new model Y owner with questions on charging

[stlgrym3]

i just picked up my 2023 MYP 2 days ago, have couple questions on charging.

1. the battery system keeps making noise while charging constantly. i know they have something in place to keep the battery temperature within normal range, and the car was sitting in cold last few days prior my delivery, but it's making this humming sound constantly whenever i plug in to charge at home. is this normal?

2. my previous car was a 2018 model 3 dual motor. at the time of purchase (5 years ago), i was told by Tesla to plug in whenever i get a chance. even when it's fully charged, just plug in to conserve the battery. last year when i had a mobile service call, the tech told me the newer Teslas are the opposite, they now recommend to deplete the battery as low as possible before you plug in to charge. which way is the correct charging etiquette now for newer Teslas?

 

[GtiMart]

When the car is awake, it will run pumps to circulate coolant. You might hear the pumps. If the car needs to generate heat to heat the battery, for example during preconditioning or to charge if the battery's cold, you'll also hear humming from the motors or your heat pump running. All that is normal.

That second comment doesn't make sense. The recommendation to plug the car when you can still applies. That's just so the car can charge if its SOC ever gets lower than your charge target. There's nothing else to it. As for the actual target SOC that you configure, that's up to you. There are plenty of threads you can read around here that will describe the pros and cons of all options. There is no "perfect" SOC that optimizes all variables.
However it is not true that Tesla would recommend letting the car go low. That comes from discussions around here.

 

[zoomer0056]

they now recommend to deplete the battery as low as possible before you plug in to charge

That's a new one.

 

[stlgrym3]

That's a new one.

i don't remember his exact words, but was something like the battery needs to experience low depletion once a while. if you keep the battery at full or near full all the time, then something might go wrong when it start charging from fully depleted state, or something like that.

 

[stlgrym3]

When the car is awake, it will run pumps to circulate coolant. You might hear the pumps. If the car needs to generate heat to heat the battery, for example during preconditioning or to charge if the battery's cold, you'll also hear humming from the motors or your heat pump running. All that is normal.

That second comment doesn't make sense. The recommendation to plug the car when you can still applies. That's just so the car can charge if its SOC ever gets lower than your charge target. There's nothing else to it. As for the actual target SOC that you configure, that's up to you. There are plenty of threads you can read around here that will describe the pros and cons of all options. There is no "perfect" SOC that optimizes all variables.
However it is not true that Tesla would recommend letting the car go low. That comes from discussions around here.

so it's normal for the sound to go on for the entire night?

 

[spsheridan]

On item number 2, it’s not clear whether you’re talking about home charging or public charging. At home, the recommendation is still to keep your car plugged in to maintain your desired SOC. However, your etiquette comment implies you’re referring to public chargers. Guidelines for the use of public charging would be different than at home. When using public charging, particularly on a road trip, it’s better to let the battery drop to a fairly low (but safe) SOC before charging again and then not charge to a full 100% but just enough to reach the next charger, with some margin. This minimizes the time you spend charging and is kinder to others who may be waiting to use the public charger. It's possible the tech was referring to letting the SOC drop for charging on road trips. The Tesla app provides good guidance on when and where to charge at Superchargers and for how long on road trips.

 

[zoomer0056]

the battery needs to experience low depletion once a while

Ok, now you're giving us more info than the original post. Do a search on TMC for battery threads. A lot of them say the BMS needs a high depth of charge (deplete low then charge high) "once in a while" to calibrate . . . but I really don't know.

 

[starise]

i don't remember his exact words, but was something like the battery needs to experience low depletion once a while. if you keep the battery at full or near full all the time, then something might go wrong when it start charging from fully depleted state, or something like that.

I remember several saying it isn't good to rountinely go below 20% . Going below a certain threshold apparently resets the BMS in some way. Seems the guess-o-meter can get slightly skewed sometimes and running the battery back down to 20% resets it.

The only batteries I have heard that can be charged to 100% all the time are the LFP batteries in M3 base. You "can" also do the same with li-on batteries in the Y, but due to their composition it's better to charge to 80/90% unless you are taking a long trip. What we "can" do and what is best seem to be two different things.

In attempting to make sense of this, It seems to me the 2170 Li-on batteries in the LR Y like to have some play because you save some cycles into the future by not fully charging. Or a person "could" just charge to 100% but it may affect longetivity of the batteries slightly. Regular supercharging to max is what makes the biggest hit on the batteries. I'm sure someone will correct me if I'm wrong.

 

[jjrandorin]

i was told by Tesla to plug in whenever i get a chance. even when it's fully charged, just plug in to conserve the battery. last year when i had a mobile service call, the tech told me the newer Teslas are the opposite, they now recommend to deplete the battery as low as possible before you plug in to charge.

i don't remember his exact words, but was something like the battery needs to experience low depletion once a while. if you keep the battery at full or near full all the time, then something might go wrong when it start charging from fully depleted state, or something like that.

These two statements are pretty different. The first one implies "all the time" and the second one says "once in a while" (which matches many other threads information on the topic), and doesnt contradict at all the statement to "plug it in all the time.".

 

[GtiMart]

so it's normal for the sound to go on for the entire night?

If you are plugged in a 120V outlet and live in a cold climate, it might need to heat the battery regularly during the night yes. Otherwise I would not expect heating to happen all night, but I would certainly expect the pumps to run all the time as the car charges or is otherwise awake yes.

