LiFePo battery?

[N941WR]

....

I would like to make a suggestion.

Remove the plate nuts from the battery box and rivet them to the aft side of the firewall. That will allow you to remove the battery box from outside the plane rather than having someone hold the box while you work upside down headfirst in the foot well, should you ever want to replace / repair it in the future. Why Van's has you put the platenuts on the battery box is anyone's guess.

 

[scard]

I ended up buying some .032 4130 SHEET and fabricated another box.
6.55w x 3.4d x 5.0t

I modified the existing PC680 box with a similar result. I put a spacer in the bottom and can still drop a PC680 in there at a moments notice with the same hold downs.

EarthX, This PC680 mount is a standard kit sold by Vans that many of us use. It is on their plans and is therefor one of the "standard" methods. If you had a battery that simply dropped into the standard PC680 mount that many of us already have bolted to the firewall, I certainly would have bought your battery.

(prior to final welding and paint)

other images

 

[Mike S]

As the aircraft market has found us and we have sold 100's of these batteries now to this market, that is not to say we will not become an expertise in this market and start design and development geared towards aircraft specifically---------------

----------------- so keep that in mind with your "wish" list on what you would like for your planes but anything can be done! But we listen to what you all say and work on developing a battery designed 100% towards aircraft use ----------

Odyssey------------- are you listening??????????????

 

[CharlieWaffles]

You are absolutely right, our battery is .4" wider than the PC680 and to be honest, up until just now, no one has pointed that out as a problem. Our cases are designed for the power sport industry, for example, the ETX36D is an exact case size of the YTX20L-BS or the YTX20HL-BS as this is a very popular OEM size in our market. At this moment, that is our expertise and what our product is developed towards, a starter battery for the power sport market. As the aircraft market has found us and we have sold 100's of these batteries now to this market, that is not to say we will not become an expertise in this market and start design and development geared towards aircraft specifically.

That being said, if we were to have a case designed just for your planes, what size would you want it to be? We can either copy the PC680 for example, or we can design a case to the exact dimensions you want. Also, if you could have the capacity you wanted, what would that be? The aircraft lead acid market uses batteries that are designed for 80% depth of discharge. The Odyssey PC680 is a 16 amp hour battery and at 80% DOD, you have 12.8 amp hours to use. Our lithium batteries in the ETX36 batteries are an actual 12 ah and you can use 100% of it's capacity, which is less capacity than the PC680 by .8amps. But the cost of a lithium battery goes up with the amount of amp hours, so keep that in mind with your "wish" list on what you would like for your planes but anything can be done! But we listen to what you all say and work on developing a battery designed 100% towards aircraft use but at this moment in time, it is not a perfect replacement.

The other very common battery is for the RV10s which use a larger battery due to larger engines (generally). A very common Lead Acid battery in use is the Pc925 http://www.odysseybatteries.com/batteries/pc925_series.htm

 

[Lan Vinh Do]

i second for the pc925 equivalent.

I fly RV-10 in instrument condition so i like the capacity of the odyssey 925. I have one magneto and one electronic ignition and can always turn off the electronic ignition. So it's not my ignition that i am afraid of losing but more my avionic.

If there was a direct replacement for the 925 that fit in the tray i would buy one . It would resolve my CG limitation when i have heavy passenger.

I will wait to see what happening and see if i buy 2 smaller and put it in parallel but would really prefer to put only one and have less connection and less modification.

If you need a picture of how it's mount on the rv-10, let me know and i will email one. ( it's on it's side )

Lan Vinh Do

 

[Flying again!]

I fly RV-10 in instrument condition so i like the capacity of the odyssey 925. I have one magneto and one electronic ignition and can always turn off the electronic ignition. So it's not my ignition that i am afraid of losing but more my avionic.

If there was a direct replacement for the 925 that fit in the tray i would buy one . It would resolve my CG limitation when i have heavy passenger.

I will wait to see what happening and see if i buy 2 smaller and put it in parallel but would really prefer to put only one and have less connection and less modification.

If you need a picture of how it's mount on the rv-10, let me know and i will email one. ( it's on it's side )


Lan Vinh Do

I just replaced an Odyssey 1200 in my RV-10, saved 30 pounds and moved CG fwd 1.75 inches. See my post here.

http://www.vansairforce.com/community/showthread.php?t=108532&page=3

Looking at the specs below it wound take some shims that come with the battery but the Shorai LFX36 should drop in. I can swap batteries in 10 minutes. It looks like you could lose 19 pounds and move the CG forward by at least 1.5 inches.

