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EarthX 680 puffed

thorpdrvr

Member
Has anyone ever had their EarthX battery swell up like this? Puffed on two large vertical sides. Worked fine one flight and two days later has about 1 volt showing when I attempted to turn on master switch. Will not accept charge following the EarthX procedure. Battery was never overcharged or discharged to the 9 volt cutoff. The master was NOT left on between flights. It is about 4 years old. Mounted forward of firewall, but Odyssey batteries lived in same location for over 10 years with no issues.
Thanks
 

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Batteries

Odyssey batteries are NOT lifeo4 chemistry. Is it possible that the heat exceeded the recommended value for the earthX when mounted on the firewall?

Just spitballing...
 
Bob,
Yes, it is entirely possible.

Bernie,
Did you get a short LED warning flash, 2 secs on/2 secs off? Per the EarthX manual, that light sequence means your battery was exposed to temperatures over 65 degrees C or 150 degrees F. The manual's limitations section also warns to never expose the battery to over 85 degrees C environmental temperature. I you haven't installed the LED or connected it to your EFIS, I really recommend you do that.

Because my ETX 680 is also firewall mounted (HOT HOT HOT), I did the following. I ran a blast tube from the aft engine baffle to the battery's top. I also mounted the battery in EarthX's thermal battery box, designed for the ETX series of batteries. It has a bracket on top designed to hold the blast tube in place.

https://earthxbatteries.com/shop/thermal-battery-box-etx680-900-900-vnt-1200

Gotta treat these batteries right. They'll treat you right, right back.
 
Odyssey batteries are NOT lifeo4 chemistry. Is it possible that the heat exceeded the recommended value for the earthX when mounted on the firewall?

Just spitballing...

I suppose it is possible, but the first EarthX lasted over a year before it had a dead cell and was replaced (no puffing),and this one lasted about 4 years with no puffing until it died a few days ago. My lipo chemistry batteries used for radio controlled plane and heli flying regularly puff as they age, but the hobby LiFE chemistry batteries never do.
 
You know, 4 years is a nice ripe old age for most any battery. Aside for the aforementioned temperature concerns, you might want to go ahead and call the EarthX folks.
 
My ETX1200 was in the tailcone of my RV-10. Puffed up and cracked itself in half. It was 3 years old.
Back to hauling lead again...

Lenny
 

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My ETX1200 was in the tailcone of my RV-10. Puffed up and cracked itself in half. It was 3 years old.
Back to hauling lead again...
Lenny, any idea what might have caused this? Probably more a question for Kathy, but happy to get any hints or tips to avoid it on my little lifepo4.
 
Unfortunately I was never able to find out, that's why I switched back to lead. My airplane is electrically dependent, and couldn't afford that uncertainty with my risk budget.

Just like the OP, I never completely discharged this battery, and when I ran the avionics for an extended period I always charged it back up with the approved Optimate charger.

There's one thing I think may have helped destroy the battery. A few months before I discovered the swollen battery I had a failed rectifier bridge in my alternator. Normally the EarthX maxes out the alternator after startup for a few seconds to a minute. I would see 60+ amps during that time. With the failed bridge (and a missing phase) it would only go to 40 amps or so.
These batteries don't seem to be liking pulsed power. See Rotax notes in the manual. My battery was 3 years old.

From what I understand, puffed cells are likely the result of an overvoltage event. There were none of those in my case. I have crowbar OV protection on my alternators, and OV audio alarms in my Efis. If a cell shorts out (there are 4 connected in series), the others will see a higher voltage and it will puff up the rest of the cells.

I wish EarthX would investigate these events more to come up with an improved BMS. They designed a great system, but maybe they haven't thought of everything.

There's a lot more to our diverse electrical systems than a benchtest setup. We have a bunch of load dump events, voltage spikes from solenoids, and the possibility of missing alternator phases that these cells might not like to be handling. Btw, I do have a load dump Mosorb in my RV-10, and all solenoids/relays are transient protected with TVS diodes.


Lenny

Lenny, any idea what might have caused this? Probably more a question for Kathy, but happy to get any hints or tips to avoid it on my little lifepo4.
 
