drbrake
Posts: 11
Joined: Thu Dec 05, 2019 6:13 pm
Delivery Date: 06 Dec 2019

How much "invisible" battery management does my Leaf do?

Wed Oct 21, 2020 6:41 am

I have been looking at battery university and it says https://batteryuniversity.com/learn/art ... arge_table, battery lasts longest when operating between 30 and 80 percent SoC. But I also remember reading somewhere that some vehicles don't actually use some of the battery at first in order to make them last longer. And of course the manufacturer might mis-label the state of charge (SoC) to protect owners from themselves..

So if my 2017 Leaf says my battery is at 10% is it really? Has the way Leaf battery management works changed in the last few years?

goldbrick
Posts: 1021
Joined: Tue Aug 01, 2017 3:33 pm
Delivery Date: 01 Aug 2017
Leaf Number: 311806
Location: Boulder, CO

Re: How much "invisible" battery management does my Leaf do?

Wed Oct 21, 2020 10:42 am

My $0.02 is that batteries are not like gas tanks. There really is no ambiguity when a gas tank is at 0% of 100% (empty or full). A battery is not like that. What is 100% SOC? Is it the point where the battery catches on fire or explodes? Ditto for 0% SOC.

Every manufacturer or design team has to determine their definition of 0% SOC and 100% SOC. At first glance, this is probably just a voltage level (average or min/max) of the individual cells, but the value may vary based on temperature, recent charge/discharge history, battery age, etc.

So yeah, there is some 'hidden' capacity at 0% SOC and 100% SOC in a Leaf but it's there for a good reason. In general, try to avoid the extremes at either end since that is where battery degradation is the fastest.

TL;DR, probably a few % at top and bottom but it's there for a good reason.

1byte
Posts: 11
Joined: Mon Oct 05, 2020 12:10 pm
Delivery Date: 01 Aug 2020
Leaf Number: 301105

Re: How much "invisible" battery management does my Leaf do?

Wed Oct 21, 2020 10:50 am

LeafSpy (to my understanding) shows a more correct and accurate SOC for your battery vs what the dash shows... The dash is not that far off though, at least not on my 2017 Leaf.

Some real world examples:
Dash LeafSpy
100% 97%
50% 50-49%
10% 13-14%
6% ~10%

Meaning I find the dash and Leafspy to be pretty close to one another around 50-60% SOC.

What's your SOH and/or how many capacity bars do you have left?

I'm at 77% SOH at 11 bars left. I'm expecting the 2nd bar to drop any day now.
2017 Leaf - 11bars - 40,000 miles
Central Texas - SOH=77% - Hx=50% - 61.9 AHr
427QC - 647 L1/L2

drbrake
Posts: 11
Joined: Thu Dec 05, 2019 6:13 pm
Delivery Date: 06 Dec 2019

Re: How much "invisible" battery management does my Leaf do?

Thu Oct 22, 2020 7:51 am

Not sure what you mean by SOH and I haven't installed LeafSpy. I have all my capacity bars so far!

estomax
Posts: 277
Joined: Fri Jan 20, 2017 9:23 pm
Delivery Date: 21 Jan 2017
Leaf Number: 424033
Location: Seattle

Re: How much "invisible" battery management does my Leaf do?

Thu Oct 22, 2020 7:55 am

SOH is state of health as the battery management system calculates it. It relates to the battery bars and you will have all 12 bars if you are above 85% SOH. After that it will drop a bar and then every 6.25% thereafter.

if you own a Leaf and are savvy at all you will want to get LeafSpy and an OBD2 dongle to use it with to see these values and many other parameters available. You can also read trouble codes if you ever have a problem with the car.

cheers
Marko
2013 Leaf SL Premium
27k, 93% SoH 2/17 32k, 96% SoH 6/17
46k, 94% SoH 2/18 52k, 88% SoH 6/18
62k, 87% SoH 2/19 68k, 84% SoH 6/19
75k, 83% SoH 2/20

LeftieBiker
Moderator
Posts: 15781
Joined: Wed May 22, 2013 3:17 am
Delivery Date: 30 Apr 2018
Location: Upstate New York, US

Re: How much "invisible" battery management does my Leaf do?