TJ


SHORAI LFX Lithium-Iron Powersports battery, 36Ah PbEq 12V eq, "A" polarity, Case Type 3
Length 6.55"
Width 3.39"
Height 6.10"
Sku: 4897034420388
Part Number: LFX36A3-BS12
5 pounds

The PC 925 measures 6 15/32" long, 6 7/8" wide, 4 7/8" tall and weighs 24 pounds

 

[EarthX Lithium]

I just replaced an Odyssey 1200 in my RV-10, saved 30 pounds and moved CG fwd 1.75 inches. See my post here.

http://www.vansairforce.com/community/showthread.php?t=108532&page=3

Looking at the specs below it wound take some shims that come with the battery but the Shorai LFX36 should drop in. I can swap batteries in 10 minutes. It looks like you could lose 19 pounds and move the CG forward by at least 1.5 inches.

TJ


SHORAI LFX Lithium-Iron Powersports battery, 36Ah PbEq 12V eq, "A" polarity, Case Type 3
Length 6.55"
Width 3.39"
Height 6.10"
Sku: 4897034420388
Part Number: LFX36A3-BS12
5 pounds

The PC 925 measures 6 15/32" long, 6 7/8" wide, 4 7/8" tall and weighs 24 pounds

Hi TJ,

I am responding to this post as I am concerned you are using a grossly undersized battery for your plane and I worry about your safety for you and your family.

The PC1200 has 42 amp hours (taken from the Odyssey website) that are 80% useable (DOD) which means you can use 33.6 amp as a power source to run your accessories. It also has 1200 peak cranking amps, and 550 CCA's based on the SAE industry standards. The replacement battery you put in your plane has most likely 12 amps (there is no regulations in the lithium battery world for saying what the equivalent amp hours are so it can be different with each manufacturer so this is an educated guess as to the true amp hours) that can be used as a power source, has 550 peak cranking amps (they use the CCA rating as their peak cranking amps) and if it was tested to the same industry standard as the PC1200, the CCA's would be closer to around 200. Big difference.

The PC925 has 28 amp hours, and at 80% DOD, you have 22.4 useable amps. It has 380 CCA, and 925 peak cranking amps. Again, if you were to use the battery you mentioned even for this replacement, it is grossly undersized.

The only way you could replace the capacity and power you need for your plane would be to put 3 of the lithium batteries in parallel to replace the PC1200 and you would need 2 of the lithium batteries in parallel to replace the PC925.

PC1200:
CCA: 550
PCA:1200
usable ah: 36.6

PC925:
CCA: 380
PCA: 925
Usable ah: 22.4

LFX36:
CCA: 200
PCA: 540
usable ah: 12


Kathy

 

[humptybump]

Kathy,

Can you share the testing you performed to generate the results you listed for the LFX36 battery?

You listed: LFX36 @ CCA: 200, PCA: 540, usable ah: 12
MFG Lists:  LFX36 @ CCA: 540, PCA: ???, usable ah: 36

My unscientific testing (aka usage) does not appear to confirm the lower numbers you reported.

 

[sailvi767]

Are there any certified light aircraft using these batteries at this time? The weight savings especially in a LSA have to be compelling to manufactures. If they felt they offered a reasonable level of safety they would be in widespread use. I am not sure but I think I read one LSA type was using them. Anyone have any data?

George

Edit: was it the carbon cub using one?

 

[DonFromTX]

My sole objection is that the battery has stamped on it that the maximum charge rate is 10 amps, with warnings of bad things to happen when you exceed that. My alternator puts out a charge rate of 45 amps. I am considering an external regulator that can control the charge to 10 amps. Most of the snowmobiles and scooters using this battery only has a small charging rate.

 

[Flying again!]

Kathy,

Can you share the testing you performed to generate the results you listed for the LFX36 battery?

You listed: LFX36 @ CCA: 200, PCA: 540, usable ah: 12
MFG Lists:  LFX36 @ CCA: 540, PCA: ???, usable ah: 46

My unscientific testing (aka usage) does not appear to confirm the lower numbers you reported.

As I recall you did an unscientific test of the LFX18 that powered your primary EFIS, backup EFIS/EMS, COMM receive only, audio panel, AP but no active (i.e. no servos), and Garmin 795 for 3 hours. I have a similar panel and with the LFX36 one would expect it should power it for close to 6 hours! I would be landing well within an hour with alternator failure so I do not see this as putting myself or my family in danger as Kathy implied.

The best way to settle this would be to get theEarthX battery and the SHorai both rated at 36eqah and do a test of them under the same load.

RocketBob also did a "torture" test of the Shorai and it did very well as I recall.

TJ

 

[EarthX Lithium]

Kathy,

Can you share the testing you performed to generate the results you listed for the LFX36 battery?

You listed: LFX36 @ CCA: 200, PCA: 540, usable ah: 12
MFG Lists:  LFX36 @ CCA: 540, PCA: ???, usable ah: 46

My unscientific testing (aka usage) does not appear to confirm the lower numbers you reported.

