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Earth X vs AGM - help me understand something...

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meloosifah

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The previous thread was closed, so I won’t be surprised . [ed. Text bashing my management style and how I run this site removed. Please read the posting rules. dr] The reality is that until fairly recently no one knew that an overload situation could cause the battery to irrupt into smoke. This seems like a catastrophic failure that is extremely dangerous. Yet no one knew this would happen. Now we have a measure in place to prevent it. Until fairly recently no one knew the BMS could catastrophically fail, slagging the battery. What if this happened in flight, wouldn’t that be a catastrophic failure?

Isn’t one of the purposes of this forum to discuss potential problems and failure points in our airplanes? I realize that the chemistry is different in this battery versus the 787 batteries, so the same type of failure is not going to occur. However the facts are indisputable that these batteries have had two significant failure modes that were not identified prior to the company getting an FAA certification. Ironically that FAA argument put forth in the previous thread is completely invalid. The 787 batteries were certified. FAA certification does not prove that these batteries are safe. It merely proves that we haven’t identified the failure modes yet. All systems have a failure mode. The real question is how severe and how frequently will they occur.

[ed. Text bashing my management style and how I run this site removed. Please read the posting rules. dr]

To recap:
1. [ed. Text bashing my management style and how I run this site removed. Please read the posting rules. dr]
2. If you disagree due to the PROVEN FACT that these batteries have failed in potentially catastrophic ways, despite being FAA certified, please just be quiet and don’t ask questions.
3. FAA certification automatically imparts safety, despite the failure of FAA certified batteries previously - just don’t look at the man behind the curtain.

Seriously though - given the short time these have been in mainstream installations, isn’t a certain level of questioning a good thing?

When my plane flies it may very well be with an Earth X but I want to be well informed about the concerns and “it’s FAA certified” should not put anyone’s mind at ease.


[ed. I'll chime in one last time - when it starts to sound like vendor bashing to me I lock it down. Please respect the rules. dr]
 
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I didn't see the previous thread. But what you describe is what I thought the failure mode was for many types of lithium ion batteries?

Why did people think differently?
 
Full disclosure, I have a pair of EarthX batteries in my RV-10.

For awareness, they aren?t Lithium Ion, they are Lithium Iron Phosphate (LiFePO4).

I have no problem discussing factual issues, pro or con. I?m interested in understanding failures as much as anyone else.

The problem that I do have is understanding the failure rate and metrics of the various failures. It?s difficult to make a risk management decisions without the whole picture.

For example, what?s the failure rate of the BMS circuits? A couple or hundreds? My decisions would be influenced by that answer. If it?s just a few, we need to work with EarthX so they understand the root cause and eliminate the defect out of future product.

Everything we put in our aircraft has a mortality rate. It most cases that percentage is very small. We, as experimental aircraft builders, need to understand the potential failures. Then determine what is your plan should that device fail for the known failure modes.

Yes, it sucks if you had a failure. Do we know if the failures are due to a manufacturing defect, the technology just isn?t cutting it, or some local environmental factor? I?m all for constructive dialogue and engaging the vendor to participate in that dialogue. Then it becomes a win for all.
 
failure modes

Same here - I have an earthx (not yet flying) and I want to know about any and all possible failure modes. Li battery chemistries differ, so it's important to make sure we're talking about the same thing. I assume my battery will have a failure, and when it does, I'll land. If it's on fire, I'll land faster.
 
I had a EarthX in my RV6. It was trouble free for the 3 years I had the battery. I am considering switching in my F1 however it presents some CG issues. That can be handled. Failure modes do concern me however the BMS shutting down the battery should not create a critical emergency in a aircraft with a proper electrical system. I also note the only BMS shutdown I am aware of occurred on the ground.
Smoke and fire concerns me greatly however I am not aware of a EarthX failure involving a fire inflight. I believe I read one report of smoke in flight. Not sure if that was before or after adding the battery monitor system. Most of the LI battery smoke and fire issues I have read involved cheap Chinese batteries often with no BMS.
If I switch to a EarthX again I am not really concerned that it reduces safety. Given the failure rates of conventional batteries including smoke and fumes you might even be able to make a case that the EarthX is safer overall. I don?t however have access to those stats.
G
 
