LiPo battery charging safe

Jamo1911 · Feb 11, 2015

Has anyone here considered using a fire safe like they sell in Home Depot, to store and charge their batteries? I was figuring on drilling a hole for the cord and for gasses to escape. Looking at the video's of LiPo bags in action it's obvious that they are not good enough. I had considered using concrete block and cement board but I want something a little more attractive.

Nate H · May 6, 2015

Made this today for about $10. I feel better about it than the lipo bags I used to store batteries in.

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m00se · May 7, 2015

I havent (touch wood) had any problems with Lipos yet, and never leave them charging when im not close by.
I did however find a flaw in Hitec chargers about 1 year ago, whereby the Pb charging mode would not actually cut off at the full voltage, the beeping would happen and the screen showed it as finished, but the ammeter on the PS still showed the current as being used.

The result was a very very hot and puffed leaky Pb battery on my desk at work the next morning.

They immediately took it seriously and changed the firmware, but I dont know if old chargers were updated..........

If this happened with a Lipo you would be really gutted, and, as a precaution, I made a relativly safe place to charge batteries by taking some metal shelving and boxing in five of the six sides with metal sheeting. nothing was stored on top of the shelves and it was in a room with a smoke detector.

I thought about using an arduino to monitor temps at the charging locations and cut off power if it got too hot. but never did.

Kilrah · May 7, 2015

Nate H said:
Made this today for about $10. I feel better about it than the lipo bags I used to store batteries in.

Note that while this is good the location it's in might not be very appropriate - even with these bricks should a lipo catch fire you'd still have a 1m long flame or ball of burning gases shooting out and potentially setting fire to your carpet.

Nate H · May 7, 2015

Kilrah said:
Note that while this is good the location it's in might not be very appropriate - even with these bricks should a lipo catch fire you'd still have a 1m long flame or ball of burning gases shooting out and potentially setting fire to your carpet.

I know. A concrete floor would be best. I don't really have anywhere else to store them that's better unfortunately. Any ideas on making the bunker or area more secure? Still, a step better than leaving them in the Inspire case I think.

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Jimmyholster · May 7, 2015

I bought an ammunition box from aussie disposals (a military surplus store in Australia). Stuck a smoke detector on the inside, and strapped an extinguisher on the side. As it's got a handle already, it's a very portable solution =) and it's air tight too.

Kilrah · May 8, 2015

Jimmyholster said:
and it's air tight too.

That's the last thing you want.

Jimmyholster · May 8, 2015

Kilrah said:
That's the last thing you want.

Why? Fire can't flourish in something with limited oxygen... Also, these batterie do not give off gases when charging like car batteries. Why wouldn't I want it air tight?

Kilrah · May 8, 2015

The problem is that a lipo failure releases its own oxygen once it reaches cathode breakdown temperature.

So if one goes bad it will start by releasing large amounts of hot and flammable gases that will severely raise the pressure in the container if it's tight (already not good), then dump oxygen into the mix and risk causing a nice explosion.

Jimmyholster · May 8, 2015

Fair enough =) I was watching a YouTube video where a bunch of "supposed" experts recommended doing it themselves. It made sense to me. I'm new to lipo batteries so any advice helps. Thanks! =)

Kilrah · May 8, 2015

For those technically inclined I recently found this site, it's the first time I find a decent resource about the detailed working of Lithium battery chemistry that actually explains the how and why better than the usual armchair theories. That page is about the failures but it links to others with tons more info.

Jimmyholster · May 8, 2015

Kilrah said:
For those technically inclined I recently found this site, it's the first time I find a decent resource about the detailed working of Lithium battery chemistry that actually explains the how and why better than the usual armchair theories. That page is about the failures but it links to others with tons more info.

Thanks, I'll check it out =)

Mazz · May 8, 2015

Ammo boxes have been recommended by model fliers for YEARS. They have also saved many homes and sheds (even one that I know of). I can not speak enough for the importance of lipo safety so thanks for bringing it up again. Nice to remind everyone.

Jimmyholster · May 8, 2015

Mazz said:
Ammo boxes have been recommended by model fliers for YEARS. They have also saved many homes and sheds (even one that I know of). I can not speak enough for the importance of lipo safety so thanks for bringing it up again. Nice to remind everyone.

this is my setup.

jmstone · May 8, 2015

Exactly how often do these batteries... you know... catch on fire? I mean, LiPo batteries are fantastically ubiquitous these days (smartphones, many laptops, etc), and yet I don't personally know anyone who's ever had an issue with one.

Mazz · May 9, 2015

Jimmyholster said:
this is my setup.

I like the attached extinguisher and detector. Good idea.

Kilrah · May 9, 2015

jmstone said:
Exactly how often do these batteries... you know... catch on fire? I mean, LiPo batteries are fantastically ubiquitous these days (smartphones, many laptops, etc), and yet I don't personally know anyone who's ever had an issue with one.

Very rarely. TBH the probability of a lipo fire happening is pretty tightly coupled to the operator's reliability... Probably >90% of incidents are due to user error (setting charger wrong, overcurrent during charge or discharge, overdischarge, not letting the battery cool down between cycles, short circuits, imbalance, mechanical damage...). As common RC batteries are totally unprotected and exclusively rely on the user doing things right that's quite obviously where most accidents happen.
For batteries with a protection/management circuit such as phones, laptops, and the Phantom/Inspire batteries all of those are pretty much elimintated so all that's left as potential cause is basically manufacturing defect and physical damage, which can cause shorts either internal or external to the battery. Extremely rare, but happens.

What's "funny" as can regularly be seen here is that when you put protection circuitry that is able to eliminate 90% of the reasons for failure you then get people who have no idea nor will to learn how things work complain and try to circumvent them to charge faster/save a few bucks on chargers/etc putting the user error risk back in the equation