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  #111  
Old 10-21-2017, 05:42 AM
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Default Kitplanes December 2017

There is a write up on EarthX in the December 2017 issue of Kitplanes
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  #112  
Old 10-21-2017, 03:15 PM
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Quote:
Originally Posted by Kalibr View Post
Seriously though, Kathy, thank you for clarifying the difference between EarthX and Shorai and similar batteries. That gives additional food for thought at least.
OTOH, a bunch of us are using Shorai batteries with no issues - i've got well over 700 hrs on mine. Opinions are worth what you pay for them of course, and mine is that the Shorais, mounted on forward side of the firewall and installed in conjunction with a crowbar OV and annunciation of out-of-spec voltage conditions provide an excellent alternative to the PC680 at a. enter price point than the EarthX. The value of the BMS is questionable.
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  #113  
Old 10-21-2017, 06:10 PM
Kalibr Kalibr is offline
 
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Brad, I hear you loud and clear and so far I am leaning towards a Shorai or similar battery. I think with crowbar OVP and voltage/amperage system monitoring, a non-BMS lithium is at least as safe as a battery with BMS. I would argue that a non-BMS battery may actually be safer than a battery with a BMS that disconnect it from the electrical system during moderate overvoltage event, but then fails when voltage reaches a higher threshold. I think it is quite possible that the BMS disconnecting the battery at the first sign of slight overvoltage triggers the death of the alternator/voltage regulator (load dump), which in turn results in runaway overvoltage, subsequent failure of the BMS and etc etc. I think Charlie was alluding to this earlier. This is all speculation, of course. And the scenario I just described is impossible with a crowbar OVP. However, my point is that the value of BMS might as well be questionable and may not be worth the "aviation" price premium.
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Last edited by Kalibr : 10-21-2017 at 06:12 PM.
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  #114  
Old 10-21-2017, 07:05 PM
maus92 maus92 is offline
 
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My understanding is that the BMS system on EarthX batteries does more that just OV protection between ~16 and <=60v. In my case, it alerted me to a cell imbalance, which was more or less inconsequential other than cancelling the flight and replacing the battery as a precaution. Maybe it prevented a AOG away from my home airport, or worse.
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  #115  
Old 10-21-2017, 07:20 PM
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Steve Melton Steve Melton is offline
 
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still running my old heavy Concorde battery. I never think about it.
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  #116  
Old 10-21-2017, 09:25 PM
Kalibr Kalibr is offline
 
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Quote:
Originally Posted by maus92 View Post
My understanding is that the BMS system on EarthX batteries does more that just OV protection between ~16 and <=60v. In my case, it alerted me to a cell imbalance, which was more or less inconsequential other than cancelling the flight and replacing the battery as a precaution. Maybe it prevented a AOG away from my home airport, or worse.
I thought the BMS is supposed to balance the cells...

From EarthX website list of features: "5- cell balancing technology built in"

I understand a charger is used to balance cells from time to time on lithium batteries, just like the desulfation function does for lead/acid batteries. I am not sure how big of a deal it is in any case.
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  #117  
Old 10-21-2017, 09:46 PM
maus92 maus92 is offline
 
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Originally Posted by Steve Melton View Post
still running my old heavy Concorde battery. I never think about it.
My heavy old Concorde battery holds the door in the hanger open, while doing double duty as a power supply....
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  #118  
Old Today, 12:23 PM
Kalibr Kalibr is offline
 
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I asked Shorai if they have a built-in BMS in their batteries. Here is a reply I got. This is just for completeness of information.

"The Shorai LFX batteries have an internal balancer that turns on if a cell exceeds 3.65V. At this time Shorai has elected not to use a low voltage cut out because our testing shows that the cells are very durable and can tolerate rare occurrences of over discharge as long as they are recovered with the Shorai BMS01 charger which provides battery diagnostics and more precise balancing. We have found that in too many real world situations the use of a full BMS design can prohibit battery use in critical times and create customer inconvenience. Our approach is to build a very good cell pak that can tolerate occasional abuse and permit full use of the batteries abilities."
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  #119  
Old Today, 03:00 PM
EarthX Lithium EarthX Lithium is online now
 
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Quote:
Originally Posted by Fearless View Post
There is a write up on EarthX in the December 2017 issue of Kitplanes
Kitplanes was kind enough to send me the .pdf of the article so if you want it, send me an email at sales@earthxbatteries.com and I can attach it for you.
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