Lithium Battery Fire Risks: Sorting It Out.

      5 Comments on Lithium Battery Fire Risks: Sorting It Out.

Exponential market growth!

Lithium battery technology has made exponential market penetration in the last decade or so. Once an exotic and expensive platform, today nearly every battery-powered device uses lithium. Along with increased market acceptance comes attention, both good and bad. Most of the bad news circulating about lithium batteries relates to their fire risk. Is the danger real, or a big nothing burger? What concerns about lithium battery fires should off grid hams have and what can be done to mitigate the risks?

It’s not a nothing burger, but let’s keep it in context.

The U.S. Occupational Safety & Health Administration (OSHA) states that there are over 5000 lithium battery related fires in the U.S. every year…and that is a 2018 statistic. It’s become such a large problem that the City of New York recently enacted legislation requiring lithium batteries to meet certain minimum safety standards

While I could not find more recent information on how many lithium battery fires occurred in the entire United States, we can reasonably conclude that, nationwide, incidents well exceed the 2018 numbers.

But let’s keep things in context. In 2021, the most recent full-year reported, there were 1.353 million fires (by all causes) in the USA. That includes everything from simple trash can fires all the way up to multi-square mile wildfires. So while several thousand fires from lithium batteries is not “nothing,” they represent a small fraction of a percent of all fires.

lithium battery fires


Outsized representation and reputation.

Although lithium batteries account for a very small portion of all fires, they “make up for it” in the sense that a lithium battery fire is never a small affair. Once a lithium battery begins to combust, it’s difficult to extinguish. Due to the principle of thermal runaway and the internal chemistry of lithium batteries, a fire can burn hot and long. For example, a standard five-person fire crew can usually put out fires in traditional internal combustion-powered cars in a matter of minutes or even seconds.  If a battery powered car catches fire, it’s almost always a major-response incident requiring several thousand gallons of water.

If you’re thinking, “I just have a few small lithium batteries. That’s not comparable to a Tesla”. Well, you’re right, but you’re missing the point. The takeaway is that if your lithium batteries catch fire, no matter how small they are, it’s going to be intense.

I postulate that lithium battery fires receive media attention disproportional to their comparatively low occurrence for several reasons. A) lithium batteries are still a relatively new product, B) the fires are particularly fierce and hard to put out, and C) the media loves to stir up drama.

What you can and should do.

Lithium batteries are generally regarded as safe, but there are things an off grid ham can do to minimize the risk.

  • Never operate a lithium battery that is visibly damaged: cracks, loose terminals, etc.
  • Charge batteries within their specified charge parameters and with the proper charger.
  • Any battery that is excessively hot, discolored, bulging; making hissing, ticking, or boiling sounds; or discharging smoke, liquid, or weird smells is an immediate emergency concern. If possible, move the battery and/or device to a safe place where it will not set fire to surrounding materials. If this is not possible and no appropriate fire extinguisher is available, evacuate the area and call the fire department.
  • If a lithium battery is removed from service, for any reason, store it in a place where it is not a combustion hazard to other materials. Do not keep decommissioned batteries in your possession for extended time periods even if they are safely stored. Bring them to a proper recycling facility as soon as possible.
  • Store batteries in a metal or other fireproof enclosure away from flammable material.
  • Use only batteries from known, reputable sources.

Fire extinguishers….it’s complicated.

Regarding fire extinguishers, you’ll first need to know what type of batteries you have. Lithium batteries and lithium-ion batteries are not the same thing. They cannot be treated the same for fire fighting purposes. Lithium ion battery fires are considered B-class fires so ordinary household ABC-class extinguishers or water will be effective on these fires.

Only D-class fire extinguishers are certified for metallic fires, which includes lithium (not ion) batteries. If you’ve never heard of a D-class extinguisher, it’s probably because they are specialty items used mostly in the aerospace, automotive, and metalworking industries. They are not available off the shelf at your local home improvement store. D-class extinguishers are only sold by fire suppression specialists & industrial product suppliers.

If you feel you need a D-class fire extinguisher, brace yourself for eye-popping sticker shock. D-class extinguishers can cost over $1500.00 USD and you’re unlikely to find a good one for less than $800.00 USD. Be sure to read the data sheet carefully and fully understand what you are buying because some D’s are certified for lithium (the metal) but not lithium batteries.