Thu Oct 22, 2020 11:10 am

Also, Battery University is more like Battery Grade School. A useful enough resource for newbies, but not extremely accurate or sophisticated when it comes to advanced battery strategies.
Scarlet Ember 2018 Leaf SL W/ Pro Pilot
2009 Vectrix VX-1 W/18 Leaf modules, & 3 EZIP E-bicycles.
BAFX OBDII Dongle
PLEASE don't PM me with Leaf questions. Just post in the topic that seems most appropriate.

drbrake
Posts: 11
Joined: Thu Dec 05, 2019 6:13 pm
Delivery Date: 06 Dec 2019

Re: How much "invisible" battery management does my Leaf do?

Thu Oct 22, 2020 11:27 am

Has anyone done a "Leaf University" guide specifically to help keep battery life and/or maximise range?

One thing I wondered about - does "B" make any difference to battery range or brake pad wear compared to "D" or is it just a matter of taste?

LeftieBiker
Moderator
Posts: 15781
Joined: Wed May 22, 2013 3:17 am
Delivery Date: 30 Apr 2018
Location: Upstate New York, US

Re: How much "invisible" battery management does my Leaf do?

Thu Oct 22, 2020 1:25 pm

The Cliff's Notes to EV battery life extension are:

* Don't let the battery sit above roughly 70% charge, or below 25% charge.

* Avoid charging the battery when it is hot.

* Especially, Do NOT leave the battery sitting fully charged for more than a couple of hours. Leaving an EV with a fully or nearly full battery for months does harm to the battery. We just leased a 2020 SV Plus that came off the lot with 2% of the capacity already lost, because it was kept fully charged.

B mode is helpful in lower speed driving in which you have to slow down frequently but not necessarily stop (If you have ePedal and have to stop & go a lot, use that) . It does no good in highway driving, except to increase regeneration on steep downhill sections.
Scarlet Ember 2018 Leaf SL W/ Pro Pilot
2009 Vectrix VX-1 W/18 Leaf modules, & 3 EZIP E-bicycles.
BAFX OBDII Dongle
PLEASE don't PM me with Leaf questions. Just post in the topic that seems most appropriate.

1byte
Posts: 11
Joined: Mon Oct 05, 2020 12:10 pm
Delivery Date: 01 Aug 2020
Leaf Number: 301105

Re: How much "invisible" battery management does my Leaf do?

Fri Oct 23, 2020 2:03 pm

drbrake wrote:
Thu Oct 22, 2020 11:27 am
One thing I wondered about - does "B" make any difference to battery range or brake pad wear compared to "D" or is it just a matter of taste?
Honestly, it comes down to personal taste. Sure there is some percentage better I'm sure, but probably not a whole heck of a lot.

I use "B" for in-town driving, especially for red lists and stop signs... You know you are going to have to come to a complete stop anyways so might as well put some juice back into the battery.

I use "D" for HWY driving and whenever using the cruse control. The car is less aggressive on downhill regenerative breaking when you've set the cruse and forget to take it off for the downhill stretches.

In short it doesn't harm anything driving in either mode... I had a Prius with 174K miles and still the original brake pads. "D" or "B" your brake pads are going to last a LONG time.
2017 Leaf - 11bars - 40,000 miles
Central Texas - SOH=77% - Hx=50% - 61.9 AHr
427QC - 647 L1/L2

salyavin
Posts: 203
Joined: Thu Sep 26, 2019 9:51 pm
Delivery Date: 30 Dec 2019
Leaf Number: 318726
Location: Littleton , CO

Re: How much "invisible" battery management does my Leaf do?

Fri Oct 23, 2020 4:15 pm

B mode in a Prius is a very different thing though, I think of it like engine breaking I used it going down mountains.

2% loss on a 2020 surprises me!!

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