Mel,
Nope, no kickbacks, just a real believer in the product and company. My frustration lies in folks repeating the same old flawed analysis and conclusions based on inaccurate info and assumptions about the lithium battery Babayaga. When an iPhone cooks off in the news, folks freak out here in VAF and assume wrongly that the EarthX will do the same. It’s not the same chemistry. Every battery of every type (including EarthX and Odyssey) has a risk of rupture or explosion in the right conditions, some more than others. But EarthX is way less prone to do so.

Yes, you are correct: The VAF is a great place to discuss safety issues, but it also runs the risk of misinformation, however innocent. I don’t want EarthX (or any other company) caught in a web they shouldn’t be in. I can see why you would find that ‘childish’.
 
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Yes, you are correct: The VAF is a great place to discuss safety issues, but it also runs the risk of misinformation, however innocent. I don’t want EarthX (or any other company) caught in a web they shouldn’t be in. I can see why you would find that ‘childish’.

If every thread that contained misinformation over the history of VAF had been shut down the archives would be much, much smaller.....and a lot of good info lost..... ;)
 
This seems like a catastrophic failure that is extremely dangerous. Yet no one knew this would happen.

Sure we did, from the first post. I stated it as well as others with Li professional battery experience. It got lost in the words, but it has always been there.

The real question is how severe and how frequently will they (failures) occur.

No, the real question and answer is how to mitigate it and move on. EarthX realized this and responded accordingly with some recommendations for smoke events ( the work did take some time). Contain and vent.

Seriously though - given the short time these have been in mainstream installations, isn?t a certain level of questioning a good thing?

When my plane flies it may very well be with an Earth X but I want to be well informed about the concerns and ?it?s FAA certified? should not put anyone?s mind at ease.

You will have to go back to the early posts on LiFeP chemistries to see the EarthX and other vendors discussions. The information you seek is there is not more hidden than any core truth on a forum.

It is incumbent on the builder to evaluate anything that is out of the mainstream, and make a decision on your own, not on a recommendation unless that comes with some history.

If I were to use a LiFe chemistry, it would be with a voltage regulator set to 13.8-14.0 volts, not higher, and set a custom OVPM at less than 16.0 volts. [ Check the A123 technical literature for maximum float voltage with a 100% initial charge. It is 16.0 volts.] The battery would be either contained for thermal events or protected externally against. (Voltage and temperature controls.)

There are 10,000 battery chemistries, it is very hard to generalize, but they do fall into classes. Check for professional papers on containment from thermal runway testing. Dry and super detailed but educational.

EarthX people do respond and have continued to learn and improve. I don't feel they over promote the safety, but definitive answers to some questions are not fully satisfying. No different than any aviation vendor and better than most.

The final decision is always by the builder/purchaser. You and I.

Scroll is enthusiastic, but has always seemed to be honest with his posts. Nothing wrong with that!
 
battery

"... has a risk of rupture or explosion in the right conditions, some more than others..."

I had the unpleasant experience of seeing a lead acid battery explode...acid everywhere...my uncle was standing near the battery when it happened and it was just luck that he was wearing sunglasses at the time. He was hit in the face with the acid...
 
Smoke and fire concerns me greatly however I am not aware of a EarthX failure involving a fire inflight. I believe I read one report of smoke in flight. Not sure if that was before or after adding the battery monitor system.

EarthX with BMS. No fire, but lots of smoke and a melting case. BMS failed when subjected to voltage in excess of 60 or so following VR failure, initiating meltdown. Subsequently, manufacturer issued a bulletin requiring independent alternator over-voltage protection. Reportedly, there was none on the subject aircraft.

OV protection is always a good idea, even with a lead acid battery, because it can save other gear, notably EI's and avionics. If installed aft of the firewall, the available sealed and vented battery box is also a good idea...a belt and suspenders approach to ensuring no smoke in the cockpit.