Unfortunately I was never able to find out, that's why I switched back to lead. ...
Thank you Sir. Not exactly the answer I was hoping for, as it sounds like you did everything right, and still suffered a failure.
 
I forgot to mention one important point. The battery never actually failed. It cranked the engine just fine. It was just puffed up, cracked, and a terminal was loose, cause it was no longer being held the case. No fault light either.

Lenny

Thank you Sir. Not exactly the answer I was hoping for, as it sounds like you did everything right, and still suffered a failure.
 
I started the post as I was wondering if the chances of puffed battery were one in a hundred or one in a million😁

Seems like it’s not rare, but probably not dangerous either....other than potentially losing battery on short notice. No technology/chemistry is perfect though.

I was hoping to get the 5 to 8 years of normal life advertised, but 4 years isn’t too bad.
 
I am curious what size alternator those of you with the puffed cases have installed. I noticed one post in this thread stated he saw more than 60 amps when charging a low battery. EarthX is very specific on Max charging amps for each series battery or damage may occur. For the 680 series that Max is 60 Amps. If you have a alternator capable of putting out more than 60 amps you need to go to a 900 series which EarthX says is capable of a 80 amp charging rate. Please note that some 60 amp alternators may be capable of more than 60 amps.
G
 
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I am curious what size alternator those of you with the puffed cases have installed. I noticed one post in this thread stated he saw more than 60 amps when charging a low battery. EarthX is very specific on Max charging amps for each series battery or damage may occur. For the 680 series that Max is 60 Amps. If you have a alternator capable of putting out more than 60 amps you need to go to a 900 series EarthX capable of a 80 amp charging rate. Please note that some 60 amp alternators may be capable of more than 60 amps.
G
Good point! I have a 680c with a 60 amp PP alternator and I always see a spike of charging current coming from the alternator of between 40 and 61 amps just after starting for the first time of the day. I don't leave my battery on a charger. The higher current from the alternator usually lasts for between 1 and 4 mins. I guess if I had a 120 amp alternator the EarthX would pull as much from it as possible, much like me in front of a Christmas dinner spread. :D

Battery charging spike - HB-YMM - PlanePower - EarthX.png
 
I just asked my wife to give away the chocolate pie and and pour out the eggnog. My internally regulated food meter fails when within 6 feet of chocolate pie every single time! That’s forces me into using externally regulated systems!
 
Good point! I have a 680c with a 60 amp PP alternator and I always see a spike of charging current coming from the alternator of between 40 and 61 amps just after starting for the first time of the day. I don't leave my battery on a charger. The higher current from the alternator usually lasts for between 1 and 4 mins. I guess if I had a 120 amp alternator the EarthX would pull as much from it as possible, much like me in front of a Christmas dinner spread. :D

View attachment 6258

Mickey,
That high charging amperage right after engine start is NORMAL for EarthX LiFePO batteries. It recharges with a wide open spigot, then decreases to a normal sustaining amperage. No worries. Just make sure you have the right size cable from the alternator to the battery: It’ll get a high amperage workout every time.
 
Mine was an ETX1200 charged by a PlanePower 60A and a PlanePower standby.
After engine start the main alternator would be charging at 60A+ (I've seen up to 65A out of this alternator), bus voltage would sag to 13.6V, indicating that the alternator wasn't able to keep up with the charging demand of the battery/bus. My bus is taking about 20A.

Because of the low bus voltage the standby alternator would also kick in and push about 15A for a minute or two.
Probably not a good idea to have an automatic standby with an ETX680, but the ETX1200 is good to 120A (24A x 5C) of alternator output.

Ideally these lithium batteries should have a specialized voltage regulator that limits charge current for a few minutes so the alternators don't get overworked. That initial load can't be good for the rectifier diodes, the v-belt, the bearings, and probably not great for the battery either.


