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

Re: LEAF's 12V battery behaviors - and why they go bad

Mon Feb 20, 2017 6:21 am

Awesome. But there are not a lot of devices on a Leaf that draw 750W on 12V system.
Ok, now we know that there might be a voltage drop due to inverter not being instantaneous (at least on 2011/12 model).
In terms of energy quantity this has more or less no effect on battery state of charge.


I would add more new information around the main topic: LEAF's 12V battery behaviors - and why they go bad

I have one BMW OEM AGM battery that was fully charged 4 months ago. It was just sitting for all that time.
Measured voltage before doing anything: 12.5V at room temperature.
We have some guys here who think that this is something something...
So.. lets do a really easy experiment.
I connected a trickle charger, that is limited to 13.99V and 1A charge rate.
As soon as I made connection it started charging the battery. At around 0,7A.
Only 15 minutes later battery was at 13.43V and charge rate dropped to 0,55A.
An hour later voltage jumped to 13.7-13.8V and charge rate dropped below 0.4A.
I've been keeping the power supply connected for few days now. And it still pushes
0.3-0.5A. Battery voltage more or less stable.

So what can we learn from that? Battery did not discharge noticeable. Actually not even 5%.
And it is absolutely pointless to try to charge it any further because it will not accept it.
But it will accept eloctricity. Around 5W is being pushed in by a charger/power-supply that doesn't
stop like smart trickle chargers do. Aka what normal DC-DC converter would do.

And this is ONE of the reasons why Leaf switches to 13.0V mode.
I will just, in the name of the science, keep the power supply active for a day or two just to be absolutely sure
that no more charge can be absorbed. And will disconnect supply. Will measure voltage again. A day and a week later. As a proof.
All this matches scientific data that I collected in this topic earlier.
Short range EVs <30kWh -- Medium range: 30-60kWh -- Long range: >60kWh
Charging: Trickle <3kW -- Normal 3-22kW -- Fast 50-100kW -- Supercharging >100kW

GerryAZ
Gold Member
Posts: 1454
Joined: Mon Nov 22, 2010 6:47 pm
Delivery Date: 12 Jun 2011
Location: Phoenix, AZ

Re: LEAF's 12V battery behaviors - and why they go bad

Mon Feb 20, 2017 12:43 pm

The voltage of the original 12-volt battery in my 2015 was 12.543 (as measured with my Fluke 289 at the battery terminals) this morning about 6 hours after unplugging the L2 EVSE. The car is just over 2 years old with a little over 35,000 miles and I have never connected an external charger and never even removed the vent caps to check the electrolyte level. Therefore, the charging algorithm is ideal for my usage pattern.

Gerry
Gerry
Silver LEAF 2011 SL rear ended (totaled) by in-attentive driver 1/4/2015 at 50,422 miles
Silver LEAF 2015 SL purchased 2/7/2015

DaveinOlyWA
Gold Member
Posts: 12225
Joined: Sat Apr 24, 2010 7:43 pm
Delivery Date: 10 Nov 2016
Leaf Number: 314199
Location: Olympia, WA
Contact: Website

Re: LEAF's 12V battery behaviors - and why they go bad

Tue Feb 21, 2017 11:05 am

GerryAZ wrote:The voltage of the original 12-volt battery in my 2015 was 12.543 (as measured with my Fluke 289 at the battery terminals) this morning about 6 hours after unplugging the L2 EVSE. The car is just over 2 years old with a little over 35,000 miles and I have never connected an external charger and never even removed the vent caps to check the electrolyte level. Therefore, the charging algorithm is ideal for my usage pattern.