That's basic installation safety. Owners must also understand the operating differences, and the BMS warning system, in order to operate safely. Any Scarecrow can live with lead acid, while all lithium chemistry requires a trip to Oz.

None of us have enough data to seriously estimate reliability, even for lead acid.
 
Yeah that's why I'm gonna go with the Shorai FWF and OV protection on my main alt (but not the secondary). Avoid any drama with a convoluted BMS.
 
Knowledge is Power

If a person is going to build a plane in their garage, they had better know what they're doing. Two ways to know that you're doing:

1. Stick with the plans and build exactly according to the instructions written by people who already know what they're doing.

2. Possess/acquire specific knowledge and make a truly informed decision on your own way of doing it.

Knowledge isn't what someone said on the internet. Whether it's "it didn't work for me so it's bad for everyone" or "I got away with it so you'll be alright", that's not knowledge.

Many of the posts about LiFePo batteries in particular seem to fall into one of these two categories. It's painfully apparent that many folks still don't understand (haven't bothered to educate themselves about) the different kinds of chemistry and construction of Lithium batteries. That's OK, if you don't understand it, use a lead/acid battery and be happy, but don't lecture other people on the perils of the new technology without a thorough understanding of it.

On the other hand, if you've taken the time to educate yourself, understand the limitations and failure modes, include OV protection in your electrical system, limit inrush charge current between reserve batteries etc. then you're probably not going to add 20-30lbs of lead to a plane you've spent years building as light as possible...
 
"... has a risk of rupture or explosion in the right conditions, some more than others..."

I had the unpleasant experience of seeing a lead acid battery explode...acid everywhere...my uncle was standing near the battery when it happened and it was just luck that he was wearing sunglasses at the time. He was hit in the face with the acid...

Perhaps not a fair example, given he was jump starting incorrectly at the time. Wouldn't want readers thinking lead acid batteries just blow up without reason.

It's a big deal in the car business, at least among dealers who train employees.
 
Yes, you are correct: The VAF is a great place to discuss safety issues, but it also runs the risk of misinformation, however innocent. I don’t want EarthX (or any other company) caught in a web they shouldn’t be in. I can see why you would find that ‘childish’.

My issue is that if you go back and reread your posts, you indicate that because it hasn’t failed in a very small sample set and it has been approved by the FAA, it is safe.

Neither FAA approval, becoming a vendor on this site or a very very short history that includes at least 2 unknown failure modes constitutes a safe product. I agree that we should educate people on the various chemistries but your approach has blinders on it. “It’s safe because someone said so”.

All I am saying is that when there is a failure mode discovered, we should dig deep to identify cause, prevention and possible effects. Not state it is FAA approved for a Cirrus. We have been assured for years these things can’t run away. Then we discover that they can. Now we have discovered the BMS can actually slag the battery. If this happens in flight, does current continue through the unit? Are there electrical ramifications to be addressed to ensure our panels remain operable? I don’t know, but worth a discussion. Did Earth X know about these failure modes? How often have they occurred?

I’m not trying to upset anyone - just make an argument based on fact not lack of fact.
 
I’m the guilty party that started the debate after my Earth X battery had an issue. So I want to clarify a few things. I’m a firm believer that you should know before you go. This is why this forum is so great for all of us. I am not saying do not buy an Earth X, I am not saying they are junk. I am saying there are certain situations that may occur with an Earth X that will not occur with an AGM battery. So some quick bullet points:

When the Battery Management System failed (just prior to takeoff) the battery had a charge, but the BMS protection had failed. I did not launch because of the failed BMS.

I called Earth X. This is what they told me. On the certified version, the BMS failure is a yellow caution warning light, which is what they recommended now for the experimental one. They said you may continue flight to your destination. You should monitor the voltage input for any sudden over voltage condition, and if there is any indication of an OV, to shut down your alternator/charging system. Once on the ground, the battery needs to be replaced prior to your next flight. The BMS on the Earth X does not guarantee it will prevent a thermal runaway, it is a safety feature in the battery. They said you should always monitor your charging system in cause there is any sudden voltage spike.