Lenny


I am curious what size alternator those of you with the puffed cases have installed. I noticed one post in this thread stated he saw more than 60 amps when charging a low battery. EarthX is very specific on Max charging amps for each series battery or damage may occur. For the 680 series that Max is 60 Amps. If you have a alternator capable of putting out more than 60 amps you need to go to a 900 series EarthX capable of a 80 amp charging rate. Please note that some 60 amp alternators may be capable of more than 60 amps.
G
 
Mine was an ETX1200 charged by a PlanePower 60A and a PlanePower standby.
After engine start the main alternator would be charging at 60A+ (I've seen up to 65A out of this alternator), bus voltage would sag to 13.6V, indicating that the alternator wasn't able to keep up with the charging demand of the battery/bus. My bus is taking about 20A.

Because of the low bus voltage the standby alternator would also kick in and push about 15A for a minute or two.
Probably not a good idea to have an automatic standby with an ETX680, but the ETX1200 is good to 120A (24A x 5C) of alternator output.

Ideally these lithium batteries should have a specialized voltage regulator that limits charge current for a few minutes so the alternators don't get overworked. That initial load can't be good for the rectifier diodes, the v-belt, the bearings, and probably not great for the battery either.


Lenny

EarthX does have a small standby battery that can be used by any alternator as it regulates charging amperage at the battery. They certainly could add that system to the bigger batteries.
 
Bill, it is still a "set and forget" adjustment.

Lithium stuff likes a variable charge.

If you really want the maximum form Li stuff, you also need to balance the individual cells. Not sure if EarthX has a balance magic djinn inside it or not.

Take a look at state of the art R/C model chargers.
 
How low are you going to set it?

At 13.6V the alternator is still cranking out over 60A when the battery is "hungry". The PlanePower does, not sure about the B&C, but likely very similar. At that voltage the battery will not fully charge.

Lenny

You can adjust their regulator down as needed. I don't think any development is needed.
 
Cable size

Mickey,
That high charging amperage right after engine start is NORMAL for EarthX LiFePO batteries. It recharges with a wide open spigot, then decreases to a normal sustaining amperage. No worries. Just make sure you have the right size cable from the alternator to the battery: It’ll get a high amperage workout every time.
Thanks Colonel. This is exactly what Kathy told me. I've got a short length of AWG#4 or AWG#6 welding wire between the 60amp PP alternator and the battery, protected by an 80 amp littelfuse inline.

img_9454.jpg
 
Bill, it is still a "set and forget" adjustment.

Lithium stuff likes a variable charge.

If you really want the maximum form Li stuff, you also need to balance the individual cells. Not sure if EarthX has a balance magic djinn inside it or not.

Take a look at state of the art R/C model chargers.

I did knot know you were talking smart variable V/A. I understand and well aware of the cell balance in programmed, controlled volts and amps for them but that is a long way off to separate it from the one, constant voltage system we have now. I think, JMO, that these cells are being maintained at too high a voltage for a fully charged cell. It fits the failure modes seen here. The B&C adjustment is at least a step in right direction and might just be enough to keep it from getting hot, bothered and puffed.

Experimenting is good, but with full awareness. This tech is not ready for prime time, install and forget, reliability. Again, JMO.

And- they all (NiMH, LiPO, LiFePO4 and the thousand of variants) like a "special" just-for-them charging profile. The common buss on a hybrid, or all electric, does that with inverters between the common buss and each source/sink.
 
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Has anyone done a dissection of the puffed battery and can post pictures of what this thing looks like inside?

Here is a good site for marine uses of LFP batteries. They have done a lot of testing. It is long so look/search for "DURATION AT TARGET VOLTAGE (Over-Absorbing):" It describes the charging challenges. Once the battery reaches 100% SOC, then the excess voltage will damage the battery capacity and may puff - according to this article. It is a good read from a group that has tested the units.
 
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Mine has a 30 amp externally regulated alternator with crowbar overvoltage protection and overvoltage alarm on engine monitor. Regulator set to 14.2 volts. Just a month over 4 years old when it puffed and died.

I am curious what size alternator those of you with the puffed cases have installed. I noticed one post in this thread stated he saw more than 60 amps when charging a low battery. EarthX is very specific on Max charging amps for each series battery or damage may occur. For the 680 series that Max is 60 Amps. If you have a alternator capable of putting out more than 60 amps you need to go to a 900 series which EarthX says is capable of a 80 amp charging rate. Please note that some 60 amp alternators may be capable of more than 60 amps.
G
 
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My earthx battery puffed after about 100 hours. EarthX replaced it under warranty.

