What battery to choose after your last one burned your house.

dogman dan

1 PW
Joined
May 17, 2008
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Las Cruces New Mexico USA
Well, its been two years now since the fire, and I'm finally going to buy a battery.

I really got tempted to go back to lifepo4, and get another pingbattery. But the low discharge rate, heavy, and large size still turns me off.

I came to the conclusion that what type does not matter all that much, since no e bike battery is ever going to enter my house or garage again. Storage is now in the old smoke damaged electric stove in the backyard, and the top of it makes a great charging table. So why do I need the extra cost and weight of lifepo4? No battery will ever burn my house again, that is for sure! Might get my van when I travel, but I have some ammo boxes for storage that should give me time to kick the damn thing out the door if I have to.

So my new battery will be a modest 12s 10 ah, of 6s turnigy packs. Nice and small and light, so I can run my off road bike again, and carry it in the rear rack box. Any heavier, and it would handle too shitty, so no ping for that ride. Old y frame, so no carrying it in the triangle.

Later on if I feel like it, I can bump the pack to 18s, and run that on my cruiser.
 
remote bunker storage charging for the win
 
I'm having trouble making up my mine. I have a 24s of A123 20ah and is heavy. A 16s is doable because of there hagh amps. I want a 18650 Samsung 30q 20s 9p. But all those connections and series buss bar proplem at 90 amps ?. All other 15ah 20ah cells don't fit evan A123 20ah are to big and heavy..
 
18650 is the only way.

the reason why a single cell pouch fail is so destructive is because of the amount of energy stored and the bag itself provides zero protection.
a single 18650 hold roughly 10~12Wh, cannot puff up and at worst so some venting at the top. oh, and you need a hammer and chisel to pierce the sides.
so if a 18650 goes thermal you have only a small fraction of your pack going. usually you can acutally still use it. a pouch fail usually means either your bike, car or house burns down because a single cell can hold 100Wh or more in a single plastic bag.

just for these reasons i refuse to work with pouches and people that want them in their products i just point them to your pictures of your old house and other burned down vehicles and tell them to go elsewere.
 
flippy said:
18650 is the only way.

the reason why a single cell pouch fail is so destructive is because of the amount of energy stored and the bag itself provides zero protection.
a single 18650 hold roughly 10~12Wh, cannot puff up and at worst so some venting at the top. oh, and you need a hammer and chisel to pierce the sides.
so if a 18650 goes thermal you have only a small fraction of your pack going. usually you can acutally still use it. a pouch fail usually means either your bike, car or house burns down because a single cell can hold 100Wh or more in a single plastic bag.

just for these reasons i refuse to work with pouches and people that want them in their products i just point them to your pictures of your old house and other burned down vehicles and tell them to go elsewere.

A single 18650 that goes thermal gets as hot as 800°C.
In most configurations that means that the neighboring cells will also get too hot and fail.
And then your whole pack is on fire.

Now 18650s are definitely much safer than pouch cells but good physical protection and a good (smart) BMS is key to avoid shortcuts, overcharging, charging at too low temps, unbalance, underdischarge etc.

I also see many packs were 18650s are just stacked together, secured with some tape around and then welded.
Glued packs or quality cell holders and additional paper rings on the positive side are a must for a safe pack.

There's a few quality battery pack manufacturers that can offer this, like em3ev.
So either build one yourself properly or buy it from a reputable brand and not some small chinese sweatshop.
 
Well flippy, this is what an 18650 going thermal can do. This is why the bunker storage and outside charging will be my only way to go in the future, regardless of chemistry. I've run through a lot of cheap ass hobby king packs, and they do have their limitations. They puff a little in a few months use, but good ones don't puff much more even years later. They last about two years, then put out about 60-70% capacity for another two. What they do that 18650's cant, is pull a lot of amps from a light, small, 10 ah pack. So I can spend $250 on a 12s 10 ah pack, and still run my big motor cruiser on it.

I'm not going to start recommending noobs start out with lipo, far from it. But its the chemistry of choice, if you want to pull 40 amps from 10 ah. The obvious danger of handling lipo will not matter so much to me, since I'm never trusting a battery again.

My 18650 pack, was not good cells though, so it lasted 18 months then burned down the house. Best guess on the cause was failure to stop the charge by the bms. Or maybe, the cause was even simpler, I trusted a cheap ass bms.

P2110075.JPG


 
None of the lithium chemistries are fireproof. I was moving to lifepo4 because I heard it was the safest chemistry but when I shorted one (A123 26650) of them out, it burned as good as a tesla cell.

Instead of trying to find the safest one, I over build the safety features into my packs. Make sure it has a good bms that you tested to work, I have an over/under voltage alarms (very cheap), and I always have an overvoltage protection relay(5 dollars), if battery voltage goes above limits it kills the charging. I also have LCD or LED meters to monitor the balancing. Sometimes people don't keep track of the balancing on there cells or only checked them occasionally, I check the balancing every time. Its very easy for a pack to go out of balance when fast charging.