I would be happy to. The test set forth by the Society of Automotive Engineers (SAE) is what lead acid batteries have used for decades to rate their CCA's, a detailed description can be found at: http://batteryuniversity.com/index.php/learn/article/how_to_measure_cca_cold_cranking_amp. The test results are recorded when you measure how much cranking amps is put out at -18°C (0°F) for 30 seconds without dropping below 7.2 volts. It does not matter if the technology is lead acid or lithium for this test.

The PCA , or some manufactures call it the PHCA, does not have an industry standardized test but is typically done at 77 deg F for a 5 second period of time. Again, the results are recorded when you measure the amount of cranking amps.

And for capacity, it depends on the manufacturer on the depth of discharge (DOD) they recommend, the Odyssey is an 80% DOD but the average lead acid is around 30% DOD. All lithiums are close to 100% DOD which is why you can use all of the amp hours and how the equivalent rating got started vs. an actual amp hour listed.

 

[EarthX Lithium]

As I recall you did an unscientific test of the LFX18 that powered your primary EFIS, backup EFIS/EMS, COMM receive only, audio panel, AP but no active (i.e. no servos), and Garmin 795 for 3 hours. I have a similar panel and with the LFX36 one would expect it should power it for close to 6 hours! I would be landing well within an hour with alternator failure so I do not see this as putting myself or my family in danger as Kathy implied.

The best way to settle this would be to get theEarthX battery and the SHorai both rated at 36eqah and do a test of them under the same load.

RocketBob also did a "torture" test of the Shorai and it did very well as I recall.

TJ

Hi TJ,

I am not saying, and I want to be very clear here, I do not recommend the EarthX ETX36 as a replacement for either of these lead acid batteries, the PC925 or the PC1200. We would be grossly undersized as well!!!

My comments were based on the differences in what the battery can do in an emergency situation. This is a quote from the Shorai website on how they measure CCA. "Our LFX are CCA rated to deliver 9V for a 5-second crank at the CCA rated current." This is different parameter test than what the CCA test calls for. When the SAE test is performed, at o deg F for 30 seconds, it is closer to 200, not 540.

And for amp hours, again, this is quoted from Shorai's website on their amps hours: "The internal "completely discharged" capacity of a Shorai LFX is 1/3 the rated "PBeq" capacity. For example, the LFX18 12V series have 6Ah cells internally." Hence, you take the equivalent amp hours and divide by 3. We do the exact same thing here based on the same reasoning. So that being said, it is a true 12 ah that you can use 100% of.....but that is still much less than either of the PC925 or the PC1200.

You can do as you like...I am not trying to scare you.....I just wanted you to know that you are not using apples to apples. And this is another quote from the Shorai website on their warranty exclusion page; "?Applications Not listed on the Shorai website product finder such as: Aircraft, Automotive, Motive power (LFX as main power source, not engine starter)." They must have a reason to exclude aircraft use.

 

[PerfTech]

Extra Info!

... I've put about 60 hours on my Shorai battery installation and am very happy so far. I used the largest one with the highest output they offer and still was able to save 23 lbs. over the Odissy 925 battery. The starting is great and it spins up better than ever. I noticed it doesn't like a continuous draw as with avionics on and engine off. The surface voltage declines rapidly in comparison to the lead acid battery. The manufacturer says that this is normal and you should size their battery at two times the amp hour rating of the one you are replacing. Even with this increase, the bad side is if you were to lose the alternator, your time on battery power is still somewhat limited as compared to the Odissy battery. At any rate, it is performing very well for what I do and have no bad things to say! Thanks, Allan...

My sole objection is that the battery has stamped on it that the maximum charge rate is 10 amps, with warnings of bad things to happen when you exceed that. My alternator puts out a charge rate of 45 amps. I am considering an external regulator that can control the charge to 10 amps. Most of the snowmobiles and scooters using this battery only has a small charging rate.

... I should have stated some extra information about my charging system in my last post as it looks like this is a concern to some. My alternator is 80 amp and this is not an issue for the Shorai battery. The high charge rate is only a few seconds after start-up, as the surface voltage comes up very rapidly on the battery. If you are showing a high amp charge rate from your alternator as when you are using a lot of power for lights etc. this is not going to the battery and has virtually no effect on it. What you are seeing is a high output from your alternator to power the demands of the accessories. This is being used up by them and is not going to the battery as a charge rate. At night when I have everything turned on, including electric heat and landing lights, my alternator output is 52 amps. The battery is fully charged and is not accepting any of this current as a charge. As a test bed, I have the same Shorai battery installed in my one ton E-350 ford van. This vehicle is very electrical dependent with front and rear duel air conditioning units etc. The alternator is 130 amps and the starting loads are very substantial as well. I have run the Shorai battery down on purpose, requiring a jump to start the engine to measure what would take place. The alternator puts out at a high rate only until the surface volts come up (only a few seconds) and then tapers off rapidly to its normal low charge rate. The Shorai battery is performing well and shows no signs of deterioration or ill effects from the testing and abuse. I am very confident with this technology now, and would do this again when it becomes necessary to replace the battery. Hope this helps people on the fence. Thanks, Allan...

