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Why Odyssey PC680 and not EarthX ETX680?

Pilot135pd

Pilot135pd

Well Known Member
First question:
Does a 300hp IO-540 need more battery cranking power than a 180hp O-360 engine?

Second question:
Have you ever felt the need or considered installing a battery with more CCA to start in cold weather?

Third question:
For those who are using the Odyssey PC680, ASIDE FROM THE PRICE, why haven't you changed to the EarthX ETX680?
 
First question; yes.

Second question; no. I use two PC-625 batteries in parallel (RV-8 and RV-10). More than ample cranking power. During testing I did try starting the IO-540 on just one of the batteries. No problem but the engine did crank slower. I would not want that for the only option.

Third question; not applicable. For my planes I do not find any advantage to using a couple of EarthX batteries over the PC-625s (my power distribution requires two batteries), and some disadvantages.

Note - a per plans RV-10 requires some weight in the back. If you use EarthX in that plane you will need to add weight someplace.

Carl
 
Starter type

This will depend on whose starter you use. The SkyTec lightweight starter is a known amp hog.

Always re-examine CG tolerances when changing weight (going to and from a Earth X battery) and for me I’ve run the numbers using Earth X in the 10 and hopefully going with a composite prop (as a lot of us have and are doing) offsets the reduction of weight in the rear. Others use A/C to add weight in the rear. For me I’m saving ~50 lbs going with Earth X and Whirlwind. Well worth adding a few bottles of water in the rear baggage area if required. And BTW a single Earth X battery will spin a 540 (even with the lightweight starter) very well even in the cold.
 
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Carl Froehlich said:
I use two PC-625 batteries in parallel (RV-8 and RV-10).
Carl
Click to expand...

Thanks. You use the lead acid PC-625 over the AGM PC-680, any specific reason?


dmattmul said:
This will depend on whose starter you use. The SkyTec lightweight starter is a known amp hog.

Always re-examine CG tolerances when changing weight .
Click to expand...

I have a 70amp SkyTec :(. Regarding CG, that's part of my brainstorming right now, thanks.
 
dmattmul said:
Well worth adding a few bottles of water in the rear baggage area if required…..
Click to expand...

+1. A lot of -10’s will go out of aft cg (especially at low fuel levels) before going over gross. The ‘water bottle method’ is an easy way of getting maximum load flexibility. I do this myself even with an Odyssey battery.
 
Pilot135pd said:
Third question:
For those who are using the Odyssey PC680, ASIDE FROM THE PRICE, why haven't you changed to the EarthX ETX680?
Click to expand...

After researching the possible failure modes of various lithium based batteries as well as videos of the resulting (nearly inextinguishable) fires I do not trust them in any vehicle especially my airplane. The safety of a lithium based battery is dependent on an internal computer (BMS or battery management system) and I trust neither the computer nor the battery cell materials. Granted in Earthx's case the cells are lithium iron phosphate, which are more stable than lithium ion types.

The Odyssey PC680 battery uses AGM (absorbed glass mat) technology which means the battery acid is absorbed into fiberglass mats instead of being a free flowing liquid. Thus it is made without ventilation caps and is basically unspillable. This technology allows more lead plates per volume than flooded acid batteries and results in lower internal resistance giving greater cranking power per weight. This is enough technology for my airplane.

And yes, while not inexpensive, they are much cheaper than EarthX batteries
 
terrye said:
After researching the possible failure modes of various lithium based batteries as well as videos of the resulting (nearly inextinguishable) fires I do not trust them
Click to expand...
It should be noted that lithium batteries do come in many different chemistries, used for many different applications, such as engine starting, pace makers, or equipment operations. The most common is Lithium Cobalt: used in cell phones, I-pads, and lap top computers, all with BMS's and there are trillions of them in our world today. This is the type of battery chemistry that can result in a "nearly inextinguishable fire", but it is quite rare, regardless of the videos found online. Does this mean you do not use any of these electronics, especially while in your plane? Or in your home?

You also state you do not trust the BMS within a lithium battery? May I ask why? All your aircraft electronics have BMS's, such as a Garmin or Dynon EFIS. Is it just a lithium battery BMS you don't trust or all of them you don't trust? Please explain. Or maybe you only use mechanical gauges and paper maps?