The only safe way to charge a lithium is with a balance charger, any other method you need to have multiple safety features built-in like I do. If your paranoid add 2 alarms (in case 1 fails) , all these safety features are very cheap insurance. They add complexity to your pack but its worth it.

picture of lifepo4 that caught on fire it got shorted out
 
flippy said:
18650 is the only way.

Nope. There are lots of large format cells out there made for cars, which are just as good and consistent as name brand 18650s, but which don't require all the flawed nonsense that 18650s do to build an e-bike pack.

Small cylindrical cells have the advantages of high maximum energy density and versatile configuration. But I'm happier with my 1P pack made of 25Ah cells with screw terminals than I was with my 18650 pack.
 
I want the size of the 18650 pack I like having two connections on my 20ah cell I want it to fit in my triangle. So 80volts 20ah @ 80 amps. Long life. Pouch is ok. Right now I have heavy 24s A123 20ah for 5yrs 1,390 cycles 23,000 miles still good. But needs the triangle and rear rack yes big and heavy. But 360 connections and 180 cells plus weak series buss bars and my garage fire with used Makita cells blowing flames out the top.
 
flippy said:
so if a 18650 goes thermal you have only a small fraction of your pack going. usually you can acutally still use it. a pouch fail usually means either your bike, car or house burns down because a single cell can hold 100Wh or more in a single plastic bag.

just for these reasons i refuse to work with pouches and people that want them in their products i just point them to your pictures of your old house and other burned down vehicles and tell them to go elsewere.
Except...his pack WAS 18650.

Plenty of other 18650 fires of various chemistries that resulted in complete destruction, some documented here on ES.

You might want to also look up Justin LE's destructive testing for the LiGo packs. Some of the videos show one cell going thermal, then that setting of the next, and the next, and so on.
 
amberwolf said:
Except...his pack WAS 18650.

Plenty of other 18650 fires of various chemistries that resulted in complete destruction, some documented here on ES.

You might want to also look up Justin LE's destructive testing for the LiGo packs. Some of the videos show one cell going thermal, then that setting of the next, and the next, and so on.

i know, usually i see "pack ending" events because cells are stacked or glued against each other without any form of spacing. especailly for high current packs i never use any form of honycomb fill but use the much safer square method. it uses up more real estate but it keeps about 1mm of spacing between each cell at the closest point with much more room diagnoal and as long as the gasses has a way to spread fast and exit the pack easy (using the room between the cells) they wont flash over to other cells.

usually with DIY packs all of these things are done wrong, honycomb setup, big sheets instead of strips forcing gasses to go directly into the PTC of the next cell, glued together, taped hermetically shut and no way for the gasses to exit. at that point you have done everything you can to start a flashover into other cells and should not be surprised when a pack goes nuclear.
 
Plenty of "State of the art ". Tesla 18650 packs have burned like a firework display.
Good pack design and construction techniques will minimise the risk , but as has been said,... Nothing will eliminate the possibility of a pack ( and property) destroying fire.
 
Hillhater said:
Plenty of "State of the art ". Tesla 18650 packs have burned like a firework display.
Good pack design and construction techniques will minimise the risk , but as has been said,... Nothing will eliminate the possibility of a pack ( and property) destroying fire.
Usually when tesla pack go thermal is because they have been wrapped around a tree at 100mph
 
Yep, gotta agree with that flippy, batteries will burn when you wrap the vehicle around a tree, or whatever.

I found no mystery when the hoverboard packs were starting fires. So many videos of learning to ride it, with the board flying off into a wall.

The only reasons I started this thread was to let some friends know I was going back into e bikes again. I was seriously shopping another gas motorcycle for off road riding. Half my dilemma was deciding to go with "safe" chemistry or not, especially after safe type burned my garage.

The other reason was to repeat, endlessly, keep that battery outside. No matter what it is. Or at least, some kind of indoor bunker. In the oven, in the fireplace, in a bunker you built.


If I won the lotto, the first thing I'd put in the design of my dream house, is a 20 foot metal covered carport separating the house from the garage full of teslas. And a fire suppression system in the house.
 
dogman dan said:
The only reasons I started this thread was to let some friends know I was going back into e bikes again. I was seriously shopping another gas motorcycle for off road riding. Half my dilemma was deciding to go with "safe" chemistry or not, especially after safe type burned my garage.

its very good to see you "coming back", and what you might do different considering your history.
 
Hoverboard fires ?5years ago I worked at a pedago dealer I looked at how cheap there packs were made I told him to get a fire box and put the batteries in there with a pipe to the outside.
 
