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Letter from ABYC President re LiFePo4 safety on boats

l00semarble

l00semarble

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I hope they release a good complete report with photos and such. Interesting work done.

ABYC President's Message
Common Sense​
​


​
ABYC is built on a tradition of common sense and real world experiences. Early in my technical days, I was told ABYC designed the Standards so the backyard boatbuilder could achieve desired results. Testing and methodology were crafted in plain language for a “common sense” approach to a safe product.

We did not set aside best engineering practices for simplicity; the technical committee is packed with engineers and data-crunchers overseeing the process of drafting and updating the Standards. This balance has helped ABYC create useable, reliable, and relevant documents that help to achieve an unmatched level of safety in our industry. This is why, when the US Coast Guard asked us to look into potential problems with Lithium Iron Phosphate (LiFePO 4) batteries on boats, we jumped at the chance.

The ABYC Technical Department, with input from the industry, recreated a number of scenarios based on accident narratives that claimed LiFePO 4 batteries to be the cause of a fire. In our on-site test lab, our team subjected batteries to conditions ranging from “normal” operations to extreme use and abuse. We purchased units built for the marine environment with robust battery management systems. We also included recycled batteries available from mass retailers, with an “optional” battery management system and no clear instructions from the battery or cell manufacturer. We tried to replicate sketchy behavior which is the fear of insurance companies and regulators alike.

Do you know what we found? We couldn’t start the fire (Sorry Billy Joel). We witnessed swollen cells, completely dead batteries, and multiple safety cutoffs (when not bypassed). We had a very hot summer here in MD. Even the high heat didn’t come close to a spontaneous combustion scenario.
​


Image20220928130659.jpg
We arranged calls with industry experts, and we asked them what we might be missing in our testing. What can we throw at these batteries to replicate the accidents we were hearing about? No one had anything to add, short of putting these batteries directly in a fire (which we did). We were able to add LiFePO 4 batteries to a local International Association of Arson Investigators (IAAI) boat burn--even there, no one detected any indication that the batteries themselves contributed to the fire. Many of us were fully expecting a report where we were able to replicate an unsafe situation and make some recommendations.

Our full report will be sent to the USCG in due course, and then ABYC will report on our findings. This being a mere President's letter please take it as what it is: My observations while watching our Technical Department do some great work. But, the research and testing may show us that we must take this discussion to the test labs for another round. Our common sense approach to testing has proven again to be the foundation for getting to the bottom of a scenario many of us (including myself) thought would reveal itself in short order. Stand by for formal reporting as we continue our work.

 
Well, we have seen some unexpected Lifepo4 fires here on the forum. While this chemistry is pretty safe, it's not bulletproof.

I recall maybe one or two posts in an RV/Camper and a few at a home/shed.

I think that as many of us tried to predict what caused those fires, we saw some of the following:
1. User error (DIY build): Sometimes using wrong components (wire guage, cheap fuse blocks) or just not having correct torque on the connections. Various shorts with surroundings (metal enclosures, fixtures etc...)
2. Using cells that were damaged to begin with.
3. Environmental: Putting a Lifepo4 pack on the under side of a camper with adequate protection, for example (yes, there was one, I think with a Sprinter van). Water/flooding (recall one too). Rats/mice chewing up on the cables.

I think using a BMS is already consensus these days, so not even mentioning cases where no BMS was used.

So in general I agree with the ABYC President's sayings, but he make it sound like creating a Lifepo4 fire is impossible. But it is possible, like we have seen on this forum.

Just giving my 2 cents, as someone (unexperienced) that's reading the ABYC letter might think that these batteries and this chemistry is "bulletproof" and let themselves be careless.


Stay safe!
 
meetyg said:
Well, we have seen some unexpected Lifepo4 fires here on the forum. While this chemistry is pretty safe, it's not bulletproof.

I recall maybe one or two posts in an RV/Camper and a few at a home/shed.

I think that as many of us tried to predict what caused those fires, we saw some of the following:
1. User error (DIY build): Sometimes using wrong components (wire guage, cheap fuse blocks) or just not having correct torque on the connections. Various shorts with surroundings (metal enclosures, fixtures etc...)
2. Using cells that were damaged to begin with.
3. Environmental: Putting a Lifepo4 pack on the under side of a camper with adequate protection, for example (yes, there was one, I think with a Sprinter van). Water/flooding (recall one too). Rats/mice chewing up on the cables.

I think using a BMS is already consensus these days, so not even mentioning cases where no BMS was used.

So in general I agree with the ABYC President's sayings, but he make it sound like creating a Lifepo4 fire is impossible. But it is possible, like we have seen on this forum.

Just giving my 2 cents, as someone (unexperienced) that's reading the ABYC letter might think that these batteries and this chemistry is "bulletproof" and let themselves be careless.


Stay safe!
Click to expand...

Maybe they are just testing the capability of the cell itself to ignite/burn, not the ability to light nearby materials on fire?

It seems like when fires do happen it's something else other than the cell itself igniting. One recent thread had what looked to be thick cutting board strapped to the pack, and it appeared the plastic material is what ignited, it didn't look like the cell itself had been burning.

