Raptor on Fire

[agniusm]

Nobody posts in such topics for one reason, the answer to a battery fire 95% of the cases is incompetence, misuse of the batteries. Lots of people here and diyelectriccar saw bms/pcm as evil and were using top or bottom balancing techniques and saw them to be superior to that electronic management of the pack. Well, few years down and we see more and more people using some sort of protection, not this case thou.

 

[999zip999]

Millions of batteries and thousands of types. And a billions of battery build ideas, since the pyramids. And who did they copy.
King Tut's battery fire while gold electroplating his

 

[sansander.ebike]

a safe alternative 48V 15Ah lead acid battery

 

[cwah]

my guess:

A short caused by:
1. Loose clamping of the cells with tape and maybe a bit of glue? You need something stronger such as steel hose clamp or something similar to hold vibration:
http://www.ebay.co.uk/itm/301351283122?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

2. No insulator between each cell series. Vibration/chaffing has probably worn out the glue and the thin cell heatshrink between 2 serie of cells... causing a short!
Get some chafing tape or insulator to prevent this.


I've always been surprised by the small precaution people are having when building their pack when the risk as so big! Build your pack properly!

 

[Hillhater]

a safe alternative 48V 15Ah lead acid battery

Not necessarily much safer if they are not monitored....but certainly a huge step down in technology, and performance

 

[TheBeastie]

Most of you guys are talking as if the op built the battery pack he clearly states he didn't, considering the amount of words like "build your pack" etc... This is why we only see a fraction of the bike fires that go on out there.
I instead say let's ban and perm firewall those who haven't read and responded to this thread properly.

 

[Lurkin]

The speculation will stop when the OP comes clean and tells the whole story. Who built it and whether he can confirm why it failed. Until he states who did build it, it could be considered a cover for a poorly self built pack gone wrong.

Without it, forum members will continue to have to guess based on the photos.

 

[sansander.ebike]

everyone criticized my thread, this and that is shit....
but makes a productive proposal,
propose what remain positive for the future, so anyone this disaster happened.
Time for Holiday....

 

[Lurkin]

Theres been a few dramatic responses in the thread, but really everyone's interested to fully understand your situation as it could impact who they purchase from and how homemade packs are made in the future. Information like this is really valuable to the other people writing back to you, because it assists their understanding for the future and represents a positive interaction on your part.

Providing half the information is really just a tease.

If you really want to make a contribution, and avoid a repetition in the future for someone else, you could be forthcoming about who made the pack and why you are protecting them.

 

[tomjasz]

You could be forthcoming about who made the pack and why you are protecting them.

THIS is important. I don't understand the protection of a bad build. Someone could have an even more serious event. But, I'm repeating, one look at the pack and it's easy to imagine why it failed.

 

[KarlJ]

Just quietly.....

Up until 4 months ago i did not appreciate the effort Cellman (EM3EV) went to, to ensure the most possible safety of his packs.
fiberglass barriers to chaffing, cell level fuses for BMS wires, heavy duty heatshrink, RTV applied with similar care as delivering babies,
BMS units that DO fully cutoff in and out until everything is disconnected and pack is either charged or discharged to resolve the fault.

IMHO, regardless of the apparent poor build, a cell balancer was used, not a proper overvoltage / undervoltage cutout BMS (battery management system)

WHY? is Simple- at 90V+ and likely 50A+ they are EXPENSIVE! vs balancer board which is comparatively dirt cheap

I just bought one to suit 14S 50A continuous and 100A peak and by the time it gets to AU is well over $100.
Typically i build with multiples of 7S 30A boards ie 2 for 8-14S and more if i want more current - cheap at ~$15 each.
Note that BMS boards also get warm mostly under load (perhaps another reason fo not using one)

INTERESTINGLY..... I'm building a 32E samsung pack for a friend right now and at just 1A charge, they get VERY warm to HOT......
this is typically just 0.27C rate of charge....Surprised me!

I myself spent $450AUD on a Grin satiatiator today as i figure i'm in ebikes for a long time and the cheapie chargers and their failures + cost of batteries will pay for itself many times over in the long run.


Anyhow I think we have learned what we needed to learn
-BMS is better than balancer
-cheap Chinese chargers may have issues periodically (i know of 8 failures all of which resulted in no charging but anything is possible)
-PAY ATTENTION when your bike is on charge and treat it with respect

IMHO last but not least, low rate charging is a good idea if you have the time EG laptop Powersupply + DC-DC converter provides ~1.5A into a 14S pack from a typical 90W laptop power supply. At this rate even with a failure or two, tough to see 75W into the battery causing a fire

k

 

[agniusm]

WHY? is Simple- at 90V+ and likely 50A+ they are EXPENSIVE! vs balancer board which is comparatively dirt cheap
k

No, lack of knowledge is expensive. There is no point in large BMS with many fets and bulky heatsinks. What it does? It adds more looses, increases the price. You need a bms capable to support your charge current, so if you are charging at 10 amps, 15 amp bms will suffice to have some overhead and run bms cooler. I charge at 30 amps, but my system is 10S and my bms cost 30usd, and i have peak 300A discharge. You dont discharge your battery through bms, controller does your current limiting. You connect your bms to contactors coil and thats it, it cant be more simple than that. Using contactor not only eliminates the need of a large powerful bms but also adds a safety feature to the system, its a win win combination. I dont understand why people make it more complicated?

 

[tomjasz]

I have $12 BMS that work just fine. Nobuo is using similar in his packs and the performance is decent. Fair quality BMS are accessible and cheap. You don't have to spend $100 on Bestech. Who, for the average Joe, provide horse sh!^ support.

 

[KarlJ]

i use my batteries for other purposes (off grid/hybrid systemd) and the LVC occasionally gets used. (agreed not often on the ebike)
over discharging is a problem too for the poorly educated

 

[sansander.ebike]

now only the battery, I think next week I think the end of next week is completed.

 

[sansander.ebike]

for all controllers from February 2015. http://adaptto.com/Support/
Big thanks to Artur from Vector in Munich for technical Support.

 

[sansander.ebike]

The Raptor is finished, the first test drive was OK, but to beginning the controllers had difficulties to start, New Firmware is running .... http://adaptto.ru/Podderzhka/
Thanks to Artur vector-bike for Support.

 

[sansander.ebike]

the end.

 

[SlowCo]

Very nice result, congratulations!
Enjoy the riding.

 

[Artur]

Was glad to help you with a controller. Ride safe! Glad that at the end you are again on your bike, this is the most important thing in all this story!

 

[Lurkin]

Curious - whats the weight of the new battery vs the old (pre fire)?