This seems like a great way to burn down your house and potentially injure firefighters coming to your rescue. Seriously this is quite a few leagues above normal DIY territory. Proceed with caution.
I got a crash course on battery charging subtleties when building battle bots and there are many ways this can so south quickly, not the least of which is a battery in the middle of the pack developing dendrites and deciding its time to burn. The only way to prevent that is to have temperature sensors on every battery and a good enough model of the heat convection between the internal battery and the surface to recognize the temperature rise of a battery on its way to failing. Even with modern "battery monitor" chips like the ones Maxim and others sell there are corners in charge rate/temperature/battery that can get away from the algorithm before it recognizes a battery failure.
The reasons this is "easy" with flooded lead/acid batteries is that, when they fail, the lead doesn't then turn into a torch at 500 - 600 degrees F. So you have a chance to fix failures and move on.
I see this blanket assertion in lots of comment threads, but never with a citation.
> (just like it doesn't cover fires caused by storing gas or propane in your garage)?
This is an assertion I have never seen before. It is extremely common to keep gas cans in the garage around here (IL, USA), where else would you keep them that is safer?
although IANAL, storing a large quantity of lithium ion batteries seems likely to be considered negligence, which is generally not covered under insurance.
My impression from them was they were very dubious about "off book" uses of things as well, which leads to my expectation that they would push back on covering a loss due to a "home made" battery wall. Could I sue them and get them to cover it? I don't know, perhaps. But, as with my propane tanks, I would keep this stuff out away from the house to limit my losses and avoid having to go there.
> “We” do not pay for loss resulting directly or indirectly from...the discharge, dispersal, release or escape of any solid, liquid, gaseous or thermal irritant, pollutant or contaminant, including smoke, vapors, soot, fumes, acids, alkalis, chemicals and waste
I checked another insurer (State Farm) and they had similar language:
> We do not insure, however, for loss...caused by...Discharge, dispersal, seepage, migration, release or escape of pollutants...Pollutants means any solid, liquid, gaseous or thermal irritant or contaminant, including smoke, vapor, soot, fumes, acids, alkalis, chemicals and waste
"...into or upon the land, the atmosphere or any course of or body of water, whether above or below ground."
and
"but this exclusion does not apply if such discharge, dispersal, release or escape is sudden and accidental."
I'm pretty confident you will find them, or something similar.
My Erie policy was emailed to me, but here is a State Farm policy (not the one I quoted above) that has a similar exclusion:
http://www.opic.texas.gov/images/TDI_Approved_Policy_Forms/S...
That said, from googling I gather that there has been a lot of litigation over what counts as a "pollutant," including specifically whether gasoline counts. So I don't think that the presence of this clause means that an insurance company will always try to exclude any losses involving gasoline. I just think maybe they would have an argument if they wanted to.
"This (pollution) exclusion does not apply to bodily injury or property damage:
... (3) caused by common household chemicals used to maintain the residence premises."
Additionally, and perhaps even more importantly, this exclusion is in the "Personal Liability" section of the policy. The coverage/exclusions for the "Dwelling" are on pages 8-12.
In any case, thanks for the responses. My gut reaction is to agree with you that a lot of these "homeowners insurance will deny your claim if you do X!" warnings are based on third-hand knowledge or misinformation. I don't have any special knowledge though. (Do you?)
Edit: oops, you're right of course that I was reading the wrong part of the State Farm document! I swear I am not reading the Erie one so carelessly though.
Imagine a company whose only product is one that if anyone uses, they lose profit. It doesn't take a huge leap of imagination to believe insurance companies will blame literally anything to deny coverage on a house fire.
Likewise if you decide to put together an array of lithium batteries in your bedroom most homeowners policies should cover that. After all those batteries already are in products in the house (as opposed to gasoline which would only exist in a lawn mower in small quantities in the garage).
For anyone who isn't aware, California has seen a number of large scale disasters over the last couple of years which have destroyed many homes. From the fires in Santa Rosa to mudslides in Santa Barbara. And I have a number of friends and acquaintances who have been having painful discussions with their insurance companies about what they will and won't cover. I am fortunate that I have not suffered a loss. Seeing that pain though led me to call up and have a long, recorded, and detailed discussion with my insurance company about how they decide what to cover and on what basis they feel entitled to deny a claim. As with people who have actually lost their homes I was surprised at the number of things that they would use as a reason for not paying a claim.
One consistent theme was "unusual hazards that the insurance company was not made aware of." This ranges from people who have turned their garage into a place to do car repairs (adding lifts etc) to people who brew beer under the sink in the kitchen.
On the basis of that conversation, and the assumption that my insurance company was 'typical', I don't expect the battery fire to be covered. :-)
aww
This what makes them so deadly on a plane: you cannot get away.