 

[humptybump]

As I recall you did an unscientific test of the LFX18 that powered your primary EFIS, backup EFIS/EMS, COMM receive only, audio panel, AP but no active (i.e. no servos), and Garmin 795 for 3 hours. RocketBob also did a "torture" test of the Shorai and it did very well as I recall.

Yes, that is one of my tests. That test was actually on the LFX18 that had been my aircraft's primary and only battery for more than a year - acting as both starter and ground operations battery before becoming the "backup battery" it is now. It was originally put into service as a one-for-one replacement for an Odyssey PC680. Both the LFX18 and the PC680 gave identical starter performance.

With my new panel being electronic with redundant electronic instruments, I wanted a second battery. I went with the LFX36 (thinking more is better).


Kathy / TJ - thanks for all the information you are providing to this thread and this community. We are all smarter (or at least better educated) for your participation.


Thanks for explaining the details - testing methods, ratings, and calculations - you had provided earlier. I didn't pick up on the fact you were not singling out Shorai - rather, your concern was between the deep cycle lead acid battery and any of the current LiFePO4 batteries on the market - EarthX, Shorai, etc.

BTW: when it comes to warranties, it seems everyone finds a means to limit risk exposure. The EarthX exclusion clauses do not call out specific applications but has a number of scenarios and a broad general statement. It seems our application isn't covered by either vendor - except, perhaps the cost of the battery.

 

[EarthX Lithium]

Need help with an Odyssey question

Yes, that is one of my tests. That test was actually on the LFX18 that had been my aircraft's primary and only battery for more than a year - acting as both starter and ground operations battery before becoming the "backup battery" it is now. It was originally put into service as a one-for-one replacement for an Odyssey PC680. Both the LFX18 and the PC680 gave identical starter performance.

With my new panel being electronic with redundant electronic instruments, I wanted a second battery. I went with the LFX36 (thinking more is better).


Kathy / TJ - thanks for all the information you are providing to this thread and this community. We are all smarter (or at least better educated) for your participation.


Thanks for explaining the details - testing methods, ratings, and calculations - you had provided earlier. I didn't pick up on the fact you were not singling out Shorai - rather, your concern was between the deep cycle lead acid battery and any of the current LiFePO4 batteries on the market - EarthX, Shorai, etc.

BTW: when it comes to warranties, it seems everyone finds a means to limit risk exposure. The EarthX exclusion clauses do not call out specific applications but has a number of scenarios and a broad general statement. It seems our application isn't covered by either vendor - except, perhaps the cost of the battery.

I have really been trying to do my research here and I have even tried calling Odyssey direct to find an answer to these questions but as of yet, I have not had a phone call back. Maybe you all can point me in the right direction....I tried to find a charging amp rating they recommend, specifically the max charge amps but I can not find it. I can only find voltage parameters. Second, I couldn't find an application on their site at all for airplanes.....is there a place to find this that list which planes and which batteries they recommend or how did you all decide on the PC680, PC925, or the PC1200? And thirdly, I can't really find anything about aircraft use on their website, technical brochures etc. so should I assume the are not a certified aircraft battery?? I did review their warranty; http://www.odysseybattery.com/documents/US-ODY-WS-12_0212_000.pdf and it does not exclude aircraft on there nor does ours, it was only the Shorai website that excludes aircraft that I found.

 

[scard]

I have really been trying to do my research here and I have even tried calling Odyssey direct to find an answer to these questions but as of yet, I have not had a phone call back. Maybe you all can point me in the right direction....I tried to find a charging amp rating they recommend, specifically the max charge amps but I can not find it. I can only find voltage parameters. Second, I couldn't find an application on their site at all for airplanes.....is there a place to find this that list which planes and which batteries they recommend or how did you all decide on the PC680, PC925, or the PC1200? And thirdly, I can't really find anything about aircraft use on their website, technical brochures etc. so should I assume the are not a certified aircraft battery?? I did review their warranty; http://www.odysseybattery.com/documents/US-ODY-WS-12_0212_000.pdf and it does not exclude aircraft on there nor does ours, it was only the Shorai website that excludes aircraft that I found.

Being new to the arena, you'll quickly learn that we refer to them as "Offroad vehicles" when talking to vendors .

 

[EarthX Lithium]

Ha!

Being new to the arena, you'll quickly learn that we refer to them as "Offroad vehicles" when talking to vendors .

