I think we have derailed this thread on to a lipo vs A123 cell debate :lol: :lol: knew this would happen! I like the A123 cells (think I had a few dreams about them a few years back) ha ha but my Lipo dealer kept this Junkie fixed up over this baron dream filled battery void :lol: now I am so hooked I cant get off em :wink: and I have a new dealer that gets me my fix cheaper and faster, I know the risks, I know all drugs are bad for ya! he he.
Nasty LiPo fire
- Thread starter Kepler
- Start date
Don't get me wrong, i am a lipo fanboy for sure, and believe them to be very safe after initial pack tests + using them with safe parameters ( don't discharge below 3.5v/cell, don't charge above 4.15v/cell )
^-- this gets charged on the bike, in an apartment.
BUT..... i am just saying that oatnet has a great point. The AMP20 cells really kick the snot out of lipo as far as cycle life per $ goes, and the size / weight advantage of lipo goes byebye when we're talking about packs made up of these cells.
^-- this gets charged on the bike, in an apartment.
BUT..... i am just saying that oatnet has a great point. The AMP20 cells really kick the snot out of lipo as far as cycle life per $ goes, and the size / weight advantage of lipo goes byebye when we're talking about packs made up of these cells.
My last post was drum roll!! my 2000! got a lot of catching up to do compared to some on here though, I would post more but I am always out in the garage checking my batteries dont burst in to flames :wink: :wink: still cant beat em on price for here in the UK cycle life isnt a problem for me should see 600-700 before I swap em out, they are small, light, cheap and powerful 8)
Still just in case there is a QC issue with the packs its got to be worth letting HK know about it though, not that they would admit to it if there were an issue? anyway whos going to send Amberwolf their old or new packs of Lipo, he doesnt want to burn them or pierce them (as much as we love to see it) he wants to give them a new home on his crazybike, he tells me a bit of fire damage on the bike would jazz the colour up bit anyways :lol: :wink: :wink:
Lets start a new thread get AW some Lipo..
cmon guys he nearly busted his leg for us in the spooky race id chuck 50 bucks his way to start the ball rolling what you say Luke?
Still just in case there is a QC issue with the packs its got to be worth letting HK know about it though, not that they would admit to it if there were an issue? anyway whos going to send Amberwolf their old or new packs of Lipo, he doesnt want to burn them or pierce them (as much as we love to see it) he wants to give them a new home on his crazybike, he tells me a bit of fire damage on the bike would jazz the colour up bit anyways :lol: :wink: :wink:
Lets start a new thread get AW some Lipo..
cmon guys he nearly busted his leg for us in the spooky race id chuck 50 bucks his way to start the ball rolling what you say Luke?
liveforphysics
100 TW
neptronix said:Oatnet, i read your post, and was like pshaw dude! we all know lipo is lighter and more compact!
Then i did the research:
A123 20AH:
480g x 12 = 5760
Turnigy 20C 5ah 5S lipo:
666g x 10 = 6660
you're more right than you thought you were.
I still like lipo for it's modularity and ease of replacing bad bits and pieces. But when you take the weight and size waste of the A123 cylindrical cells out of the equation, indeed.. lipo looks like a silly choice.
My 20Ah A123 cells are 571grams.
This website shows correct specs:
http://www.a123rc.com/goods-468-Excitingly+Powerful+A+123+PRISMATIC+CELLS.html
The have ~64w/hrs per 571g cell, which makes 112watt-hours per kg at the bare cell level.
Hobbyking LiPo (the cheap stuff, not even the good stuff) is 112g/cell, and 18.5w-hrs, which makes it 165watt-hours per kg at the bare cell level.
Please please avoid continuing the spreading of bad battery specs/info on ES. It seems like our forum has 10 incorrect posts regarding batteries for every 1 post with good battery info. That's gotta make it kinda a nightmare for newbs trying to figure out something.
Thanks for the correction.
I searched the web and 80%+ of the posts said 480g was the weight. Only a handful said 560g+ was the weight.
I am only repeating what i have read, with no intention to misinform.
So, 571g x 12 = 6852G ( bare cells ) vs.
6660G for turnigy 20C 5S 5AH packs..
Mind you, some of the weight for the cheaper 20C lipos would be redundant wires and connectors.
It's hard to do a 100% spot on comparison, but the point i'm trying to make is that the weight difference is not so big. Maybe ~2 pounds for a 20ah pack after assembly if you are using interconnects designed for under 5C loads. ( that's 100 amps.. )
20AH A123 is still an appealing alternative if you are making a large pack and the idea of lipo makes you pee your pants.
I searched the web and 80%+ of the posts said 480g was the weight. Only a handful said 560g+ was the weight.
