diy solar

diy solar

House burned down

This really sickens me to hear about the OP’s loss. I’m glad no one was physically harmed.
I’d be a bit pessimistic about the actual cause, because the fire could definitely obliterate it. The fuse, though not my favorite shouldn’t have caused the problem. The fact that it happened at a low demand period makes this more confusing. My only takeaways are perhaps an insulation failure of a battery case to another cell or metal structure in the vicinity? I hadn’t seen any visible cell isolation. A loosened terminal somewhere in the system that spat arcs & sparks? I’ve noticed that terminals do loosen over time but mostly early on, so it’s always a good idea to check all torques of every connection. As mentioned before, a good smoke detector could have perhaps given early warning and if home at the time to intervene before the damage was so extensive. A smoke detector with combination photo & ionic detectors wired into the house system would be advantageous. Mine is so sensitive that I can’t do a few moments of heat shrinking near it. Again this is rough., sorry. 😞
 
42OhmsPA said:
Sorry for your loss and good luck on the rebuild. The good thing is everyone in your family was OK.

Has an insurance adjuster reviewed everything yet?

Do you plan to use Class T fuses when you rebuild?
Click to expand...
The next question is insurance going to cover a DIY installed solar system? Or was this professionally installed with a permit?
 
The nest protects were all on full battery. The alarms went off, but 20 minutes to late.

Some clarification on the insurance matters: back in the days i teamed up with another electrician and started making battery installs at several customers based on this system. Before doing that, we made sure the system had an CE certification. Based on this, the system was complient to all demands.

Keep it safe yall
 
Jejochen said:
Cant reply to all posts, but;

Also had the Android flir attachment.

Maintenance was done very regularly, like checking all bolts etc...
I can even say the last time was 2 weeks ago, and no issues.
Click to expand...
I guess that answers any questions about loosened bolts over time etc.
 
First of all to the OP I'm ever so sorry this has happened to you.
I cannot see why a fuse tried to blow when your system was idling in the middle of the night, I'm still more likely to think a connection was loose and looking at your other thread I do not like the look of those fuse holders.
Right here is the very reason that NEC wants all DC wiring and components in metal enclosures.
 
So one thing I notice in all the pictures of the battery cells. It appears there is no separator between the individual cells? Seems like I remember reading that if they are under any sort of compression or even straight confinement sonthe expansion is limited there should be some sort of separator used?

I know in one of the threads the OP had one or more vented cells. Could that be a cause? Cell vent which off-gases hydrogen among other things. Shorted cell generates heat and with the hydrogen confined it just needs a spark. If the high current causes the fuse to blow but arc keeps it alive it will melt the casing and catch fire. One reason I don't like the ANN, ANL, and all their cousins.
 
robbob2112 said:
So one thing I notice in all the pictures of the battery cells. It appears there is no separator between the individual cells? Seems like I remember reading that if they are under any sort of compression or even straight confinement sonthe expansion is limited there should be some sort of separator used?

I know in one of the threads the OP had one or more vented cells. Could that be a cause? Cell vent which off-gases hydrogen among other things. Shorted cell generates heat and with the hydrogen confined it just needs a spark. If the high current causes the fuse to blow but arc keeps it alive it will melt the casing and catch fire. One reason I don't like the ANN, ANL, and all their cousins.
Click to expand...
Yes I saw that, I always worry about liquid oozing out and weakening fiber based shelves:

Screenshot_20240428_141746_Chrome.jpg
 
upnorthandpersonal said:
I think most here on the forum know I have been hammering on the use of Class T fuses since forever (and at times received push-back). I also talked to Victron (and other) reps at several occasions about using class T fuses (or at least similar, like BS88 etc), and did the same with BMS manufacturers when paralleling of batteries comes up. I'm glad to hear there are some signals appearing that vendors/etc. are finally addressing this.
Click to expand...
Class T fuses are not cheap. And they are not instant, either. When I was doing my research on this (on account of the high price tag for Class T), I discovered that whereas I had thought they were almost instant, they also have a delay before blowing. Another fuse, at a much cheaper price, which is said to have a similar delay, is what I ultimately went with for my system. The Class T fuses, for my locality, seemed uncommon, whereas the NH fuses are in common use.

Here's one example: https://www.solar-europe.co.za/product/dc-200a-fuse-link-500v-fl200a/

I have not seen much discussion on the forums about the NH fuses. Apparently, they have a lag time on par with Class T, and some sites I have found from users in Europe appeared more confident in the NH fuse than in a Class T fuse. I'm interested in learning more on this comparison, if anyone here has intimate knowledge of both, their advantages and disadvantages. The main advantage to the NH1 fuse for me was the price. The fuse itself is rather bulky, and occupies roughly the lower third of my breaker box--virtually an entire row to itself under two rows of breakers.
 
