Walmart sues Tesla over solar panel fires

[bdunham7]

Solar panel fires?  Really?  I'd like to know the root cause here...

https://www.bloomberg.com/news/articles/2019-08-20/walmart-sues-tesla-energy-operations-over-solar-panel-fires

[floobydust]

It's happened at 7 stores. I was wondering what is going on as well.
These are SolarCity panels I believe.

edit: pic source from court filing: https://markets.businessinsider.com/news/stocks/walmart-sues-tesla-after-solar-panel-fires-at-stores-2019-8-1028460917

[Bud]

Holy crap... I do not want those panels on my roof...

[john61ct]

More likely human error in the wiring.

Electricity is electricity

[maginnovision]

Walmart just wants their money back and tesla to take it all back, and pay for investigations into cause. It won't affect tesla(their losses are large enough it doesn't matter) and Walmart will just get new panels from someone else.

[schmitt trigger]

This photo gives a new meaning to the term: Fire Sale.

[Psi]

i dunno, some of the things you see at Walmart stores would make even concrete spontaneously combust

[Jeroen3]

https://www.gelderlander.nl/rheden/zonnepanelen-mogelijk-oorzaak-brand-gazelle~aaaa7d3f/

This happens occasionally. Probably poor wiring. Maybe defective panels.
Not sure if they are Tesla setup.

[floobydust]

I'm wondering if the solar panels and wiring have significant inductance.  Enough to sustain a DC arc that etches across the solar cells? Or is it a ground fault.

There seems to be nothing that can interrupt the arc- a thermal fuse or AFCI for the purpose.

[David Hess]

I'm wondering if the solar panels and wiring have significant inductance.  Enough to sustain a DC arc that etches across the solar cells? Or is it a ground fault.

The voltage versus current curve of a photovoltaic source makes it self ballasting so no inductance is required.  They operate more as a constant current source under arcing conditions.

This happens occasionally. Probably poor wiring. Maybe defective panels.
Not sure if they are Tesla setup.

My guess is environmental contamination causing electrolysis and eventually arcing.

[Bud]

 Yes, the bad Walmart carma emitted from under the roof.

[chickenHeadKnob]

I have never seen one  of these panels up close. Can someone helpful tell me exactly what substance is sustaining that level of combustion? Is the backing to the panels a polymer?

[IanB]

I have never seen one  of these panels up close. Can someone helpful tell me exactly what substance is sustaining that level of combustion? Is the backing to the panels a polymer?

I don't know the details in the Walmart case, but consider this:

Solar panels produce tens of kilowatts of power, and that's a lot of heat if it goes astray. Imagine getting some giant mirrors and focusing all the Sun's energy on a single spot. Anything will burn given that kind of heat. Solar panels do the equivalent. They collect the Sun's energy over a large area and concentrate it in one place (the wires going to the power converter). Just imagine what could happen if there's a fault.

[floobydust]

I have never seen one  of these panels up close. Can someone helpful tell me exactly what substance is sustaining that level of combustion? Is the backing to the panels a polymer?

I don't know the exact Trina solar panel construction, but in the sandwich the mid sheets and back-sheet are plastic resins.
EVA film (Evathane, Luperox) ethylene vinyl acetate seems to have a low melting temp. 71°C and no mention about flammability.
Back Sheet Tedlar/PET good to 107°C and no mention of flammability.

I'm assuming a hot spot on the panel starts the plastics on fire, and it spreads to adjacent panels. The field wiring should be UL-94 for flame travel like most electrical plastics.

[orion242]

It doesn't sound like anything with the panels themselves but the installation in general.

When morons use bolts for fuses, walk on the panels, mis-match the DC connectors, and ignore ground-fault alarms coming from "de-energized" systems, things are bound to happen.

A read of Walmart's court filing is pretty interesting.

https://www.eevblog.com/forum/eevblab/eevblab-64-tesla-solar-panels-are-catching-on-fire!/

[bd139]

Perhaps someone shot them? 

Lots of people shooting guns around Walmart I understand.