders in at the moment and I'd considered asking to have a bunker constructed as part of the works, but this looks a more cost-effective option.  An alternative was a combined garden seat and storage container, so that I could sit outside when I'm sanding balsa and such like, perched on top of several dozen lipos. 🙂

[Geoff S]

14 minutes ago, leccyflyer said:

I'll have a look when it arrives - at the worst It would involve drilling some small holes low down, so the rain can't get in and making them small enough so the critters cannot get in. The idea has been hatching for a while - we've got the builders in at the moment and I'd considered asking to have a bunker constructed as part of the works, but this looks a more cost-effective option.  An alternative was a combined garden seat and storage container, so that I could sit outside when I'm sanding balsa and such like, perched on top of several dozen lipos. 🙂

 

You can probably keep mice out (they'll eat anything - I've had holes in nylon pannier bags and rucksacks!) but I think insects etc would get in any hole big enough to be effective.

 

 

[leccyflyer]

It was mice, and especially voles, that I was referring too Geoff. I have no expectation to be able to keep insects or arachnids out - this place is spidey central and first job in the workshop each morning is to hoover up the previous night's arrivals.

[RottenRow]

38 minutes ago, leccyflyer said:

I could sit outside when I'm sanding balsa and such like, perched on top of several dozen lipos. 🙂

Heated garden seat eh… that’s the luxury version.

 

Brian.

[leccyflyer]

Geoff - to answer your question on whether it is necessary to vent a container, from the videos that I've seen, the quantity of gases that even a small lipo can produce when "venting with flames" is quite impressive and containing those gases in a closed container would likely make things much worse than them venting off to the atmosphere. That's why it's important to vent the ammo boxes that so many folks use - easily done just by removing a small segment of the rubber seal from the lid. Otherwise you are literally making a bomb, if you enclose the lipos in a totally sealed container.

[J D 8]

        Those garden box's like Leccy is getting are waterproof but not sealed.

[leccyflyer]

Thanks JD8 - that would be great if that is the case. I'll be looking to add some insulation, a max-min thermometer and I have a bunch of battery operated smoke alarms, so I'll pop one of those in there as well.

[aidan mcatamney]

I store all my lipo batteries in metal ammo boxes now, but it was a different story 16 years ago.  Our house was burned to the ground and it took 6 months to rebuild it.  My elderly Aunt whom I lived with for 35 years had to be rescued and escaped with her life as the fire from an exploded lipo ripped through our home.  It was a terrifying experience as she was on a walking frame and aged 86 at the time.  It turned out that the brand new chargerthat I had bought was faulty and resulted in leaving us homeless.  It could have been a lot worse though if lives had have been lost.  Never leave them unattended and always charge them in a fireproof container outside of the house.   Luckily enough our house insurance covered the cost of rebuilding our bungalow.  It was a hard lesson learned on the dangers of these batteries.   Suffice to say I've been using and charging them eversince without a problem.   Just be careful and treat them with respect.   

[Cuban8]

1 hour ago, Nigel R said:

 

London Fire Brigade seem fairly unbiased on this front.

 

 

https://www.whatcar.com/news/how-safe-are-electric-cars/n25839

Obviously more complex than a simple numbers exercise. I'd be very curious to know, for instance, about EV fires that occurred when driving and those that occurred when charging or simply parked up. 

[toto]

Charging in an explosion proof bag ....... that's laughable given the extremely short leads they come with.

 

I'd like to comply with that but as a result of the leads, I dont. They are on a worktop and out in the open.

 

Just ordered an ammo box now as well.

 

Toto

[leccyflyer]

2 minutes ago, toto said:

Charging in an explosion proof bag ....... that's laughable given the extremely short leads they come with.

 

I'd like to comply with that but as a result of the leads, I dont. They are on a worktop and out in the open.

 

Just ordered an ammo box now as well.

 

Toto

It's the length of the charging lead that matters Toto, not the length of the lead on the battery. The length of the lead on the battery and ESC is governed by the requirement to keep ESC-Battery lead as short as reasonably possible - typically less than 200mm. The charging leads do not have such a constraint.

[toto]

So I need to make up extension leads from my charger to the battery to give enough length to place the battery into a charging bag.

 

I'll post up a picture of my charger and battery set up later when I get the chance.

 

Cheers

 

Toto

[leccyflyer]

Either that or you just set up your charging bag closer to the charger 😉

[toto]

Not really possible as it tends to pull the leads from the charger ..... crappy set up given how dodgy they can be.

 

Toto