Charging while parked & unused (over 2 weeks) in cold weather - recorded data

[PrimeRisk]

Yes, so true!

My curiosity stems from all the 12v battery failures in under 3years that have been reported on the forums and what is going on with that.

It also seems to be an issue on the Nissan Leaf forum I am on as well.

It is so ironic that with all that stored energy in the HVB, it isn't being used effectively to keep the 12v batteries topped off and healthy.

Hence my 2 AGM mode trickle chargers, one on the Leaf and one on the Lightning.

What year Leaf? I had a 2015 with the modem-hangup issue that would completely flatten the LVB in about 4 hours because the cell modem would phone home with status and never disconnect. I resorted to keeping a pair of needle nose pliers in the car and manually pulling the cell modem's fuse every night when I got home from work. Nissan had to replace the battery 5 times under warranty until they finally had a patch.

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[chl]

I think this could be accomplished with the appropriate logic , no changes needed to hardware at all.

Yes, maybe so...just put in code to fire up the AC-DC and DC-DC converters and activate the EVSE to connect to the grid when the truck is plugged in, if that can be done without needing to physically connect the HVB into the mix.

I going to have to review some of those old videos about the Lightning and see if I can glean anything from them about the hardware connections and control.

Ford must have all the info/details we'd need.

You'd hope that if it could be done easily they would have done it already with all the battery replacements under warranty and hassle owners have been put through.

Not to mention some other EV makers (except Tesla?) who seem to have the same issues with the 12v battery.

From what AI tells me about Tesla, they keep the 12v battery topped off from the HVB all the time, whether ON, OFF, charging or not, rain or shine,hot or cold.

Since cancelling the Lightning and moving to the Universal EV Platform, not gonna happen now I guess.

 

[chl]

What year Leaf? I had a 2015 with the modem-hangup issue that would completely flatten the LVB in about 4 hours because the cell modem would phone home with status and never disconnect. I resorted to keeping a pair of needle nose pliers in the car and manually pulling the cell modem's fuse every night when I got home from work. Nissan had to replace the battery 5 times under warranty until they finally had a patch.

I have a 2012.

The big drain on mine was apparently the charge timers.

Nissan put out a bulletin I think which said to turn them off when the Leaf is sitting unused for a while, but it came out sometime after I had a problem.

My 12v got discharged to the point I had to jump it with my 2001 Ranger after I was away for several weeks after I first bought it.

I had to buy a long jumper cable to reach it - it was nose first into the garage.

Ever since, I just keep it on a trickle charger in my garage - still on the original battery now 14 years later.

Batteries love to be at 100% and reward you with longevity!

And it is still a nice little local trip vehicle to this day.

 

[chl]

About the Teslas - got it from this back in 2023...alas, Ford has not fixed it apparently:

https://www.f150lightningforum.com/forum/threads/why-isnt-the-12v-battery-always-charged.14005/

 

[Thunder⚡️ Lightning]

Our 2025 Lariat has been parked, completely unused, for a little over 2 weeks (since December 10), and I've been collecting data on the power drawer. It is plugged into a Level 2 charger (Emporia EVSE) with no limitations configured on the truck or charger about when it can charge - maximum available current is 48A. The State of Charge limit is set to 80% and it was at that level before we left it. No Departure Times are configured.

The truck is in Vermont where, as you can see from the bottom chart, temperatures have largely been below freezing, dipping as low as -4°F (-20°C), but averaging somewhere around 20°F (-7°C). We locked up the truck and left it on December 10. On December 23 I connected via FordPass and remote started the truck, just to see if that would have any effect on the sleep.

The top chart above shows cumulative energy usage in December, so essentially each time the line goes up, that's the truck pulling power. It looks like a pretty distinct change in behavior around December 17, exactly 1 week after the truck was last used. While it does appear to pull more power (in both frequency and total energy) in colder temperatures, it definitely seems to have slowed down after the first week.

