Trickle charge 12V battery to stop vampire drain?

[Manta]

aerodyne - Yes, I agree about the Service Center and I do understand that SMT just reads when the car is awake. I just got carried away with my rant about the Service Center. As for pulling data off the CANBus, I can definitely see how useful it can be, but I'm not quite there yet. You have gotten me to start considering it though!

brkaus - Yes. In fact, at one point I had about 3-4 connected apps, and it turned out one was pinging the car every 4 minutes according to Tesla the first time I contacted them about this issue back in March 2021. I reset my password and tracked my battery drain on a spreadsheet for months. Since I had a baseline, I was able to add back two apps that don't interfere with my car's sleep.


As for the latest developments, I noticed (on my 3rd party app) that while my car was at the Service Center last week, it spent a good amount of time asleep, but when I brought it back to my garage, it doesn't sleep at all. (In fact, I had to email the developer because I didn't realize the app tracked sleep until now!) The only difference I can think of between Tesla's parking lot and my garage is the proximity of a wifi network and my cell phone when in my garage. (My home office and router are above my garage.) My fob is kept the bedroom and is probably(?) out of range. (I'm in a townhouse—my office and bedroom are on the second floor. The office is in the front, the bedroom is in the back.)

On a hunch, I deleted the home wifi network from the car. When I've gone to the garage since then, it's been quiet—no hum from the front of the car almost every time. I'll post an update when I've gathered more data.

 

[brkaus]

Interesting. I would also suspect service mode stopping some app activities.

Wonder if you have a partial download or something keeping it awake?

 

[Manta]

Interesting. I would also suspect service mode stopping some app activities.

Yeah, I hadn't considered that. Then again, I left my car in the back of the parking lot, so there's that.

Wonder if you have a partial download or something keeping it awake?

My car has been able to update its software a few times since this started, so I'm guessing that's not the issue.

 

[Manta]

A review of my car's activity shows that it hasn't slept since the day before I picked it up at the Service Center.

Since bringing my car home from the Service Center, I've tried deleting my home wifi network, putting the fobs in an old Altoids tin (makeshift faraday cage) while storing them 30+ feet away on the floor above the garage, and turning off the Exclude Home option of Walk Away Locking--no luck. (Blueish area = time asleep)

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I did notice some odd behavior though. I keep Cabin Overheat Protection turned OFF, but yesterday, I had the car parked outside on a warm (low 70s) sunny day, and the interior temp briefly triggered Cabin Overheat Protection. (Green area = time Overheat Protection is running)

Now the MCU acts glitchy more often than not, and a reboot will usually straighten things out for a while (at least until the next reboot). I'm hoping that's the case here, so I rebooted this morning. We'll see.

As far as the third party apps go, as I mentioned before, I only use two now. One that pings the car 3x a day to collect battery health data, and the other that I use in place of the Tesla app that also gives me access to more data (i.e. these charts). My dad's 2017 Model 3 is also on my account. He lives about 100 miles away and parks his car in a carport in range of wifi, and both apps access his car too. My dad has been under the weather lately, so he hasn't driven his car in a few days. As you can see below, his car is sleeping like a rock except for the 3x/day it gets pinged for its battery health data. (Last 24 hours shown below.)

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I'm just mentioning this here to show that the apps I'm using aren't preventing my car from sleeping.

 

[Manta]

The mystery is solved.

I took my car to a new Service Center that just opened up near me. Fortunately for me, they weren't as fixated on my 3rd party accessories and apps as the other Service Center and actually found the cause of my excessive battery drain.

It turns out one of my powertrain coolant pumps was failing causing the other pump to run overtime to compensate. After replacing the pump, my car finally sleeps again and so far only loses about 4.5 miles/day.

 

[The Enterprise]

4.5 miles a day in phantom drain is still a lot of power lost esp when I drive about 20 to 30 miles a day.

 

[brkaus]

4.5 miles a day in phantom drain is still a lot of power lost esp when I drive about 20 to 30 miles a day.

I agree. It's the biggest problem I see with a Tesla.

I also turn the room light off when it's empty.

 

[Manta]

4.5 miles a day in phantom drain is still a lot of power lost esp when I drive about 20 to 30 miles a day.

Yes, but I was losing as much as 15 miles/day for over a year. The 4.5 miles/day was measured during the first few days out of the shop and without any driving. Hopefully it will improve as I gather more data, but for a 2013 Model S, I'll take what I can get.

 

[Big Earl]

I agree. It's the biggest problem I see with a Tesla.

I also turn the room light off when it's empty.

I'd argue that Tesla has mostly solved this problem. Both of my Model 3s can be parked for an entire week and lose fewer than 4.5 miles of range. We don't run any third-party apps.

 

[brkaus]

I'd argue that Tesla has mostly solved this problem. Both of my Model 3s can be parked for an entire week and lose fewer than 4.5 miles of range. We don't run any third-party apps.

I certainly hope so - thanks- that’s great to hear! My 2017 S and 2018 3 aren’t bad, but definitely more than 4.5 miles per week.

 

[Cal1]

The mystery is solved.

I took my car to a new Service Center that just opened up near me. Fortunately for me, they weren't as fixated on my 3rd party accessories and apps as the other Service Center and actually found the cause of my excessive battery drain.

It turns out one of my powertrain coolant pumps was failing causing the other pump to run overtime to compensate. After replacing the pump, my car finally sleeps again and so far only loses about 4.5 miles/day.

This was what I averaged on my 2013 P85. I think things are back to normal now. Never understood the focus on the 12volt system. I don’t think its any part of vampire drain on the 400 volt battery. To my knowledge charged miles are not affected by the 12 volt system. I do believe vampire drain is caused by things running in the background that are run off that 400 volt system and unlike a computer, our cars seem more difficult to completely turn off.

 

[Big Earl]

This was what I averaged on my 2013 P85. I think things are back to normal now. Never understood the focus on the 12volt system. I don’t think its any part of vampire drain on the 400 volt battery. To my knowledge charged miles are not affected by the 12 volt system. I do believe vampire drain is caused by things running in the background that are run off that 400 volt system and unlike a computer, our cars seem more difficult to completely turn off.

The high voltage system is what keeps the 12-volt system charged, so a 12-volt drain will ultimately cause a high voltage drain via the process of recharging/maintaining the 12-volt system.

 

[zoomer0056]

I'd argue that Tesla has mostly solved this problem. Both of my Model 3s can be parked for an entire week and lose fewer than 4.5 miles of range. We don't run any third-party apps.

What is the equivalent percent battery charge lost per day?

 

[Big Earl]

What is the equivalent percent battery charge lost per day?

Less than 2% per week. Model 3 is about 4 miles per %.

 

[zoomer0056]

Less than 2% per week. Model 3 is about 4 miles per %.

That's good. My S looses 1% in two days.

 

[Wesexcellence]

So here is my drainage issue.
I installed a massive audio system and another lithium battery!
I used to get 210 on a charge and now I get about 170 miles.
I’m ok with that as I’m a realtor and generaodomt drive 170 miles daily.
However I am curious if I disconnected the extra battery if I would still lose as much mileage?

I’m a huge music listener and that’s why I installed this in my garage at home.

I need to build a trim panel for under hood but the sound is unbelievable!