Electrical Cooking The Battery - nearly well done.

[Rockape]

HI @Drover ,
Seeing what happened to your battery is frightening. Out of curiosity what is the current output of your projecta charger and solar charger. Reason being I bought home today a 75ahr dep cycle battery with a collapsed cell that still takes a charge. I want to do a comparison with a good matching battery to see what my bench charger will do when hooked up as well as hooking up my solar panel. Just doing a quick 10 minute charge test, the voltage on the good battery rose and the current dropped, where as the battery with the bad cell had its voltag rise slightly, but the current continued to rise to the maximum the charger and solar could supply. The battery with the bad cell started to get warm and that was only after 10 minutes!
I want to do more testing on the weekend.
Cheers
Nick

 

[Drover]

Yep @Rockape thats what the battery guru's reckon happened to mine, I can't recall what my chargers actual figures were doing with my other battery but it followed your good battery. I've shut it all down for the night but I'm pretty sure all is good and it was the battery.
I'm going to do some more tests later just so I know for sure how these two systems work normally, the Projecta I think also chargers the Breakaway so I have some multi meter time ahead to get it all sorted in my head how it all runs in this rig.

 

[Axl]

Wow lucky you caught that @Drover but I would be rechecking your chargers I wouldn't think that a dropped cell would cause this in such a short time. Looking forward to @Rockape 's reply once he has done some testing.

 

[Drover]

@Axl they can cook up in a couple of hours or less actually, especially these sealed units, GEL and AGM's, cell drops out, gets hot, valve doesn't release gas and they just keep getting bigger and hotter, the battery fellas gave me all this info to read about why AGM's and GELs are so good but when they go bad they are really bad. Where the old wet jobs just boil themselves dry then explode sometimes.

 

[Axl]

Interesting if a battery in the vehicle drops a cell it simply dies over time (wet cell) all the while the alternator is delivering the best part of 14 plus volts at 100amps give or take, this brings me back to the argument that a lot of people say a wet cell is all you need saving you money......bring on lithium ion I reckon.

Whilst I understand that wet cells can give of gas in an enclosed space so can the AGM's obviously from what you have posted, good to here you got it in time looking forward to the testing.

 

[Drover]

@Steve1307 , strange just found your post and yep thats what it was thermal runaway, even though the compartment is well ventilated, it was explained that it could go bang but more than likely split and ooze .
Have read some good tech info on them now, not bloggers info and found it most interesting.

 

[Bellbirdweb]

bring on lithium ion I reckon.

If a thermal runaway on an AGM battery is exciting, waIt till you see what happens to a lithium battery that runs away !!

 

[boots33]

Wow @Drover lucky escape there, have seen many cooked batteries over the years. A lot from shorted cells but most from overcharging. Of course overcharging can eventually lead to a shorted cell as well due to the heat buildup warping the plates. Keep a close check on your chargers just to make sure.

 

[Drover]

If a thermal runaway on an AGM battery is exciting, waIt till you see what happens to a lithium battery that runs away !!

Pics ?? pics ???? .......................pity Mythbusters is finished they could do a fantastic story on this.......

Yep, @boots33 watching like a hawk, went to do some checks on my Projecta charger IC2500 and the power dropped off for a minute and when it came back on the damn thing won't work, err 04 showing and of course the manual or website doesn't give error codes, nothing else tripped or shutdown.......................stuff it over this battery power crap...............hurricane lamp was so much easier.

 

[Dobbie]

Candles???

Though no good for beer.

You did well to carry a camera so you could share the sizzle...

 

[Steve1307]

@Steve1307 , strange just found your post and yep thats what it was thermal runaway, even though the compartment is well ventilated, it was explained that it could go bang but more than likely split and ooze .
Have read some good tech info on them now, not bloggers info and found it most interesting.

I found this info specifically (googling).
http://www.cdtechno.com/pdf/ref/41_7944_0712.pdf

Basically the battery gets hot due to the charging+ environment.
Cannot dissipate the heat faster than it is generated.
The hotter battery has lower impedance so can accept higher current charge
.... and this in turn heats it up more at faster rate.

I haven't read this whole thing but It says that the AGM batteries seem to be more susceptible since they are tightly packed.

Recommendation is to have temperature monitoring to limit the charging.

The SETEC in my old Jayco Swan didn't have a battery temperature probe as part of the AC charging.
I did fit a DC-DC charger (CTek 250D) in the van for when hooked up to the car and this had a temp probe.


I'm glad they generally just cook and split / ooze rather than explode. If not discovered I guess you still could have a fire on your hand.

My Jeep GC has a huge AGM battery directly under where i place my backside when driving. On long trips I don't like the old prank of turning the seat heaters on any more.

"Thermal Runaway" sound scary especially if you're familiar with a "Diesel Runaway" or a "Nuclear power station Thermal Runaway".