That's why I also mentioned BS88 fuses.

In principle, you want either aR/gR or gS class fuses. The first ones are very fast acting, semiconductor protection fuses. The latter one is for battery protection. NH type fuses are available in these classes.
 
Last edited:
Quattrohead said:
First of all to the OP I'm ever so sorry this has happened to you.
I cannot see why a fuse tried to blow when your system was idling in the middle of the night, I'm still more likely to think a connection was loose and looking at your other thread I do not like the look of those fuse holders.
Right here is the very reason that NEC wants all DC wiring and components in metal enclosures.
Click to expand...
Been thinking of the middle of the night aspect. Pure speculation, but that’s when mice are most likely to be chewing on insulation. Still…an appropriate fuse close to the battery should have prevented this.
 
Skypower said:
My only takeaways are perhaps an insulation failure of a battery case to another cell or metal structure in the vicinity?
Click to expand...
That's my takeaway from both fires so far. Both have evidence of how the short unfolded and what it caused, but not a clear answer afaik as to how the short started. I would suspect by default that case shorts are most likely.

I am glad I did not start with DIY until after the community started insisting on FR4.
 
hwy17 said:
That's my takeaway from both fires so far.
Click to expand...
Both DIY batteries.

Not clear to me from the photos I've seen on the OP's build thread whether the individual cells had an isolation barrier between them. It does not appear so:
20200903_152447-jpg.21756


I noted they reported leaking cell a couple of years ago. Perhaps a portent of other issues.
diysolarforum.com

LFP Powerwall

newbie here. why does it matter whether the p or s comes first Mechanically and electrically they are different and that has implications on BMS strategies. From the inverter standpoint it doesn't matter because the total voltage is the same.
diysolarforum.com diysolarforum.com

Just glad no one was killed/injured but such an experience is traumatic. I wish them well with their home recovery.
 
Norwasian said:
Class T fuses are not cheap. And they are not instant, either. When I was doing my research on this (on account of the high price tag for Class T), I discovered that whereas I had thought they were almost instant, they also have a delay before blowing. Another fuse, at a much cheaper price, which is said to have a similar delay, is what I ultimately went with for my system. The Class T fuses, for my locality, seemed uncommon, whereas the NH fuses are in common use.

Here's one example: https://www.solar-europe.co.za/product/dc-200a-fuse-link-500v-fl200a/

I have not seen much discussion on the forums about the NH fuses. Apparently, they have a lag time on par with Class T, and some sites I have found from users in Europe appeared more confident in the NH fuse than in a Class T fuse. I'm interested in learning more on this comparison, if anyone here has intimate knowledge of both, their advantages and disadvantages. The main advantage to the NH1 fuse for me was the price. The fuse itself is rather bulky, and occupies roughly the lower third of my breaker box--virtually an entire row to itself under two rows of breakers.
Click to expand...


Tidbit about the NH fuses - this makes picking the right fuseable link difficult. You have to derate by half the ampacity and also adjust the time curve.

DC applications
Eaton’s Bussmann series
NH fuse links can be used
on DC applications. In all
cases the fuse links can be
used at half of their AC rating
with a time constant of no
more than 10mS. The time
constant is the rate of rise of
fault current and should be as
close to a 50Hz AC half cycle
as possible.

 
Brett V said:
Been thinking of the middle of the night aspect. Pure speculation, but that’s when mice are most likely to be chewing on insulation. Still…an appropriate fuse close to the battery should have prevented this.
Click to expand...
You hit upon one of my fears of rodent damage. Years ago voles(like a mouse but bigger) chewed through the cords of my favorite power tools, random spots in a full 250’ roll of romex and for good measure almost though the hose of a full outboard motor’s portable fuel tank. Ever since I sealed all the door gaps and twice a year put out new glue traps. Never found evidence of any new voles in the traps, just bugs.
 
upnorthandpersonal said:
That's why I also mentioned BS88 fuses.

In principle, you want either aR/gR or gS class fuses. The first ones are very fast acting, semiconductor protection fuses. The latter one is for battery protection. NH type fuses are available in these classes.
Click to expand...
Actually, this looks most promising for time curves and interupt current.. not as good as a class T in several respects, but better than others we commonly use. And DC rated and available from mouser.

 
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