EBAT FL

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pchristie
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EBAT FL

Post by pchristie »

I have recently taken ownership of a Liberty XL2 powered by a Teledyne Continental IOF-240-b. I made an initial uneventful 50 minute general handling flight out of Old Sarum (EGLS) but the following day the EBAT FL annunciator remained illuminated after engine start. Furthermore, during the run up check switching off FADEC A caused the engine to quit indicating that there is a real fault in the SPSC. I have since replaced the emergency battery with a like type, fully charged Camdenboss BEG120120 but this has not resolved the problem. More worrying is that on the initial engine start after the battery replacement the EBAT FL annunciator remained extinguished but the engine still quit when FADEC A was switched off. I am seeking professional qualified help to get this problem sorted.

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paulmilo
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Re: EBAT FL

Post by paulmilo »

Does not sound great and I’m not really qualified to assist unfortunately, but obviously an electrical gremlin there somewhere.

If your #2 battery was suspect, not a big deal, but sounds like main power is not getting to the FADEC and it’s running on battery #2, but if that was the case, you are also supposed to get a HSA annunciation. Strange. Main battery ok? Was it being charged in flight. 14.1-14.2V is typical on the VM1000 in flight or even just after start. Mine typically has a resting voltage of about 11.9-12 depending and then goes to 14.2 after engine start.

I assume FADEC checks pre flight #1 were OK? If so, this has obviously manifested itself in flight. I’d hate to think that main power to the FADEC has failed and you have not got a HSA warning. If you go onto secondary power and did not know, the first indicator you might get is an engine failure after about 1hr which sounds like where you may have been on flight#1. If one of the FADEC’s have failed, I am not certain what you get warning wise tbh, but caution or more likely warning on the HSA would be a good start. I’m going to look that up now!

In any case, if I could be selfish and ask you a question. Did you notice any difference in starting between the flights, pre and post fitment of the new battery in particular? I’m having some hard starting issues which I suspect is being caused by the secondary battery not holding a good charge, but not certain. I have no power in my hanger and it’s 1.5hr round trip, so even just trickle charging the secondary battery is problematic. I’m hoping to hear flight 1 was a good start, flight/start # 2 was a hard(er) start with depleted battery, start #3 with a new battery was a good start also...or something like that.

Good luck solving your issue though, hopefully something small like a fuse/CB...but given its aviation, it will be something more expensive no doubt :-(
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Milo VH-KXY
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pchristie
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Re: EBAT FL

Post by pchristie »

Just to be clear paulmilo, the second flight did NOT take place, after the failed run-up checks I taxied back to the stand!!

I'm now seeking an engineer familiar with the IOF-240 and equipped with the appropriate test gear to take a look.

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paulmilo
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Re: EBAT FL

Post by paulmilo »

No understood, I would have done the same. I was just interested in whether the aux battery replacement improved the start.

That said, in my case I just went out and purchased a new aux battery as It was almost due anyway and it made starting much easier.

Good luck getting to the bottom of your issue though. Sorry I could not be more help. I’ve had electronic gremlins on bikes, most frustrating to fault find at times.

Cheers,
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Milo VH-KXY
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N645XL
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Re: EBAT FL

Post by N645XL »

I’m experiencing the same EBAT issue. Did you get a resolution you can share?

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paulmilo
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Re: EBAT FL

Post by paulmilo »

Is yours just the EBAT or is it cutting out on one FADEC as well?

If its just the battery light, my issue resolved with the new aux battery. Starting also improved. In fact, I am thinking about trickle charging just the aux battery as main battery spins the crank easily but it would not start, so the issue was getting elec power for the ignition from the aux battery I assume.

Good luck
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Milo VH-KXY
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Re: EBAT FL

Post by N645XL »

EBAT light only. When I flipped FADEC A off the engine died. I charged last year’s battery and installed it but the issue remains similar to the issue leading this topic.

Pchristie: I too experienced an engine shutdown when FADEC A was cycled and there was no EBAT caution light.

Addendum: I contacted Joe T last evening about the issue. Joe was Liberty’s A&P/IA extraordinaire for many years. He’s directing me to the EBAT fuse (10 amp slow blow). It’s mounted on the aft fuselage hull next to the battery. Apparently they are known for partial failure after hard starts. The partial fuse failure will give an EBAT caution. I’m posting this suggestion now in case I forget later. I’ll replace the fuse soon and hopefully remember to update this post with results.

Addendum #2: It wasn't the fuse. It appears to be an intermittent relay contact. I need to research the schematics but the path from the alternator that recharges the EBAT appears to be the issue. Based on the reaction when I'd cycle the Alt switch I suspect whatever relay is in the circuit. Unfortunately or fortunately with all the Alt switch cycling the issue disappeared. Now that it's working it may be more difficult to diagnose conclusively.

The Standby Power Source Circuit (SPSC) breaker feeds the HSA box which provides the EBAT charging current. I suspect our unseasonably cold temps (as low as 7 degrees F) May have played a roll in this issue. Unless it recurs it will be hard to diagnose. The XL2 is being loyal to its warm FL upbringing.

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Re: EBAT FL

Post by Bigphoto »

Just my two cents so that I understand better...I was told and what I thought I comprehended in my readings that the alternator itself does not charge the standby battery at all or provide anything to the standby battery? One of the reasons that 60 mins is the max (providing the standby battery is fully charged). The main battery provides the HSA box which provides the charging current for the standby battery. Am I wrong in my thinking?

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Re: EBAT FL

Post by N645XL »

AFM Section 7 page 7 is about the most comprehensive description Liberty provided of the EBAT charging system and it isn’t much:

"During normal electrical system operation the secondary battery is continually recharged by the airplane primary electrical system via the SPSC (Standby Power Source Circuit) circuit breaker."

I haven’t looked in the Continental documentation that Liberty provided at the purchase. There could be more FADEC detail buried in there. So my memory tells me the SPSC circuit breaker is tied to the main buss (battery and alternator fed). The SPSC circuit feeds the HSA box which provides the isolation between the primary and emergency busses.

22 Dec 2019 Addendum: We had a nice day today with temps in the mid-40's (F). I also put a small heater on the pilot side floor under the instrument panel. Everything worked after the cockpit preheat!

A symptom of the malfunction was having everything turned off, if I flipped up the FADEC B switch nothing came up. Today with preheat when I engaged FADEC B the HSA caution and warning lights illuminated and my backup attitude indicator came alive. I can only guess some condensation froze on something and caused the issue. I will now add cockpit preheat (the instrument panel) along with the engine preheat to the cold weather checklist. A side benefit of a warm cockpit is the memory foam cushions are soft. Cold they're like sitting on a concrete bench.

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