Okay, airplane use being "offroad" is pretty funny....and technically correct!

 

[RVbySDI]

. . . And thirdly, I can't really find anything about aircraft use on their website, technical brochures etc. so should I assume the are not a certified aircraft battery??

I think this is a safe assumption on your part. There is a world of difference between a certificated aircraft and an experimental aircraft when it comes to components that go in either. Pretty much everyone you converse with on this forum lives in the experimental world. In the experimental world things such as "certification" are dealt with just a little bit differently than in a "Certificated General Aviation Aircraft".

 

[grayforge]

My buddy with a certified aircraft (Bonanza) is extremely jealous about the variety of things I can put in my plane.

 

[Bill.Peyton]

Odyssey does produce batteries for certified aircraft applications.

 

[DonFromTX]

I am glad it has worked out so far for you, but of course you realize that at the first startup you have voided the warranty. I can live with that, but both manufacturers have repeatedly told me that when charging above their stated limit (even if it is for a few minutes only) I can expect not only very early failure of the battery, but a fire hazard as well. Both don't want to discuss such abuse or look for a cure, simply state DO NOT DO IT!
Offering a simple regulator would seem to be the thing to do if they wanted uses in the automotive world.

... I should have stated some extra information about my charging system in my last post as it looks like this is a concern to some. My alternator is 80 amp and this is not an issue for the Shorai battery. The high charge rate is only a few seconds after start-up, as the surface voltage comes up very rapidly on the battery. If you are showing a high amp charge rate from your alternator as when you are using a lot of power for lights etc. this is not going to the battery and has virtually no effect on it. What you are seeing is a high output from your alternator to power the demands of the accessories. This is being used up by them and is not going to the battery as a charge rate. At night when I have everything turned on, including electric heat and landing lights, my alternator output is 52 amps. The battery is fully charged and is not accepting any of this current as a charge. As a test bed, I have the same Shorai battery installed in my one ton E-350 ford van. This vehicle is very electrical dependent with front and rear duel air conditioning units etc. The alternator is 130 amps and the starting loads are very substantial as well. I have run the Shorai battery down on purpose, requiring a jump to start the engine to measure what would take place. The alternator puts out at a high rate only until the surface volts come up (only a few seconds) and then tapers off rapidly to its normal low charge rate. The Shorai battery is performing well and shows no signs of deterioration or ill effects from the testing and abuse. I am very confident with this technology now, and would do this again when it becomes necessary to replace the battery. Hope this helps people on the fence. Thanks, Allan...

 

[grayforge]

How difficult to build/expensive to purchase would an amperage regulator be?

 

[grayforge]

Answering my own question... here's one on eBay that limits 12V charging to 7 amps and also limits battery discharge to 11V. The latter feature wouldn't be needed for an EarthX battery. Cost: $19.99

http://www.ebay.com/itm/7AMP-12VOLT...OLLER-7A-CHARGE-REGULATOR-W-LVD-/171203243856

In case the link becomes invalid over time, just search eBay for "amp charge regulator"

 

[erich weaver]

I am glad it has worked out so far for you, but of course you realize that at the first startup you have voided the warranty. I can live with that, but both manufacturers have repeatedly told me that when charging above their stated limit (even if it is for a few minutes only) I can expect not only very early failure of the battery, but a fire hazard as well. Both don't want to discuss such abuse or look for a cure, simply state DO NOT DO IT!
Offering a simple regulator would seem to be the thing to do if they wanted uses in the automotive world.

See post 137 of this thread

Erich

 

[chaskuss]

Why not make a container to fit the batteries you already make?

You are absolutely right, our battery is .4" wider than the PC680 and to be honest, up until just now, no one has pointed that out as a problem. Our cases are designed for the power sport industry, for example, the ETX36D is an exact case size of the YTX20L-BS or the YTX20HL-BS as this is a very popular OEM size in our market. At this moment, that is our expertise and what our product is developed towards, a starter battery for the power sport market. As the aircraft market has found us and we have sold 100's of these batteries now to this market, that is not to say we will not become an expertise in this market and start design and development geared towards aircraft specifically.

That being said, if we were to have a case designed just for your planes, what size would you want it to be? We can either copy the PC680 for example, or we can design a case to the exact dimensions you want. snipped

Kathy,
Do I assume correctly that your use of the word "case" in the second sentence quoted above, you mean the case of the battery? If so, it seems much more logical for you or another vendor like Anti-Splat Aero to simply offer battery boxes made for the batteries you already produce?
Considering how much lighter your batteries are, this may allow the battery box to be fabricated from aluminum, rather than 4130 steel. This would save a little more weight, which would go hand in hand with using a weight saving battery.