It has flown in the summer in the south and the warning light blinked about high temperature. It may have also been exposed to a transient short circuit.

I installed an earthx insulated battery box and blast tube and a thermal strip to monitor temperature on the battery. So far the warning light hasn’t blinked and the battery has been reliable.
 
Comment

I am surprised Kathy from EarthX hasn't commented. She usually is right on it when there is a post here. She has a reputation of excellent service.
 
1) Puffing is an indication that the internal resistance of the battery is too high for normal use and standard 1C charge rates.

2) Dendrites build up and the BMS cannot fully compensate.
 
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I am surprised Kathy from EarthX hasn't commented. She usually is right on it when there is a post here. She has a reputation of excellent service.

Look at the calendar - some folks still enjoy taking the holidays off of work...
 
I am surprised Kathy from EarthX hasn't commented. She usually is right on it when there is a post here. She has a reputation of excellent service.

Just as Kathy and the EarthX crew have a well-deserved reputation for excellent service, they are probably taking a well-deserved breather for the holidays.

Edit: Oops, I didn't mean to pile on Ironflight, but we're both saying the same thing.
 
Hi Scott, thanks for sharing. Do you have more pictures of the PCB that's connecting the cells?
 
Inquiry minds want to know!

Hello Van's Forum readers! I wish I could say that I was busy enjoying the holidays but other than Christmas day, this is my 29th day in a row of full days working. We have been very busy here at EarthX and have GREAT things that are going to be announced in 2021!

But I would like to try to address the question of "why do lithium cells puff?" Also note that we bring a "dissected" battery to the tradeshows for many years now and have provided photos and videos of what's inside during several different webinars, such as EAA webinars. This is not a proprietary "secret."

Why is my battery swollen? Simply put, it is because gas is building up inside the sealed cell causing it to expand (swell). Gas generation in lithium ion batteries is a normal thing; throughout the life of a lithium battery gas is generated through a process called electrolyte decomposition.

All lithium ion batteries use an electrolyte to aid in the transport of charged Li ions from one plate (anode) to another (cathode). During the chemical reaction which occurs during charging or discharging, lithium oxide or just oxygen is formed. The excess oxygen is what causes the battery to swell. The electrolyte decomposition occurs even faster if you over-discharge a battery, over-charge a battery or overheat a battery.

EarthX batteries have built-in protection to prevent over-discharge and over-charge, plus it has temperature monitoring to warn you of a high operating temperatures. That said, any high temperature operation shortens the battery life.

Is a swollen battery a safety issue? Our batteries are very safe, even a swollen battery, but a swollen battery is another indication that it is at the end of its life and should be replaced.

I hope the helps answer questions. You all have a fantastic New Year ahead and we thank you for helping EarthX grow to the most used and trusted lithium battery in the experimental aircraft market.........and our next horizon is in view.
 
Lifecycle

with all that being said Kathy, what is the life expectancy of these earth X batteries?
 
Question for Kathy

Yes, because inquiring minds want to know. The ETX680 contains 8 cells, controlled by the BMS motherboard as depicted. My battery was manufactured on 9 April 2017:










Looking at the photos this would appear to be a 4s2p configuration.

It also appears that the three small wires (white, yellow, and green) are for balancing the pack.

Is this correct?
 
Are the cylindrical cells less likely to swell?

I also assume all cells would have some sort of pressure relief to avoid a exploding cell...........
 
Looking at Scott's 3rd picture shows " made in China " are any of these super light weight batteries made in the USA?
 
I think one will find that most of the cells are made in China. If one looks close at the BMS PCB image, it does say made in USA.

20201228-104634.jpg
 
Looking at Scott's 3rd picture shows " made in China " are any of these super light weight batteries made in the USA?

I've seen many pictures of the EarthX facility in Colorado - their design work and assembly is done there.
 
with all that being said Kathy, what is the life expectancy of these earth X batteries?

This is from their website.


