Safe cage, Really that important?

[Debunker]

I got a litium 52v 24ha pack made out of genuine panasonic GA cells, trusted vendor, whit BMS and smart charger, and I charge the thing in the house inside my room.

Everyone says that a battery pack can turn into a big toxic fireball and burn you, your house, your family, your dog and your friends alive.

Is important to make a safe cage? I'm thinking of buying an old ATX pc cage and roll several lairs of aluminium foil in the insides to do the trick, but.. honestly I could invert the time in something better... is it THAT risky to charge a lithium battery?

 

[cal3thousand]

Is it risky to smoke while filling up your car with gasoline? I'm sure it can be done thousands of times without a problem, but it's about that one time that is the problem.

Maybe that's not a great analogy, but the idea is that even if it's something that is rare, if it DOES happen, you really want that away from the rest of your property. Just search for fire here on ES. There have been VETERANS of the ebike game that well knew the risks and still had incidents. No one is immune.

Take that advice and do whatever your risk tolerance levels allow.

 

[jonescg]

If you can, try and do all your charging outside or in a shed. As said elsewhere, the odds are low if you're doing it all properly, but if the worst happens, at least the collateral is minimised. I've never had a battery go thermal on me mind you.

 

[amberwolf]

Exactly what cal3thousand said.

It's all about the one time a failure happens, and whether the results of such a failure are catastrophic to you and your surroundings, or just "oops, I guess I need a new battery".


How likely a failure is depends on so many factors that it's essentially unpredictable.

Cell quality
pack construction method
pack construction equipment
constructor skill
pack construction materials
handling of cells (by every single person that touches it)
handling of pack (by every single person that touches it)
mounting of pack to bike
charging method
charging voltage
BMS design
BMS quality (materials, construction, handling, ESD encounters, etc)
charger design
charger quality (same as above)
AC power to charger (quality, voltage, brownouts, surges)
temperatures pack is used at, charged at, stored at, at all stages from bare cells to on-bike usage)

I'm sure I left factors out....

Any combination of those might contribute to a failure, and any combination of failures might eventually lead to a catastrophic failure or fire.


As for how to build an enclosure--lots of ways have been theorized, but few of the many ways people have built enclosures have been fire-tested.

Some contained it, and some did not. Some may have made the fire worse.

If you want to build one you know will contain a fire, you have to either build and test it to destruction, to find it's limits (which also means destroying batteries like those you will use, so the test results are for the actual situation it must endure), or you have to build one that has already been tested in such a fire and contained it.

Anything you build that is not the same as a proven design, or that you don't test, is an unknown, and can't be trusted to contain any fire that does happen.


Whether any of this matters to *you* is up to you, as is what you do about it.

 

[spinningmagnets]

I only charge my battery when I am at home and awake...I do it in my garage, and my plan is that...if I smell smoke and the alarm goes off, I will roll the bike out into the driveway. Maybe it's a crappy plan, but...that's what I'm doing right now.

 

[dogman dan]

Obviously I trusted the pack that did this to my house too much.

How to store a large, bike size battery in your house is a dilemma. Big steel toolbox? Old dirt cheap kitchen stove, keep it in the oven?

Certainly do not make the mistake I did, I was charging my battery about 2 inches from the foam seat of a motorcycle full of gas.

 

[Debunker]

I see... maybe I can put something out of my old pc case, seeing a bunch of advised fireproof bags engulfing in flames whit just shitty small lipo's on youtube, I think I take the bet whit something of my own, at least I can feel double stupid if the case don't do the trick either.

 

[cal3thousand]

81mm mortar cans:

[strike]I'm going to get 2 of the Luna Battery cans. Decent deal for $34 (but shipping kills it)[/strike]

Found a local surplus store selling them for $15 each online. I can handle painting and modding them on my own, so $32 for 2 tall cans is a stellar deal. I just have to drive about 10 miles to pick them up.

Most ammo cans won't hold a full battery pack, but they will hold the lipo cells. So I put my loose cells in a .50 cal ammo can when not in use, otherwise, they are outside and will be using these for charging.

Funny thing: Wife just asked me about why we charge the batteries outside, today. I told her: "Even though I'm quite sure in my pack building and care, I have no guarantees about everything else. So all I can guarantee is that I would learn from others and charge outside."

 

[Swe]

What if you have a steel bike with built in battery? Like in my case Stealth FUTR Beta:
https://endless-sphere.com/forums/download/file.php?id=193757

You don't have much choice than charge on bike, and maybe you want to store the bike in the basement.

Sure smoke will get out, but is that all? (I know smoke can do damage too). If not lean against something burnable.

 

[dogman dan]

Picture the floor under you looking like this. Store there might be fine, but charge someplace else.

 

[spiros]

The levels of danger in case that somethings go wrong are proportional with the C and the Ah of the battery?
If yes, could be more safe consider old types of batteries like Samsung 29E instead 30Q for example or it doesn't matter?

 

[cal3thousand]

What if you have a steel bike with built in battery? Like in my case Stealth FUTR Beta:
https://endless-sphere.com/forums/download/file.php?id=193757

You don't have much choice than charge on bike, and maybe you want to store the bike in the basement.

Sure smoke will get out, but is that all? (I know smoke can do damage too). If not lean against something burnable.

Like this? [youtube]tRUC_05KmkU[/youtube]

 

[Swe]

Thanks for example video. Kind of what I was thinking, only smoke that also can damage a lot but at least no flames outside burning up the house. That was lipo but mayby it looks similair with 18650.

 

[cal3thousand]

Thanks for example video. Kind of what I was thinking, only smoke that also can damage a lot but at least no flames outside burning up the house. That was lipo but mayby it looks similair with 18650.

Could be... But 18650s tend to shoot off like fireworks since the gasses usually escape off the end until it pops. That MAY or MAY NOT cause the projectiles to pierce the plastic shell. Maybe fiberglass or some metal would be better in that case.

Come to think of it, intumescent goo like Tesla's could help.

 

[Debunker]

I made it! a home-made shitty fireproff (I hope) case.


Made out of a old ATX PC case (no remaining plastic inside, all metal) whit crappy aluminium thinfoil capes to cover the holes, teoretically, if the battery decides to allahu akbar, my house are safe now.... frock at least I try it.

 

[amberwolf]

If there is ever a fire in that, the foil will burn (or at least burn thru), probably pretty quickly with jets of hot/flaming gases on it.

Hopefully you also removed any of the raised edges and bumps and other hardware in there that will damage or puncture cells or wiring.


I would strongly recommend re-reading my other post in this thread about battery containment recommendations.

 

[Debunker]

Dont underestimate the power of aluminion thinfoil.

 

[amberwolf]

I'm not; I've burned foil like that (and even thicker stuff like soda cans) before in various ways, which is why I am advising you to try something else.

Also, a foil like that (with a plastic liner) is often used for the pouches of various cells; not always much left after burning one.


Up to you to choose how to protect your stuff, though--we can only provide our experience-based advice.