Loose connections, undersized wire, and faulty distribution systems, while dangerous, can't really be blamed on the cell chemistry. Although I guess with the current potential of lifepo4 there is more chance of a small issue becoming a big one.
 
I guess it depends on what you mean by "fire" too. I have seem many photos of dramatic meltdown events but probably many(or most) of them don't involve open flame.
 
From I've heard that the danger is often not the battery itself, but rather by the equipment connected to the battery when the system has a fault.

For example, a battery charging directly from alternator with no DC-DC converter. BMS triggers over-charge-current protection (typically at a low SOC), causes a MASSIVE voltage spike, and this voltage spike is where the danger lies, often blowing up inverters, controllers, ECU's, etc.

Sure, proper design on this equipment often causes fuses to blow when damage occurs, and it doesn't lead to a fire.. but the one system I saw go south had 90vDC on a 12v system...I can see that leading to a fire one way or another.
 
Wow - that report is encouraging by actually specifying the LiFePO4 chemistry, and not just a generic "Lithium", as was common 10 or so years ago.

Seems like we're all on the same page - regardless of chemistry, one should follow the ABYC to help prevent secondary problems like lighting your charging / wiring *infrastructure* on fire with inadequate fusing etc.

And just common sense - don't hide that unsightly power distribution board behind drapery.

Still - the bigger issue regardless of chemistry is to get some to actually follow the ABYC, even if it costs a little more up front to be safe in the long run.
 
Very encouraging, few organizations seem to explain how safe LiFePO4 is compared to other chemistries. I hope they use this information in a future revision of E-13.

Is there a link to the original source of this letter?
 
Maybe we will eventually get some updated battery rules from the NEC and Fire code here in the states that doesn't treat LiFePO4 like they are going to explode/self-combust at any moment. They have good reason to treat other lithium chemistries that way, but not LiFePO4.
 
Currently there are three types of lead-acid cell used in the US. Navy's fleet of nuclear-powered submarines...

Apparently the Navy is not ready switch. NASA likes lithium-ion.

In its final configuration, the space station now has three lithium-ion batteries for each channel, each with a service life lasting nearly 10 years. With eight channels, 24 lithium-ion batteries on board replaced 48 nickel-hydrogen batteries.

www.nasa.gov

Spacewalkers Complete Multi-Year Station Battery Upgrades

Spacewalkers Complete Multi-Year Effort to Upgrade Space Station Batteries
www.nasa.gov www.nasa.gov
 
meetyg said:
Well, we have seen some unexpected Lifepo4 fires here on the forum. While this chemistry is pretty safe, it's not bulletproof.

I recall maybe one or two posts in an RV/Camper and a few at a home/shed.

I think that as many of us tried to predict what caused those fires, we saw some of the following:
1. User error (DIY build): Sometimes using wrong components (wire guage, cheap fuse blocks) or just not having correct torque on the connections. Various shorts with surroundings (metal enclosures, fixtures etc...)
2. Using cells that were damaged to begin with.
3. Environmental: Putting a Lifepo4 pack on the under side of a camper with adequate protection, for example (yes, there was one, I think with a Sprinter van). Water/flooding (recall one too). Rats/mice chewing up on the cables.

I think using a BMS is already consensus these days, so not even mentioning cases where no BMS was used.

So in general I agree with the ABYC President's sayings, but he make it sound like creating a Lifepo4 fire is impossible. But it is possible, like we have seen on this forum.

Just giving my 2 cents, as someone (unexperienced) that's reading the ABYC letter might think that these batteries and this chemistry is "bulletproof" and let themselves be careless.


Stay safe!
Click to expand...
Thinking about it, I wonder how much of those would be more correctly classified as Electrical Fires? LFP can put out an astonishing amount of current, which driven through improperly built systems, will release an enormous amount of heat and light stuff off.

The battery pack I built for my boat alone has 5kWh of power stored in it. You run that much energy through a tight enough space quickly, you're goign to light stuff on fire. This is why I probably took more time to lay out my wiring and put in enough protective devices, than many do.
 
Will has provided a practical test on his site.
. IMHO, this disproves a lot of assumptions posted concerning the safety of LFP chemistry.
 
cs1234 said:
Nice slow burn, not sure if you are trying to say LFP is good or not.
Click to expand...
IMHO, LFP are a safe as any other chemistry when properly applied. Imagine the mess should someone drill into an FLA battery.

Also, the “drop a wrench across the terminals” scenario is a bit silly. Sure that is a possibility when the installer is careless. It doesn’t matter the battery type it’s gonna cause some damage.
 
sailingcal21 said:
Will has provided a practical test on his site.
. IMHO, this disproves a lot of assumptions posted concerning the safety of LFP chemistry.
Click to expand...
Will also provided thei video of another Lithium Ion chemistry that had much different result when drilled into :
Which chemistry battery would you choose ?
 
RandyP, let's not cause confusion. The topic is "...LiFePo4 Safety on boats" not Solid State Lithium Ion which is clearly not the same chemistry as the video shows.
 
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