Gerry


it is ideal for most users. I think we need to realize that although it works for some, it is not the best option by a long shot hence some people will have issues. So why not fix it? who knows? but its likely that the fix is more involved than we want it to be. So now its a cost/benefit analysis still searching for an answer the bean counters can accept. If it was up to the engineers, my guess is that we would be hashing out something else right now.

although the 12 volt battery is not in play from the car when the DC inverter is on, it is still connected and still has voltage. so momentary drops in voltage means nothing. The battery is still out of play. with a normal running voltage of 13.2 volts, this insures the battery is out of play. So using LEAF Spy to make these kinds of conclusions is not a good idea. You should look at the cell voltage screen. Watch how half the pack's cell voltage will drop 300 to 500% farther than the other half. Again, shocking but not something I would concern myself with.
2011 SL; 44,598 miles. 2013 S; 44,840 miles.2016 S30 (build 10/2016)"low water marks" 26,100.2 miles.363GID Ahr 79.55Hx95.35%kwh28.1QCs227,L2's 237
My Blog; http://daveinolywa.blogspot.com" onclick="window.open(this.href);return false;

VitaminJ
Posts: 374
Joined: Tue Jan 03, 2017 11:46 am
Delivery Date: 07 Jan 2017
Leaf Number: 415775
Location: Morrison, CO
Contact: YouTube

Re: LEAF's 12V battery behaviors - and why they go bad

Tue Feb 21, 2017 11:16 am

arnis wrote:Ok, now we know that there might be a voltage drop due to inverter not being instantaneous (at least on 2011/12 model).

My model is 2013 and I proved there was a drop. My point was that with a weak 12v battery, pressing on the brake pedal causes a drop in voltage and then the DC-DC converter increasing voltage causes the brakes to grab harder than they originally did...leading to poor braking at low speeds. I've experienced this on like 5 Leafs before I bought one. It's a common issue on these cars. My car does not do it with my lithium battery but did with a weak lead acid. That's all.

What does your test with a good-condition AGM prove? Does your Leaf have an AGM? No? Ok thanks I guess :roll:



GerryAZ, your battery should be at 12.6v or higher. But oh well. You live in the frigid, icey snow covered lands of northern Phoenix. I'm sure if it works for you it will work for anyone!

DaveinOlyWA, "momentary drops in voltage mean nothing" this is complete wrong! It makes the brakes feel poor, it makes lights dim, and it makes windows roll up slowly. All of these issues are documented on this forum. It seems like I'm the only guy reading this forum sometimes!
2013 Ocean Blue SV w/ QC and LED
- +0.2 mi/kwh Aeromods
- 2lb 5Ah LiFe 12v battery

DaveinOlyWA
Gold Member
Posts: 12225
Joined: Sat Apr 24, 2010 7:43 pm
Delivery Date: 10 Nov 2016
Leaf Number: 314199
Location: Olympia, WA
Contact: Website

Re: LEAF's 12V battery behaviors - and why they go bad

Tue Feb 21, 2017 11:22 am

VitaminJ wrote:
DaveinOlyWA, "momentary drops in voltage mean nothing" this is complete wrong! It makes the brakes feel poor, it makes lights dim, and it makes windows roll up slowly. All of these issues are documented on this forum. It seems like I'm the only guy reading this forum sometimes!


my comment was only made in reference to the role of the 12 volt battery after the car is running.

but your comments are interesting. so if I precondition my inverter with A/C my windows will roll up quicker?
2011 SL; 44,598 miles. 2013 S; 44,840 miles.2016 S30 (build 10/2016)"low water marks" 26,100.2 miles.363GID Ahr 79.55Hx95.35%kwh28.1QCs227,L2's 237
My Blog; http://daveinolywa.blogspot.com" onclick="window.open(this.href);return false;

VitaminJ
Posts: 374
Joined: Tue Jan 03, 2017 11:46 am
Delivery Date: 07 Jan 2017
Leaf Number: 415775
Location: Morrison, CO
Contact: YouTube

Re: LEAF's 12V battery behaviors - and why they go bad

Tue Feb 21, 2017 11:26 am

DaveinOlyWA wrote:my comment was only made in reference to the role of the 12 volt battery after the car is running.

but your comments are interesting. so if I precondition my inverter with A/C my windows will roll up quicker?

