Jehu helps with VW 18650 Battery Packs

hbpowerwall

hbpowerwall

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Dang. Guess the moral is Disconnect and isolate when not in use. tsk tsk.

The sad part is their real lack of knowing why it occurred.
Since everything was so fuse on a per cell level, im going to call inso short on this one too, not the batteries fault.

This is also why i like the cradle arrangement vs the block of batteries.
 
this is only going to give the naysayers more fuel. Hopefully it can be used as a learning tool to not neglect your batteries. Without an active bms, never store batteries connected to the charging circuits. Even a tarp over a solar panel, some uv could get through and charge the battery.
 
One clue is the 3s pack has 2s of smoke damaged cells, 1s of destroyed cells.

Two possibilities I can see:
1. A selfdischarge from one or more cells, dropped that row to 0V, which then overheated when solar power was restored.
2. The busbar arrangement consists of two rows joined by a short busbar. That bar is held in place with solder, it's not an overlapping joint. Possible for that busbar to break loose (vibration) and short busbar to cell casing (dead short) or arc and start a fire.
 
I want to know what charge controller was used.

Cold weather, cold panel, rapid transition to high sunlight levels =

Is J Who a member here ?
 
Sean said:
I want to know ....
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From the vid they seemed pretty clueless, like the kind of people you would just tell to get a couple of lead acid batteries.
I like how she chimed in that it might just have been one battery going bad that started the whole thing ...

Its a shame really, gives JG a bad name associating him with this whole thing.
 
Does anyone else think these fuses are WAY to thick? They are using resistor legs. I know there are other members here using resistor legs as well. Has anyone actually tested at what current they melt?


image_vdpuml.jpg


I don't think it was cold temp charging. I have charged mine at ridiculously low temperatures and haven't see any side effects. Then again, the charge current was at most 10A split across 120 cells (0.08A per cell) and may have served as a good defroster.
 
It's hard to determine without all information about the fuse wire rating (and tested !), cells charging voltage, possible miss-construction, etc.
But i think like you, fuse too thick or short like the guy from this forum, bussbar directly touching a cell so fuse is useless in that case.
Or something else like the charger caught fire and ignited the 18650 ?
 
coolfx said:
Or something else like the charger caught fire and ignited the 18650 ?
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I'm not even convinced they were using a proper charger. All he says is there is a "DC to DC to regulate the incoming voltage from the solar panel". There is no mention of charger, model number, charge voltage, or anything like that. If all he did was use a simple regulator, very very possible it wasn't even charging at the right voltage. This seems like a general lack of knowledge to me, unless I missed something? I would think Jehu knows what he is doing though and would have provided them with advise. Whether they took that advise or not and just wanted to cheap out is a different story...
 
mike said:
Does anyone else think these fuses are WAY to thick? They are using resistor legs. I know there are other members here using resistor legs as well. Has anyone actually tested at what current they melt?
Click to expand...

I've just asked someone on the FB page (who said use resistor legs) about the current rating - I've mentioned this point a few times - folks are being told they can use resistors legs - but with no mention of what wattage resistors or what length of wire - they just assume any thin looking wire will do the job.

My point about the temperature didn't relate to the cells but to the output from the PV which is at its highest when cold (in direct sunlight)
 
Sean said:
My point about the temperature didn't relate to the cells but to the output from the PV which is at its highest when cold (in direct sunlight)
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Honestly those two are clueless, even if they had a couple of hundred watts of panel, the order of magnitude increase of charge current due to cold would be no more than 20 odd percent even in ideal cold conditions (-10c), if your charge regime is running that close to the wall .... its a few extra amps at most.

The reasoning they gave for fail just seemed like a few random suggestions from someone else.

Im on the busbar-short bandwagon, that leading to inso fire.

Failed cells rarely catch on fire. Ive deliberately low and high volt killed nearly 100 cells in testing, nothing interesting happened yet.
My mate on the other hand screwdrivered a dell bay module with 9 x samsung 30b's in it, started and inso fire with a short, got a cell to forcefully vent, which then completed the fire triangle with inducted air and started a real nice flame thrower.

Ill make a cell blow up one day ...
 
Few know of the effect that happens when solar panels get very cold and still get sunlight. Lets say you have a 24V panel with a VOC of 30V (Voltage Open Circuit).
The inverter is rated just above 30V, so it's all good, except when it's really cold and the panel outputs 35V.

Also mentions the circuit to power the batteries off the solar panels being DIY. Given the Arduino generation of inventers call anything that involves joining wires into an ebay bought PCB as a "DIY project", I think Mike is correct in assuming it's a dumb DC-DC converter. Hence there is no "low current cutoff" commonly known as "end of charge detection".

I also wonder if the deleted scenes on Patreon contain some clues.

I found this video where Jehu meats the Kombi Life team.

In a flashback section is a set of photos all dated 2014, including this one.

image_kdwpgp.jpg


image_akiuvy.jpg


Of note is the green jumper, when it clearly summer in CA and everyone in the 2016 video is wearing tshirts.
I see some sort of charge indicator, but no charger, and a busbar run down one edge.

Could it really be this entire issue happened 2 years ago ? Or did Jehu just screw up his video editing by inserting a teaser for a current event?
 
Sean said:
My money is on PV and inverter connected direct to battery ......
Click to expand...

... and the busbars (cringe)

Ive seen a few ppls busbar connects, its not pretty. Thats why i bolt everything.

Welding is just not reliable, then running interconnects along the block like that, tiny tolerance between huge DC failure.

Love what JG does, but the execution is cringe-worthy.

I get a lot of flak for my design, but the big bangs wont happen.

Block designs ... well, lets not get into that discussion.
 
 
Upload dated May 5, 2016

Seems anything not a vlog is upload months after the fact, it's all very hard to follow.
Having the fire occur before they met Jehu, makes the time paradoxes in Back To The Future look easy.

Not found anything that shows the actual charge controller they were using. Does Jehu even remember what was used ?
Most likely it still that mice chewed the edge of the back where the busbar bridges ran, given they are completely missing in the post fire pack.
 
Jehu did one too from memory .. or at least talked about it in one of his videos..
 

The "solar controller" looks like one of those generic controllers with a few USB outlets on it - that J Who puts into a custom case .......

I'm pondering if there's been a face saving agreement cooked up between the interested parties, so no one has the finger pointed at them, either for design niaevity or useage ignorance.
 
that sounds plausible, at the end of the day they'll make their losses back from the video :) Fire sells really well on YouTube
 
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