You also state you do not trust the battery cell materials? Please explain. How is the materials to make a lithium battery untrustworthy? And why are the materials in an AGM battery trustworthy, what is different?

I look forward to your explanations.
 
EarthX Lithium said:
It should be noted that lithium batteries do come in many different chemistries, used for many different applications, such as engine starting, pace makers, or equipment operations. The most common is Lithium Cobalt: used in cell phones, I-pads, and lap top computers, all with BMS's and there are trillions of them in our world today. This is the type of battery chemistry that can result in a "nearly inextinguishable fire", but it is quite rare, regardless of the videos found online. Does this mean you do not use any of these electronics, especially while in your plane? Or in your home?

You also state you do not trust the BMS within a lithium battery? May I ask why? All your aircraft electronics have BMS's, such as a Garmin or Dynon EFIS. Is it just a lithium battery BMS you don't trust or all of them you don't trust? Please explain. Or maybe you only use mechanical gauges and paper maps?

You also state you do not trust the battery cell materials? Please explain. How is the materials to make a lithium battery untrustworthy? And why are the materials in an AGM battery trustworthy, what is different?

I look forward to your explanations.
Click to expand...
The difference is emotion; it doesn’t matter what the data or engineers say, it is all about what gives you peace of mind and makes you feel good.

That said, I’m more of a data guy and I am really happy with two ETX900s in my RV-10!
 
terrye said:
Thus it is made without ventilation caps and is basically unspillable.
Click to expand...
Not true. There IS a vent hole hidden on side of the Odyssey battery. Mine leaked in flight on the way back from Osh; down the firewall and down the belly, corroding everything along its path. A royal pain to clean up.
 
One thing to consider, particularly as our airplanes become more electrically dependent, is that the Odyssey stores about 25% more energy (amp hours) than the EarthX.
 
BruceW said:
Not true. There IS a vent hole hidden on side of the Odyssey battery. Mine leaked in flight on the way back from Osh; down the firewall and down the belly, corroding everything along its path. A royal pain to clean up.
Click to expand...
I recently had a new Odyssey leak a small amount of acid into the airframe of my -10. I choose the Odyssey because I judged it to be more reliable. With 20/20 hindsight, I would go with the EarthX.
 
Kyle Boatright said:
One thing to consider, particularly as our airplanes become more electrically dependent, is that the Odyssey stores about 25% more energy (amp hours) than the EarthX.
Click to expand...
Hi Kyle,
That depends on which battery models you are comparing.

The Odyssey PC680 has a 1 hour 1 C rate of 12.3Ah. The EarthX ETX680 has a 1 hour 1 C rate of 12.4Ah.
 
EarthX Lithium said:
Hi Kyle,
That depends on which battery models you are comparing.

The Odyssey PC680 has a 1 hour 1 C rate of 12.3Ah. The EarthX ETX680 has a 1 hour 1 C rate of 12.4Ah.
Click to expand...
And for the same case size the ETX900 is rated at 15.6Ah at 4.9 lbs. and the ETX1200 is rated at 20.0 Ah and 5.6 lbs.
 
EarthX Lithium said:
Hi Kyle,
That depends on which battery models you are comparing.

The Odyssey PC680 has a 1 hour 1 C rate of 12.3Ah. The EarthX ETX680 has a 1 hour 1 C rate of 12.4Ah.
Click to expand...

How long will each battery pour out 5A, while maintaining voltage >10? That (5 amps, maybe less) is roughly where my airplanes would net out if I load shed in the case of an alternator failure. And >10V keeps most of the items in the airplane working when/if I need 'em.
 
Kyle Boatright said:
How long will each battery pour out 5A, while maintaining voltage >10? That (5 amps, maybe less) is roughly where my airplanes would net out if I load shed in the case of an alternator failure. And >10V keeps most of the items in the airplane working when/if I need 'em.
Click to expand...
I did some what I call "leak down" tests to compare the ETX-680 to the PC-680 that I was replacing in the 6.

It took getting GRT to provide the option to log data WITHOUT the engine running. I turned on the avionics and just let it run.

When the data logging stopped, it meant that the voltage was below what the EFIS required (~10v +).

