[RE-wrenches] Batteries in parrallel Failure

[jay peltz]

HI Dan,

I"m really curious about what the CC saw.

Can you tell us, was it hydro, pv or wind 
and
what was the voc?

jay

peltz power
On Apr 19, 2011, at 8:18 PM, Dan Fink wrote:

> We almost had a house fire in the neighborhood a couple months ago from a parallel battery bank failure....an aging 2x8 L16 48v battery bank (16 of them), and one bat in bank one got a short and thermal runaway. I teach in my firefighter safety classes that thermal runaway is really rare, but it sure happened here fast. How rare is it? Smoke was pouring out of the bat box. Good thing the homeowner was there. He instinctively hit the main DC buss bar breakers, which was logical but didn't of course help the fire situation.....and the result was that all Outback electronics from charge controllers to the 2 inverter set being fried from too high DC voltage coming in the wrong end.
> 
> Was something designed or wired wrong here? What is a high-voltage (up to 150 VDC)  off-grid MPPT PV system supposed to do when the battery bank effectively disappears instantly from the system?
> 
> I didn't design or install the system, but I want to know if I have missed something obvious here.
> 
> Wind turbines have had the same issue here  -- better hit the turbine shutdown switch before disconnecting the battery bank, or you'll backfeed high Voc and fry some expensive electronics.
> 
> 
> All feedback appreciated!
> 
> Dan Fink
> Executive Director;
> Buckville Energy Consulting
> Buckville Publications LLC
> NABCEP / IREC / ISPQ accredited Continuing Education Providers
> http://www.buckville.com/
> info at buckville.com
> 970.672.4342 (voicemail)
> 970.373.1311 (fax)
>