Non random battery drain

[albanick]

I am the recently new owner of a 4 year old M3P and have noticed a very consistent battery drain issue. I've been reading threads on here for weeks and still can't figure this one out.

Every Wednesday, my battery 'loses' 4% while parked (not plugged in) at my work.

I downloaded teslafi to see if it gave me any more insight and all I can see is that I lose 4% while parked and the vehicle is sleeping.
Sentry mode is disabled and I don't have the self summon.
I raised a service ticket with Tesla and they said there is nothing abnormal in the log and it must just be the battery (bms) recalculating the actual available charge.
Bur every Wednesday (3 in a row) and always 4%. This surely can't be right.

Does anyone else have similar experience and importantly, has anyone found a fix (or at least the cause)?

Appreciate any help you can give.

 

[ewoodrick]

I know that you said you didn't have it on.

But have you looked at the Sentry Mode setting and confirmed it is completely off, not just off at home and work?

 

[redmunds]

My routine is pretty fixed. Charge to 80% on a Monday, short journeys to and from work Monday to Friday, move the kids about at the weekend.

Try mixing up your routine, such as starting Wednesday morning at 80%.

 

[GoergeJetson]

Another update, two days in a row I had 0% energy loss while parked at work for 9 hours. What changed? I changed my navigation destination to an address that I pass by before turning into my work address. This seems to end navigation and when I park the car, it goes to sleep and doesn't lose the 5%-6% of energy that I was losing on a daily basis, sometimes that much in the first few hours of being parked. I am not totally convinced I found the issue but this is the first time I've lost 0% energy while parked at work two days in a row. I think if I can experience no energy loss for 3 consecutive days or even full a week, I will have found the culprit, a bug in the software not allowing the car to sleep due to the nav system keeping the car awake, or on stand-by, while parked. I will update this thread again in another week or so.

 

[victor4v]

Have sou find a solution ?
I’ve got exactly the same problem for 5 months on my 2019 Model 3… 3 tickets at Tesla saying they detect nothing wrong… they just told that it was HVAC system that was keeping moisture out of the car after a drive. Sometimes this consumes more than the drive itself….. hope we’ll find an answer soon.
On my side i don’t think this has anything to do with the navigation because i end it every time like 5 minutes before arriving at work and still have this issue.

 

[GoergeJetson]

No, still have not figured it out, the drain is random, some days 5%-6% other days 2%-3% or occasionally less than 1%. It could be ambient temperature dependent, it seems like the days were I get less drain are cooler days, however we are now getting into the high 80's and the drain is as little as 2%. Standby mode just seems buggy to me. The other morning it showed a 5% loss within 1 hour of parking the car, there is no way the car can lose nearly 4 kW while parked and all systems off. I'd also guess it's BMS error but, the car is using a bit over 8 kW each way to get to and from work, all other percentages look consistent. It's still a mystery. Also, probably due to my my software revision, I never received the FSD trial.

 

[3sr+buyer]

No, still have not figured it out, the drain is random, some days 5%-6% other days 2%-3% or occasionally less than 1%

Does the Energy Screen's Park tab show anything interesting after the apparent drain?

 

[victor4v]

Does the Energy Screen's Park tab show anything interesting after the apparent drain?

This is what the Energy tab shows

 

[3sr+buyer]

This is what the Energy tab shows

The 4.9% vehicle standby consumption is over how long?

 

[victor4v]

The 4.9% vehicle standby consumption is over how long?

9 hours, but if I left the car 1 week it will not consume more. it really is like 5% for a parking session of more than an hour without sentry

 

[GoergeJetson]

9 hours, but if I left the car 1 week it will not consume more. it really is like 5% for a parking session of more than an hour without sentry

I continue to have the same issue, however, as it's gotten hotter over 90F lately, it seems the 5% loss over 9 hours has dropped to around 2% loss. Not sure if it's temperature related or not though.

 

[Neanor]

I had the same issues as many have reported in this thread. Like many others the drain occurs between 60-66%. Each day I would charge to 80%, then drive 40 miles to work. My solution was to start charging to 66-68%, so when I got to work, SOC would show about 55%. The drain problem doesn’t occur, I have found any time I get to work with battery readings in the 50s% (so far it works 52-57%).

Use this method whether your commute is a few miles or much longer like mine. Avoid leaving car in the 60-66% SOC range. Calculate 55% plus battery percentage used to get to work, and set that as your charge limit.

 

[GoergeJetson]

I had the same issues as many have reported in this thread. Like many others the drain occurs between 60-66%. Each day I would charge to 80%, then drive 40 miles to work. My solution was to start charging to 66-68%, so when I got to work, SOC would show about 55%. The drain problem doesn’t occur, I have found any time I get to work with battery readings in the 50s% (so far it works 52-57%).

Use this method whether your commute is a few miles or much longer like mine. Avoid leaving car in the 60-66% SOC range. Calculate 55% plus battery percentage used to get to work, and set that as your charge limit.

I might give that a try. Similarly if I bumped the SOC up to 90% and I get to work with 78%, that should work as well.

 

[GoergeJetson]

I had the same issues as many have reported in this thread. Like many others the drain occurs between 60-66%. Each day I would charge to 80%, then drive 40 miles to work. My solution was to start charging to 66-68%, so when I got to work, SOC would show about 55%. The drain problem doesn’t occur, I have found any time I get to work with battery readings in the 50s% (so far it works 52-57%).

Use this method whether your commute is a few miles or much longer like mine. Avoid leaving car in the 60-66% SOC range. Calculate 55% plus battery percentage used to get to work, and set that as your charge limit.

So I bumped my SOC from 80% to 85% so when I get to work, I have 73%, doing so has basically eliminated the 5%-6% drain I was seeing when my SOC was at 68% upon arriving at work. I'm going to keep this up for a while and see if it continues to resolve the issue.

 

[KenC]

So, battery voltage discharge curves are very flat. It doesn't take much change in measured voltage for the SOC to be very different. Notice that temperature has an effect upon SOC as well. This example is for large temperature differences, but still, you can imagine how small temperature variations can have an effect upon measured voltage and the resulting SOC calculated by the BMS.

 

[GoergeJetson]

So, battery voltage discharge curves are very flat. It doesn't take much change in measured voltage for the SOC to be very different. Notice that temperature has an effect upon SOC as well. This example is for large temperature differences, but still, you can imagine how small temperature variations can have an effect upon measured voltage and the resulting SOC calculated by the BMS.View attachment 1056552

Sure but not all Tesla owners see this issue, if it were just a matter voltage vs temperature, everyone would notice this type of phantom drain. Besides fuel gauging is much more complex with specific fuel gauge chips that use coulomb counting as one method of gathering data for estimating state of charge. Also the temperature change is not significant when we are talking about seeing a 4% change after 1 hour of parking.

 

[saveforests]

I also have the same issue with my Model 3 SR+ 2019. I will lose 3 to 4% at the end of my trip and sometimes I gain the same amount at the end of charging cycle at night time. The temperature does not seem to make any difference. I have the problem for about 8 months now, so it has gone through nearly 4 seasons. Reached out to Tesla 2x and was dismissed, the first time I was told to let the car sleep (unplugged) for a few days, secondly was told as a normal behaviour for battery SOC to fluctuate by up to 5%.

 

[GtiMart]

That's it, it's not "a problem" that the SOC fluctuates a bit. State of charge is an estimate, not a precise measure. It will change a bit as the BMS adjusts/recalculates/works its magic. Battery temperature is one of the things that can affect that value that's all.