Charlie

 

[sailvi767]

Kathy,
Do I assume correctly that your use of the word "case" in the second sentence quoted above, you mean the case of the battery? If so, it seems much more logical for you or another vendor like Anti-Splat Aero to simply offer battery boxes made for the batteries you already produce?
Considering how much lighter your batteries are, this may allow the battery box to be fabricated from aluminum, rather than 4130 steel. This would save a little more weight, which would go hand in hand with using a weight saving battery.

Charlie

If at some point I ever go with LifePo battery I would only want it in a steel case. Aluminum would make me very nervous given how they burn. Even if not the fault of the battery a engine fire with the battery on the firewall would be unsurvivable if the battery ignited.

George

 

[chaskuss]

If at some point I ever go with LifePo battery I would only want it in a steel case. Aluminum would make me very nervous given how they burn. Even if not the fault of the battery a engine fire with the battery on the firewall would be unsurvivable if the battery ignited.

George

George,
Considering that in a crash, the engine mount will likely puncture the battery regardless of whether the box is made from steel or aluminum, your concern would best be cured by mounting the battery in the rear. In a crash, you are almost guarantied to have fuel and/or oil leaks. The ruptured battery will supply the spark to start a fire. A battery box made of thin 4130 won't change that. Even it the battery does not get punctured, it will be crushed against the steel box, with the same results. Best to keep the battery out of the engine bay, in my view.
Charlie

 

[chaskuss]

If at some point I ever go with LifePo battery I would only want it in a steel case. Aluminum would make me very nervous given how they burn. Even if not the fault of the battery a engine fire with the battery on the firewall would be unsurvivable if the battery ignited.

George

Perhaps I misunderstood you. I believe you mean that a steel battery box would give superior containment of the battery, should it catch fire or explode? You are correct there. However, my comments of the last post still hold true regarding a crash. [Thinking worst case scenario]
Charlie

 

[grayforge]

I don't know how much containment our battery boxes provide, seeing as how most of us add lightening holes.

Personally, I wouldn't use Aluminum because of its higher likelihood of fatigue failure. But lighter duty steel might be appropriate. Either slightly lighter gauge or more lightening holes.

 

[sailvi767]

Perhaps I misunderstood you. I believe you mean that a steel battery box would give superior containment of the battery, should it catch fire or explode? You are correct there. However, my comments of the last post still hold true regarding a crash. [Thinking worst case scenario]
Charlie

I was actually more concerned about a fuel or oil feed fire torching off the battery in flight. I agree in a crash there will be lots of issues.

George

 

[DonFromTX]

This seems to be evading the real question. You are somehow expecting me to believe that the battery is so smart that it can detect if the charge is coming from a battery charger or an alternator, and accept it from an alternator? Where is this technology located in the battery, amps are amps regardless of origin. Why don't the maximum charge rate of 10 amps stamped on the battery SAY that the warning is ONLY for chargers and not alternators? I fully understand that part of my 45 amp charge is going to power accessories, but the remainder is more like 30 amps, three times the stated allowable limit, which you clearly say will damage the battery, and might cause fires etc. I am having trouble believing that the battery descriptions and warnings are all false just because you say they are..

That has been the million dollar question we have received all week! The warning on the top of the battery is for using a charger, not your alternator output. Most power sport chargers are 5 amps or less and this warning is to try and prevent someone from using a car charger that can go up to 80+amps or even higher. When your alternator is charging up the battery, it is also running all of the instrumentation as well and the full amount doesn't go into the battery, therefore, it will not harm your battery if the battery is correctly sized. Our ETX36D is designed to take a lot more amps than say our baby one, an ETX6A. Hope that answers your question.

 

[akskyhawk]

donfromtx
Don, this might help you understand why you won't overcharge your battery.
The alternator output rate is affected by the regulator. When voltage drops on the bus the regaulator excites the alternator by a varing rate, the more the voltage drops on the bus the more the regulator excites the alternator thus the more the amps put out.
That being said, the reason the voltage drop is use of the system by consumption of items such as landing lights. So when the alternator starts putting amps out it is because of demand, so the amps is actually going to the device thats calling for it not the battery. The alternator only puts out enough amps for the load demanding it.
The battery in flight is actually taking on very little charging or providing very little power or amps. The battery only takes on a heavy charging when it has been drawn down otherwise it takes on very little charge because there is no demand on it.
If you had a old ampmeter that was supplied in many of the old planes you would actually see this at work. During flight the ampmeter would barely deflect towards a + charge side, meaning the battery was taking on a small charge. If your alternator failed you would see the meter swing way to the other side showing a - discharge, meaning the battery is now supplying all the power and current.
Hope this helps.