 

[jcanoe]

If you are plugged in a 120V outlet and live in a cold climate, it might need to heat the battery regularly during the night yes. Otherwise I would not expect heating to happen all night, but I would certainly expect the pumps to run all the time as the car charges or is otherwise awake yes.

In the Tesla Model Y battery warming only occurs when preparing to charge, while charging or while preconditioning. Battery warming can also take place while driving and when preconditioning for Supercharging (also while driving).

Charging in low temperatures, i.e. less than 5C using Level 1 (120V) charging can take longer than expected as the Tesla Model Y will have to warm the battery if the battery is cold before charging can begin. The power to warm the battery comes from the battery and is replenished from the grid power. (This extends the total time needed to charge the battery.) A good strategy when charging using 120V in winter is to start charging as soon as you arrive at home or work so that the battery is already warm from the Tesla Model Y just having been driven.

If your Tesla Model Y is making sounds while parked it could be due to cell balancing. The computer requires cooling and has a coolant valve and pump so that could be what you hear; also the radiator has a fan. The Tesla Model Y will regularly send data to Tesla, this could trigger the CPU cooling cycle.

 

[stlgrym3]

If you are plugged in a 120V outlet and live in a cold climate, it might need to heat the battery regularly during the night yes. Otherwise I would not expect heating to happen all night, but I would certainly expect the pumps to run all the time as the car charges or is otherwise awake yes.

Yes I’m using 120v outlet and I’m in Southern California, over night outside temperature has been about low 40s in my area, but my car parked in a garage with no heater on.

 

[stlgrym3]

i remember my previous model 3 would make occasional noise while charging at home with 120v, but my new MYP is making high pitch (not loud) sound when charging (using 120v home outlet) seemingly whenever i go to the garage. i heard it when it started charging, couple hours into it, and in the morning when i drive the car. so i'm not sure if the noise actually did stop middle of the night or it gone on the entire night.

here's my theory, the car had been sitting in cold for a few days before i took delivery last week, and temperature in socal recently is pretty cold (low 40s to mid 50s), and i'm using 120v outlet to charge. all these factors contribute to battery heater has to work overtime to keep battery warm while charging at slow speed, hence, the constant noise from the battery management system is my theory correct? today i'm going to supercharge it hoping the battery management system can finally get enough juice at once, and see what happens later when i charge it at home.

 

[stlgrym3]

another factor to add. i'm using the leftover mobile wall connector from my 2018 Model 3 to charge my new MYP, could this be a factor for the high frequency noise when charging? the wall charger is almost 5 years old.

 

[jcanoe]

i remember my previous model 3 would make occasional noise while charging at home with 120v, but my new MYP is making high pitch (not loud) sound when charging (using 120v home outlet) seemingly whenever i go to the garage. i heard it when it started charging, couple hours into it, and in the morning when i drive the car. so i'm not sure if the noise actually did stop middle of the night or it gone on the entire night.

here's my theory, the car had been sitting in cold for a few days before i took delivery last week, and temperature in socal recently is pretty cold (low 40s to mid 50s), and i'm using 120v outlet to charge. all these factors contribute to battery heater has to work overtime to keep battery warm while charging at slow speed, hence, the constant noise from the battery management system is my theory correct? today i'm going to supercharge it hoping the battery management system can finally get enough juice at once, and see what happens later when i charge it at home.

When temperatures are below 40F the Tesla Model Y may warm the battery prior to charging or while preconditioning before driving. You could be hearing the sounds of the coolant pump as the battery warming is performed. Battery warming in the Tesla Model Y uses the drive unit stators. The drive unit motor stators are fixed, I am not sure if any sound produced from the motor stators as they warm up and the warm coolant from the drive unit is sent through the battery pack. Stator heating uses 3.5kW per drive unit (for a total of 7kW). (This is ~5X the power that is available from Level 1 charging at 120V and 12 amps so the power used for stator heating, warming the battery comes from the battery.) It would take additional time, perhaps 30 minutes or longer to replenish the energy taken from the battery to warm the battery, extending the time time needed to complete the charge cycle.

 

[stlgrym3]

When temperatures are below 40F the Tesla Model Y may warm the battery prior to charging or while preconditioning before driving. You could be hearing the sounds of the coolant pump as the battery warming is performed. Battery warming in the Tesla Model Y uses the drive unit stators. The drive unit motor stators are fixed, I am not sure if any sound produced from the motor stators as they warm up and the warm coolant from the drive unit is sent through the battery pack. Stator heating uses 3.5kW per drive unit (for a total of 7kW). (This is ~5X the power that is available from Level 1 charging at 120V and 12 amps so the power used for stator heating, warming the battery comes from the battery.) It would take additional time, perhaps 30 minutes or longer to replenish the energy taken from the battery to warm the battery, extending the time time needed to complete the charge cycle.

thank you for the thorough reply, so it's normal to have high frequency sound coming out of front end of the car for long stretch of time when using 120v charging? wish i can upload my video, but i don't have a youtube account.

 

[jcanoe]

thank you for the thorough reply, so it's normal to have high frequency sound coming out of front end of the car for long stretch of time when using 120v charging? wish i can upload my video, but i don't have a youtube account.

Level 1, Level 2 charging each require the on-board charger to step up the voltage from the grid to ~360V to 400V to charge the high voltage battery. Supercharging bypasses the on-board charger as the DC voltage from the Supercharger station can be sent directly into the high voltage battery. The Tesla Model Y can produce many different sounds as there are coolant circulating pumps, radiator cooling fan, and electronics active during charging.