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Is vampire drain still a thing?

jjrandorin

Moderator, Model 3, Tesla Energy Forums
Nov 28, 2018
11,364
13,199
Riverside Co. CA
It is completely fine to leave it plugged in AFAIK but the key difference here is about the lack of use (see musings below).

As jjrandorin implies the car won’t constantly micro charge (e.g. from 89.5% to 90%) but will wait until it has dropped a few percent then charge back up to your set limit (”87 to 90”). These kind of very shallow partial cycles aren‘t very harmful to lithium ion batteries compared to deeper discharges (other than the fact that using/cycling the battery at all puts wear on it, as does age).

The “charge to 90% and then set 70% and allow to fall, then repeat” strategy is likely aiming at getting to 90% fairly often (possibly for something like cell balancing, keeping the BMS estimate accurate) but not staying sat permanently at “high” SoC all the time due to lack of use mentioned. Hence allowing charge to fall gently down to 70% allows the battery to spend more time at a lower SOC which is nicer for battery life but still means you have a useful amount of charge at all times in case you do need it. This manually optimised pattern may be slightly better for the battery of a car that doesn’t see much use at the cost of a little effort but I suspect the difference is still likely to be small over the car’s lifetime so I wouldn’t sweat it very much either way.

[note: If the car is used most days then leaving it plugged in with a scheduled charge and the limit fixed makes most sense - the car won‘t spend long at a high SoC anyhow before it gets used and will sit at a lower SoC the remainder of the day until it’s time to charge again for the next day’s use. This is what I do - mostly because I have very cheap overnight electricity rather than worrying about the battery per se.]

In my specific case, I am not trying to balance the battery or anything (although I agree with your explanation here). In my case, I charge to 90% simply because thats what I have done since I picked up the car 2.5 years ago. My normal commute to work is 80 real miles round trip, and I plug in every time my car hits my garage, no matter how far I go.

Because I work a lot from home now (for the same reason many others do, as I mentioned), I can go days without driving, instead of driving 80 real miles a day. I have comparatively low battery degradation for my model 3, compared to some others who micro manage it.

I only change the slider to attempt to minimize somewhat contactor opening and closing, since I am not going anywhere.
 

2021srplus

Member
Jul 10, 2021
63
106
SF Bay Area
New Model 3 owner. I just discovered (the hard way) of easily losing at least 10 miles of range just being parked overnight with sentry mode ON, climate protection ON, and no 3rd party apps. This is my 3rd EV, but first Tesla, and I've never seen anything like it. With the climate protection OFF, sentry OFF, and no 3rd party apps on my phone, vampire drain is now (thankfully) almost non-existent.
 

jjrandorin

Moderator, Model 3, Tesla Energy Forums
Nov 28, 2018
11,364
13,199
Riverside Co. CA
New Model 3 owner. I just discovered (the hard way) of easily losing at least 10 miles of range just being parked overnight with sentry mode ON, climate protection ON, and no 3rd party apps. This is my 3rd EV, but first Tesla, and I've never seen anything like it. With the climate protection OFF, sentry OFF, and no 3rd party apps on my phone, vampire drain is now (thankfully) almost non-existent.
The term "vampire drain" has morphed a bit since I bought my model 3 (late 2018) and it was talked about then, till now.

The original meaning of "vampire drain" was "energy lost that we have no idea where its going, like a vampire coming in and sucking blood out of a victim in the night, where they dont remember it in the morning".

In other words, if the drain / energy loss had an explanation, it wasnt "vampire drain" back then, it was just "energy usage" or "drain".

Over time, however, the term has seemingly morphed to mean simply "energy lost". Lots of people use the term "vampire drain" along with "I had sentry mode on" for example (I am not picking on you at all, just pointing out the usage of the term now).

I find it somewhat interesting how even slang terms / internet speak can morph over time with different accepted meanings, just from usage.
 

brkaus

Well-Known Member
Jul 8, 2014
8,137
6,703
Austin, TX
New Model 3 owner. I just discovered (the hard way) of easily losing at least 10 miles of range just being parked overnight with sentry mode ON, climate protection ON, and no 3rd party apps. This is my 3rd EV, but first Tesla, and I've never seen anything like it. With the climate protection OFF, sentry OFF, and no 3rd party apps on my phone, vampire drain is now (thankfully) almost non-existent.
And if you have FSD, turn off summon standby. These are all features other EVs do not have. I wish Tesla would default everything to off or even run through a first time setup quiz that educates and enables features.
 

2021srplus

Member
Jul 10, 2021
63
106
SF Bay Area
Over time, however, the term has seemingly morphed to mean simply "energy lost". Lots of people use the term "vampire drain" along with "I had sentry mode on" for example (I am not picking on you at all, just pointing out the usage of the term now).
Agreed that the "vampire drain" has now morphed into "generic energy loss when vehicle is not actually in motion".
And if you have FSD, turn off summon standby. These are all features other EVs do not have. I wish Tesla would default everything to off or even run through a first time setup quiz that educates and enables features.
No FSD in mine. Even better would be if everything was default OFF, and when turning to ON a confirmation screen pops up that actually quantifies the % of battery loss per day to be expected when turning said feature on. Likewise, the % of battery loss per day that's displayed should vary depending on the usable capacity of the battery (greater % loss for SR, SR+ and reduced % loss for MR, LR, LR AWD).
 
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MaskedRacerX

Member
Dec 13, 2020
353
422
Vilano Beach, FL
We had our M3P parked in the covered parking at the Orlando (MCO) airport, from a Friday ~3p through Tuesday ~12p, all "active systems" turned off - i.e., no overheat, no sentry mode, car doesn't have FSD. I also made a point to not ping it pretty much the entire time, my first wakeup/check was Monday afternoon.

IIRC, we parked it with 48% charge, and got back, it was sitting with 46%.

(I think I originally thought just 1% back when I originally posted about this, but we all compared notes and the above seems correct)

Edited to add: I believe I was on 21.4.18.10 at the time.
 
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MG535

3SR+ ordered 7/22 (blue/black/19s). EDD 9/10-16
Jul 22, 2021
150
106
NJ USA
As long as you have everything turned off, Dashcam, Sentry mode, Smart Sunmon, climate over protection mode and any other 3rd party apps that will poll your car like Teslafi or A better route planner etc… you should be fine, I use TezLab to push it into Deep Sleep mode and leave it alone. Zero miles or % loss.

Fred
How much does Sentry Mode consume? I lost about 50 miles over slightly less than 48 hours.
 

AlanSubie4Life

Efficiency Obsessed Member
Oct 22, 2018
11,141
14,108
San Diego
How much does Sentry Mode consume? I lost about 50 miles over slightly less than 48 hours.
Seems about right. Depends on the vehicle. SR+ consumes substantially more miles (20% more) than a Performance 2021 (but exactly the same amount of energy of course - so it is the same).

My rule of thumb is 200W for Sentry mode (which may be slightly high). So it all works out beautifully, exactly as expected.
 

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