I'll be honest, I was somewhat surprised to see how much energy it's used - approximately 70kWh in 17 days, so an average of somewhere around ~4kWh per day. I realize I could have unplugged it and put it in "storage", but I was honestly just intrigued to see what would happen if I left it plugged in.

Another notable point is that it does not appear to have changed behavior 2 weeks after I last used it, which I had expected based on what I had read. Perhaps remote starting it after 13 days was enough to stop that, perhaps something has changed, or perhaps I misunderstood how the deep sleep works. Regardless, I can confirm that it pulled power today, the last refresh in FordPass via Home Assistant was 7 hours ago, and there's nothing in the FordPass app suggesting it's gone to sleep.

It also looks like it is keeping the 12V battery charged:

So anyway, no real question here, but just thought this was interesting as I hadn't seen data from a truck left plugged in for a prolonged period (> 2 weeks) in cold conditions recently.

Very interesting what was the state of charge when you first plugged it in?

 

[MattVT]

Very interesting what was the state of charge when you first plugged it in?

80%

 

[bc1]

Was it ever covered with snow during that time? Snow will act like an insulator and inside the temperature will maintain a constant approxmate 32 degrees F just like in an ice cube.

Learned that from my Army survival training in the mountains sleeping in snow caves. Dig a cave in the snow and sleep in the old mummy sleeping bags on a poncho. Light a candle to run around the walls to melt it just enough to form back into ice when packed by hand. Keep the entrance open and light the candle every once in a while along with body heat will warm the place right up.

I remember the old Diehard battery commercials from the 60s with a car sitting all winter up at Frostbite Falls, Minnesota and the wipers would knock off about 6" of snow. They didn't tell us and I didn't know that the snow was maintaining about 32 degrees F under the hood of the car all winter. That would be a lawsuit today.

 

[Thunder⚡️ Lightning]

80%

One more question how did you manage to track the charging data for the 12 V battery?

 

[PrimeRisk]

I have a 2012.

The big drain on mine was apparently the charge timers.

Nissan put out a bulletin I think which said to turn them off when the Leaf is sitting unused for a while, but it came out sometime after I had a problem.

My 12v got discharged to the point I had to jump it with my 2001 Ranger after I was away for several weeks after I first bought it.

I had to buy a long jumper cable to reach it - it was nose first into the garage.

Ever since, I just keep it on a trickle charger in my garage - still on the original battery now 14 years later.

Batteries love to be at 100% and reward you with longevity!

And it is still a nice little local trip vehicle to this day.

That's awesome! I loved my '15 SV model, but I sold it when I purchased my first Tesla in 2021. I worked for the local public utility and there was a special offer for employees to purchase an in-stock Leaf for as little at $10k after state and federal incentives combined with 0% financing. I wanted more features than the S offered, so I went with the SV and after the incentives the vehicle cost $13,500 all-in with taxes, title, and delivery. After 6 1/2 years I had 60k miles on her and was ready for the next step. Tesla only offered me $5k on trade, but I went through kbb.com and got a cash offer for $8,900, so I took it. That car only cost me $4,600 + 2 tires due to an errant drywall screw. Literally $125 in total maintenance cost (reduction gear oil change at 30k). The maintenance schedule states that you need to replace the brake fluid ever 15k, but the dealer would check it every time I brought it in for free tire rotations and inspection and always came back saying that fluid tested perfect, so they didn't recommend the service.

We own places in Myrtle Beach we use for Short Term Rentals and we travel out there about 5 times a year. We are heading toward retirement (the Mrs. retired in 2022) and the plan when I fully retire is to snowbird in Myrtle Beach. Currently we have an older Suburban out there as we need a big vehicle for hauling things and when friends and family come to town. I've been considering buying an older Leaf as a run-around vehicle as the Suburban gets terrible gas mileage. Locally I can find dozens of 2015+ Leafs for $3k - $5k, but they seem to be harder to find at reasonable prices around Myrtle Beach. I'd buy one locally, but getting it to Myrtle Beach would be a nightmare.

