TimLee
Posts: 2810
Joined: Thu Jan 20, 2011 9:40 am
Delivery Date: 17 May 2011
Leaf Number: 2026
Location: Chattanooga, TN

Re: 12v Battery

Fri Oct 14, 2016 12:38 pm

arnis wrote:... Also it appears that with any cycle (plugging in or putting car in Ready) it first goes to 14.x mode and (I expect) when
amps fall too much (or voltage gets too high) it switches to 13.x mode. And that is perfectly normal.
This can also be tested by draining 12V battery and then cycling the controller.

... Nissan, most likely, tries to keep 12V not boiling. They, most likely, failed with standby
consumption. My vehicle is fine after a week of doing nothing. ...

Mostly correct.
Where Nissan messed up was on standby power use for some people.

They do not appear to ever do what an inexpensive battery maintainer does.

Most of what they do is all based on current that has been measured coming out of the battery.

When LEAF is OFF they see nothing so they miss standby losses.

Tim Lee
Chattanooga, TN

Man. Date: 03/10/11, VIN # 2026
Delivered 05-17-2011
Blue Ocean, 2011 SL-eTec

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Stanton
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Posts: 1945
Joined: Thu Feb 03, 2011 10:56 am
Delivery Date: 01 Sep 2011
Leaf Number: 7458
Location: Plano, TX
Contact: Website Twitter

Re: 12v Battery

Fri Oct 14, 2016 3:11 pm

arnis wrote:And most important for convenience: LeafSpy 12V reading is DEAD-ON. It does lag for a second or two but it
keeps numbers very close (max 0.05V difference). Anything less than 0.1V is marginal.
Now the last thing is to measure draw during sleep.


This is true for LeafDD as well.
FWIW, 13.1v is great for charging my LiFePO4 battery, not to mention the cells absolutely can't see > 14.4v (which never happens in the Leaf). Even better, Lithium batteries tend to be fine sitting at 50%-80% charge (no such thing as sulfation).
Last edited by Stanton on Sat Oct 15, 2016 8:00 am, edited 1 time in total.
2011 Blue Ocean SV w/floor mats & window tint
12v LiFePO4 battery & FIAMM 74100 horns
Wet Okole seat covers (front)
Tor's low-power heater mod
2013 sun visor
3G modem upgrade
L2 EVSE Upgrade
Battery Pack replaced (Rev E) @51 months and 41k miles

RockyNv
Posts: 204
Joined: Mon Sep 19, 2016 10:35 am
Delivery Date: 17 Sep 2016

Re: 12v Battery

Fri Oct 14, 2016 8:45 pm

Marktm wrote:
powersurge wrote:I have been with cars for many years, and have never heard so much arguing over a darn 12 volt battery!! Let's get realistic...


powersurge - you think "on and on" discussions on this forum are excessive? - go to the off-grid solar forums for real excessive!! HOWEVER, battery/capacitance technology (IMO) is one of the important factors in our future success with our conversion to "renewable" based grid (and off-grid) energy supply.

I do agree, the 12 volt battery has literally been "beat to death" with good/bad information, but the more good information, the less dead lead goes to recycle.


The lead battery industry uses very little new lead from what I understand and unlike the other technologies it is more easily recycled into new batteries without the need for financial subsidies from the government. When a lead battery gets replaced and turned in just about everything in it gets reused including the plastic in the case and lead so that along with how cost effective it is to do so make lead batteries with an effective recycling program quite an environmentally and economically sound choice.

https://www.youtube.com/watch?v=adk4V24Es3g
https://www.youtube.com/watch?v=oJj5iIwF8p4

arnis
Posts: 743
Joined: Sat Jan 23, 2016 3:21 pm
Delivery Date: 23 Jul 2014
Leaf Number: 015896
Location: Estonia, Europe

Re: 12v Battery

Sat Oct 15, 2016 5:21 am

New observations.
Leaf falls asleep a minute-two after last input. Without OBD adapter it consumes less than 0,3amps, somewhere around 0,15-0,2A. This includes my mandatory aftermarket siren crap.
WITH obd adapter it consumes around 0,4A and if it detects BT device (Leafspy) consumtion jumps to 0,8Amps.
Therefore OBD is big NONO to keep plugged in.

Also I noticed 14,48V reading while L2 charging today. That must have continued for an hour at least. Went for a drive and voltage dropped to 13,06V few minutes after takeoff.

