Comment by jbm | Hacker News Reader

Comment by jbm | Hacker News Reader

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I have a model 3 from 2019 that is not quite as extreme, but gets similar issues. It should have 350 km of range. I see some people posting insane wh/km numbers, but I think I'm doing a pretty decent job (130-140 wh/km or ~225.31 wh/mile average outside of the winter); I barely get 270-280km, max.

The issue isn't the driving range, but rather the unexplained loss of range. I'm talking about losses of 7.5% if I leave it parked in front of my house for an hour or two. I have photos too; if you reach out to Tesla, they curtly tell me the battery is fine.

A vague "you need to keep your car plugged in" is frankly insane, what if I went on a 100km trip, left my car outside for an hour or two, and came back without enough range to go home? I've heard people say to disable the app on my phone, but that frankly seems like a Tesla problem, not a "me" problem.

I still enjoy driving the car. I just wouldn't trust it for long range driving. I probably will buy Hyundai or BYD (if Canada lets them in) next time.

Tip: if you turn off both the overheat protection and sentry mode, the phantom drain becomes 0%. I know this because I left my car idle for 2 months and it only lost 1% during that time.

It is fine to turn these off, other cars don't even have these and they are fine.

Don't you want the overheat protection at the end of a long drive? [edit: or is this just for the cabin temperature?]

I've also noticed a bit of drain when camping. It doesn't help that you often open/close the doors/trunk to access stuff ;)

My understanding is that it is for the cabin.

BTW, for the cabin I did two things:

- I installed a permanent shade for the sun roof. The sun roof is the stupidest thing ever, I hate it.

- In the summer, I usually put one of those shiny umbrellas to the front windshield when parked.

These two things alone reduce the cabin heat to an okay level.

I live in Calgary, overheat protection is only needed in one month in summer ;) I also installed the sun screen, the glass roof had a stress fracture and I didn't want to pay the $2k to fix it.

Idle draw is a pretty common complaint for Teslas.

Yes, I think that's a definite issue for the generation of Model 3 that I have. I had to disable sentry because it was taking a significant chunk too (and I didn't even bother putting a disk inside).

While the idle draw is relatively high on Teslas compared to other EVs (even without sentry mode enabled), 7.5% is quite high. I track my stats with Teslamate and it estimates typical SoC loss of 1% over a day.

What I have seen is that the BMS may update its SoC estimate after driving, and I've seen it adjust the estimated SoC up or down by as much as 5% in some cases.

I get that from a planning perspective, it still stinks to have range than you thought you did an hour ago, but it's not all that different from the variation you might get with an analog dial on the gas tank, just that it's much easier to notice and track when it's digital and showed as a precise number.

5% to 7% is pretty normal for me - in both summer and winter. This is just leaving the car in front of my house for a few hours (let's say I don't want to park it in the separate garage).

https://imgdrop.io/image/IMG-2984.ADiI7

It's not the end of the world for driving around town with less than my whole family (which is 90% of my driving) but it's definitely annoying to come back to a car with 50% charge and see it with 43. I imagine it would be terrifying for a 20 -> 13, especially with the lack of supercharging infrastructure where I live (Calgary).

Huh, that's quite a bit more than I would expect. You already ruled out the 12V battery in the other thread, but there could be some other factors that would keep your car awake.

Does it only happen when you park in front of the garage at home, or does it also happen if you go out somewhere? For example, it might be struggling to connect to your WiFi at home (if you set it up with your home WiFi credentials) to download updates or upload telemetry, which would keep it awake longer than normal as it tries to make do with kilobits per second of usable bandwidth.

First, I appreciate the suggestions; thank you.

The issues do happen a lot in front of my house (which has very poor cell phone coverage). I've had lessor drops elsewhere.

I was wondering about the wifi myself too. I don't have wifi in front of the house and I didn't configure wifi either; I've actually installed wifi in my garage and left the car inside to see and I would get similar power losses.

I wonder if there is (a) a battery warming issue or (b) an issue because my phone w/ the Tesla app & bluetooth on is too close to the car, leading to it not going into standby mode? I don't think it is the former because it would be categorised differently (and it would not happen in summer). Turning off bluetooth on my phone everytime I come inside is honestly a bit insane and I would put that in the "It's a Tesla App problem"; but I don't hear about that issue from other drivers.

The real unfortunate part is that there is no way for me to get this diagnosed. It's been a problem since I bought the car, but it seems to be getting worse over time.

I’ve only seen an EV do that once. The 12V battery died about a week later. (Or, rather, I left it parked, and after pouring 10% (!!) of the high voltage battery into the 12V, it gave up and completely shut down.)

Anyway, I wonder if Tesla’s are missing the “if 12V is completely shot, give up” logic. Replacing it is cheap and might fix the car. Some models let you monitor the 12V charger with an OBD-II dongle.

That’d let you prove me right or wrong.

Just to be clear, I actually had Tesla replace the 12V last year because I was worried that was the cause.

The problem did not improve.

I'll be getting a leasing Hyundai Ionic 6 at the end of this month. Hit me up if you want my thoughts on it later.

My Y has been parked at an airport garage for two weeks. It has lost 1% in that time.

My M3 was parked for 3 months and went from 80% to 60% which I'm perfectly happy with. Just arrived home, got back in it and drove. It was on WiFi, no sentry, and checked in on it only every 3 weeks or so.

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