With a weak battery the car will run and drive but all sorts of problems happen like brake issues, slow windows, warning lights, etc.

Yes if the 12v system voltage is at 14.4 because you used an accessory the windows will move faster than if they start at 13v. Faster still than if you relied on only the 12v battery itself. Anyone who's owned an ICE car knows the windows are slower with the engine off.
2013 Ocean Blue SV w/ QC and LED
- +0.2 mi/kwh Aeromods
- 2lb 5Ah LiFe 12v battery

DaveinOlyWA
Gold Member
Posts: 12225
Joined: Sat Apr 24, 2010 7:43 pm
Delivery Date: 10 Nov 2016
Leaf Number: 314199
Location: Olympia, WA
Contact: Website

Re: LEAF's 12V battery behaviors - and why they go bad

Tue Feb 21, 2017 11:47 am

VitaminJ wrote:
DaveinOlyWA wrote:my comment was only made in reference to the role of the 12 volt battery after the car is running.

but your comments are interesting. so if I precondition my inverter with A/C my windows will roll up quicker?

With a weak battery the car will run and drive but all sorts of problems happen like brake issues, slow windows, warning lights, etc.

Yes if the 12v system voltage is at 14.4 because you used an accessory the windows will move faster than if they start at 13v. Faster still than if you relied on only the 12v battery itself. Anyone who's owned an ICE car knows the windows are slower with the engine off.



on the brake issues there are some that feel that cycling traction control helps on at least a temporary basis. Have you tried that?
2011 SL; 44,598 miles. 2013 S; 44,840 miles.2016 S30 (build 10/2016)"low water marks" 26,100.2 miles.363GID Ahr 79.55Hx95.35%kwh28.1QCs227,L2's 237
My Blog; http://daveinolywa.blogspot.com" onclick="window.open(this.href);return false;

VitaminJ
Posts: 374
Joined: Tue Jan 03, 2017 11:46 am
Delivery Date: 07 Jan 2017
Leaf Number: 415775
Location: Morrison, CO
Contact: YouTube

Re: LEAF's 12V battery behaviors - and why they go bad

Tue Feb 21, 2017 11:50 am

Yes I pretty much always drive with TCS turned off. I have also done the pedal calibration procedure. The biggest improvement was replacing the 12v battery.
2013 Ocean Blue SV w/ QC and LED
- +0.2 mi/kwh Aeromods
- 2lb 5Ah LiFe 12v battery

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

Re: LEAF's 12V battery behaviors - and why they go bad

Tue Feb 21, 2017 2:13 pm

What does your test with a good-condition AGM prove? Does your Leaf have an AGM? No? Ok thanks I guess :roll:

GerryAZ, your battery should be at 12.6v or higher.



No it should not and that is exactly what I proved. AGM is lead acid battery. Still the same lead and acid.

Brake booster has integrated capacitor bank. I would expect it is operational even while having normal driving.



PS: removed the power supply 24h ago. Voltage is 12.7V. Charge state is somewhere between 95-105%.
Lets wait little more.
Short range EVs <30kWh -- Medium range: 30-60kWh -- Long range: >60kWh
Charging: Trickle <3kW -- Normal 3-22kW -- Fast 50-100kW -- Supercharging >100kW

VitaminJ
Posts: 374
Joined: Tue Jan 03, 2017 11:46 am
Delivery Date: 07 Jan 2017
Leaf Number: 415775
Location: Morrison, CO
Contact: YouTube

Re: LEAF's 12V battery behaviors - and why they go bad

Wed Mar 29, 2017 2:04 pm

5Ah 2lbs battery still going strong after 60 days. Rain, snow, and shine, heater/AC, turtling, everything still working as normal.

VitaminJ wrote:Image
2013 Ocean Blue SV w/ QC and LED
- +0.2 mi/kwh Aeromods
- 2lb 5Ah LiFe 12v battery

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