“All batteries have a life span, even if left in the box and never used. Time is a factor even if properly cared for, eventually, all batteries die. An EarthX battery is rated for 5-8 years if properly maintained, which means it is not left in a discharged state (below 13.28V); used in a properly functioning charging system; used with a proper charger; not shorted; and proper temperature ratings have been followed. All batteries will self discharge and depending on the amp hour of the battery, and it’s temperature it is stored in, the level of discharge and amount of time are variable. Always keep your lithium battery above 13.28V for longest life.”

As I understand it, the EarthX batteries are protected from undercharging and overcharging by the BMS....as long as the charging amperage is not exceeded. That would leave the only parameter stated to hurt the battery to be an over temp condition. That can also be monitored. If none of these three conditions are exceeded or occur, how long do they typically last?

That being said, I wonder (probably along with many others) what the real world lifespan of typical aircraft installations of EarthX batteries are (or any LiFEPO4 battery for that matter)? Real world lifespan would take into consideration any abuse the battery may have encountered. I know the numerous Odyssey’s I have used lasted about 2.5 to 3 years on average.

The first EarthX I had lasted about 1 year and the second one just over 4 years. So average lifespan for me is about 2.6 years. Not bashing the lithium technology, but they have been in use long enough for a “typical” lifespan to be known. Maybe “typical” life will fall in the “rated” 5 to 8 year lifespan?

PS: How long do your “50,000 hour rated” LED bulbs last?
 
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SNIP. I know the numerous Odyssey’s I have used lasted about 2 to 3 years on average.

Interesting. I’ve run dual Odyssey PC-625 batteries on all three of my RVs, replacing one battery every three years - so I’m getting six years from each battery. That and the pulled batteries go on a few more years in the lawn tractor or neighbor’s John Deer. I started out replacing one battery one every two years (no battery more than four years old) but eventually gained confident to go to three years.

The only time I replaced a battery early was the one time I left a master on and killed it.

Carl
 
Lithium batteries tend to have their lifespans reduced by high charge rates, especially when cold or near fully charged. It’s one of the reasons Tesla carefully regulates charging speed and dramatically reduces it if the battery is cold or when it reaches 80% capacity. They are required to warranty the batteries for 8 years.It would be interesting to see how lifespan is for aircraft kept in warmer verses cold climates. When a Tesla is enroute to a Superchager station the car automatically heats the battery pack before arrival. I also think a 60 amp alternator is going to reduce the lifespan of the smaller 680. It might be prudent to load the alternator up a bit specially after cold starts to reduce the amps going to the battery. On cold days I also put a load on the battery prior to start. Normally I put the master on when I arrive at the hangar. This warms the battery internally before you slam it with a big demand for amps with the starter.
G
 
Li batteries

From what I know about Li ion batteries, they are never vented. Something about Li and air going boom.
 
Lithium batteries tend to have their lifespans reduced by high charge rates, especially when cold or near fully charged. It’s one of the reasons Tesla carefully regulates charging speed and dramatically reduces it if the battery is cold or when it reaches 80% capacity. They are required to warranty the batteries for 8 years.It would be interesting to see how lifespan is for aircraft kept in warmer verses cold climates. When a Tesla is enroute to a Superchager station the car automatically heats the battery pack before arrival. I also think a 60 amp alternator is going to reduce the lifespan of the smaller 680. It might be prudent to load the alternator up a bit specially after cold starts to reduce the amps going to the battery. On cold days I also put a load on the battery prior to start. Normally I put the master on when I arrive at the hangar. This warms the battery internally before you slam it with a big demand for amps with the starter.
G
Very interesting info. Do you feel putting it on the charger a few minutes before starting would make a difference, or does it need to be discharging to warm up?
 
aren't at least some earthx batteries vented? i would expect you would never see this with them

From what I know about Li ion batteries, they are never vented. Something about Li and air going boom.

The cells themselves are not vented. Some of the batteries can be purchased in a sealed variety where the secondary container is sealed, with vent connections to route overboard, in case of thermal runaway. The sealed battery case will contain the heavy nasty smoke that results from a thermal runaway, and the vent connection sends it overboard rather than out into the local environment. Those should be used when the battery is mounted aft of the firewall, especially.

I use the ETX900VNT battery (sealed, vented version of the 900) aft of my baggage compartment with vents going down through the belly.
 
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