dmacarthur
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Leaf Number: 306556
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Re: Dead 12V battery question

Yes confusing- the car went into turtle and then stopped completely, I wish I had checked the 12V battery then but did not, towed it to a Level 2 (was tempted to try to charge while towing but lacked the cojones...) and that is when it would not charge the traction battery before a jump to the 12V. But as you say this could all be random. LeafSpy showed me 12.0V system voltage the day this all happened, now showing 13 plus, so evidently when system voltage gets below a certain point there is simply not enough juice to activate some of the chips.... putting the old 12V battery (the original, from 2019) on my old battery tester (the kind with the glowing resistance coil inside) the voltage drops to around 10.5.
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GerryAZ
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Re: Dead 12V battery question

When the car shuts down due to discharged traction battery (shortly after hitting Turtle mode), the car basically goes into accessory mode so auxiliary things like lights, radio, HVAC blower, wipers, etc. are being fed from the 12V battery. If the driver does not turn the car off, the 12V battery will soon be discharged low enough to be unable to close the main DC contactor after plugging the car in. Therefore, it is necessary to charge the 12V battery or use a booster battery to get charging started. Once traction battery charging starts, the DC-DC converter will charge the 12V battery while the traction battery is charging.
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; traded 8/10/2019 at 82,436 miles
White LEAF 2019 SL Plus purchased 8/10/2019
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knightmb
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Leaf Number: 306291
Location: Franklin, TN

Re: Dead 12V battery question

GerryAZ wrote: Sat Oct 08, 2022 4:01 pm When the car shuts down due to discharged traction battery (shortly after hitting Turtle mode), the car basically goes into accessory mode so auxiliary things like lights, radio, HVAC blower, wipers, etc. are being fed from the 12V battery. If the driver does not turn the car off, the 12V battery will soon be discharged low enough to be unable to close the main DC contactor after plugging the car in. Therefore, it is necessary to charge the 12V battery or use a booster battery to get charging started. Once traction battery charging starts, the DC-DC converter will charge the 12V battery while the traction battery is charging.
To add, my wife seems to be good at forgetting to charge and ignore all those dash warnings :lol:
Multiple times now, she has drained the 12V battery completely after main pack shutdown (well beyond turtle mode) because she left all the lights on, fans, seat heaters, etc. She has a Lithium 12V battery that will run for nearly an hour this way and still manages to discharge it completely. :x
As GerryAZ says, if you run your Leaf into complete main pack shutdown, pull over to a safe spot if possible and turn everything off to save your 12V battery. Unless you need to charge your cell phone or something, don't leave everything on and running accessory mode (fans, seat heater, wipers, lights, etc). It will make it harder to move or charge your Leaf later if it is "completely" dead on both the 12V and main battery pack. :shock:
2020 Leaf SL Plus - (Manufacture Date March 2020)
2018 Leaf SL - (Manufacture Date February 2018)
2013 Leaf SV - (8 faithful years of service before trade in at 75,679 miles LeafSpy-Data)
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DaveinOlyWA
Posts: 16146
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Re: Dead 12V battery question

knightmb wrote: Sun Oct 09, 2022 10:12 am
GerryAZ wrote: Sat Oct 08, 2022 4:01 pm When the car shuts down due to discharged traction battery (shortly after hitting Turtle mode), the car basically goes into accessory mode so auxiliary things like lights, radio, HVAC blower, wipers, etc. are being fed from the 12V battery. If the driver does not turn the car off, the 12V battery will soon be discharged low enough to be unable to close the main DC contactor after plugging the car in. Therefore, it is necessary to charge the 12V battery or use a booster battery to get charging started. Once traction battery charging starts, the DC-DC converter will charge the 12V battery while the traction battery is charging.
To add, my wife seems to be good at forgetting to charge and ignore all those dash warnings :lol:
Multiple times now, she has drained the 12V battery completely after main pack shutdown (well beyond turtle mode) because she left all the lights on, fans, seat heaters, etc. She has a Lithium 12V battery that will run for nearly an hour this way and still manages to discharge it completely. :x
As GerryAZ says, if you run your Leaf into complete main pack shutdown, pull over to a safe spot if possible and turn everything off to save your 12V battery. Unless you need to charge your cell phone or something, don't leave everything on and running accessory mode (fans, seat heater, wipers, lights, etc). It will make it harder to move or charge your Leaf later if it is "completely" dead on both the 12V and main battery pack. :shock:
There is NO reason whatsoever to hit main pack shutdown. You have warnings well before that happens and waiting is simply idiotic.
2011 SL; 44,598 mi, 87% SOH. 2013 S; 44,840 mi, 91% SOH. 2016 S30; 29,413 mi, 99% SOH. 2018 S; 25,185 mi, SOH 92.23%. 2019 S Plus; 37,001 mi, 90.19% SOH
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knightmb
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Re: Dead 12V battery question