 

[chl]

That's awesome! I loved my '15 SV model, but I sold it when I purchased my first Tesla in 2021. I worked for the local public utility and there was a special offer for employees to purchase an in-stock Leaf for as little at $10k after state and federal incentives combined with 0% financing. I wanted more features than the S offered, so I went with the SV and after the incentives the vehicle cost $13,500 all-in with taxes, title, and delivery. After 6 1/2 years I had 60k miles on her and was ready for the next step. Tesla only offered me $5k on trade, but I went through kbb.com and got a cash offer for $8,900, so I took it. That car only cost me $4,600 + 2 tires due to an errant drywall screw. Literally $125 in total maintenance cost (reduction gear oil change at 30k). The maintenance schedule states that you need to replace the brake fluid ever 15k, but the dealer would check it every time I brought it in for free tire rotations and inspection and always came back saying that fluid tested perfect, so they didn't recommend the service.

We own places in Myrtle Beach we use for Short Term Rentals and we travel out there about 5 times a year. We are heading toward retirement (the Mrs. retired in 2022) and the plan when I fully retire is to snowbird in Myrtle Beach. Currently we have an older Suburban out there as we need a big vehicle for hauling things and when friends and family come to town. I've been considering buying an older Leaf as a run-around vehicle as the Suburban gets terrible gas mileage. Locally I can find dozens of 2015+ Leafs for $3k - $5k, but they seem to be harder to find at reasonable prices around Myrtle Beach. I'd buy one locally, but getting it to Myrtle Beach would be a nightmare.

Interesting, thanks for sharing. I enjoy hearing other peoples stories.

That was a good deal on the Tesla!

Yes, virtually no maintenance on the Leaf - what a joy that is. I used to go in for the yearly battery check, but after 4 years and no problems, why bother?

I see you're in Denver. I lived in Denver back in the late 1970's, played in a couple bands and met my first wife there.

I played drums with Eagle Park Slim and the Mile High Blues Band, and then my wife and I formed an all originals band with two other locals called Omnibus. I'll attach a couple Rocky Mountain News clippings about the bands.

Back then disco was still popular in most clubs so not the best location for live music. We all had day jobs. In ski season we'd play resorts.

When my first child was on the way, I decided to go back to school, electrical engineering. Then as I was finishing a masters degree, I got a wild hair and took the LSAT and enrolled in Law School. I got a job at the US Patent and Trademark Office examining computer related patent applications during the day, and went to law school at night for 4 years - what fun!

After graduating law school and passing the bars in Virginia, Maryland and DC, I worked at law firms, eventually becoming a partner.

Funny thing there were a lot of ex-musicians in both engineering and law. Just very hard to make ends meet as a musician unless you're Taylor Swift, lol.

Myrtle Beach is nice, my sister lived there for a while, and her ex husband still does.

My getaway is on the island of Montserrat West Indies where my late parents built a house in the 1970s. It's been through a lot since then, Hurricane Hugo hit in 1989, then the volcano awoke in 1996 and in 1997, buried the main city, Plymouth.

Since 2012 it has been quiet. My house is only 3 miles as the crow flies from the dome, so now and then I'd get ash, pumice or small gravel landing on the roof and yard. No fun cleaning it up, heavier than snow and it doesn't melt into water. There's always something.

My wife retired early and I am semi-retired. It is an adjustment but a lot less stress! I think.

I read about folks upgrading their Leaf battery from 24kWh to around 75kWh, mostly on the west coast since they come from China or Japan, plug and play.

If Aptera comes through with a vehicle next year as they are planning, I am thinking I'll replace the Leaf with one of those at some point.

Believe it or not there are 3 Leaf's running around Montserrat! Electricity is expensive there, but gasoline is even more expensive, so they say they are saving money. If I lived there full time I might try to get one there. But I think my next big expense will be putting in solar there. So much potential, but the Gov't owns the electric utility and they haven't gotten their act together to have net metering. But they are considering it, on "island time."

Take care.

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