My ebike caught on fire.

[john61ct]

Yes, makes you wonder how people accumulate the knowledge to "get fancy" in their dangerous experimentation

without ever absorbing the most basic 101-level "guidelines" to ensure they don't kill themselves and those around them.

As more people take on our hobbies I fear such avoidable mishaps will lead to ever more prohibitive regulations.

 

[tomjasz]

Just to make sure you've heard of Louis Rossmann's UPP fire: https://endless-sphere.com/forums/viewtopic.php?f=14&t=108518

I think pictured here it looks like there is no electrical insulation between cell groups other than the heat shrink wrappers on each cell. If those adjacent cells rub or melt through the wrappers, there will be a short circuit. Maybe a small contact at first was enough to unbalance the cell groups at first (battery shutting off on you) and heat up those cells.

I will say that I only trust ebike batteries with a smart BMS, so that I can manually verify cell group voltages periodically are still balanced. If they aren't, then there's a problem.

Two 72V batteries on a BBSHD with an "upgraded" controller. Not a good example...
That said, the reseller I worked for sold UPP batteries and had high failure rates and the shop insurance paid out $50,000 for a UPP battery fire.

 

[LewTwo]

Yes, makes you wonder how people accumulate the knowledge to "get fancy" in their dangerous experimentation

without ever absorbing the most basic 101-level "guidelines" to ensure they don't kill themselves and those around them.

As more people take on our hobbies I fear such avoidable mishaps will lead to ever more prohibitive regulations.

A bit like "playing with fire".
By the way there are people that do that for a living but in a controlled environment.

 

[FuzzyWuzzy]

Where did you purchase the battery? I'd like to avoid that manufacturer

 

[ZeroEm]

"unit power pack batteries"
Would worry more about having good safety practices when handling, using batteries from all vendors. Bad cells happen be ready for it.

 

[E-HP]

Would worry more about having good safety practices when handling, using batteries from all vendors.

Or not ignoring the warning signs. Seems like the pack was providing pretty clear signs that something was wrong, but the solution of charging for days unattended to "fix" it, seemed like a bad call.

 

[Eastwood]

Would worry more about having good safety practices when handling, using batteries from all vendors.

Or not ignoring the warning signs. Seems like the pack was providing pretty clear signs that something was wrong, but the solution of charging for days unattended to "fix" it, seemed like a bad call.

Yeah, this is what I was thinking, bad cell. It seems that he did the exact opposite of what he needed to do since the BMS shut down the pac multiple times.

But thankfully nobody got hurt most importantly!

 

[999zip999]

Consider yourself lucky no one got hurt the house didn't burn down ect.
Lightning in a box and you just want to take out a little bit of lightning at a time. I guess how that happened.

 

[ZeroEm]

This is a good thread on battery care and i'm sure Ebike92119 has learned from the experience.

 

[E-HP]

This is a good thread on battery care and i'm sure Ebike92119 has learned from the experience.

Agreed!
Summarizing the lessons learned that I could identify from the OP, there may be more:

Don't leave your bike charging while unattended. If you're leaving the house while charging, just set it on fire yourself when you leave, so you won't be surprised when you get home.

If I wasn’t home to put the fire out, it certainly woulda caught the rest of my home on fire.

Don't ignore/dismiss/condone odd battery behavior. Don't make assumptions about the cause. It almost always will lead to issues if not addressed.

The battery that caught fire kept turning off, this also happened when the battery was not wired in series. I figured the BMS was turning the battery off.

Don't assume charging will correct issues, other than balancing. Don't charge until the problem is properly diagnosed and corrected.

Charging the battery for a few days fixed the issue.

A battery shouldn't be getting hot while discharging, unless you are discharging near or above the rated output. The battery should be taken out of service until diagnosed. It could lead to a fire while riding.

While riding around with both batteries in series I noticed the battery that caught fire was getting noticeable hot, but the other battery had a normal temperature.

Sad, but almost predictable.

After leaving the bike charging for a few days that’s when the fire started. I’m unsure why the fire started.

 

[tomjasz]

Every ebike oem and every battery builder I know instructs users to MONITOR charging.

RTFD!!!

RTFD
Read the frocking documentation.

 

[E-HP]

Yup.

I added these precautions to my "DIY Newb FAQ" thread.

 

[slaphappygamer]

After reading this thread too late at night. Had a nightmare. I was sleeping and my battery was charging. I woke up to smelling burning plastic. I found a ziploc bag on my charger, that was being melted. The charger was getting so hot that it was melting the sandwich bag. I took it off and went back to sleep. I couldn’t really sleep, so I decided to check my battery and it was swelling. I unplugged the charger and it kept expanding and sizzling. Thermal runaway was in full effect. All of a sudden, I woke up, in real life, and my heart was racing. Just a dream, WHEW!

Please, always be near your charging battery. If you have to leave, for the store or to pick up kids, just unplug your battery. It’s the simplest, safest thing you can do. Also, be sure there is nothing around your charger while charging.