Supercharging limit and avoiding the dreaded 'thunk' noise

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#1
I wasn't able to find this topic covered so I apologize if it is a rehash but I am planning to use a supercharger for the first time on an upcoming road trip and had a question.

Has anyone played with reducing the amp. limit while charging to avoid excess heat while charging?

Reading about the thunking noise people hear under high charging rates, even if there isn't any permanent damage to the car, I would like to avoid excess heat and charge rates on my battery pack. My trip is actually inside my SR+'s range so I'm really only charging to make sure I can get a full charge overnight where I am staying (probably 120v plug at best). I can deal with sitting at the SC for some extra time if it protects the battery or charging hardware in any way.

Thanks!
 

Jim H

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#2
I wasn't able to find this topic covered so I apologize if it is a rehash but I am planning to use a supercharger for the first time on an upcoming road trip and had a question.

Has anyone played with reducing the amp. limit while charging to avoid excess heat while charging?

Reading about the thunking noise people hear under high charging rates, even if there isn't any permanent damage to the car, I would like to avoid excess heat and charge rates on my battery pack. My trip is actually inside my SR+'s range so I'm really only charging to make sure I can get a full charge overnight where I am staying (probably 120v plug at best). I can deal with sitting at the SC for some extra time if it protects the battery or charging hardware in any way.

Thanks!
No need to reduce amps while charging at a supercharger. As quick as the superchargers are, you would only need to charge for a short time, since your trip is within your SR+'s range. If you are charging overnight with a 120v at best, the charge amps will already be at a very low rate. 8hrs overnight at 120v might get you around 50 miles, where you can achieve that at a supercharger in less than 10 minutes, if your SOC is low enough.
Plug it in to the supercharger and be amazed by how fast the car charges.
 

Silvermagic3

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#3
Being cautious is understandable with your new car, however I don't think you have anything to worry about. I've done a ton of supercharging and have never heard a thunking noise or had any reason to believe it was overheating (and I've charged in Phoenix in the summer). But to answer your question, I do think you can adjust the charge rate on the superchargers like any other connection, however I've never tried.
 

GDN

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#4
You can't and don't want to avoid the "thunks" they are not the battery changing shape or anything under distress or heat. They are relays connecting and disconnecting for different aspects of the charging process. Could be as simple as the 12v battery charging system kicking in. They are normal. Supercharging is normal.
 

Ed Woodrick

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#6
I wasn't able to find this topic covered so I apologize if it is a rehash but I am planning to use a supercharger for the first time on an upcoming road trip and had a question.

Has anyone played with reducing the amp. limit while charging to avoid excess heat while charging?

Reading about the thunking noise people hear under high charging rates, even if there isn't any permanent damage to the car, I would like to avoid excess heat and charge rates on my battery pack. My trip is actually inside my SR+'s range so I'm really only charging to make sure I can get a full charge overnight where I am staying (probably 120v plug at best). I can deal with sitting at the SC for some extra time if it protects the battery or charging hardware in any way.

Thanks!
So, as your first time to use a Supercharger, plug the car into an unpaired pedestal, if possible and go have a break. When the car is full, move it.
That's all you need to know and stop reading about all the other crap that you're seeing posted.

If you want to try to adjust the charge rate, go for it. I'd suggest coffee instead, since you can't adjust the charge rate on a Supercharger. Feel free to sit there and listen for the thump that will probably never happen, but again, coffee is a much more productive use of time.

The only thing that you may notice is that other cars around you and at one point, possibly yours, will have the "fans" on high as the A/C is running to cool the batteries down. Don't worry about it.

In other words, plug in, take a break or get a meal and just don't worry about it. That's what I did about 8 hours ago.

