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  #11  
Old 03-04-2022, 10:54 AM
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jliltd jliltd is offline
 
Join Date: Sep 2013
Location: Rancho San Lorenzo
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I left the master on by mistake with my 3 year old EarthX and it discharged it down to zero. Now when fully charged with the LiPo4 specified charger I keep it on as a tender it has the same trouble at start getting past first compression stroke. I guess I whacked it when I left the master on for a few days. I am installing an anti-brain fart reminder light in an effort to mitigate future embarrassment. So I think a fully discharge event on the EarthX might be a death knell.
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  #12  
Old 03-04-2022, 11:17 AM
wawrzynskivp wawrzynskivp is offline
 
Join Date: Feb 2018
Location: Incline Village Nv
Posts: 333
Default Battery Monitoring System BMS

Jim,

Did your battery have a BMS? My understanding is that that system will prevent damaging discharges (if working properly).

I bring that up because our engine compartments can very easily overheat the Earth-X. Stick on temperature tell-tales will go on my next battery for sure.
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  #13  
Old 03-04-2022, 03:29 PM
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airguy airguy is offline
 
Join Date: Oct 2006
Location: Garden City, Tx
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I'm in the middle of my annual this year, and with a 4-year old ETX900 I wanted to know how long it would last without an alternator in the air. 3 times in the history of this battery it has been run down flat to the point where the BMS took it offline and I had to charge it back to health.

My airplane is electron dependent for both engine power and nav, so I have dual alternators - what I was curious about was what would I have left in the event I had a legit double alternator failure while airborne. In that case I can loadshed down to just the critical components to keep the engine running, which would draw 9 amps. I have a backup Dynon Skyview battery that's good for 45 minutes minimum for the EFIS. I set up the panel today to simulate that 9 amp draw with a combination of instruments (no running engine) and started a timer. Beginning voltage was 13.2, at 45 minutes the voltage was 12.9. I increased the current load to 12 amps, and 20 minutes later the voltage was 12.6 and I got the first alarm from the BMS system (5-sec on/off flash). I discontinued the test at that 1:05 point.

So that's one datapoint - a 4 year old ETX900 that has been drained flat on it's face 3 times, still has a solid 10 amp-hours reserve capacity, at a minimum.

For my purposes, it means I can lose the primary alternator and continue on the backup, then lose it, and have a reliable 45 minutes of full EFIS capability to find a good place to get down, plus at least another 20 minutes with an EFIS that could give up any moment. That's sufficient for my personal risk aversion model.

EDIT - my battery is installed aft of the baggage compartment, not exposed to heat.
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Last edited by airguy : 03-04-2022 at 03:59 PM.
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  #14  
Old 03-04-2022, 06:59 PM
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jliltd jliltd is offline
 
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Quote:
Originally Posted by wawrzynskivp View Post
Jim,

Did your battery have a BMS? My understanding is that that system will prevent damaging discharges (if working properly).

I bring that up because our engine compartments can very easily overheat the Earth-X. Stick on temperature tell-tales will go on my next battery for sure.
1.) All EarthX batteries have a BMS. It is built into the battery itself. So the answer is yes. In my case the BMS alert wire it is connected to a discrete G3X system GEA 24 input to flash a "EarthX Battery" warning message on the flight deck screen. It hasn't ever tripped since set up and testing, at which time it was working properly.

2.) My battery is behind the baggage bulkhead in the back of the fuselage. It is the vented EXT900-VNT model.
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  #15  
Old 03-05-2022, 06:17 AM
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olyolson olyolson is offline
 
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Default EarthX Battery charger

Quote:
Originally Posted by RV6_flyer View Post
Is there a battery tester like the one I use on my AGM battery that can test the health of the Earth-X battery?

The battery tester I have allows one to test different types of batteries but LiFePO4 batteries are not one of the types listed in the menu.
Gary,

EarthX has a battery charger/maintainer/power supply specifically for the EarthX batteries. Looks like you could leave it plugged in continuously.

https://earthxbatteries.com/shop/opt...attery-charger
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Last edited by olyolson : 03-05-2022 at 06:20 AM.
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  #16  
Old 03-05-2022, 02:14 PM
clam clam is offline
 
Join Date: Oct 2005
Location: Lakeland, TN
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Default already on there

Quote:
Originally Posted by jliltd View Post
I left the master on by mistake with my 3 year old EarthX and it discharged it down to zero. Now when fully charged with the LiPo4 specified charger I keep it on as a tender it has the same trouble at start getting past first compression stroke. I guess I whacked it when I left the master https://www.theblaze.com/news/actors...aking%20Newson for a few days. I am installing an anti-brain fart reminder light in an effort to mitigate future embarrassment. So I think a fully discharge event on the EarthX might be a death knell.
Leave your nav lights on. They make a great “already installed” indicator light.
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  #17  
Old 03-05-2022, 06:40 PM
David Z David Z is offline
 
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Location: Thunder Bay Ontario
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That's been my go-to. Also a great external reminder and prevents the walk across the apron to go check. Can look at the plane from across the apron and see the nav lights are on/off to answer the question. Quick double check before closing the hangar door. Easy to see from a distance.
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  #18  
Old 03-05-2022, 06:54 PM
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RV6_flyer RV6_flyer is offline
 
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Quote:
Originally Posted by olyolson View Post
Gary,

EarthX has a battery charger/maintainer/power supply specifically for the EarthX batteries. Looks like you could leave it plugged in continuously.

https://earthxbatteries.com/shop/opt...attery-charger
Oly:

The link I posted will give SOH and SOC of lead acid batteries without discharging the battery. Would be nice if something was available for other chemistry batteries.
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  #19  
Old 03-05-2022, 07:13 PM
CamTom12 CamTom12 is offline
 
Join Date: Jul 2016
Location: Newport News, VA
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Default

Quote:
Originally Posted by jliltd View Post
I left the master on by mistake with my 3 year old EarthX and it discharged it down to zero. Now when fully charged with the LiPo4 specified charger I keep it on as a tender it has the same trouble at start getting past first compression stroke. I guess I whacked it when I left the master on for a few days. I am installing an anti-brain fart reminder light in an effort to mitigate future embarrassment. So I think a fully discharge event on the EarthX might be a death knell.
I did the same thing - now I just leave my strobes on all the time. When I walk away if the strobes are on then so is my master.
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  #20  
Old 03-06-2022, 12:01 AM
crabandy crabandy is offline
 
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Quote:
Originally Posted by CamTom12 View Post
I did the same thing - now I just leave my strobes on all the time. When I walk away if the strobes are on then so is my master.
Thread drift but I’m guessing the lights are still on a switch like the master, I suppose you could wire the lights to the master switch.
I developed a habit of checking the 4 M’s (Music/Mixture/Master/Mags) before shutting the door/canopy when exiting.
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