999zip999
100 TW
It not just the fire but the sooth that the packs expell as this stuf will coat and stick to everything. You will need a sand blaster to remove it.
Building a Battery that will NOT cause you to wake up dead
- Thread starter Arlo1
- Start date
bowlofsalad
100 kW
999zip999 said:
This sounds like another fine reason to charge a battery in a fireplace or something.
etriker
100 kW
dm9876 said:
I hope everyone reads that. It helped me become a better master BMS.
The master BMS is human. The slave BMS is the master BMS's electronic tools that he watches over.
The slave BMS does not know if the battery is being charged in the house or way out in the yard.
The master BMS does.
Reading this forum is a good way to become a better master BMS.
etriker
100 kW
One of my slave BMS tools is a Hyperion 1420 charger.
The firmware can be updated in the Hyperion 1420.
It is my job as the master BMS to make sure the firmware in the Hyperion 1420 stays updated.
I also have to make sure the firmware in the master BMS stays updated.
Stay on top of it kids !
The firmware can be updated in the Hyperion 1420.
It is my job as the master BMS to make sure the firmware in the Hyperion 1420 stays updated.
I also have to make sure the firmware in the master BMS stays updated.
Stay on top of it kids !
el_walto
10 kW
I just got a Hyperion 1420. It is awesome. I would recommend it to anyone messing around with lipo. Only thing i wish is that they would make it a bit more compact.
bowlofsalad
100 kW
el_walto said:
I don't mean to offend, but I am guessing this some how relates to not causing a battery to light on fire, maybe you could elaborate?
dm9876
10 mW
amberwolf said:
I too am interested in this approach. I was looking at building a pack using these 'pelican' style hard cases, they would provide impact protection as well.
http://www.jaycar.com.au/productView.asp?ID=HB6381
My concerns with this approach are that sealing it up is also insulating it and the heat from one failure may more readily propagate to other cells. Main concern though is ABS is flammable, with its own kind of nasty smoke and its a gamble if the failing cells would generate enough heat to burn the plastic case... any thoughts on this?
From what I can see, even the expensive pelican brand cases are ABS (not 100% sure though). Polycarbonate cases (more fire resistant ) don't seem to be available in that style, only in the smaller, water proof OtterBox style cases like this
http://www.otterbox.com/otterbox-2000-cases/otterbox-2000-cases,default,sc.html
Dean
kfong
100 kW
Not sure why carbon fiber is not mentioned. This is the current approach I'm using. Nothing else could withstand my torch test. This is why the space shuttle is covered with it along with ceramic tiles. The use of LiPo bags to prevent fires works quite well. I plan to encase all my LiPo with CF this way. If I get a fire, I loose the pack and perhaps damage the bike. I consider this better than loosing the house. I would never recommend LiPo's for Ebikes, but I still use them because of the cost and power density. I charge in the garage, and always balance charge with a quality RC charger.
johnrobholmes
10 MW
CF is conductive. Its similar to a lightly painted steel box in risk, any abrasion to the resin exposes conductive material.
kfong
100 kW
Easily solved by using an inner layer or two of fiberglass cloth.
dm9876
10 mW
Re: My earlier statement about ABS vs polycarbonate cases. I found some data here: http://www.tcforensic.com.au/docs/article10.html
(Celcius)
ABS: melt range 88°-125°, ignition 416°
Polycarbonate: melt range 140°-150°, ignition 580°
Also found there are polycarbonate cases available from progressive RC, They quote 6mm thick, which sounds pretty solid.
http://www.progressiverc.com/prc-hardline-cases.html
I cannot find much real data on lipo burn temperatures. Some news articles seem to quote 600 deg. C (yeah I know, solid source of data but I guess is it dependent on if it just fails and vents or if it actually ignites, which might be prevented or reduced in a sealed enclosure.
I'm no thermal design engineer but I guess the temperatures reached are more determined by the rate of heat release from the batteries and how fast the heat is removed (probably not too fast in the sealed plastic case scenario)
wrapping in some heat resistant material may limit localised melting and slow the transfer of heat to adjacent cells, but it still seems that anything short of metal is not going to deal with the situation.
Also need a vent of some sort, so as not to make a bomb. Everyone says no to metal, but properly lined and insulated it seems to be the way to go and is also what all the commercial packs seem to use.
Dean
(Celcius)
ABS: melt range 88°-125°, ignition 416°
Polycarbonate: melt range 140°-150°, ignition 580°
Also found there are polycarbonate cases available from progressive RC, They quote 6mm thick, which sounds pretty solid.
http://www.progressiverc.com/prc-hardline-cases.html
I cannot find much real data on lipo burn temperatures. Some news articles seem to quote 600 deg. C (yeah I know, solid source of data
but I guess is it dependent on if it just fails and vents or if it actually ignites, which might be prevented or reduced in a sealed enclosure.I'm no thermal design engineer but I guess the temperatures reached are more determined by the rate of heat release from the batteries and how fast the heat is removed (probably not too fast in the sealed plastic case scenario)
wrapping in some heat resistant material may limit localised melting and slow the transfer of heat to adjacent cells, but it still seems that anything short of metal is not going to deal with the situation.
Also need a vent of some sort, so as not to make a bomb. Everyone says no to metal, but properly lined and insulated it seems to be the way to go and is also what all the commercial packs seem to use.
Dean
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