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Vented battery question ?

L

Larry DeCamp

Well Known Member
I cannot get an answer from EarthX regarding " what is the fume" the battery will vent if a malfunction occurs. I am trying to compare that risk to melting wire smoke and I respect that risk level tolerance is an individual privilege.

It seems to me the top priority would be a plan to flush the fumes, of any source, to maintain external visibility and consciousness to land the airplane. Yes you can kill the electrical master, but the smoke from wires must be evacuated to succeed. Thus my question, " what is the fume from a malfunctioning battery" ?

I have pondered a negative pressure vent on the bottom of the fuse that has been discussed here before, but an effective location may vary on different ships. Maybe if your heater works, you might get enough venting,, assuming fumes are not deadly ?
 
EarthX sells a ventillation kit made of the proper materials that gets rid of any smoke overboard. I did that on my ext 900 VNT installation aft of the baggage area.
 
I have pondered a negative pressure vent on the bottom of the fuse that has been discussed here before said:
assuming fumes are not deadly[/B] ?
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Hmmm, it's what is on the bottom of fuze of a Cherokee....and I always liked the idea.
 
I have tested LiFePo batteries to a forced overheating event in the lab as a part of my job. The gas is flammable if exposed to open flame, and otherwise quite noxious. Exposure to this gas would likely inhibit the pilot from continuing safe flight and landing. I just installed an ETX 900 VNT because the battery is in the cockpit. While they use a dual redundant BMS in this battery, and a venting event should be improbable, a cell failure could cause a problem not controlled by the BMS. IMO, Venting is a good idea if the battery is located where people are. The EarthX certified installations all require venting unless located forward of the firewall.
 
The EXT1200 has the same physical dimensions as the EXT900. The EXT900 is available vented but the EXT1200 is not.

Frustrating.
 
RVDan said:
I have tested LiFePo batteries to a forced overheating event in the lab as a part of my job. The gas is flammable if exposed to open flame, and otherwise quite noxious. Exposure to this gas would likely inhibit the pilot from continuing safe flight and landing. I just installed an ETX 900 VNT because the battery is in the cockpit. While they use a dual redundant BMS in this battery, and a venting event should be improbable, a cell failure could cause a problem not controlled by the BMS. IMO, Venting is a good idea if the battery is located where people are. The EarthX certified installations all require venting unless located forward of the firewall.
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This ˄. I am 100 percent with the venting. Glad that my farm boy hunches on this is are reinforced by someone who knows their stuff. I say if venting is too much trouble stay with an Odyssey. I would do a vented EarthX again in a heartbeat.
 
Looking for education that will hopefully serve all of us . Venting is like “ motherhood and apple pie”, a good thing. The certified applications are vented, but why ? Available internet discussion claims the product of thermal runaway is hydrogen and oxygen, explosive yes, noxious /poisonous/ debilitating not mentioned.
Can anyone tell us what comes out the vents ?
 
First, I am not a chemist. Lead acid batteries primarily vent hydrogen, oxygen and other acidic vapors during normal operations. They are very flammable which is why they are vented overboard in all aircraft. The AGM lead acid batteries use technology to reabsorb those gasses in normal operation and are basically sealed.
Lithium Colbalt, Maganese and Lithium Iron Phosphate batteries are sealed. In normal operation Lithium Ion batteries do not vent. They are equipped with pressure vent valves, which prevent bursting of the cell container during failure conditions. During failure conditions they may vent CO2, CO, H2, CH4, C2H4, C2H6, carbonates and fluorinated compounds like HF and CH3F. These form Hydrogen Flouride, which when breathed combines with moisture to create hydroflouric acid, which is quite nasty at dissolving tissues. Something you don’t want to breathe. Lithium Colbalt and Maganese batteries vent gasses that are at high temperatures when vented that results in ignition when exposed to free oxygen in the air. I have measures cell temps as high as ~500c at the time of venting. Lithium Iron Phosphate batteries vent at much lower temperatures and they do not ignite when vented unless exposed to open flame. But you do not want to breathe them.
 
Larry DeCamp said:
Looking for education that will hopefully serve all of us . Venting is like “ motherhood and apple pie”, a good thing. The certified applications are vented, but why ? Available internet discussion claims the product of thermal runaway is hydrogen and oxygen, explosive yes, noxious /poisonous/ debilitating not mentioned.
Can anyone tell us what comes out the vents ?
Click to expand...

Hello Larry, we do offer and recommend the ETX900-VNT (vented) model in the experimental aircraft line for in-cabin installations. https://earthxbatteries.com/product/etx900-vnt/ This battery is designed so that in the event of all safety features in your aircraft failing, (extremely improbable) and your alternator continuing to operate (again, very improbable as the alternator would also fail and stop working with this type of voltage) and the energy from the alternator exceeds the protection of the battery, the smoke produced in a thermal runaway is vented overboard. There is no fire, there is no explosion. Here is a video of what happens to an EarthX battery with many different destructive tests, including a 2,000 deg Fahrenheit simulated engine fire for 15 minutes. The battery does not contribute to an engine fire, it does not explode, it does not cause damage to any surrounding parts. I should note that the FAA will not do this same test with a lead acid battery as it is very explosive in this scenario. Do EarthX lithium batteries explode? - YouTube (The venting feature of the battery does not however provide any relief from the melted wire fumes, blown breakers/fuses, and eventually alternator failure).

