Identifying contactor clicks

[whitecotton]

Does anyone have an idea on the amount of contractors or the wiring pattern involved in the Model S. I noticed when I plug in my car the amount of clicks is more frequent then when I walk up to the vehicle to enter and then drive. I also noticed when I pre heated the car today (50 degree) outside temperature it sounded as though the coolant pumps or some else up front were running.

 

[roblab]

Does anyone have an idea on the amount of contractors or the wiring pattern involved in the Model S. I noticed when I plug in my car the amount of clicks is more frequent then when I walk up to the vehicle to enter and then drive. I also noticed when I pre heated the car today (50 degree) outside temperature it sounded as though the coolant pumps or some else up front were running.

Sounds normal. And after 3 years, the contact noises won't mean much. You get used to it. You should hear more clicks when you plug in than when you drive. Heat is by heat pump (A/C) I think, so you should hear compressors running. After a while you will worry if it doesn't click and hum. :smile:

 

[whitecotton]

I've already concluded its smarter than me so I try not to worry, however with my curious mind when it comes to mechanics (particularly Tesla mechanics) I can't help but wonder.

 

[CHG-ON]

My car makes all sorts of crazy sounds when sitting in the garage. It moans, groans, clicks and hums. It also self levels periodically. My friends are baffled by it and I find it very amusing. And software updates are even better. My neighbors used to ask what the heck was going on in my garage in the middle of night.

 

[Caligula]

Your neighbors can hear your car while its inside the garage?

 

[apacheguy]

When you plug in at night the contactors fully cycle (close, open). When you open the car door they only close.

 

[Ingineer]

There are basically 3 contactors (2 mains and one small relay) that are located in the pack. The small one is used for precharge, and usually you'll hear a clunk ... clack when it precharges, then closes. When it opens just one clunk as both drop out.

The coolant pumps (3) come on at full speed initially, then slow down to idle when the car first powers up.

There is no heat-pump mode in the Model S (unfortunately), but the A/C will run in the winder for cabin humidification.

There is also a line relay and a precharge relay in each charger (if you have 2) located under the rear seat.

When Supercharging, there are 2 more contactors also located under the rear seat that close. So there is a total of 4 large contactors, and a lot of small relays.

 

[AudubonB]

The small one is used for precharge, and usually you'll hear a clunk ... clack when it precharges, then closes. When it opens just one clunk as both drop out.

If I try translating that into English will you let me know if I've done it correctly? As follows:

"When the small contactor opens for a precharge, what you'll hear is a single 'clunk', as both legs of the contactor drop out simultaneously."

That's the best I've been able to do. Am I close? Is "legs" an appropriate term?

 

[whitecotton]

What exactly does the pre charge relay do?

 

[Ingineer]

The devices that use high-voltage have storage capacitors in them. Such as the Drive Inverter, Charger, DC-DC converter, etc. If the contactor were to just close and provide full battery power to these devices, there would be massive inrush current as the pack tries to fill the hungry capacitors and this would be very bad for the contactor's contacts (arcing). So the car closes the precharge relay which puts a resistor across one contactor (still open), and then the close the other contactor, wait and watch the voltage come up (relatively slowly) on the HV rails, then when it's equal to battery voltage they close the remaining contactor.

In the event of a fault, such as a short on the HV rails, the precharge resistor will never allow much current, so the rails will stay low, the car will detect this and can re-open the first contactor.

When the car goes to sleep, it opens the contactors together. It may also have a method to safely discharge the HV rails, such as by connecting the precharge resistor across the rails or by instructing the Drive Inverter to use power. (I have not determined this yet)

 

[apacheguy]

@Ingineer - The Model S used to open contactors in quick succession. Somewhere in 6.x they changed the contactor behavior such that one opens followed by about 30 s until the other opens. Is there any benefit to delaying the opening?

 

[a1syd]

I have an interesting problem - hoping you may help.

Car 2014 S85 39K miles,

I have a replacement 12v battery (but as i couldn't obtain exactly the same configuration, i have drilled and tapped the Lead contacts to make it like oem) however, they work loose from time to time, and have furred up) So past couple weeks, I have the usual please replace battery message. Anyhow, I for the first time in the last 10k miles, turned off Range mode on friday and had the heating up and fan up and really drove the car hard. Saturday, I drove the car, 1 mile and stopped at a destination, then went to drive home 10 mins later, and boot wouldn't open, lights were dim, and the batt went flat on me.

Put in a replacement 72AH car lead acid battery and bolted connections to the jump posts which has been adequate in the past.

However, this time, i cant hear the contactors clicking and i get loads of error messages, car may not restart, unable to drive, car needs service, traction control error etc.

Today, I towed the car home disconnected the 1st response and remove batt and made a more permanent connection. Then reconnected everything and if I listen really carefully, i can hear the contactors clicking in the normal pattern, but as quiet as a relay and not actually actuating.

I am still getting messages about low 12v power etc, even though I have 13.4V but I assume as the contactors haven't operated its down to them why I am seeing this 12v message still.

So, I would fairly confidently assume common dead contactor.

However, if I sit in vehicle, and on the screen select the full power off option, then press brake to activate, the contactors come and start clicking and everything is normal again and I can drive - although I still have the message about "Car may not Restart".

in this condition, I cannot restart the car if i turn it off (other that performing this procedure again) and I cannot charge the car.

Does anyone have any suggestions? checked all the 12v fuses and thermal etc, 12v power is ok, and contactor appears to operate under this test.

Can I get to contactors without fully removing batt back to test? can I find the cables to test the coil voltage?

I am not supported by Tesla so am a little stuck here.

Thanks

 

[Ingineer]

sounds like you have low iso and probably could use diags. Send me an email address and I'll send you some info. [email protected]

 

[terofin]

Hi, i have exactly same sound problem, did u get any help?

I have an interesting problem - hoping you may help.

Car 2014 S85 39K miles,

I have a replacement 12v battery (but as i couldn't obtain exactly the same configuration, i have drilled and tapped the Lead contacts to make it like oem) however, they work loose from time to time, and have furred up) So past couple weeks, I have the usual please replace battery message. Anyhow, I for the first time in the last 10k miles, turned off Range mode on friday and had the heating up and fan up and really drove the car hard. Saturday, I drove the car, 1 mile and stopped at a destination, then went to drive home 10 mins later, and boot wouldn't open, lights were dim, and the batt went flat on me.

Put in a replacement 72AH car lead acid battery and bolted connections to the jump posts which has been adequate in the past.

However, this time, i cant hear the contactors clicking and i get loads of error messages, car may not restart, unable to drive, car needs service, traction control error etc.

Today, I towed the car home disconnected the 1st response and remove batt and made a more permanent connection. Then reconnected everything and if I listen really carefully, i can hear the contactors clicking in the normal pattern, but as quiet as a relay and not actually actuating.

I am still getting messages about low 12v power etc, even though I have 13.4V but I assume as the contactors haven't operated its down to them why I am seeing this 12v message still.

So, I would fairly confidently assume common dead contactor.

However, if I sit in vehicle, and on the screen select the full power off option, then press brake to activate, the contactors come and start clicking and everything is normal again and I can drive - although I still have the message about "Car may not Restart".

in this condition, I cannot restart the car if i turn it off (other that performing this procedure again) and I cannot charge the car.

Does anyone have any suggestions? checked all the 12v fuses and thermal etc, 12v power is ok, and contactor appears to operate under this test.

Can I get to contactors without fully removing batt back to test? can I find the cables to test the coil voltage?

I am not supported by Tesla so am a little stuck here.

Thanks