Questions on 12V Battery

[PianoAl]

I had my KW902 dongle on all day while the car was sitting. The voltage of the 12V battery was 11.7 V (according to LEAFSpy and confirmed with a multimeter). I put the car in drive mode, and after 10-15 minutes, the voltage was up to 14.4 V (confirmed with multimeter).

1. Do you think it would have stayed higher if I hadn't left the dongle on?
2. I had assumed that the dongle wouldn't draw enough current to be a problem. Was that a bad assumption?
3. At what voltage level might the low battery cause problems?
4. I'm surprised that it could charge up to 14.4 V so quickly. Is that possible?

Thanks.

 

[cwerdna]

(My OBD2 dongle isn't calibrated so I have no idea how off it is vs. a volt meter) The 14.x volts is kinda normal not long after power up. Unfortunately, the voltage drops back down fairly quickly. I'm guessing that's just the output voltage of the DC to DC converter trying to charge the 12 volt, but not for long enough (which is a well known Leaf design flaw, it seems).

If you run the windshield wipers, the 12 volt bus voltage will go up for a little while and stay there before dropping back down.

 

[eastocean]

There are threads talying everything 12 very battery. It doesn't seem to be a standard size car battery.

I just had to replace mine (2013) after 37 months. It seems to have died with the onset of cold weather, and after sitting unused for 2 weeks, unplugged. It had lasted 3 weeks several times before. I frutzed around with it, my multimeter, trickle battery charger, making measurements for a week, before I declared it dead.

I found charging l with the car would drive it initially to 14v, but would shortly fall back to 13.1 in a while. On the bad battery, much below 12v, starting became problematic, and would throw out odd messages on the display. If your foot was on the brake when starting with low battery, the petal will drop to the floor, and the car wont start or charge. Charging with the trickle charger would up to 12v to 13 very, and it would start. Overnight it wold fade ànd not start.

 

[cwerdna]

There are threads talying everything 12 very battery..

Yeah. I haven't read all of http://www.mynissanleaf.com/viewtopic.php?t=22752 nor watched the video yet. There are tons of other threads on the observed behavior of the 12 volt charging algorithm.

I haven't even had a chance to skim http://www.mynissanleaf.com/viewtopic.php?t=19471.

 

[ElectricEddy]

I had my KW902 dongle on all day while the car was sitting. The voltage of the 12V battery was 11.7 V (according to LEAFSpy and confirmed with a multimeter). I put the car in drive mode, and after 10-15 minutes, the voltage was up to 14.4 V (confirmed with multimeter).

1. Do you think it would have stayed higher if I hadn't left the dongle on?
2. I had assumed that the dongle wouldn't draw enough current to be a problem. Was that a bad assumption?
3. At what voltage level might the low battery cause problems?
4. I'm surprised that it could charge up to 14.4 V so quickly. Is that possible?

Thanks.

I can confirm that the charging algorithm has been changed in my 16 compared to the 13.

After 1/2 hour parked in run mode listening to music eating lunch etc. the terminal voltage at the battery was 14.5V.
The 13 voltage would tend to drop and stop charging after a few minutes.

The no load off state voltage was measured the day previous at 12.5V.

I have only trickle charged the battery twice since I purchased the 16 and both times the float voltage equals 12.5V, the 13 I would trickle charge bi-weekly and its float voltage was closer to 12V. (older battery).

There is a noticeable depreciation in state of charge (traction battery) of about 1% to 2% / hour (with no hvac running) on the Leaf while doing this .

The above measurments where done with a Fluke 179 true rms multimeter.

 

[baustin]

I had my KW902 dongle on all day while the car was sitting. The voltage of the 12V battery was 11.7 V (according to LEAFSpy and confirmed with a multimeter). I put the car in drive mode, and after 10-15 minutes, the voltage was up to 14.4 V (confirmed with multimeter).

1. Do you think it would have stayed higher if I hadn't left the dongle on?
2. I had assumed that the dongle wouldn't draw enough current to be a problem. Was that a bad assumption?
3. At what voltage level might the low battery cause problems?
4. I'm surprised that it could charge up to 14.4 V so quickly. Is that possible?

Thanks.

When I first got my Leaf, I ran into a couple no-start issues with a very low 12v battery when leaving the bluetooth dongle plugged in. After having to do a couple jump starts, I checked the battery and found all the cells low. I topped off the cells with distilled water, gave it a charge, and have not had any issues since then. I would recommend checking the battery at least twice a year.

I also tried to remember to remove the dongle after using it, since I only use it periodically to take battery health readings. I went looking for it one day, and found that I had left it plugged in for quite a while. I had not had any problems during that time, but I bought an OBD cable with an on/off switch just to make sure there would be none (also to minimize wear on the OBD port). https://smile.amazon.com/Tonsiki-Female-Diagnostic-Extension-battery/dp/B00UR5XBMW/ref=sr_1_8?ie=UTF8&qid=1482209287&sr=8-8&keywords=obd+extension+cable