bdgriner
Posts: 5
Joined: Wed Feb 24, 2016 7:41 pm
Delivery Date: 31 Jan 2016
Leaf Number: 300675

Battery Percent Indicator

Sat Oct 07, 2017 9:17 am

I’ve been driving EVs for 5 years and had my most recent Leaf for 2. I understand the miles remaining is very inaccurate but suspect the percent remaing isn’t either. I rountinely Drive 75 miles a day to and from work and get the second low battery alarm and blank screen for miles or battery remaining. I have the 30KW Leaf and when I recharge, I get between 19 and 21KW on my charger. The question I have is why am I getting an alarm for 10% remaining when I should have 30% left? It’s one of the first 30KW models and wonder if something is not set right in the software? Anyone else seen this? Any suggestions?

cwerdna
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Joined: Fri Jun 03, 2011 4:31 pm
Delivery Date: 28 Jul 2013
Location: SF Bay Area, CA

Re: Battery Percent Indicator

Sat Oct 07, 2017 12:48 pm

bdgriner wrote:I’ve been driving EVs for 5 years and had my most recent Leaf for 2. I understand the miles remaining is very inaccurate but suspect the percent remaing isn’t either. I rountinely Drive 75 miles a day to and from work and get the second low battery alarm and blank screen for miles or battery remaining. I have the 30KW Leaf and when I recharge, I get between 19 and 21KW on my charger. The question I have is why am I getting an alarm for 10% remaining when I should have 30% left? It’s one of the first 30KW models and wonder if something is not set right in the software? Anyone else seen this? Any suggestions?

Battery capacity is measured in kWh not "KW". The amount of energy that comes out of your "charger" (likely an EVSE w/no charger because for level 1 and 2 AC charging, the charger is on-board the car) and "wall" is also measured in kWh.

I can't speak for the 30 kWh Leaf since I don't have 1, but on the '13 Leaf, as I stated at viewtopic.php?f=31&t=17895, LBW (1st warning) used to sound at ~17-18% and VLBW (2nd warning) at 7-8% per the car's dash display. Those values have gone up slightly as the battery has degraded (and I have a different '13 Leaf now). The gid values (you need something like Leaf Spy to see them) at viewtopic.php?p=387707#p387707 seem correct for 24 kWh Leafs. Can anyone chime in on what gid and dash display values they sound on 30 kWh Leafs?

What value on the dash display do LBW then VLBW sound at? How many capacity bars have you lost, if any? http://www.electricvehiclewiki.com/File ... bars_s.jpg is a 3 bar loser.

Also, not all the energy coming out of the wall makes it into the battery. And, not all 30 kWh are usable. Nissan leaves some portion at the top and bottom in accessible. IIRC, TonyWilliams has asserted 30 kWh Leaf has about 26.5 kWh usable, on a new battery. Don't know how accurate that is, but that's likely close.

Also, as the battery degrades, since it will have less capacity, if you charged from 0 to 100% on such a degraded battery, less energy will come out of the wall than vs. a new one.

If you really want to have a better idea of what's going on, you should get Leaf Spy. If you want to see why it can be useful, watch this 11 minute video at https://www.youtube.com/watch?v=cgE8lmySdMI. If the talking to too slow or repetitive, use the gear icon on PCs or Macs to increase the playback speed.

Background info on charger vs. EVSE at:
viewtopic.php?p=262630#p262630
http://www.sae.org/smartgrid/chargingprimer.pdf
http://www.sae.org/smartgrid/chargingspeeds.pdf
https://openev.freshdesk.com/support/so ... -sae-j1772

'13 blue Leaf SV w/premium package (owned)
'13 blue Leaf SV w/QC + LED & premium packages (lease over, car returned)
'06 Prius

bdgriner
Posts: 5
Joined: Wed Feb 24, 2016 7:41 pm
Delivery Date: 31 Jan 2016
Leaf Number: 300675

Re: Battery Percent Indicator

Sun Oct 08, 2017 8:25 am

Big thanks. This gives me the info i need to research further into the issue. I will provide an update in a few weeks with my findings.

johnlocke
Posts: 145
Joined: Fri Jan 08, 2016 3:47 pm
Delivery Date: 14 Dec 2015
Leaf Number: 300582

Re: Battery Percent Indicator

Sun Oct 08, 2017 11:06 am

On the 2016 Leaf the LBW warning is fixed at 50 GID's (About 4KWH remaining) VBLW is fixed as well at about half the value of LBW. As the battery loses capacity over time, the percentage where the LBW warning occurs rises. I've found that the percentage gauge seems to be reasonably accurate while the guess-o-meter becomes more accurate the closer you are empty. When new, my car hit LBW at 13%. Now with two bars gone, LBW hits at about 18%. Hope that helps.
Jamul, CA
San Diego East County

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Nubo
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Delivery Date: 31 Oct 2014
Location: Vallejo, CA

Re: Battery Percent Indicator

Sun Oct 08, 2017 1:52 pm

The goal is to protect against any cell going too low, which is bad for the cell. Or even worse, polarity reversal which is almost certain death for the cell and can escalate into a catastrophic failure of the entire pack, and dangerous consequences. It's the weakest cell-pair that drives the low battery warnings, if I'm not mistaken. So you cannot always expect the warnings to correlate with an exact watt-hours remaining in the pack.

