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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: eagle19952 on October 08, 2015, 03:30:20 PM

Title: Thermal Run Away
Post by: eagle19952 on October 08, 2015, 03:30:20 PM
Can anyone explain this ?

It appears to be the same problem Clifford had...

(https://scontent-ord1-1.xx.fbcdn.net/hphotos-xpa1/v/t1.0-9/12122715_10153655466843826_2775078488768667359_n.jpg?oh=35dc5397a36fafcc73e019cacafec38d&oe=5685BE4B)
Title: Re: Thermal Run Away
Post by: eagle19952 on October 08, 2015, 05:46:47 PM
well i guess it's all about battery bay temperature....
Title: Re: Thermal Run Away
Post by: gus on October 08, 2015, 06:36:38 PM
Was any one of the batts shorted out, this will usually kill at least some of the others.

Happened to me with two start batts, shorted one killed the other.
Title: Re: Thermal Run Away
Post by: Brassman on October 08, 2015, 07:27:20 PM
agm batteries? What's are the charging voltages?
Title: Re: Thermal Run Away
Post by: eagle19952 on October 08, 2015, 07:36:23 PM
these were not mine, just thought it was interesting, apparently it is more common than i realized... ??? ???
Title: Perhaps Just Defective Batteries?
Post by: HB of CJ on October 08, 2015, 09:42:52 PM
I am thing here a massive internal short out.  Perhaps bad factory batteries?  Yep ... sometimes you get a cascading effect.  Years ago I had a Nickel Cadmium 180 amp hr cell establish a very definite internal short.  Very spectacular to say the least.  Were the bad batts rated for a high vibration installation?
Title: Re: Thermal Run Away
Post by: Geoff on October 09, 2015, 08:15:42 AM
I've had batteries swell up when they get old, apparently someone made these with plastic that would not expand so they just cracked under pressure.

--Geoff
Title: Re: Thermal Run Away
Post by: Jeremy on October 09, 2015, 08:27:50 AM
I'm curious to know what the white substance is that's visible through that crack - is that rampant sulphation (which might well account for the swelling), or are these AGM batteries and that's the mat showing? If these were flooded batteries I'd hate to think where all that acid ended-up..

Jeremy
Title: Re: Thermal Run Away
Post by: luvrbus on October 09, 2015, 08:29:35 AM
Mine the cases melted together I liked to never got them to come a part.It is more common than you think if you read the fine print the AGM's are the happiest at 77 degrees which is almost impossible to achieve in a RV application  

Those are not the sealed pressure regulated AGM batteries so venting and expansion should have not been the cause
Title: Re: Thermal Run Away
Post by: Iceni John on October 09, 2015, 11:08:51 AM
If every battery were individually fused, such as with the Blue Sea battery-terminal fuses, would that help in this case or not?   If one battery catastrophically shorted out internally, how much current would the other batteries try to push into it?

I have 300A Class T catastrophe fuses on each battery bank's negative cable (per Sean Walsh's recommendations), plus fuses and circuit breakers on each load's positive cable, but nothing protecting each individual battery.

John