Possible EarthX ETX-900 failure at only two years?

[Neal]

It's a little early to tell but my EarthX ETX-900 ordered on 1/1/2024 from Aircraft Spruce may be failing. I had a weak start yesterday and on the second try it turned over and started. I flew a 1.1 and the amps remained higher than normal around 14 and then down to 11 as expected the starter battery has been sitting for a while.

I can't remember the starting voltage today but nothing got my attention and now with the ETX-104 backup ignition battery the two gauges mirror one another in values. Today another weak start, same as yesterday. Prop didn't turn-over on first attempt, good start on second attempt. OAT 60F today in VA. Flew a 1.1 and amps stabilized down to about +4 which is around normal for the battery being charged.

After landing I turned on MASTER and the starter battery showed 13.1, the ignition backup 13.9 I believe it was. Starter was definitely lower and seemingly abnormal. I raised the seat and checked for a fault light on the battery, no light.

I checked the @earthxbatteries warranty and it shows 2 years, yaye, I'm at 2 years and one month I would expect LiFePO4 batteries to last 5+ years.

It's on the charger now so we'll see what happens and if I can get a good charge but I think this battery may be end of life sadly, prematurely as well.

 

[Neal]

I went to the plane today and the Optimate charger which has been on for about 20 hours showed green. The voltage was only showing around 13.1 to 13.3, can't remember, I expected 13.6 to 13.7 for a charged starter battery. I decided to put a load on it using only pitot heat and it dropped the voltage quite a bit to only recover to maybe 13.0. I did not try to crank the engine, not flying as we have high winds with a front coming through but wish I would have as I'm curious.

I called EarthX while at the hangar and explained the last two flights where the battery would not turn over the prop on the first attempt which is not normal as it's always been a solid start and never seemed stressed. It wasn't cold out these days, around 35F the first day, 60F the next day. Both days had the same behavior. I told him I was 2 years and 1 month from the purchase, one month outside of warranty. He was super nice about it and said they're not going to worry about the month and a new battery is being shipped today and said no need to return the old one. Way nice! Excellent customer service.

In order to warranty replace the battery he needed the code on the back side of the negative terminal, mine was "J23" which I did not record. So I had to pull the battery, never fun in these planes, but wasn't that bad and got him the info he needed.

I'm not sure the best procedure for a long lasting starter battery. I would expect 5-10 years on a LiFePO4 battery. I rarely put mine on the charger as I haven't needed to. It always started strong and the duration of the flight had it fully charged. I do realize cell balancing is very important with LiFePO4 batteries and I would hope and assume the flight duration would bring the battery to 100% which is needed for cell balancing but we have nothing that tells us state of charge (%) in our planes like I have in my RV. I may move to using a charger more frequently in the future for this purpose of cell balancing.

We just had the major discussion(s) about the importance of the ignition backup battery such as I just completed my ETX-104 mod. Another reason I cannot trust this current ETX-900 is it is the primary backup for an alternator failure and I'm not going to trust a weak starter battery that is not behaving as it has the prior two years of use. Even if I had to buy another, $460 is nothing every two years if needed for a trustworthy battery. Knowing I would be facing replacing this battery I did look at the 680 vs 900 and cannot pass up more amp hours so I'll be sticking with the 900 series.

Thank you EarthX for the excellent customer service and warranty support!

Side note: I asked if they were going to continue to produce the ETX-104 that I just installed for my ignition backup as I wonder what I'll do when that needs to be replaced. While nothing is firm it sounds like it is the end of the road for the ETX-104 as the EBBS is their new solution. So I hope those pursuing better solutions for the PowerSonic ignition backup battery from the factory continue to come up with a better solution that people can adopt.