As I recall (don't have the data before me at the moment, the ETX680 kept the avionics running considerably longer that the PC680 did when each was fully charged.
The slope of the PC680 is a gradual continuance so to speak. Meaning that it may get BELOW the 10v earlier BUT have more juice that can be provide for "something". It also gives an early warning as some components will "flicker" as their threshold is approached. The ETX680, on the other hand, holds the voltage high enough for a longer period but when it gets close to the magic voltage, it a all over (BMS shutdown).

I had the voltage and current warning thresholds set inappropriately (for EXT680) and upon an alternator failure, the avionics just ran and ran and ran, until they didn't! o_O
I have since fixed that oversight.

Personally, I like having the battery hold the voltage up at the level I need as long as possible.
 
EarthX Lithium said:
It should be noted that lithium batteries do come in many different chemistries, used for many different applications, such as engine starting, pace makers, or equipment operations. The most common is Lithium Cobalt: used in cell phones, I-pads, and lap top computers, all with BMS's and there are trillions of them in our world today. This is the type of battery chemistry that can result in a "nearly inextinguishable fire", but it is quite rare, regardless of the videos found online. Does this mean you do not use any of these electronics, especially while in your plane? Or in your home?
Click to expand...

Not relevant as the amp draw in a cell phone battery is no where near the amp draw in a battery in a vehicle especially one that is used to start an engine.

As stated above by rocketman1988, it is an emotional decision since it is about risk management. We all manage it differently. This maybe a new never ending debate issue.
 
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plehrke said:
Did you take any battery case temperature readings especially as you got to very low voltage?
Click to expand...
No, I did not.

BUT ...

A long time ago, in a galaxy far away (the EARLY days of EarthX), I worked with Widget and an installation of dual EarthX batteries in his RV8. We did install temperature probes and while I do not remember the exact temperatures, I do remember that they never exceeded the number given to me by EarthX engineering.

During this time, I did "punish" a battery or two (with EarthX's "blessing" [meaning they were made aware of what I was doing:)] and the worst I ever got was a swollen battery or two. Several changes/improvements were made to handle some of the (maybe stupid??) things that I did. That was YEARS ago and the only thing that I have had go wrong since is that batteries that I had PLANNED to use, sat for a VERY LONG time and decided that they were no longer going to play with me. When I spoke to Kathy about them, she asked me how old they were ("I am not sure!") and asked me to give the letter that was on a sticker. To my EMBARASSMENT, **years** had passed. "Ooops! My Bad!".:rolleyes::rolleyes:
 
Carl Froehlich said:
First question; yes.

Second question; no. I use two PC-625 batteries in parallel (RV-8 and RV-10). More than ample cranking power. During testing I did try starting the IO-540 on just one of the batteries. No problem but the engine did crank slower. I would not want that for the only option.

Third question; not applicable. For my planes I do not find any advantage to using a couple of EarthX batteries over the PC-625s (my power distribution requires two batteries), and some disadvantages.

Note - a per plans RV-10 requires some weight in the back. If you use EarthX in that plane you will need to add weight someplace.

Carl
Click to expand...
Or loose weight on the nose. My Whirlwind prop is supposed to be 12 pounds lighter than a Metal HZ.
 
Kyle Boatright said:
How long will each battery pour out 5A, while maintaining voltage >10? That (5 amps, maybe less) is roughly where my airplanes would net out if I load shed in the case of an alternator failure. And >10V keeps most of the items in the airplane working when/if I need 'em.
Click to expand...
With that amount of load, it would be 148 minutes or 2.5 hours of energy from the EarthX battery.
 
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EarthX Lithium said:
With that amount of load, it would be 148 minutes or 2.5 hours of energy from the EarthX battery.
Click to expand...
I was thinking the EarthX held voltage relatively steady, then fell off the table sooner than a conventional battery. Looks like the EarthX is a 2.5 hour battery at that load, and the PC-680 is probably slightly better. (Correct me if I'm wrong.) But the difference is within the margin of error depending on battery age, etc.

Is that fair?
 
Kyle Boatright said:
I was thinking the EarthX held voltage relatively steady, then fell off the table sooner than a conventional battery. Looks like the EarthX is a 2.5 hour battery at that load, and the PC-680 is probably slightly better. (Correct me if I'm wrong.) But the difference is within the margin of error depending on battery age, etc.

Is that fair?
Click to expand...
Hi Kyle,
Fair and correct assessment. :)
 
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