I am only repeating what i have read, with no intention to misinform.
So, 571g x 12 = 6852G ( bare cells ) vs.
6660G for turnigy 20C 5S 5AH packs..
Mind you, some of the weight for the cheaper 20C lipos would be redundant wires and connectors.
It's hard to do a 100% spot on comparison, but the point i'm trying to make is that the weight difference is not so big. Maybe ~2 pounds for a 20ah pack after assembly if you are using interconnects designed for under 5C loads. ( that's 100 amps.. )
20AH A123 is still an appealing alternative if you are making a large pack and the idea of lipo makes you pee your pants.
Kepler
10 MW
oatnet said:
Everyone here I am sure has no interest in putting their family at risk and need to make sure they can comfortably sleep at night. I feel comfortable now I have my storage sorted. My Bomber is the only bike I charge with the batteries in place. These are bulk charged to 4.12V and have done 100 cycles now. Packs are Turnigy 6S 5000 mah 20C which seem to be a good choice in relation to quality. Bike is in clear corner of the shed and as mentioned before, batteries encased within a 2mm cro-mo space frame. I certainly will be staying clear of Zippies.
Kepler
10 MW
liveforphysics said:
Luke,
Next time you do a distructive LiPo test, would it be possible to put the pack in a sealed amo case? I would really be interested to see how well the failure is contained.
liveforphysics said:
incorrect,
the 20ah a123 cells are between 480 and 495grams (going by over 100 that i have, made in korea or usa and some of them from the very shop you quoted)
that gives us a theoretical 140 wh/kg and after testing cells at random, the real world gives us 132wh/kg
just looking at 2 examples of the much heralded nanotechs at hc, you get 106wh/kg to 145wh/kg, so averaged out, looking at the capacity you can reliably use, they are all pretty dam similar capacity for kg.
in my mind it doesnt leave any good reason to use lipos over a123 cells as the have around 5 to 10 times shorter life and no real advantage, i spose lipos can be of use for short life/slap together/testing stuff out type projects (and i use them for this myself), but if the the project is going to be one that is alive/raced/commuted on for any length of time..
Hillhater
100 TW
Err ? .. has anyone actually done any "destruction" testing of these A123 pouch cells ( in the same way HK lipo has been "flamed") ?
I know the cylindrical 123's have been hacked and abused, but i dont recall seeing the A123 pouches distroyed.
..Just asking really, ...do we KNOW the 123's pouches are safer ?
I know the cylindrical 123's have been hacked and abused, but i dont recall seeing the A123 pouches distroyed.
..Just asking really, ...do we KNOW the 123's pouches are safer ?
Hyena
10 GW
Another warning to heed guys, my car recently burst into flames.
I thought they were safe but this incident has really put me off gasoline and the thought of using it makes me soil myself. Since electric cars also use lithium batteries I'm now too scared and feel I have no option but to abandon cars all together. Now I'm tossing up whether to retrofit my ebike with SLA or buy a horse. Technically the SLAs could leak acid and so the horse is probably the best option. Can anyone recommend the best brand of horse to buy ? Also does anyone know a place in the CBD where I can get food for it? I'm hoping I can commute to and from work without having to feed it. Maybe I should carry a small pack of feed just incase ? I'd hate to run out a mile from home and have to push it the rest of the way...
I thought they were safe but this incident has really put me off gasoline and the thought of using it makes me soil myself. Since electric cars also use lithium batteries I'm now too scared and feel I have no option but to abandon cars all together. Now I'm tossing up whether to retrofit my ebike with SLA or buy a horse. Technically the SLAs could leak acid and so the horse is probably the best option. Can anyone recommend the best brand of horse to buy ? Also does anyone know a place in the CBD where I can get food for it? I'm hoping I can commute to and from work without having to feed it. Maybe I should carry a small pack of feed just incase ? I'd hate to run out a mile from home and have to push it the rest of the way...
Hillhater
100 TW
..
remember ..what a horse did to Superman !
liveforphysics
100 TW
All types of cars can and do burn somtimes.
But some types do seem to burn more often than others.
But some types do seem to burn more often than others.
I dunno that it's the "same way" but there's a recent video in another thread with somewhat unexpected results.Hillhater said:
Kepler said:
X2.... I'd love to see what it takes to actually CONTAIN the explosion. I'm finding it hard to believe it would blow through a 1/8" thick aluminum battery box, or a steel ammo can (someone did mention the ammo can's weak-point is the lid, so perhaps that should be tested also w/ it BOLTED or locked closed).
I'd also like to see what happens w/ a battery box in which it only has small "breather" holes. I imagine a fire would not be lit for long as the oxygen to feed it would be lacking.