999zip999 said:
Hoverboard fires ?5years ago I worked at a pedago dealer I looked at how cheap there packs were made I told him to get a fire box and put the batteries in there with a pipe to the outside.

many hoverboars are actually banned from sales and use on public places in holland because they tend to expode with the person standing on it.
 
flippy said:
Hillhater said:
Plenty of "State of the art ". Tesla 18650 packs have burned like a firework display.
Good pack design and construction techniques will minimise the risk , but as has been said,... Nothing will eliminate the possibility of a pack ( and property) destroying fire.
Usually when tesla pack go thermal is because they have been wrapped around a tree at 100mph
Sure,.. But some were also just parked in the street or in a garage also !
But, you are avoiding the point, ..nomatter what the cause of initiation,.. (damage, overcharge, human interferance, etc),.. The fact remains that 18650"s burn just as ferociously as any other lithium pack once ignited.
...even if they are designed and built to the best known standards.
 
999zip999 said:
Remember when the debut the new Boeing plane and it's new battery caught fire I forgot why or what batteries they were using.
pouches/prismatic cells:

https://upload.wikimedia.org/wikipedia/commons/2/20/1-7-12_JAL787_APU_Battery.JPG

Hillhater said:
Sure,.. But some were also just parked in the street or in a garage also !
But, you are avoiding the point, ..nomatter what the cause of initiation,.. (damage, overcharge, human interferance, etc),.. The fact remains that 18650"s burn just as ferociously as any other lithium pack once ignited.
...even if they are designed and built to the best known standards.
and howmany cars that run on liquid dino juice burn down every day for no reason? each time it happens with a electric car it makes the national news. i dont see that happening with a GM tahoe goes up in flames...
nobody claims perfection, but its still a extremely rare event that needs to be seen as such: extremely rare.
 
I think what some people forget, is that anything with a high current capability can start a pretty good fire, even if the chemistry itself can't burn.

Lead acids have been known to start fire, even though neither lead plates, not sulphuric acid burns - this is even true, when there's no suggestion the battery was gassing (Hydrogen obviously does burn).

Anything stored with huge potential energy - whether chemical or even kinetic, has the ability to start a fire.

All of my batteries, including my Ryobi One+ cells, are stored in an all metal case in front of my house. Its locked, but visble from the street. That way if it catches fire, a passer by could see it and call the fire brigade.
 
The other thing to consider is that REAL energy density does'nt just depend on the lithium chemisty. It also strongly depends of state of charge.

Store some elastic rubber bands at rest and they won't move a bit, even if you leave them unattended for ages. Store elastic bands completely stretched out and some will burst over time.

Store Lithium ion charged to 30% and it's unlikely to start a fire, even if you put nails through the cells.
Store Li-Ion charged at 100% and if one cell shorts outs, it could go "nuclear chain reaction" on the surrounding cells and start a big fire.

I think LiFePO4 are slightly safer because they pack a smaller absolute quantity of energy into a larger volume and a larger mass compared to smaller and lighter Lithium-ion chems like NMC. I don't think LiFePO4 chemisty is safer because of any specific quality inherent to specific proprieties of the chemical used... At least to my knowledge (I'm a chemist, organic chem to be specific, but i'm not an electrochemist).

But I'm pretty sure an NMC cell charged at 60% SOC is less likely to start a fire than an A123 cell (LiFe-nanoPO4) at 100% SOC, just like that fully stretched out elastic rubber band is more likely to burst than the one at rest, because it stores more energy...

Current rating are also important factors if a short was to happen, as pointed out in an earlier post.

Matador
 
flippy said:
.......
and howmany cars that run on liquid dino juice burn down every day for no reason? .....
Sure,.....but again you are avoiding the point...that there is no totally safe, non flamable , 18650 lithium pack .
Remember your statement earlier....
flippy said:
18650 is the only way.
a single 18650 hold roughly 10~12Wh, cannot puff up and at worst so some venting at the top. oh, and you need a hammer and chisel to pierce the sides.
so if a 18650 goes thermal you have only a small fraction of your pack going. usually you can acutally still use it.....
 
Imagine if tesla cars would run on hypergolic fuel (1,1-dimethylhydrazine and nitric oxide)... They'd burn even more...
 
dogman dan said:
Well flippy, this is what an 18650 going thermal can do. This is why the bunker storage and outside charging will be my only way to go in the future, regardless of chemistry. I've run through a lot of cheap ass hobby king packs, and they do have their limitations. They puff a little in a few months use, but good ones don't puff much more even years later. They last about two years, then put out about 60-70% capacity for another two. What they do that 18650's cant, is pull a lot of amps from a light, small, 10 ah pack. So I can spend $250 on a 12s 10 ah pack, and still run my big motor cruiser on it.

I'm not going to start recommending noobs start out with lipo, far from it. But its the chemistry of choice, if you want to pull 40 amps from 10 ah. The obvious danger of handling lipo will not matter so much to me, since I'm never trusting a battery again.

My 18650 pack, was not good cells though, so it lasted 18 months then burned down the house. Best guess on the cause was failure to stop the charge by the bms. Or maybe, the cause was even simpler, I trusted a cheap ass bms.

What cells were they ??? I know they were 18650 format, but any specific brand/chem/model ?
 
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