 

[DonFromTX]

I fully understand what you are saying, and have tried to enlarge and color red the part that worries me. For instance, my last aircraft was an Ercoupe with the 60 amp alternator STC I installed. EVERY start the amps would peg the scale at nearly 60 amps and gradually ramp back until the battery was recharged. This is as it should be.
You are suggesting that in your opinion perhaps "short bursts" of excessive charging like this is allowed, you may be correct, but NONE of the battery makers will give me this OK, nor even tell me how long I can far exceed their warnings nor by how much.
I am not suggesting that it will be an overcharge, only that the CHARGE RATE will exceed the makers very strong warning of maximum charging amps. This could be easily controlled by an external regulator limiting the charge rate to the maximum charging rate allowed, yet I cannot get this guidance from any of the makers either.
The wide use in small motorized recreational vehicles, and as recommended, all have very small charging rates, with alternators often in the 7-10 amp max charge rates.

donfromtx
Don, this might help you understand why you won't overcharge your battery.
The alternator output rate is affected by the regulator. When voltage drops on the bus the regaulator excites the alternator by a varing rate, the more the voltage drops on the bus the more the regulator excites the alternator thus the more the amps put out.
That being said, the reason the voltage drop is use of the system by consumption of items such as landing lights. So when the alternator starts putting amps out it is because of demand, so the amps is actually going to the device thats calling for it not the battery. The alternator only puts out enough amps for the load demanding it.
The battery in flight is actually taking on very little charging or providing very little power or amps. The battery only takes on a heavy charging when it has been drawn down otherwise it takes on very little charge because there is no demand on it.
If you had a old ampmeter that was supplied in many of the old planes you would actually see this at work. During flight the ampmeter would barely deflect towards a + charge side, meaning the battery was taking on a small charge. If your alternator failed you would see the meter swing way to the other side showing a - discharge, meaning the battery is now supplying all the power and current.
Hope this helps.

 

[digidocs]

I asked a similar question about the EarthX charge current limitation and got this answer from their engineering department:

The 10A statement on the battery is so people use a small (1-5) motorcycle
charger. The internal circuitry will protect the battery from over-charge
even if the charger is faulty or has no voltage regulation (like really
old chargers). Our battery cells are designed for high charging currents and
the ETX36C can handle 90A for short periods, which it would be.

So yes, you can use our battery on a car with a 60A alternator.​

Hope that helps with some of the confusion.

David

 

[grayforge]

If amperage output of the alternator is related to voltage level of the system (low voltage = high amperage charging), wouldn't the fact that LiFePo batteries maintain a higher voltage (flat discharge rate) mean that the charge amperage would be lower than a similarly discharged (by percentage) lead acid battery?

 

[DonFromTX]

I like the answer you got, when I asked them the same question I got this reply (direct quote from the response). Not sure just what qualifies as a "car charger" but that is normally an alternator. No mention of short period ability to take a bigger charge:

"Dear Don,
The max charge rate from a charger is 10 amp hours. Most power sport chargers are 2 amps or less. This rating is to make sure someone doesn?t use a car charger. Let me know if you have any additional questions and I would be happy to assist."



"

I asked a similar question about the EarthX charge current limitation and got this answer from their engineering department:

The 10A statement on the battery is so people use a small (1-5) motorcycle
charger. The internal circuitry will protect the battery from over-charge
even if the charger is faulty or has no voltage regulation (like really
old chargers). Our battery cells are designed for high charging currents and
the ETX36C can handle 90A for short periods, which it would be.

So yes, you can use our battery on a car with a 60A alternator.​

Hope that helps with some of the confusion.

David

 

[DonFromTX]

Good thinking, I had considered that as well. However those with alternators and these batteries are saying that their alternator regulators seem to treat these the same or nearly so, as a lead acid battery.

If amperage output of the alternator is related to voltage level of the system (low voltage = high amperage charging), wouldn't the fact that LiFePo batteries maintain a higher voltage (flat discharge rate) mean that the charge amperage would be lower than a similarly discharged (by percentage) lead acid battery?

 

[9erDriver]

Lithium e-bus performance?

I'm still confused as to the alternator out (e-bus activated) performance of these new batteries as compared with the PC680 technology. Being an Aaeroelectric disciple -aka Knuckollhead- I regularly test my battery with a controlled 5.5a discharge, mimicking alternator out e-bus load for my critical avionics. I expect to see 2.5 hours or better at this discharge rate win a PC680.

What could I expect to see under similar circumstances with a Shorai, Balistic, or similar?

Thanks- Steve

 

[EarthX Lithium]

New techical information coming soon!

First off, thank you VAF forum as we have received questions and purchases from around the world after posting on here!

We are very busy working with aircraft manufacturers and engineers in the aerospace market to compile important and technical information for you. We would like to request the information you really want to know and send that to: [email protected]

We plan on having a frequently asked questions (FAQ) section geared towards the aircraft market and updating our technical information and manuals to include this type of an application.

