I flew the family from KVGT to KSNA yesterday, an uneventful trip except that on 10nm approach into John Wayne, the battery fault indicator lit on my instrument panel. The light was solid, not blinking, meaning that a hardware problem had occurred and could not be reset. I prioritized flying the airplane to a safe landing while I switched the Alternator off to avoid trying to push more charge into the battery with an unknown fault.
Once the dust settled and I had parked and unloaded the family into the air-conditioned comfort of the ACI Jet terminal, I set about troubleshooting. I took the rear cabin panel off and checked the condition of the battery itself. It was not hot, or smoking and there was no indication of any damage of any kind. With the Master switch on I checked the volts and amps and as expected the battery voltage had depleted slightly but otherwise everything was normal except with the fault warning light on.
I re-read the operator's manual for the EarthX and it was clear that there was a hardware fault detected and the battery would need to be replaced.
I then called EarthX and was put through to technical support (‘Reg’) who was very knowledgeable and said that the most likely cause they have seen with this issue is that one of the dual redundant internal disconnectors had thrown a fault and latched the warning. He said I should try and charge it, and if as he suspected it accepted a charge normally, I should not worry about flying it home as the cells have been operating perfectly normally and take months to deviate from this practice. By lucky coincidence I had purchased an Optimate TM-291 charger as recommended by EarthX a couple of days ago and had it with me so borrowed a generator from the FBO and plugged it in. The battery charged completely normally in about 20 mins to full charge, then held the charge, didn’t get warm or anything unusual. Throughout this process Reg was engaged, looking for possible replacements in stock nearby, looking at my photos of the charger and other indications. Once charged, we left the airplane while we went to explore Laguna Beach (the reason for the flight) then returned in the late afternoon. Sure enough the battery had held its charge as usual and the engine started first time. I flew the 1.5 hours home to Las Vegas with appropriate monitoring of the electrical system behavior with nothing amiss except the warning light on. When I shut down at home base, the battery volts indicated full ~13.4V as expected, and again the battery was cool with no smoke or any other problems.
Today, I went online to EarthX website as directed by Reg and filled out the online warranty form. He helped me find a couple of the parameters and pre-warned the warranty department to expect my submission. Within minutes I had an accepted warranty exchange and the replacement battery is shipping to me now. When it arrives I can then remove the old one and return it.
Overall this has INCREASED my confidence in the Lithium battery system from EarthX and I was very impressed with the attitude and knowledge of the technical support on hand when I called. It could have been much worse.
As an aside, I asked if there was any chance they were working on a venting system for the ETX680C model to provide added safety for cabin installations. He said no, there’s no room in that form factor, but that it would be possible for the regular size ETX680 (non-compact model). I told him I thought it would encourage more in the experimental community to make the leap to their batteries as the TSO’d ETX900-TSO is eye-wateringly more expensive but is the only option with a vent kit. He agreed - I guess we’ll have to wait and see what transpires…
Also a shout out to ACI-Jet at KSNA, they were awesome all day, supplying a comfortable lounge for the family with drinks and snacks, a generator and cables, waiving the usual fees ($60) for a 10gal fuel purchase. I thoroughly recommend them if you find yourself heading to Orange County.
Also the Optimate chargers are very nicely made and work well.
A long yearned for family day at the beach was not really impacted and we all arrived safely home for dinner. And I learned stuff :-)