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So my system still charges up when I fly around, but it seems like my voltage is dropping on the ground. Typically it has been going under 13V pretty quickly, and I notice the radio doesn't transmit as well as normal. My sidetone sounds scratchy when the voltage is down. I've also recently had a battery fault indication when doing some pattern work last weekend. Is my EarthX toast? I am mostly religious about putting it on the charger between flights, except when I'm going cross country. My voltage runs around 14.5 after an hour or so.

Were you able to decode the fault? One thing EarthX is terrible about it their fault light code. Rather than just having a code that refers to a number, it's something like- if it's flashing slowly for more than 5 min, and doesn't stop after 15 min...

When you say "charger", I assume you mean the special charger made for these batteries? Those should give you a health indication as well. I only rarely charge mine other than flying, and the only problem I ever had was on a different plane. That battery worked fine one day, then did absolutely nothing the next. It got replaced under warranty with no report of what had gone wrong with it.

Rusty,
I didn't realize they had fault codes. I'll have to read the manual. I have an Optimate charger - the recommended one. Battery comes back fine. I'm just worried about taxiing around at Airventure.

I don't need to charge mine unless I have been playing around with the avionics etc.
After startup I let the battery charge while at idle. Usually have 14.2 volts in four minutes. Oil is just getting warm. I've got a Revmaster and it's easy for the EarthX to draw more current than the alternator is able to safely sustain. This fries the coils. But that's another story.

Yes, read the manual. This ain't your granpa's lead acid type of power storage device.

So I replaced my battery with a new EarthX, same model. Then I replaced the VR as I was getting no charge. Now it is charging again, up to at least 13.8V after an hour. But about 5 minutes after takeoff, I got a slow steady flashing light. Voltage was around 13.4-13.6 initially. I think this is the relevant fault from the EarthX manual:


Has anyone else seen this? I'm going to contact EarthX and ask. The flashing light went away after about 20 minutes.

I could be wrong here (wouldn't be the first time) but it appears your charging voltage is too low for the battery. No idea which EarthX battery you have but from Aircraft Spruce site they show for the ETX680 the recommended Standard Charge Voltage is 13.9 - 14.6V with max at 15v.

https://www.aircraftspruce.com/catalog/ ... -13907.php

Odyssey & EarthX batteries both require a pretty high charge rate for longevity of the battery. My plane charges my Odyssey at 14.7 which is in the recommended range. Over long periods of time low states of charge will cause sulfation and destroy a battery.

Bryan Cotton wrote:I think this is the relevant fault from the EarthX manual:

Are you using the correct EarthX battery charger to maintain the battery between flights? It is required to balance the charge across all the cells. Charging only from the voltage regulator works, but you should also use the charger between flights to make sure each cell is getting the attention they need.

XenosN42 wrote:Are you using the correct EarthX battery charger to maintain the battery between flights?

Yep, as noted above. I plug it in after every flight except away from home.

Bryan Cotton wrote: I have an Optimate charger - the recommended one.

daleandee wrote:I could be wrong here (wouldn't be the first time) but it appears your charging voltage is too low for the battery.

I have an ETX680C. With the original voltage regulator we would get 14.6V after a while. The new Sonex replacement seems a bit lower. That's a concern as well. Although sitting on charge with the Optimate I'm reading 13.8V after a few hours.

I've never heard of any requirement, or even recommendation to use the special charger between flights. I probably haven't attached mine in over a year. It's probably not a bad idea to use it periodically, but it's certainly not needed between every flight.

13brv3 wrote:I've never heard of any requirement, or even recommendation to use the special charger between flights. I probably haven't attached mine in over a year. It's probably not a bad idea to use it periodically, but it's certainly not needed between every flight.

Agreed.
My aircraft lives on a non powered airfield. Boost charging is via a solar panel. In 18 months, I have only used the panel once, when I knew I would be working on the aircraft for many hours AND the sun was shining.