Don’t overthink the fire extinguisher issue. Very few amateurs legitimately need a D-class unit.



Battery management systems (BMS).

Lithium batteries typically have a battery management system (BMS).  A BMS is built-in electronics that monitor & control charging, balancing, and other parameters. Many hams mistakenly think having a BMS means their batteries can never be overcharged or overheat due to excessive current. The BMS does somewhat provide a layer of safety, but it is not itself a safety device. Never assume the BMS will “save” you and prevent conditions that may incite a fire.

The bottom line.

This article is not meant to scare anyone away from lithium batteries! Frankly, there is no realistic way to avoid them anyway. The statistics show that lithium battery fires are uncommon when compared to all fire incidents. With a little knowledge and forethought, anyone can use them safely and without incident.


Here is a short, very informative PDF with general information about lithium battery safety.

This article from the National Fire Protection Association (NFPA) is a wealth of information.

An obscure document from the United States Antarctic Program outlines safe lithium battery protocols.

5 thoughts on “Lithium Battery Fire Risks: Sorting It Out.

  1. randall krippner

    I think the situation is a bit blown out of proportion. As you said there aren’t really that many fires caused by these batteries when compared to other causes. It happens enough that it is concerning, true, but I’m not personally all that concerned. I’ve never had a lithium battery fail for any reason except reaching the end of it’s normal life span.

    After a spate of fires linked to e-bike batteries in New York I did a bit of digging and found that in a lot of cases the fires were attributed to e-bikes owned by delivery people where the batteries were being abused by being charged at higher voltages and amperages than was recommended to try to get faster recharge times. And to “discount” batteries that were obtained from less than reputable sources off PayPal, Alibaba, Amazon, etc.

    Battery chemistry is important to consider as well. The newer lithium iron phosphate (LiFePo or LFP) batteries do not behave the same way. They don’t explode, don’t turn into unquenchable blow torches, etc. the way the older chemistries do. Even though the LFP batteries don’t get “explody” the way the older chemistries did, the better manufacturers take safety seriously and are including fire suppression systems in their larger capacity batteries. The big 5 kWh EG4-LL batteries I have each have fire suppression systems built into them that trigger at high temperatures. I think they’re CO2 based but I’m not entirely sure.

    That being said I’m still a bit, oh, not paranoid, let’s call it cautious? I do keep an eye on the big battery banks I have in the basement for the solar power system. I check the cell voltages and temperatures on a more or less regular basis, etc. A friend of mine who also dabbles in solar power and I went halves on a Klein Tool thermal imaging camera. Very handy for trouble shooting to find bad connections, overheating cells, etc. They go for about $250 which isn’t exactly cheap, but we figured it was worth the money considering all of the stuff the two of us play around with.

    Anyway, thanks for the article Chris! Your check list for caring for lithium batteries should be required reading.

    1. Chris Warren Post author

      I too am not paranoid but I did change some of my battery-handling procedures after doing the research for this article. At this point I think the biggest safety concern relating to lithium batteries is the proliferation of cheap slapped-together Asian junk and equally cheap and slapped-together chargers. This was the inspiration for the New York City legislation. An imaging area is a great idea for larger systems. If a camera is out of the budget, then I’d suggest a laster thermometer, which are available for less than $50.00.

  2. Steve Metz

    I just sat in on a fire fighters training workshop in Reno and learned a great deal about lithium battery fires. As per the article, such fires are rare but there are still easily a billion such batteries in the US so the stats can catch up with us. Apparently, once they start to burn, no effort will put them out – they have to burn out. But water is used to keep them cooler, making fire spread to the remaining cells slower and more manageable. The goal is merely to keep surrounding materials from joining the blaze. 4 main takeaways: 1) buy reputable brands (Samsung, LG, anything UL-listed), 2) use their supplied or similar quality charger, not cheap Chinese stuff to save a few bucks, 3) disconnect the charger as soon as the battery is fully charged (i.e. if an ebike battery needs 4-5 hrs., don’t leave it going overnight if you sleep 8 hrs), and 4) if feasible, store large batteries out and away from your house in a weather-protected setting “just in case”

    1. Chris Warren Post author

      Hi Steve, your points are excellent. How to deal with lithium batteries is becoming more and more of a priority for many fire departments. That might be a good topic for a future Off Grid Ham article.

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