DaveinOlyWA wrote: Sun Oct 09, 2022 10:16 am There is NO reason whatsoever to hit main pack shutdown. You have warnings well before that happens and waiting is simply idiotic.
Welcome to my life... :lol:
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2018 Leaf SL - (Manufacture Date February 2018)
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TimLee
Posts: 2820
Joined: Thu Jan 20, 2011 9:40 am
Delivery Date: 17 May 2011
Leaf Number: 2026
Location: Chattanooga, TN

Re: Dead 12V battery question

GerryAZ wrote: Sat Oct 08, 2022 4:01 pm ... Therefore, it is necessary to charge the 12V battery or use a booster battery to get charging started. Once traction battery charging starts, the DC-DC converter will charge the 12V battery while the traction battery is charging.
On my 2011 LEAF, I recently observed that while L2 charging the main pack, that if the LEAF is ON, the DC-DC converter is inactive and NOT available to charge the 12V battery while the traction battery is charging.

I only discovered this because I left the LEAF ON to keep the 12V auxiliary outlet powered for charging my cell phone that had LEAF Spy Pro running creating a graph of the pack charging that I planned to Save.

I only discovered the situation when I turned the windshield wipers on to have the LEAF DC-DC raise the 12V buss voltage to check the 12V battery completeness of charge and saw that the buss voltage did not change.

Turning the wipers on is a simple way to fully charge the 12V. With my AGM you know it is pretty fully charged once the current with 14.2 V on the buss drops very low to 0.86 or 0.67 amps.

I had done a similar thing a lot while using DCQC. And with DCQC charging the pack and the LEAF ON the DC-DC is active. But on my 2011 it is NOT while doing L2 with the LEAF ON.

There are also differences on HVAC availability with LEAF ON between DCQC and L2. HVAC works with DCQC, but usually NOT with L2.

One last note on killing the 12V. I killed it once with the headlights turned ON. With the headlight relay closed and 12V buss voltage very low, took a stout 12V source to be able to get the headlight relay to open.

Tim Lee
Chattanooga, TN

Man. Date: 03/10/11, VIN # 2026
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LeftieBiker
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Re: Dead 12V battery question

Turning the wipers on is a simple way to fully charge the 12V.
Yes, although to be clear to newbies, you have to either leave the wipers on, or keep tapping the wiper lever every few minutes, because the boost to 14+ volts only lasts about a minute. One way around this is to put them on Intermittent, and adjust the interval to the longest setting.
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GerryAZ
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Re: Dead 12V battery question

My 2011, 2015, and 2019 all act the same way. HVAC and DC-DC converter function normally while car is charging on L2 or DCQC as long as SOC is at least 25%. HVAC will not function while charging if charge level is below about 25%. You must have SOC above 25% and have foot on brake before pushing start button if you want HVAC to function while charging. If SOC is less than 25%, you need to turn car off and then turn it back on with foot on brake after SOC gets above 25% to activate HVAC. I don't know what mode Tim Lee had his car in to cause the DC-DC converter to be off while the car was charging (possibly accessory mode).
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; traded 8/10/2019 at 82,436 miles
White LEAF 2019 SL Plus purchased 8/10/2019
lorenfb
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Re: Dead 12V battery question

TimLee wrote: Mon Oct 10, 2022 5:34 pm
GerryAZ wrote: Sat Oct 08, 2022 4:01 pm ... Therefore, it is necessary to charge the 12V battery or use a booster battery to get charging started. Once traction battery charging starts, the DC-DC converter will charge the 12V battery while the traction battery is charging.
On my 2011 LEAF, I recently observed that while L2 charging the main pack, that if the LEAF is ON, the DC-DC converter is inactive and NOT available to charge the 12V battery while the traction battery is charging.