Was able to make a 20A load with head and taillights (incl fogs). I'll try to discharge 12V for half an hour at off state. And take a drive shortly after.
Short range EVs <30kWh -- Medium range: 30-60kWh -- Long range: >60kWh
Charging: Trickle <3kW -- Normal 3-22kW -- Fast 50-100kW -- Supercharging >100kW

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RegGuheert
Posts: 5585
Joined: Mon Mar 19, 2012 4:12 am
Delivery Date: 16 Mar 2012
Leaf Number: 5926
Location: Northern VA

Re: 12v Battery

Sat Oct 15, 2016 7:17 am

arnis wrote:Therefore OBD is big NONO to keep plugged in.
Agreed. The LEAF with an ELM327 plugged in is MUCH worse on the battery than without it. I used to keep mine plugged in, but now I instead unplug it when I get out. That's harder on the OBDII connector, but better for the battery.
arnis wrote:Also I noticed 14,48V reading while L2 charging today. That must have continued for an hour at least. Went for a drive and voltage dropped to 13,06V few minutes after takeoff.
Yes, that's the 12V charging that I mentioned that occurs during Li-ion charging sometimes. It seems to do this every time in very cold weather (below about 20F), but I have not found the pattern for other conditions (partly because I just don't look for it). FWIW, mine stopped charging the 12V battery after less than one minute today when I charged the car.

I think Nissan would do much better if they set a MINIMUM time to charge at 14.5V of 30 minutes or some such to handle the cases which they currently do not address properly.
arnis wrote:Was able to make a 20A load with head and taillights (incl fogs). I'll try to discharge 12V for half an hour at off state. And take a drive shortly after.
I won't be too surprised surprised if it restores the lost charge fairly well, since it can meter such high currents. The issue is that the measurement resolution in the LEAF is only 1A, so it cannot tell what goes on when the car is off and the current draw is very low, as TimLee has mentioned:
TimLee wrote:Where Nissan messed up was on standby power use for some people.

They do not appear to ever do what an inexpensive battery maintainer does.

Most of what they do is all based on current that has been measured coming out of the battery.

When LEAF is OFF they see nothing so they miss standby losses.
This is clearly seen in the plot I linked to previously:

Image

Note that following the charge by the external Battery Tender at midnight at the end of April 5, 2015, the resting voltage on the AGM is 13.25V. (Note that the charger was unplugged at about 4:00 AM, along with a door to the LEAF being opened. This resulted in an additional load on the battery until the LEAF went back to sleep, followed by a RISE in voltage back to above 13.2V.) Then when the LEAF is plugged in to charge on the morning of April 6, 2015, the LEAF briefly spikes up to 14.35V and then DISCHARGES the battery down to 13.10V. Then following that event, you can see that all of the activity of the LEAF does ABSOLUTELY NOTHING to increase the SOC on the battery. That is why the overall shape of the curve is simply an exponential decline (which is due to whatever standby load there is on the 12V from the LEAF). Simply put, the brief 14.5V spikes and the float voltage of 13.1V did not increase the SOC of the battery in the least. That algorithm WILL keep the battery charged to about 60% SOC (resting voltage of about 12.3V), which is the recipe for sulfation. Of course those who use the windshield wipers frequently will see better results.
RegGuheert
2011 Leaf SL Demo vehicle
2011 miles at purchase. 10K miles on Apr 14, 2013. 20K miles (55.7Ah) on Aug 7, 2014, 30K miles (52.0Ah) on Dec 30, 2015, 40K miles (49.8Ah) on Feb 8, 2017.
Enphase Inverter Measured MTBF: M190, M215, M250, S280

arnis
Posts: 743
Joined: Sat Jan 23, 2016 3:21 pm
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Leaf Number: 015896
Location: Estonia, Europe

Re: 12v Battery

Sat Oct 15, 2016 9:33 am

My battery tends to be at resting voltage above 12.5V (technically this is not OCV voltage as there is a 0.8A drain during leafspy readout)
I've never charged it myself during 28 months of use. I'll try to get a reading after 24h resting period.

According to dozen pictures searched in google, 12.5-12.6V is way above 80% threshold, except Excide sheet.
Same with my BMW. It rests somewhere around that same voltage, though it has 100Ah battery.

Logic is simple. Leaf should have a drain something like 0,1A. Maximum discharge should be something like 2,4Ah per 24h.
This is more-or-less 5% of total capacity. Battery is almost never drained, only charged at 14.5V and 13.1V (yes, this is a charge voltage if
OCV is below that). As Leaf doesn't crank the engine, it doesn't discharge at all. Except vampire drain.