What do I mean by all safety features failing? 1. your regulator fails; 2. your over voltage device fails; 3. the pilot does not turn off the alternator as instructed to do in the POH and continues to fly at "unregulated" voltages, and 4. the alternator continues to operate for 10-20 minutes at very high voltages where you exceed all your electronics protections and damage/destroy your equipment, resulting in smoke. (again, in the many safety assessments the alternator will fail too and not produce any energy if this happens, but in theory, some alternators can produce +40 volts with no regulator working).

I understand you are concerned about the fumes inside the cockpit if you did not have the vented model, but the question I would find most prudent, under what condition and reason would a pilot get to this situation?

We do offer a safety data sheet on the website, here is the link: https://earthxbatteries.com/wp-content/uploads/2022/04/EarthX_Battery_SDS.pdf The fumes would certainly be an irritant, not toxic or life-threatening, but the greatest safety concern would be mitigating the large of volume of visible impairing smoke. The electrolyte vapor which is a hydro-carbon and its combustion byproducts would be directed overboard via the battery containment and venting system with the vented models. If no containment it would empty into the compartment. The exhaust gas from a thermal runaway contains more than a dozen different gases (hydro-carbons, Cx Hx ). The most prevalent of by product is Carbon Dioxide, at approximately 40% of the volume of exhausted gas. The emissions can also contain trace amounts toxic gas (Hydrogen Flouride), which is not life-threating, but the smoke with trace amount of Hydrogen Flouride can cause irritation to skin, eyes, and respiratory tract. Again, the greatest safety concern with a LiFePO4 in thermal runaway is mitigating the large volume of visibly impairing smoke.

You ask why does the FAA requires this in certified aircraft and the answer is simple, due to the Boeing incident, the FAA mandated via the policy level, that all lithium batteries, regardless of safety assessments or chemistry, (Boeing uses Lithium Cobalt) must be vented. Period.
 
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EarthX Lithium said:
Hello Larry, we do offer and recommend the ETX900-VNT (vented) model in the experimental aircraft line for in-cabin installations. https://earthxbatteries.com/product/etx900-vnt/ This battery is designed so that in the event of all safety features in your aircraft failing, (extremely improbable) and your alternator continuing to operate (again, very improbable as the alternator would also fail and stop working with this type of voltage) and the energy from the alternator exceeds the protection of the battery, the smoke produced in a thermal runaway is vented overboard. There is no fire, there is no explosion. Here is a video of what happens to an EarthX battery with many different destructive tests, including a 2,000 deg Fahrenheit simulated engine fire for 15 minutes. The battery does not contribute to an engine fire, it does not explode, it does not cause damage to any surrounding parts. I should note that the FAA will not do this same test with a lead acid battery as it is very explosive in this scenario. Do EarthX lithium batteries explode? - YouTube (The venting feature of the battery does not however provide any relief from the melted wire fumes, blown breakers/fuses, and eventually alternator failure).

What do I mean by all safety features failing? 1. your regulator fails; 2. your over voltage device fails; 3. the pilot does not turn off the alternator as instructed to do in the POH and continues to fly at "unregulated" voltages, and 4. the alternator continues to operate for 10-20 minutes at very high voltages where you exceed all your electronics protections and damage/destroy your equipment, resulting in smoke. (again, in the many safety assessments the alternator will fail too and not produce any energy if this happens, but in theory, some alternators can produce +40 volts with no regulator working).

I understand you are concerned about the fumes inside the cockpit if you did not have the vented model, but the question I would find most prudent, under what condition and reason would a pilot get to this situation?

We do offer a safety data sheet on the website, here is the link: https://earthxbatteries.com/wp-content/uploads/2022/04/EarthX_Battery_SDS.pdf The fumes would certainly be an irritant, not toxic or life-threatening, but the greatest safety concern would be mitigating the large of volume of visible impairing smoke. The electrolyte vapor which is a hydro-carbon and its combustion byproducts would be directed overboard via the battery containment and venting system with the vented models. If no containment it would empty into the compartment. The exhaust gas from a thermal runaway contains more than a dozen different gases (hydro-carbons, Cx Hx ). The most prevalent of by product is Carbon Dioxide, at approximately 40% of the volume of exhausted gas. The emissions can also contain trace amounts toxic gas (Hydrogen Flouride), which is not life-threating, but the smoke with trace amount of Hydrogen Flouride can cause irritation to skin, eyes, and respiratory tract. Again, the greatest safety concern with a LiFePO4 in thermal runaway is mitigating the large volume of visibly impairing smoke.

You ask why does the FAA requires this in certified aircraft and the answer is simple, due to the Boeing incident, the FAA mandated via the policy level, that all lithium batteries, regardless of safety assessments or chemistry, (Boeing uses Lithium Cobalt) must be vented. Period.
Click to expand...
 
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