I only discovered this because I left the LEAF ON to keep the 12V auxiliary outlet powered for charging my cell phone that had LEAF Spy Pro running creating a graph of the pack charging that I planned to Save.

I only discovered the situation when I turned the windshield wipers on to have the LEAF DC-DC raise the 12V buss voltage to check the 12V battery completeness of charge and saw that the buss voltage did not change.

Turning the wipers on is a simple way to fully charge the 12V. With my AGM you know it is pretty fully charged once the current with 14.2 V on the buss drops very low to 0.86 or 0.67 amps.

I had done a similar thing a lot while using DCQC. And with DCQC charging the pack and the LEAF ON the DC-DC is active. But on my 2011 it is NOT while doing L2 with the LEAF ON.

There are also differences on HVAC availability with LEAF ON between DCQC and L2. HVAC works with DCQC, but usually NOT with L2.

One last note on killing the 12V. I killed it once with the headlights turned ON. With the headlight relay closed and 12V buss voltage very low, took a stout 12V source to be able to get the headlight relay to open.
Which battery technology, i.e. a flooded lead acid or an AGM, requires the higher charging voltage? Can you provide a link and supporting data?

Here's one; https://www.alpha-batteries.co.uk/blog/ ... batteries/
Most Caravans and Motorhomes up until 2017 come factory fitted with non-AGM charging systems and to make things worse some manufacturers will state that they ‘may be suitable’ for charging AGM batteries – they simply aren’t, but why? If you take a look at the datasheets and technical specifications for AGM batteries on our website, you will see that we publish specific charge settings and this ultimately centres around voltage. AGM batteries are designed to require 14.6v – 14.8v when performing a full charge from a state of discharge, whereas standard lead acid batteries need 13.8v – 14.4v, hence this is what most onboard chargers are designed to deliver – not the 14.6v – 14.8v that AGM requires.
Based on the above and what is known about the typical Leaf battery charging voltage (14.2V), it appears that the Leaf provides an inadequate AGM charging voltage.

Are there conflicting data to the above link? My original 2013 Leaf 12V battery lasted until 2020,
so I see little value in an AGM battery for my 2019. Besides anecdotal data, what're the bases'?
#1 Leaf SL MY 9/13: 76K miles, 47 Ahrs, 5.0 miles/kWh (average), Hx=70, SOH=73, L2 - 100% > 1000, temp < 95F, (DOD) > 20 Ahrs
#2 Leaf SL MY 12/18: 28K miles, SOH 105Ahrs/115Ahrs, 5.2 miles/kWh (average), DOD > 20%, temp < 105F
GerryAZ
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Re: Dead 12V battery question

I use a couple different AGM battery manufacturers for my vehicles: I replaced the Nissan OEM battery in each LEAF with an Optima yellow top D51R. In each case, the Nissan OEM flooded cell battery failed after 2 to 2-1/2 years (which is actually longer than typical for OEM batteries in gas engine vehicles in my climate). Optima recommends float voltage of 13.2 to 13.8 and alternator output voltage of 13.65 to 15.0 for their yellow top deep cycle batteries. My experience with Optima batteries (red top starting batteries and yellow top deep cycle/starting batteries) is that overcharging kills them prematurely in the hot dry climate where I live. They last far longer than other batteries as long as the alternator output voltage on a vehicle is not too high. The DC-DC converter output on the LEAF is ideal for long life of the Optima batteries because it is 14 to 14.5 volts until absorption current drops and then switches to float voltage of about 13 to 13.5 volts (both voltage levels are temperature compensated so higher when cold and lower when hot) to avoid overcharging. I use Odyssey batteries in motorcycles, Jet Skis and a Group 65 in my SUV (since Optima does not make Group 65 size). They have about the same charging voltage recommendations.

I switched to AGM batteries after getting tired of cleaning up corrosion around flooded cell batteries and having even top-of-the-line flooded cell batteries fail after 6 to 18 months.
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; traded 8/10/2019 at 82,436 miles
White LEAF 2019 SL Plus purchased 8/10/2019

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