If you have concerns about using the Earth X, I would recommend calling them and talking to them about your concerns. Then decide.

I switched to an AGM battery. My choice was because I did not want to deal with the extra items that can possibly go wrong with the Earth X. Yes, because it happened to me. I did not want to find out if lightning strikes twice in the same place.

Safe flights.
 
They said you may continue flight to your destination. You should monitor the voltage input for any sudden over voltage condition, and if there is any indication of an OV, to shut down your alternator/charging system.

How many of us can conduct a flight all the way to conclusion without taking our eyes off the voltmeter....and manually shut the system down a few milliseconds after an over-voltage event.....

Just sayin'........
 
The EarthX battery is not going to explode or smoke in a few milliseconds. It takes a sustained over voltage situation. Your avionics are a different story but the type battery installed would not matter in that regard.
 
Actually, Dan...

Perhaps not a fair example, given he was jump starting incorrectly at the time. Wouldn't want readers thinking lead acid batteries just blow up without reason.

It's a big deal in the car business, at least among dealers who train employees.

He was NOT jumpstarting anything, Dan. It is truly annoying that you would presume to know anything about this particular event...but I am not surprised...
 
How many of us can conduct a flight all the way to conclusion without taking our eyes off the voltmeter....and manually shut the system down a few milliseconds after an over-voltage event.....

Just sayin'........


Sam, these days, and I would bet anyone with a EarthX is also likely to be running a Dynon or G3x system as well, they kind of do have an eye on voltage the whole flight. providing they set their voltage alarm limits prudently.

And I must stress setting the alarm limits prudently for what it is we are wanting to detect.

An older steam gauged plane.....you have a very valid point and it would be wise to mitigate the risk somehow.
 
Sam, these days, and I would bet anyone with a EarthX is also likely to be running a Dynon or G3x system as well, they kind of do have an eye on voltage the whole flight. providing they set their voltage alarm limits prudently.

And I must stress setting the alarm limits prudently for what it is we are wanting to detect.

An older steam gauged plane.....you have a very valid point and it would be wise to mitigate the risk somehow.

But even with an alarm we can't manually shut down the alternator in milliseconds as a crowbar would. Guess the alarm would be silenced as the electronics are being fried......
 
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When my 4th Oddysey battery failed right at a year I was ready to try another option, my Oddysey failures defined as wouldn?t start the airplane. I don?t use a maintainer and it was within weeks of the last flight. I know many have great results with their Oddysey batteries lasting years. Perhaps my installation is hotter than others firewall forward mounted batteries (perhaps not). I also operate in the lower single digits to triple digit temps.
My 7 is a single battery, Plane Power alternator and SD8 Dynamo and dual electronic ignition that continues to run with the battery disconnected.
I?ve read the manuals on both batteries, is it safer to run a marginal lead acid battery that won?t start the airplane and fly or a EarthX that the BMS May shut the battery off?
I installed an EarthX almost 2 years ago, we?ll see. So far it has outlived the Oddyesey battery by 10ish months. Both battery types were subjected to overheating, I never knew until I installed the EarthX because the Oddysey doesn?t have the BMS.
So far my EarthX has outperformed my Oddysey by almost double in useful life
and I have no reason to replace it. My avionics don?t ?brown out? on start up, the EarthX retains enough voltage during starting to keep my avionics up. I?ve had to redo my checklist, I now click the power on before I step in the airplane so everything is booted up by the time I strap in and it stays lit up during startup. Cranking power is hardly a comparison between the two batteries.
My EarthX has not been babied, nore my Oddyseys via environmental conditions. My EarthX has been subjected to slow drains unlike my Oddysey.
Recently my panel light LED strip has shorted to ?on,? it?s powered via the batt bus and I didn?t notice till not flying the airplane for 2 weeks. Not sure when/how the switch shorted to on in the 2 weeks but the airplane started as normal but sucked 40 + amps for 30 minuites after it started as normal. I thought I had the LED light strip short fixed but apparently not during my condition inspection, I pulled the fuse upon further review finding the strip lit. The airplane started as normal after 5 weeks of the condition inspection and low amp LED draw.

