Thoughts on a Tesla Model 3

[triangles]

jmueller065, I read that article about vampire drain. I think part of the problem is there is no "off" button on the Tesla. You literally get out and walk away when the phone key gets out of BT range the car locks and "shuts down." Apparently Tesla's TMS is always active. Although supposedly disconnecting the 12V does shut everything down and disconnects all loads on the HV battery.

Carbuff, I consider the "design flaw" of the ffe the fact that there is nothing to prevent misbehaving modules from drawing on the 12V when they should be off and no data logging of what didn't shut down when it should have. By design the FFE and for that matter any car with keyless entry must have a small load on the 12V battery since you can't monitor for the presence of a fob without power. Most cars can do this with well under a 50mA load on the 12V battery. Most automotive 12V batteries should last more than a month with this type of load.

Since heat damages a lithium battery I supposed I could live with some vampire drain in extreme heat but there's no excuse for it sitting in a 71F garage. Cold really doesn't harm a battery so there's no need to waste energy to heat the battery. The only cold consideration I am aware of is that you really should heat the battery before you charge it when it is cold to avoid battery damaging reactions that happen at subfreezing temps.

If the Tezlab app is accurate I lose about 14 miles of range per day the car just sits. That's almost 100 miles per week!!! Hopefully they can fix this with an OTA. If not, I found a key fob controlled 12V disconnect switch when I was at my wits end with my FFE 12V issues. I think this may be what I use with my Tesla to stop the HVB vampire drain when I park the car for extended periods of time. The 8.5mA draw on the 12V battery should not be a problem and if I put the battery on a tender, in theory I should be able to store it for years and only lose a few battery %. Not that I would, it's too much fun to drive.

[jmueller065]

Is that 14 miles of range lost for sitting an 8 hour workday, or 24 hours, or overnight? That is a pretty significant amount that would add up over a week or month.

[jmueller065]

Sabotage! LOL
https://www.cnbc.com/2018/06/18/elon-mu ... otage.html

Wow... pretty serious if they have proof, if not then its just paranoia!

[triangles]

Thanks I now have that Beastie Boys song going thru my head

That's 14 miles/24h. TBH I don't know that I trust that figure. The manual says 1% per day which is more like 3ish miles/24h which is still unacceptable IMHO. I have seen rumblings on another forum that the Tezlab app either exaggerates or causes increased vampire drain by pinging the car too often not allowing it to go to sleep. Below is what my app says for the past 7 days.

It also shows the past 30 days which looks the same to me but then again I've only had the app for about a week. I suspect it's also including the energy used for preconditioning as vampire drain. That would make a lot of sense as the tallest bar on the graph that I interpret as yesterday was the hottest with the most preconditioning.

When I first got the car I let it sit for 3 days and it lost several miles, probably about 10ish. I wasn't keeping track so I don't have exact numbers I just remember noticing I had about 10 fewer miles. I initially shrugged this off as a guess-o-meter error but now realize it was vampire drain. This seems to be more inline with 3ish miles per day or about 1% in the manual.

[jmueller065]

That is true the instrumentation you're using to measure the drain may have an affect on the system that should be accounted for.

[campfamily]

That is true the instrumentation you're using to measure the drain may have an affect on the system that should be accounted for.

Schrödinger's Cat?

Sorry, a bit early for quantum mechanics humor.....

Keith

[triangles]

Just found this in my email. apparently the app emails me a daily report. What was clipped just off the top of the screen grab is that I drove 78mi in the last 7 days. The 99% efficiency means my driving was just under what the guess-o-meter thinks I should have been able to drive. Then it breaks out how energy from the battery was used.



Looks like the sabotage was real! Disgruntled employee who didn't get the promotion he wanted. They must have caught him in the act or something.

[triangles]

So after having a Model 3 for a couple months I thought I'd post a little update. Probably the biggest difference between the way the TM3 and FFE drives is the regenerative braking. The FFE complicates things trying to blend regen with physical braking. With a Tesla things are a little more simple. You "throttle" the amount of regen by how much you lift on the accelerator. Full regen = no foot on accelerator. The brake pedal is simply just the physical brakes. Under typical driving with the TM3 you are going single digit speeds when you use the physical brakes to come to a complete stop. Almost 1 pedal driving. I absolutely love that creep can be disabled and the Hold function which allows you to take your foot off the brake pedal and not worry about rolling away. I still would like an easier way to freewheel as sometimes I like to just coast down to a stop and it's very difficult to find the spot where you aren't using any regen and aren't supplying any power to the wheels. Putting the car in neutral while a little awkward seems to work for this. There is a bar graphic right under the speedo that gives a quick visual cue as to the amount of regen or power being expended that makes controlling throttle and regen much more elegant.

And sadly while vampire drain is real with a Tesla, the 3rd party apps such as screen grabs I posted above seem to be wildly inaccurate and can actually cause greater vampire drain. I've stopped using all 3rd party apps and my car has done several OTA updates since then. So not sure what really happened but vampire drain is minimal for the brief times I don't drive it. I'll revisit this in the winter when I'm driving it less. I may end up installing a 12V disconnect as mentioned above for instances of long term storage or simply unhooking the 12V battery.