LiPo Charging Bunker

by ipetepete | January 2, 2013 | (17) Posted in Tips

So, we've all heard the stories of lipos exploding. I'm sure we've all witnessed at least one or two Youtube videos on the phenomenon. If you haven't had it happen to you, then like me you might be taking it for granted how dangerous it really can be. My flying buddy (known as HoriAkuma 'round these parts) had it happen to him, luckily he was there when it happened and prevented what could have been his house burning down.  


Build a convenient and safe bunker for charging your lipos on the cheap.

Ingredients:

  • An ammo can $5-25 (depending on size and availability at your local surplus store)
  • Zip ties $free-$3
  • Grommets $free-$3
  • Drill (Free assuming you have one)
  • Drill bits (Also free assuming you have some)


Step 1:

Decide where/how you want your charger to be orientated with the ammo can, then mark your hole for feeding your wires through and drill for your grommet.


HotTip: If you have a step-up drill bit, it will make drilling this hole much much easier, if you don't just make sure you start small and use a progressively larger drill bit. I used a 3/4" grommet and the hole had to be 15/16", I would probably use 4-5 progressively larger drill bits for a hole this size. This helps the drill not work so hard and prevents binding.


Step II:

Insert your grommet, wrestle that piece of plastic into place. This will protect your wires from getting sliced by the metal. Its not exactly easy to get the grommet into place. You just have to strong arm it, some leverage from a flat-head screw driver might help.


Step III (optional):

Strap your charger to your box, great for portability and also saves space. There are undoubtedly slicker ways of achieving this, but I went for the utilitarian zip ties, since its simple, cheap and effective. 

Decide where your zip ties will be most effective without obstructing the ports of your charger. Mark the spots to drill, then drill out a hole slightly larger than your zip ties.

Important Make sure you de-burr the holes. A chisel works well, a small round file also does the trick. Normally you could just use the drill to quickly drill in from the back side, but there probably won't be enough room in the ammo can for that.


Inside view of the zip ties. I had to use three zip ties for each strap.


Step IV:

Charge your batteries safely. For added safety you can also put your batts in a charging bag wich would add another layer of protection.



Have fun! Be safe!

















COMMENTS

wacko911 on January 3, 2013
I wonder if a battery did fail inside that what would happen. I've a feeling it might explode or it just might vent flammable gasses through the holes you drilled.

Would make an in testing video if you fancy testing it for us.
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ipetepete on January 3, 2013
I seriously doubt the box would explode, since lipos don't have a concussive effect when they go. I am sure though that the flames would come out of the wire hole, the question is how much? I am sure I would rather have a flame through the hole versus a big uncontrollable ball of flame on my hands though. I'll be sure to make a test video once I have a battery thats ready to be retired.
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wacko911 on January 3, 2013
Its the build up of pressure from the expanding gas and heat that could lead to an explosion but I guess those ammo boxes could take a lot and there are going to be a few wee holes to keep the pressure down. I wonder if a vent with wire gauze to prevent the flames from escaping would prevent an external fire. (Provided there was no external igination source). Still much better than those lipo bags, there a video on YouTube of someone testing one and it burns out possibly worse than without one.

I really need to do something as I just charge on my desk, wonder if this is the solution.
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casehatter on January 4, 2013
I agree on the gas, but I've tried to blow them outsider of course and they just smoke and stink never seen any fire?? I even dead shorted and connected a high voltage Ni-Cad Charger just stinking smoke I do stay close with a ABC fire extingousher close by. can spell need a checker on my wrist LOL
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ipetepete on January 3, 2013
Very valid points. I think adding an additional vent would help dissipate some of the gas buildup. Some kiln/forge insulation might also be a good idea for keeping the flames from escaping. http://www.sheffield-pottery.com/SUPERWOOL-607-HT-BLANKET-8-lb-1-p/tcsw607ht.htm
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gremlin88 on May 17, 2014
I would use some fiberglass insulation rather than wire gauze, because depending on how fine the gauze is and what it is made of, it could catch fire.
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sailorJohn on January 4, 2013
I use a concrete block with a stepping stone top and bottom to store my lipos in the garage.
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HoriAkuma on January 3, 2013
Great job, Pete! I would think the battery inside of the lipo bag, inside of the ammo box would be plenty of protection.... Can't wait to get it all setup....
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dammuozz on January 6, 2013
I think you need holes to let out the explosion or the bunker will explode, maybe something like a vertical exaust pipe.

