House destroyed while charging e-bike battery in Bend, OR

[mrbill]

Hey Guys:

Anyone know more about this incident?

http://www.ktvz.com/news/bend-house-fire-raises-lithium-battery-issues/27888920

 

[zener]

It could shine a bad light on ebikes.
If there would not be an average of 230 burned down houses from christmas-tree-fires. :lol:
http://www.nfpa.org/safety-information/for-consumers/holidays/christmas-tree-fires

Glad that cristmas is not so often like we charge our ebikes without BMS or cell-level-monitor. :lol:

 

[dnmun]

this fire came up in the disasters thread. it really is too too bad the guy did not grab the bike and carry it outside instead of letting it continue burning in his garage if his smoke alarm set off.

in both of the fires i had to put out myself in my houses the house woulda burned down if i had just left the fire alone to continue burning. in both fires the tenant did nothing to stop or even respond to the fire and if i had not been at the house when the fire occurred the tenants woulda just followed the fireman's advice to regular people to just leave the fire alone and let them put it out. so evil for them to tell people that. there was a time when people could do things on their own initiative.

 

[mrbill]

Hi dmun:

Can you provide a link to the "disasters thread"? I could find no other discussion about this on E-S. The fire occurred last night (9/4).

It would be helpful to know what kind of battery, charger, and charging protocol was used. E.g. Were the battery and charger sold together as a turn-key kit, or was it a more ad-hoc assemblage as we on this forum are likely to use? How sophisticated was the user?

I found another link about this incident here:
http://www.ktvz.com/news/smoky-fire-tears-through-nw-bend-home/27871540

where some interesting statements from a fire official are recorded.

I almost always charge unattended since I don't have the patience to babysit the charging process for up to 12+ hours. My bikes and batteries are stored in a detached garage equipped with an ABC fire extinguisher located near the door. I have another similar extinguisher located just inside the door of my house. Garage is equipped with a smoke detector that is wirelessly networked with my in-house detectors. It would be a bummer to lose the garage and its contents to a fire, so I take precautions:

All of my batteries are LiFe or NCA (Samsung INR-18650-29E), and all are charged and discharged through a working BMS. No exceptions. All batteries are tested when new by charging to BMS cutoff and discharging to BMS cutoff to verify capacity and that the BMS functions as expected before I will charge unattended. Chargers are also tested for max. output voltage, and all of my batteries use the same max charge voltage (29.2-29.4 volts). The LiFe are charged fully before storage (according to manufacturer's instructions), but the NCA batteries are charged to 3.8v/cell before being allowed to sit. Before use I usually charge to 4.1v/cell instead of the maximum 4.2v/cell. Charger hookup and wiring are designed to minimize user error.

I suppose the next step is to charge only in a fireproof vault of some sort, but after eight years of working with this stuff I've never had an incident.

 

[dnmun]

i think it is best to leave the batteries way undercharged if leaving in storage. 3.2V for lifepo4 and 3.7V for lipo.

this is where dogman dragged up this story: http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=56305&start=25

 

[LegendLength]

The problem is there are so few BMS's for LiPo these days. It surprises me because I'd imagine there is a large market for such a product.

Admittedly I haven't looked into it since a year or two ago. Back then a found a couple of chinese boards that appeared to be more dangerous that straight-up charging.

It annoys me because I can't see any major technical issues preventing such a product. Then again I feel the same way about e-bike transmissions which have failed to materialize after 5 or more years, even with the obvious market for that type of product.

You're free to say "well start a company yourself" but not everyone has capital.

 

[mrbill]

The problem is there are so few BMS's for LiPo these days. It surprises me because I'd imagine there is a large market for such a product.

Admittedly I haven't looked into it since a year or two ago. Back then a found a couple of chinese boards that appeared to be more dangerous that straight-up charging.

It annoys me because I can't see any major technical issues preventing such a product. Then again I feel the same way about e-bike transmissions which have failed to materialize after 5 or more years, even with the obvious market for that type of product.

You're free to say "well start a company yourself" but not everyone has capital.

Using LiPo without a BMS is like speeding in your car. It seems like a good idea until you crash because something happened that you didn't expect but should have expected. The probability of disaster is low, but should disaster strike, the cost is high. Most people don't properly assess long-tail risk.

em3ev.com has some good BMS boards for various configurations.

http://em3ev.com/store/index.php?route=product/category&path=42

The 7s LiPo and 8s LiFe 35A boards are "2-wire" BMS (charging and discharging through the same leads). I'd like to think I had some influence in Paul offering these as he started to carry this model after I specifically requested a 2-wire BMS for my batteries. A 2-wire assures that all charge and discharge activity is mediated by the BMS and simplifies system wiring, also eliminates possible user error of charging through discharge circuit (bypassing cell-level charge cutoff) or discharging through charge circuit (bypassing cell-level discharge cutoff). Cost is a bit higher, though.

 

[dnmun]

saying there are so few BMSs for lipo shows the depth of the lack of knowledge that is promoted on this board. amazing someone could even say that.

 

[LegendLength]

saying there are so few BMSs for lipo shows the depth of the lack of knowledge that is promoted on this board. amazing someone could even say that.

Reading comprehension can also show a lack of knowledge:

Admittedly I haven't looked into it since a year or two ago.

em3ev.com has some good BMS boards for various configurations.

http://em3ev.com/store/index.php?route= ... ry&path=42

Thanks for the link mrbill.