(and FYI, assume that 95% of the things that you read on the forums will NEVER apply to you)
 

garsh

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#8
Reading about the thunking noise people hear under high charging rates, even if there isn't any permanent damage to the car, I would like to avoid excess heat and charge rates on my battery pack.
It would be nice to get some sort of official word from Tesla that we can point to, but that thunking noise is nothing to worry about. It doesn't mean that the battery is getting too hot. Tesla has designed a very robust cooling system for the Model 3 that can easily handle the heat generated from supercharging. They also have safeguards in place so that the car will charge at a lower rate if the temperature is too high or too low. In fact, normally when people experience slow supercharging speeds, it's due to the battery pack not being warm enough to accept higher power.

The "thunk" noise is just the sheet metal above the battery pack being a little out of tolerance, and making a noise when it expands or contracts. Nothing structural is being harmed, and the battery packs themselves aren't being damaged. It's just a little unnerving the first few times you hear it.
 

orekart

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#9
The "thunk" noise is just the sheet metal above the battery pack being a little out of tolerance, and making a noise when it expands or contracts. Nothing structural is being harmed, and the battery packs themselves aren't being damaged. It's just a little unnerving the first few times you hear it.
Really? I thought it was the chunky coolant loop solenoid action cycling coolant to moderate battery pack temperature...
 
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#10
Thanks for all of the replies everyone and I will charge the car like normal! I knew most people use SC all the time with no issue and that Tesla wouldn't have designed the system to not be able to handle their own chargers but even some non-structural sheet metal moving around didn't sound appealing to me. I think getting the car back up around 50-60% as people have suggested being the most efficient way to do it will be my strategy. When I park for the night I will just finish out the charge to top things up.
 

garsh

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#11
Really? I thought it was the chunky coolant loop solenoid action cycling coolant to moderate battery pack temperature...
There are two different noises that could be characterized as a "thunk", I guess. I hear them both on my car.

One is a solenoid. It'll correspond to the start of charging. It sounds mechanical - it sounds like it "belongs".

But there's another noise that not everybody hears in their car. It's the sound of sheet metal flexing. If you pound or press on the rear floor (as seen in the videos below), you can hear it (at least in some cars). But when it's caused by heating instead of by pushing or pounding, it's this same sound, but much louder and quite startling. I'll hear it in the middle of a supercharging session, and I'll often hear it again a few minutes after a supercharging session (as things cool back down). I even heard it one time while just driving up a mountain (I assume just from the pressure change).

 

mswlogo

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#12
Sometimes I wonder if it’s what the fluff mat would have helped prevent that they eliminated because the robot had trouble putting it on.

It does sound like sheet metal “popping ” but dampened from within the cockpit.

Same sound can happen sometimes while driving too. Mostly after a super charge when things maybe cool off.

The only way to prevent (or reduce) it would be to not supercharge.

Charging in a stall paired with another car will often reduce your max charge rate.

One reason why they don’t allow charging slower is you are tying up a stall longer that could serve someone else.
 

Greg Appelt

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#16
Have any of you sat in your vehicle while a software update is installing - there are all kinds of loud thunks due to relays switching. I've heard similar (quieter) sounds while at the SC. I tend to believe the sounds are relays much more than they are due to sheet steal flexing like a cookie sheet.
 

garsh

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#17
Have any of you sat in your vehicle while a software update is installing - there are all kinds of loud thunks due to relays switching. I've heard similar (quieter) sounds while at the SC. I tend to believe the sounds are relays much more than they are due to sheet steal flexing like a cookie sheet.
Yep. As I said, I hear both kinds of sounds in my car. The metal expansion sound is sometimes soft, sometimes very, very loud. But it's a different, sharper sound from the satisfying "clunk" of a solenoid.

Bjorn actually managed to record the sound.
 

mswlogo

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#18

SoFlaModel3

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#20
Hey @SoFlaModel3 , does your car's floor have the issue shown in the videos I posted above?
He’s in SoFla... the battery is always hot and there are no altitude changes. :p
I heard thuds and thunks when charging sometimes but none of those noises otherwise. A good consistent source of heat and battery fluff help my car though ;)