BOX WITH HOLES http://www.youtube.com/watch?v=jcgfGHus5rA
AMMO BOX WITHOUT HOLES http://www.youtube.com/watch?feature=player_detailpage&v=OuH017ic6uo#t=40s


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Bob Post on June 22, 2013
The vertical pipe is the answer to the vent process, put the bottom of the pipe almost on the bottom of the bunker/ammo box, that way it lets pressure out but not flame or hot stuff.
FYI, ammo boxes are pretty tough, they were designed to carry a lot of high explosive ammunition and keep it safe.
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LanMark on January 3, 2013
Nice idea.. I think I would put the balance connectors inside of the box power wires from the charger and then seal up the hole somehow. That way the battery doesn't have to be so close to the hole you drilled and more in the middle of the box.
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LanMark on January 3, 2013
I mean put both sets of cables from the charger inside of the box so none of the battery parts have to come out through the hole.. makes hooking it up easier and keeps the battery away from the open hole on the side.
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ipetepete on January 3, 2013
Good idea, I was originally going to do that, but, I only have one balance port extension which I also use with my watt meter. Once I get another I'll definitely shove all the wires inside.
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LanMark on January 3, 2013
another suggestion I would have is to use extra strength Velcro instead of zip strips.. that way you can take your charger off the side.. and the two should have very flat / nice surfaces for sticking down the velcro... this would also prevent the need for drilling those four holes through the box.

Now I need to track down a ammo box of my own.. doh :) Great idea btw... especially for storing the Lipos and such. I think you could drill a few little holes near the top (but not on the top) that would make sure the box doesn't build up pressure.. but then again you should be more than good.. those boxes lock down nicely and even with a build up would vent pretty quick out of any holes.. which would probably just be where the lid attaches since I doubt it is air tight.
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ludodg on January 19, 2015
As a matter of fact, I think that the zip-ties are a better choice.
If ever there might be a lipo that starts to burn, what I learned from the internet, these flames are VERY hot.
Some velcro would keep the charger attached to a smoking hot ammunition-box.
I would then prefer the zipties melting from the inside and the charger dropping next to the box.
Just my 2cts
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Cyberdactyl on January 5, 2013
Another warning indicator you adds adds some ease of mind, is to loosely bind a programmable kitchen thermometer to the battery with a nylon tie. Set the alarm for around 95F.

http://www.amazon.com/Taylor-1470-Digital-Cooking-Thermometer/dp/B00004XSC5
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ludodg on January 19, 2015
I would propose another safety-trick.
Fill a plastic bag with sand and put that bag on top of the lipo.

If the lipo ever catches fire or just would become very hot, the bag will melt and the sand will drop on the lipo. As we all know, sand is the best way to extinguisch a lipo-fire and not fluids.
There might not be enough sand in a small bag, but it will be better then nothing.
Good idea about the temperature-alarm also.
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jksbusiness on April 5, 2015
I like the idea of portability. I am adding a small smoke detector, play sand and a fire extinguisher to the charging station. I think even a trip to an RC friend to get it all checked out, will be a good precaution.
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spuder on February 20, 2017
What happens when a lipo goes off in an ammo box
- LID OPEN = http://bit.ly/2m2tqBc
- CLOSED NO SEAL = http://bit.ly/2kGaxUe
- CLOSED WITH SEAL = http://bit.ly/2kTljlt
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LiPo Charging Bunker