Tech sheets for BMW-s mention that normal sleep mode draw should be below 50mA for all models. If current above 80mA is registered a fault is registered and user is notified "battery discharging while stopped".
If battery management module registers battery SOC below 60% yellow "PLEASE CHARGE" notification will be shown on the cluster, often happens with vehicles left parked for a month. Below 35% red battery malfunction will be shown.
Current sensor is always active and always counting (it is directly powered by the battery right on the terminal) and it has internal memory.
BMW-s are even programmed to kill comfort access and clock settings in the name of saving the last drop of juice for engine start. This happens about a month/two after falling asleep.
Leaf unfortunately has telematics always awake. Though it is not an excuse as it has many kWh-s in traction battery.

Excide also recommends their batteries to be recharged if they drop below 60% - 12.5V OCV voltage for all types.
If BMW and Exide both are at 60% I believe sulfation happens with anything below that.
According to the graph you showed voltage is above 12.5V the whole time. Also, is it made by OBD adapter? If so then we know
why discharge is so rapid.

Is it popular to have aftermarket siren installed in US? Leased Leafs. Do they have it?
Short range EVs <30kWh -- Medium range: 30-60kWh -- Long range: >60kWh
Charging: Trickle <3kW -- Normal 3-22kW -- Fast 50-100kW -- Supercharging >100kW

TimLee
Posts: 2810
Joined: Thu Jan 20, 2011 9:40 am
Delivery Date: 17 May 2011
Leaf Number: 2026
Location: Chattanooga, TN

Re: 12v Battery

Sat Oct 15, 2016 10:18 am

arnis wrote:...
Is it popular to have aftermarket siren installed in US? Leased Leafs. Do they have it?

No.
No.

What has been common is having OBDII adapter hooked up.
Some like Reg unplug it.

I just leave it plugged in.
But I hook up 12V battery maintainer each time.

Probably once or twice a month would be sufficient.
But I don't drive a lot, maybe five times a month.
So mostly my 12V sits in garage on battery maintainer.

Tim Lee
Chattanooga, TN

Man. Date: 03/10/11, VIN # 2026
Delivered 05-17-2011
Blue Ocean, 2011 SL-eTec

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JimSouCal
Posts: 860
Joined: Tue Feb 08, 2011 12:54 pm

Re: 12v Battery

Sat Oct 15, 2016 11:07 am

TimLee wrote:What has been common is having OBDII adapter hooked up.
Some like Reg unplug it.
To avoid wear and tear on the LEAF's port, I use and extension cable that is routed toward and into the center console...unplug the unit from that easily replaced accessory...

I *once* made the mistake of going out of town for 15 days and left the OBDII adapter plugged in... Due to a discharged 12V battery, came back to a LEAF acting bizarrely and not going to run mode; a jump start from another vehicle, and leaving in park in run mode for a half hour brought back on and off (that was the event that brought me to this thread).

Since then I checked electrolyte levels (fine), purchased a desulfating trickle charger, and run it through a weekend cycle... So far, still on original factory battery from 2011.

EVger
Posts: 1
Joined: Mon May 22, 2017 8:53 am
Delivery Date: 22 May 2017

Re: 12v Battery -- Leaf storage for four to five months

Mon May 22, 2017 12:55 pm

I am planning to leave my Leaf in the garage for four to five months. I would appreciate some information:
Can I just leave the car without the 12v likely to go dead? (Does the electrical system go to sleep and/or does the 12v draw a charge from the traction battery, but not so much as to dangerously drain the traction battery over several months?)
Should I leave the EVSE plugged in to charge the traction battery? (Which would probably maintain a 100% SOC on the traction battery for a considerable time.)
Should I use a battery tender for the 12v battery? If so, what is the most convenient way to make the connection? (Just use the alligator clips? On the negative terminal or the car frame?)
Thanks for your help.

LeftieBiker
Posts: 7170
Joined: Wed May 22, 2013 3:17 am
Delivery Date: 31 May 2013
Location: Upstate New York, US

Re: 12v Battery

Mon May 22, 2017 2:42 pm

If you have a 2015+ Leaf you might be able to use the remote climate control access to charge the battery once a week. Otherwise you might want to use a maintainer. Negative goes to one of the bolts on the thing that looks like an ICE valve cover, in the motor compartment. Others will say there is no need to use a maintainer, and you may not need it with a 2015. Your decision.
2013 "Brilliant Silver" SV with Premium Package and no QC, and 2009 Vectrix VX-1 with 18 Leaf cells.

The most offensive, tasteless phrase in use here is "Pulled the trigger." I no longer respond to posts that use it.

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