With our 2012 I had long been practicing the 80% charge method, and then happened to do an extended drive. Once at LBW, the power remaining dropped very quickly and I was lucky to make it home. I chalked it up to a lack of cell-balancing. The next 100% charge spent a lot of time in balancing mode and I made it a practice after that to do a full 100% charge on a regular basis. I'm rambling, but it illustrates the nature of LBW as a low cell-pair voltage threshold rather than a stored-energy-remaining threshold. The two are related of course, but not necessarily proportionally.
I noticed you're still working with polymers.

cwerdna
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Re: Battery Percent Indicator

Sun Oct 08, 2017 3:24 pm

johnlocke wrote:On the 2016 Leaf the LBW warning is fixed at 50 GID's (About 4KWH remaining) VBLW is fixed as well at about half the value of LBW. As the battery loses capacity over time, the percentage where the LBW warning occurs rises. I've found that the percentage gauge seems to be reasonably accurate while the guess-o-meter becomes more accurate the closer you are empty. When new, my car hit LBW at 13%. Now with two bars gone, LBW hits at about 18%. Hope that helps.

Interesting, so the gid values where LBW and VLBW sound at for the 30 kWh Leaf are or are basically identical to that of 24 kWh Leafs.

'13 blue Leaf SV w/premium package (owned)
'13 blue Leaf SV w/QC + LED & premium packages (lease over, car returned)
'06 Prius

cwerdna
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Posts: 7091
Joined: Fri Jun 03, 2011 4:31 pm
Delivery Date: 28 Jul 2013
Location: SF Bay Area, CA

Re: Battery Percent Indicator

Sun Oct 08, 2017 3:25 pm

bdgriner wrote:Big thanks. This gives me the info i need to research further into the issue. I will provide an update in a few weeks with my findings.

Until you get Leaf Spy working, you can at least tell us how many capacity bars you've lost and what % SoC on the dash display are LBW and VLBW sounding at.

'13 blue Leaf SV w/premium package (owned)
'13 blue Leaf SV w/QC + LED & premium packages (lease over, car returned)
'06 Prius

bdgriner
Posts: 5
Joined: Wed Feb 24, 2016 7:41 pm
Delivery Date: 31 Jan 2016
Leaf Number: 300675

Re: Battery Percent Indicator

Mon Oct 09, 2017 3:13 pm

I haven’t lost any capacity bars on my display. I’ve been making the same drive since I bought the car new 19 months ago and ~90% of the time have the LBW (first alarm ) and depending on my driving style, traffic and temp if I get the VLBW (second alarm) (~50%). I’ve never questioned the overall charge until recently when I went back and looked over my ChargePoint history and see between 19 and 21 KWH recharges.

The LBW comes in at 15%. The VLBW you can’t tell %SOC since the reading is unavailable. The LBW warning message covers it up. It seems like the VLBW alarms at 9 miles left and then the miles remaining goes away. You have no readings then. Most miles I’ve driven with the VLBW is about 3 miles.

Im traveling this week so That’s why it’s taking a little while to get the info with Leaf Spy.

cwerdna
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Posts: 7091
Joined: Fri Jun 03, 2011 4:31 pm
Delivery Date: 28 Jul 2013
Location: SF Bay Area, CA

Re: Battery Percent Indicator

Mon Oct 09, 2017 3:17 pm

bdgriner wrote:The LBW comes in at 15%. The VLBW you can’t tell %SOC since the reading is unavailable. The LBW warning message covers it up.

What do you mean by that? You should be able to press 1 of the 4 buttons in the cluster of 4, probably the upper left, to clear it so that the % SoC screen is back up.

However, at some point, it's likely the numeric % SoC will change to - - - % (I've personally run into this and I've seen numerous folks post pictures of it). That's when you're flying really blind w/o a tool like Leaf Spy.
Last edited by cwerdna on Mon Oct 09, 2017 4:23 pm, edited 1 time in total.

'13 blue Leaf SV w/premium package (owned)
'13 blue Leaf SV w/QC + LED & premium packages (lease over, car returned)
'06 Prius

bdgriner
Posts: 5
Joined: Wed Feb 24, 2016 7:41 pm
Delivery Date: 31 Jan 2016
Leaf Number: 300675

Re: Battery Percent Indicator

Mon Oct 09, 2017 3:23 pm

I have never tried to clear the alarm will try it next week.

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