Which brings up: How about working and prototyping a "Safe" battery-box? See just what it takes to contain a Lipo explosion. Because if you can make a safe battery-box, then it doesn't matter how dangerous Lipos are, it would be the Gas in your "Tank". perhaps an interesting design challenge for anyone with a few faulty Lipos to spare ?
What about the lipo cell that gets over discharged, due to a failed BMS or LVC and unnoticed. Than gets recharged to the recommended HVC ? Somewhere I read about this being a danger and have yet to see a test on these circumstances. Anyone ??
Just lurking and learning.
A good read Thanks All !!
Just lurking and learning.
A good read Thanks All !!
toolman2 said:
I love being jumped on for quoting a spec i saw online, have someone else agree with me, then get no response from the person that jumped on me for it. That's how we show love on the forums.
http://endless-sphere.com/forums/viewtopic.php?f=14&t=26072&hilit=a123+source&start=120
Here is a big thread, if you read along, the general consensus is about 500g for the cells.
A123 20AH:
500g x 12 = 6000g
Turnigy 20C 5ah 5S lipo:
666g x 10 = 6660g
That leaves you with approx. 1 pound for interconnections and such for an equivalent "36v" A123 pack.
If you got 12 cells for $50 ea, your cost would be $600.
If you bought 8 20C 5AH turnigy packs for $43 ea, your cost would be $344.
But the A123 would last over 3 times longer and there would only be a fire risk if you are Liveforphysics
In that case, the fire would simply be outside the box, at the vent hole, for as long as venting pressure continues.EBJ said:
awe yes, I guess that makes sense. haha. Then NO holes. Or how about covering the lipos in graphite-powder as a fire deterrent ? hahaamberwolf said:In that case, the fire would simply be outside the box, at the vent hole, for as long as venting pressure continues.EBJ said:
liveforphysics
100 TW
If folks are in the bay area, and have cases they wanted tested, I have cells and power supplies and a place to do it.
bigmoose
1 MW
Guys, someone is going to get hurt here, so I am duty bound to get a bit stronger in my language. Containing a deflagration in a closed container is lunacy. It is how pipe bombs and other shrapnel generators are made. The ammo boxes are likely ductile, will spread/vent where the cover attaches. It could also likely blow the cover off and take your head off if you are in the wrong spot at the wrong time. Notice I say likely. You won't know until you do the experiment or do a complex FEA (Finite Element Analysis) that has some connectivity to reality. It is not worth the risk.
You do not put combustible materials (fuel) and oxidizers in a sealed container and ignite them. Period. You can deflect a conflagration, you cannot contain a deflagration.
I had a very good friend almost decapitated 20 years ago when the 8 inch end cap of a agricultural tank let loose with only 60 psi inside the tank. Jim lost all his front teeth, and had his nose flattened. By the grace of the Almighty his eyes were unhurt...
If you check my old posts you will see that I encouraged guys that made sealed battery boxes to retrofit a vent hole or "blow out disk" to their battery box.
Luke my friend if you do this test, the ammo box needs to be inside a dumpster.
You do not put combustible materials (fuel) and oxidizers in a sealed container and ignite them. Period. You can deflect a conflagration, you cannot contain a deflagration.
I had a very good friend almost decapitated 20 years ago when the 8 inch end cap of a agricultural tank let loose with only 60 psi inside the tank. Jim lost all his front teeth, and had his nose flattened. By the grace of the Almighty his eyes were unhurt...
If you check my old posts you will see that I encouraged guys that made sealed battery boxes to retrofit a vent hole or "blow out disk" to their battery box.
Luke my friend if you do this test, the ammo box needs to be inside a dumpster.
amberwolf said:In that case, the fire would simply be outside the box, at the vent hole, for as long as venting pressure continues.EBJ said:
And i've mentioned this before, but make sure to cut the exit hole towards, but not aimed at the rear tire so that you have a sick afterburner.
bigmoose said:
Uhhh, I do it all the time.
I do tend to have a smallish vent hole in a graphite insert. Hmmm... I wonder what the Kp and alpha/beta constants of LiPo are? What Kn should I run them at? What kind of Isp can I get from NanoTech?And my mother always told me that if I deflagrated I'd go blind and/or grow hair on palms ... so I tend to avoid that.
bigmoose
1 MW
Ahhh but texaspyro but you are a professional at deflagration, detonation, and da-pressurization! You know when to hold them and when to run and hide!
liveforphysics
100 TW
Aww, Dave, I wanted them to learn the hard way.
You are absolutely correct though, the more you try to contain an energy release you can't stop, the more danger you create.
You are absolutely correct though, the more you try to contain an energy release you can't stop, the more danger you create.
