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What does the Hx percentage mean?

Posted: Sun Apr 05, 2015 10:19 pm
by Henchman
I did my first leaf spy scan today on a full charge on my used 2011 Leaf.
These are the results:

225 GIDs
89.1%
SOC 93.7%
17.4kwh Remain
AHr 53.40
SOH=81%
392.46V
HX= 64.82%
Odo= 19,133 mi

What does this mean in regards to the health of my battery?

Re: What does the Hx percentage mean?

Posted: Sat Apr 11, 2015 8:58 am
by jpadc
I'm surprised one of the more experienced members have not chimed in on this, but those numbers seem from what I've read here pretty typical (maybe a little low) for the age and miles. If you do a search on the forum you will find lots of threads on this.

Here is just one recent one that had a little better numbers with some details about your intended use to know how it will do for you

viewtopic.php?f=23&t=18778

Re: What does the Hx percentage mean?

Posted: Sat Apr 11, 2015 9:11 am
by Henchman
My Hx has already dropped down to 61.44% at 19.5 k miles.

Re: What does the Hx percentage mean?

Posted: Sat Apr 11, 2015 11:03 am
by RegGuheert
Henchman wrote:I did my first leaf spy scan today on a full charge on my used 2011 Leaf.
These are the results:

225 GIDs
89.1%
SOC 93.7%
17.4kwh Remain
AHr 53.40
SOH=81%
392.46V
HX= 64.82%
Odo= 19,133 mi

What does this mean in regards to the health of my battery?
After the P3227 update, Hx is very close to SOH^2 on our LEAF:

Image

Re: What does the Hx percentage mean?

Posted: Sun Apr 12, 2015 4:15 pm
by Henchman
My HX is now down to 58%

Re: What does the Hx percentage mean?

Posted: Tue Mar 22, 2016 3:05 pm
by yujungchang
Wonder if that could be Heat eXposure?

Re: What does the Hx percentage mean?

Posted: Tue Mar 22, 2016 6:15 pm
by cwerdna
yujungchang wrote:Wonder if that could be Heat eXposure?

From a copy paste of the manual the author mailed me:
Hx The meaning of this number is not fully understood but it appears to be inversely related to the battery internal resistance. As the internal resistance of the battery pack increases it is thought this percentage decreases. As internal resistance increases more energy is lost within the pack and the pack heats up more under load.

This passage is the same as what's in the app's own help.

Re: What does the Hx percentage mean?

Posted: Sat Jun 16, 2018 1:00 am
by Tsiah
cwerdna wrote:From a copy paste of the manual the author mailed me:
Hx The meaning of this number is not fully understood but it appears to be inversely related to the battery internal resistance. As the internal resistance of the battery pack increases it is thought this percentage decreases. As internal resistance increases more energy is lost within the pack and the pack heats up more under load.

This passage is the same as what's in the app's own help.

Excellent! Thank you!

Re: What does the Hx percentage mean?

Posted: Sat Jun 16, 2018 1:34 am
by cwerdna
^^^
Also, see some pointers to historical posts about SOH and Hx at viewtopic.php?p=516611#p516611.

If I read it right, Leaf Spy apparently used to show an old health value (Hlth) but that got renamed to Hx. The more newly discovered health value became SOH.

Re: What does the Hx percentage mean?

Posted: Sat Jun 16, 2018 2:45 am
by LeftieBiker
It's been my theory that Hx - at least before the 40kwh pack - represents a momentary "snapshot" of the same value that SOH represents, with the SOH being a longer term average. Maybe, maybe not. The Hx number for the 40kwh pack seems more disconnected from the SOH, at least while the packs are new.