Replies to This Discussion

Permalink Reply by Wayne Tyson on August 31, 2015 at 1:51pm

I should mention that searches on this site didn't produce anything. Is something wrong with the site or is it me?

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Permalink Reply by Ken Pavlou on August 31, 2015 at 3:42pm

I replaced the Odyssey PC680 in my 601XL with the equivalent EarthX lithium battery and have been very happy.  I saved 11 pounds as well. 

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Permalink Reply by Timothy D. McCall on September 1, 2015 at 4:12pm

Me too.  I am pleased with the EarthX  (I  put the Odyssey PC680 on my lawn mower).

Tim

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Permalink Reply by Wayne Tyson on August 31, 2015 at 5:53pm

I remember someone saying that the brand of LiFePo battery is important--I think it was because one brand held a charge better or had more cranking amps or something. Then there was the fire issue . . .

Wayne

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Permalink Reply by Steven Ward on September 1, 2015 at 9:18am

John Austin has a lot of experience on the lithium batteries and several posts about it, here is one of them, I hope it helps.

 http://www.zenith.aero/forum/topics/caution-lifepo4-battery-capacity

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Permalink Reply by Henri Luyckx on September 1, 2015 at 2:22pm

In the beginning of this year in France a pilot crashed a Cri-Cri (very small twin engine ultralight) on landing. The plane burst into flames and the pilot died. The Cri-Cri was full electric. No fuel whatsoever. It was an experienced pilot and it is not shure if he made a bad landing (in a hurry) because the batteries where already on fire or they caught fire upon impact. Made me change my mind about installing LiFePo's. If professionals have problems with it (see the Boeing Dreamliner or The Solar Impulse} I' d stay with a good conventional battery.

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Permalink Reply by John Austin on September 1, 2015 at 7:10pm

Henri, you're conflating different battery chemistries!

There are several different types of lithium batteries! The Boeing battery fires were a lithium cobalt battery, I "think" the Cri-Cri had lithium polymer batteries, which can spontaneously combust!  The EarthX are LiFePO4 (lithium phosphate) batteries - the phosphate binds the oxygen and these batteries will NOT spontaneously combust. They will burn if exposed to fire, but that means you have a primary problem elsewhere!

John

N750A

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Permalink Reply by Wayne Tyson on September 1, 2015 at 8:18pm

Thanks, John. I can always count on you to dig out the crucial distinctions.

I take it that nothing better has come along since your last treatise on the LiFePO4 (EarthX) batteries. It seems too good to be true, but I believe! I just wanted to find out whether or not there's yet another even more improved technology on the horizon.

Wayne

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Permalink Reply by Larry Zepp on September 1, 2015 at 6:36pm

Hi Wayne, Great question. The brand and lithium battery management circuit board is very important. Jan at Viking Aircraft engines recommends EarthX. This brand does have a monitoring circuit board inside the case to manage charge and temperatures. This seems superior to Shoeri - which does not claim a battery management system and requires a special charger.

I am planning to use double EarthX batteries for my Viking powered Zodiac 650B. In Early Spring, I wasn't quite ready to purchase my two batteries for the airplane, but my 2 yr. old motorcycle battery was dead. I got an EarthX battery for my 650 Suzuki and what a difference! No more labored starting and dimming of the headlight at stops. The battery supplies so much available power to the starter and engine that it starts in 1/3 the time and effort - every time. This has continued all summer without any issue.

Now I am ready to order my two EarthX batteries for the plane and am very happy with how the motorcycle is running. Good Luck!

Larry Zepp, Zodiac 650 B, Fort Wayne, IN

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Permalink Reply by Wayne Tyson on September 1, 2015 at 8:24pm

Hi Larry--thanks for the input. I'm gonna put a tip jar in the hangar like John, and when I get enough to get the lead out, I plan to "go for it." I wish I had room for a couch.

Why do you need two Li's?

Wayne

750/2, San Diego CA

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Permalink Reply by David J. Beaulieu on September 2, 2015 at 8:23am

Short note on what I've gleaned from the engineer at EarthX during a few phone conversations.  Disclaimer -  not a battery or electrical engineer!

I have two 36C EarthX batteries for my planned dual battery install, the size and form factor were too hard to beat in my opinion.  The Battery Management System (BMS) on these (36C series) batteries has what may be a significant drawback for us who fly with powerplants and systems absolutely dependent on electrical power.  The BMS when presented with an overvoltage condition of approx 15.3 volts (dependent on a few variables) will shut down the battery - no voltage allowed in OR OUT!  The BMS will restore to normal function once the overvoltage is no longer present.  The 15.3 "trip" voltage of the BMS is lower than the "trip" voltage  (16.2 V) of my B&C overvoltage protection module (OVPM).  I can envision a situation in which I am possibly providing too high a voltage to the batteries from the Alt and R/R, but not enough to trip the B&C OVPM, the BMS shutting down my battery, and then having a interruption of electrical power (if or when I lose or have to take the Alt off-line) until the BMS restores my battery function.  The B&C OVPM is relatively fact acting to an overvoltage (10ths of milliseconds) - The BMS circuitry response time is highly variable. Monitoring voltage output allows one to preemptively take a failing alternator off-line, avoiding the BMS from doing it's thing, but that is subject to my instrumentation, scan and Mr. Murphy, and I am not familiar with typical failure characteristics of a PM type alternator and R/R, so I have unknowns I know about and unknowns that are unknown (tip of the hat to Mr. Cheney)

With all that said- I have elected to go with the newer EarthX 680 series batteries.  The BMS on these are designed to maintain output to the load under all conditions until the battery is essentially discharged.  Slightly pricier, still feasible to have two batteries (considering weight concerns), certainly a bit bigger, but maintains power to the load was the deciding factor for me!  As an aside, EarthX is giving me full credit for my unused batteries in exchange for the newer series batteries. 

I've discussed this on the Matronics board, but realize that some of these questions are not answerable outside controlled conditions in a lab with test equipment.  Despite things being "experimental" we can still do failure mode risk analysis to a certain degree and come up with solutions to minimize and/or negate the risk.  I'm thinking that is what I have done with my switch from the 36C to the 680 series battery.  Please chime in with any thoughts, ideas, general discussion.

Dave

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Permalink Reply by Wayne Tyson on September 2, 2015 at 1:51pm

". . . do failure mode risk analysis to a certain degree and come up with solutions to minimize and/or negate the risk."

This seems the very essence of "experimental."

I ain't no battery engineer neither, but do you mean that you wouldn't install two batteries in an engine with mags? (I have thought of getting a Li battery for backup power for use when the lead one goes down in the back country, despite that seeming to be backward and adding rather than subtracting weight, but money aside, it would seem that the better alternative would be two Li's. Comment?

Wayne

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