No question that my Earthx has outperformed my Oddysey battery during normal use and Niether have shut off in flight. So far my EarthX has also outlived my Oddysey batteries, 10months longer and counting. I?m hoping to enjoy the better utility/longevety to offset the extra cost, I?m almost there.
 
EarthX would like to thank the VAF forum for inviting us to participate as a resource concerning LiFePo4 batteries to its members. We 100% agree that knowledge is power.


We believe it is important to once again stress the importance of having a BMS. No experimental or certified aircraft manufacturer will use a lithium battery without a BMS. Your cell phone, laptop, iPad, power tools, UPC, portable jump pack, etc. (this list could be very long) all have a BMS. In fact, any reputable product design that has a lithium battery will have a BMS as part of the product design.


We listen to our customers. We want to provide you information that is useful and understandable. If we need to provide better explanations in our manual so it is more transparent about BMS functions, we are willing to listen. We welcome your input on what is not clear or needs to be better explained.


From the EarthX manual:
ETX Hundred Series - BMS
Only the ETX ?Hundred Series? battery models are recommended for use as the primary aircraft battery (starter battery). In addition to the features found in the ETZ and ETX series motorsports batteries, critical electronic circuits are redundant, the over-charge protection is enhanced, and fault indication is included. All components associated with main electronic battery disconnect are redundant. The built-in redundancy ensures that no single point failure results in the battery unintentionally disconnecting. The design aligns with the requirements for a FAA approved lithium battery as per RTCA performance specification DO-311a and DO-160. Our ETX900-VNT includes a thermal run-away containment system making it fully compliant to DO-311a specification.

In the event of a charging system failure where the voltage increases to above 15.5V, the resistance to charging current increases, and above 16V the charging current is completely blocked. The time delay for this feature is 2 second to allow the aircraft alternator?s over voltage protection (crowbar circuit) to activate first. This design offers charge voltage protection greater than 40V. The discharge current (current out of battery) is unaffected in this situation. EarthX requires having automatic over-voltage protection (crowbar) for alternator type charging systems (not required for <20 Amp pad mount standby alternators).

The battery?s micro-controller monitors all failure modes, and reports failures with a built-in LED indicator and discrete output. The discrete output for external fault monitoring is a single wire connection with a ?? quick connect terminal. The output is a ?current sinking? type circuit (see diagram below) that can handle 100mA (connects the discrete output to battery ground if a fault is present). This output can be connected to an external 12V LED or general purpose discrete input of an EFIS. The fault output has three states; fast flashing (2 second on/ 2 second off), slow flashing (5 second on/ 5 second off) or solid.

Has the BMS technology evolved over the years, absolutely. We will continue to evolve, innovate, and produce new products. We invest in R & D continually.
If you have a specific question, or something that is not clear, or needs further explanation, let us know. You can post that questions on the forum, or call us, email us, or visit us in person as we attend many different venues. We are here to support you. You can go to the website at www.earthxbatteries.com as there is a lot of information provided there for you as well.
 
I?ve read the manuals on both batteries, is it safer to run a marginal lead acid battery that won?t start the airplane and fly or a EarthX that the BMS May shut the battery off?

The battery will never shut the battery off under normal use conditions. Never. Maybe this an area we need to explain better in the manual but the EarthX battery will never shut off under normal use conditions.
 
He was NOT jumpstarting anything, Dan. It is truly annoying that you would presume to know anything about this particular event...but I am not surprised...

Good. Are you annoyed enough to tell us why the lead acid battery exploded, rather than just splattering a useless anecdote?

By the way, was it an AGM battery? Lobbing a wet cell explosion into an AGM discussion is remarkably similar to the fellows who lob lithium ion fails into discussion about lithium iron phosphate.
 
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