Assuming that your smoke detector reacts properly to that kind of smoke, you should put one near your battery array.
What about the gas in your car or lawnmower?
Where do you store your camping stove?
The insurance texts posted downthread don't actually seem that "damning" to me. They talk about chemicals etc in a blanket sense. If insurance companies were worried about the gas can for your lawn mower, they would come right out and say it.
It's not uncommon for cities and homes associations to prohibit sheds anyway. A gas can in the garage seems a lot less volatile than one sitting in the sun that looks like it's ready to burst.
Why do you think that? I believe the purpose of the exclusions isn't to warn you about what bad things not to do, but rather to allow them to get out of covering certain losses. So broader is better (for them).
http://www.concordmonitor.com/electrical-bike-starts-fire-in...
most of my experience is from buying fresh cells to use as caving headlamp batteries back in the day.
That depends on the cell.
Some cells have charge protection. Others don't. The 18650 cell is standardized only in size-and-shape. The actual protection, chemicals, and other specifications are completely different from cell to cell.
Heck, some 18650s have 3.2V nominal voltage, while others have 3.7V.
IIRC, charge protection causes a voltage drop. So some applications prefer to use unprotected cells (with the overall device implementing charge protection elsewhere). For example, Laptops probably have ONE charge-protection circuit somewhere in their construction, rather than 6-charge protection circuits (each cell). This simple fix will cause 1/6th the voltage drop compared to 6x individual charge protection circuits.
(Some) manufacturers provide specs for their batteries, but most of them are coming from no-name factories in China with no reputation at stake, so there's either nothing published or it's exaggerated.
Just because something is in the shape of the 18650 doesn't mean that the chemicals inside of them are the same. Tesla's 18650s allegedly don't have Cobalt in them for example. Panasonic / Tesla have been working on "special chemical sauce" to make the cells work better for car purposes.
Even WITHIN a company, there are different specifications. Samsung's ICR18650-22F has different specs than Samsung's ICR18650-32A.
Lithium is a potent chemical that is EXPLOSIVE when mishandled. Lithium Fires cannot be put out by a class A, class B, or class C fire extinguisher. Lithium Fires CANNOT be put out by suffocation (they are self-sustaining and do not require oxygen). And sure, the cells are "Lithium-Ion" and not "pure lithium" (Li-Ion is a bit safer), but the potency of the core element here demands caution.
Energy storage works because you're storing energy. And if that energy decides to "stop being stored", you basically got a major, explosive fire on your hands.
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For hobby works (especially since I'm not in high-performance hobbies like Battlebots or RC Cars), I prefer the safety of NiMH cells. They're $2 each, sold by Duracell / Energizer / Panasonic / Eneloop.
The "failure" case of NiMH is that the battery vents a little bit of hydrogen gas (okay, also an explosive risk... but its not a lot of hydrogen). So basically, the cells destroy themselves if you abuse them, but otherwise vent relatively safely.
Furthermore, NiMH cells can be overcharged for days and remain fine. They're a lot more durable than Lithium Ion. In fact, a lot of NiMH chargers don't even have timers on them: a common technique with NiMH is to just keep them overcharging.
NiMH is heavier but otherwise nearly as energy dense as Lithium Ion.
Lithium-METAL batteries on the other hand require a Class D extinguisher. They are not Lithium Ion batteries. They are single use devices and can NOT safely be recharged.
Is the upside of "living in the future and building what's missing" not worth it though if you're cautious with the risk?
If those things don't disconnect when the power goes out and have a physical lockout for switch over to battery power they can easily kill someone working on the line.
Do not use the above as an excuse to not have proper backfeed prevention on your system. It is a last resort that might save a life, but there is always the possibility that the isolated section is small enough that you can supply your neighbors without blowing any breakers.
Last time I read up on backfeeding one of the common refrains was that flipping the main breaker on many homes still left one leg hot back to the transformer. Totally out of spec but common enough to be called out. Hence why a transfer switch is legally required if you're going to run your house from a generator/etc.
I don't know how common the one hot leg thing is. I know that can buy a lockout device which is just a metal device allowing either my main breaker or one other breaker to be on: thus turning my entire panel into a lockout. That implies the one hot leg thing isn't common but I honestly don't know.
I don't think that's likely at all.
This isn't plugging a generator into your house when the power's out. This is a system that's connected 24/7. That's difficult to do, requiring careful synchronization or isolation. Getting it wrong is probably harder than getting it right.
A lot of people build kit airplanes in their garage, but usually get the fuel system done by professionals.
It's not a everything or nothing game. You can still have fun and stay relatively safe.
Paging /r/osha