If you send us the questions, we will make sure our engineering staff and the consultants we are working with provide you with the correct information so you can make an informed decision!

Thanks again, Kathy

 

[Canadian_JOY]

I'm considering using a LiFePo battery as a backup battery to provide power to an essential bus in the event of an alternator failure. I don't think I've seen posted here any results of tests conducted for longer-term, lower-current discharge.

Has anybody tested these (EarthX, Shorai, Aerovoltz etc) LiFePo batteries to see how their capacity stands up against something like a PC680 when used as an essential bus backup power source? If so I would be very curious to know how the "PbEquivalent" amp-hour ratings work relative to the real Pb amp-hour performance with which most of us are more familiar.

 

[erich weaver]

My understanding from the Matronics Aeroelectric List forum is that Bob Knuckolls of AeroElectric Connection fame is in communication with EarthX to obtain some of the discharge plots to better demonstrate their performance and assist with determinations of the correct model for replacing a PC680 main battery or backup. He is also in the middle of a series of articles regarding batteries for Kitplanes so you might want to check those out.
Erich

 

[EarthX Lithium]

Website, manual and battery spec updated

We have been very busy here at EarthX gathering the information for you so you can make an informed decision.

We have talked with Vans Aircraft;chatted with some people from Super Cub; had excellent conversations with pilots from FedEx who also own private planes; communicated with Bob Knuckolls of AeroElectric Connection; and communicated with Dan Morris who designs aircraft electrical systems and works on getting batteries FAA approved.

Thank you to all of them!! They have all provided excellent questions and recommendations on what you need for information so we have updated our website, our manual to include much more technical information, and have a easy to read cross reference guide in the EXPERIMENTAL AIRCRAFT tab.

Have a great day and as my mother always says, "fly lightly".

Kathy

 

[Bevan]

Earthx size

Kathy,

Thank you for updating us and your website. I'm sure many in the experimental aircraft community are watching this lithium revolution with great interest. Thank you for recognizing this segment of the port battery market and addressing it. I have a question I would think many here have...

Your website says that even though the EXT36D is slightly bigger (in one direction), it is still an excellent fit to replace the PC680. The different is 0.3 inches (in thickness) and I'm wondering how this fits the 680 perfectly? This says to me the battery boxes are not getting modified. Are the EarthX just getting pushed into the 680 size box, slightly deforming it? I would think the box would have to be modified, ie, made thicker by about 0.3 inches. Perhaps those here that have installed the ETX36D in a pc680 box could chime in with a comment. Bevan

 

[EarthX Lithium]

Dear Bevan,

Thank you for the question and I asked my pilots who have purchased this battery to tell me exactly how they fit, if they do anything to them and their opinions as I would think the exact same thing as you, bigger is bigger, so how can it fit perfectly?

Here is a quote from a retired FedEx pilot using the ETX36D in his PC680 battery box; " Battery fits great...and really spins my prop! Much faster than the P680.” So I responded back to him, " So the .29mm difference in width wasn’t an issue? Glad to hear. Do you have a custom made battery box that you used for the PC680?" And he responded, " I made a custom made stainless steel battery box for the PC680 and it sits on the cockpit side of the firewall. Fits perfectly."

Hope that answers your question! And up to 1 day ago, the ETX36D was the closest we had in size but we now have our newest case design, the ETX36E, and it's dimensions are: 6.6" x 3.4 " x 6.1". The Odyssey is: 7.27" x 3.11" x 7.55". In my personal opinion, this is even a closer fit.

Kathy

 

[RVbySDI]

. . .The Odyssey is: 7.27" x 3/11" x 7.55". . .

Kathy, I am hoping the bolded dimension in the above quote from your post is just a typo. Can you clarify that measurement?

 

[EarthX Lithium]

It was a typo...I corrected the post as well. It should have been 3.11". As many users have used our battery as a replacement, please feel free to post on here how it really did fit in your battery box or if you needed to make any adjustments. We do not want you to think we are suggesting placing a square peg in a round hole.......

 

[grayforge]

Hi Kathy,

I suspect that the ETX36D and E will not fit in the standard Vans PC680 battery box. I measured the box and it's a little under 1/4" too narrow in the forward/aft dimension. I built a custom box using the stock box design, but made it 3.4" deep. I suspect your battery will fit this custom box perfectly.

 

[EarthX Lithium]

Thanks for the response and the fitment question! By the looks of your fancy battery box plans behind the one you built, I am sure it will be a perfect fit!

Looks great!

Kathy

 

[EarthX Lithium]

Here is an ETX36C battery in a RANS S7

Thank you Ken for sending me this picture. He used the ETX36C and built a custom box for it. Just thought I would share it. The first one is the custom box itself and the second one is with the ETX36C in the battery tray.


Kathy