 

[Bellbirdweb]

Pics ?? pics ???? .......................pity Mythbusters is finished they could do a fantastic story on this.......

Yep, @boots33 watching like a hawk, went to do some checks on my Projecta charger IC2500 and the power dropped off for a minute and when it came back on the damn thing won't work, err 04 showing and of course the manual or website doesn't give error codes, nothing else tripped or shutdown.......................stuff it over this battery power crap...............hurricane lamp was so much easier.

This video shows how a small battery can go off of over charged.

Imagine a big one that you'd find in a caravan

 

[Drover]

"Thermal Runaway" sound scary especially if you're familiar with a "Diesel Runaway" or a "Nuclear power station Thermal Runaway".

Thats exactly what came to my mind, long time since I had a diesel runaway, I killed it with a dry powder extinguisher, mechanics were not impressed..........................at least back in the anologue days if your diesel was running and the battery blew up you just didn't shut down the donk.....

Both chargers working fine now........

 

[NoWorries]

Thermal Runaway on LiFePO4 (the ones you put in Cars Vans etc) is almost unheard of, don't confuse them with normal Li-ion battery's (like you find in laptops, phones, torches, RC toys etc.) these will burn like no tomorrow if charged incorrectly or faulty cell balancers.
LiFePO4 battery's are safer than Acid/Gel battery's as long as they are charged properly

The only problem with LiFePO4 battery's are the cost of the battery and the cost of the BMS/charger
But it is coming down rapidly and almost worth installing now.

 

[NoWorries]

As taken from https://www.solar4rvs.com.au/lyp-batteries.html

Are LiFePO4 batteries safe?

Several chemistries of Lithium such as Lithium-Ion, Lithium Iron Phosphate and Lithium Polymer are available. The LiFePO4 batteries are the safest type of Lithium batteries as there is no danger of the battery erupting into flames as with Lithium-Ion. They will not overheat, and they will not catch on fire, even if punctured.

The other advantage of LiFePO4 batteries is they do not have any negative health risks or environmental risks as the cathode material is not hazardous.

 

[Drover]

I have always ran my big 6 rack charger for my drills and stuff on my metal bench, mainly with the background thought if one has a meltdown the bench wont help burn my shed down, luckily I was there when one started to cook, it was hot and a bit gooey when I managed to get it out of the charger and toss it in my water bucket. Now no chargers left on when not around, the Zumba is never left on. ( one of those vacuum robots)

 

[Bellbirdweb]

As taken from https://www.solar4rvs.com.au/lyp-batteries.html

Are LiFePO4 batteries safe?

Several chemistries of Lithium such as Lithium-Ion, Lithium Iron Phosphate and Lithium Polymer are available. The LiFePO4 batteries are the safest type of Lithium batteries as there is no danger of the battery erupting into flames as with Lithium-Ion. They will not overheat, and they will not catch on fire, even if punctured.

The other advantage of LiFePO4 batteries is they do not have any negative health risks or environmental risks as the cathode material is not hazardous.

This video shows a LiFePo4 battery exploding.

 

[NoWorries]

OK first thing they did not mention how much power was pushed into the battery to make it expand also as I stated before "LiFePO4 battery's are safer than Acid/Gel battery's as long as they are charged properly" I could not see any BMS system there.
Second as per the safety of the battery it did not explode into flames ok it got to 180deg but that is not enough to cause a fire

Do the same test with your normal AGM battery and see what happens.

Google LiFePo4 safety
What do you think Teslar and every other car company use (do you really think they would risk billions in litigation)

 

[Bellbirdweb]

OK first thing they did not mention how much power was pushed into the battery to make it expand also as I stated before "LiFePO4 battery's are safer than Acid/Gel battery's as long as they are charged properly" I could not see any BMS system there.
Second as per the safety of the battery it did not explode into flames ok it got to 180deg but that is not enough to cause a fire

Do the same test with your normal AGM battery and see what happens.

Google LiFePo4 safety
What do you think Teslar and every other car company use (do you really think they would risk billions in litigation)

Any battery can pretty much do the same thing if pushed.

Just wanting to make the point that whilst LiFePo4 batterys are far safer and more stable than LiPo, any battery can cause a fire if not properly managed and charged, as was seen in the original post in this thread.

And yes, Tesla would indeed be expecting this to happen in a percentage of their products, as happens with petrol engines, that why we train aroun d the specifics of electric cars and the various hazards with all of our firefighters

 

[Drover]

and sometimes things just break, we used to call them accidents but now there seems to have to be something or someone to blame.................sh#t happens sometimes and thats about all it is............

@Bellbirdweb and @NoWorries your links have really expanded my knowledge on all these batteries and I hope others have had a good read as well, I'm 99% sure mine was a battery failure which the battery guru's in town reckon it was and reading the info I can also see why it happened, cell failure, even though my battery compartment has big vents I'm even considering fitting an old computer fan to increase air flow, once I figure out an intake that won't just pump dust.