Main Fuse

did you try looking in the pdf for first responders?

https://www.teslamotors.com/en_CA/own/service/firstresponders

I don't think there is a single main fuse - more like dozens of individual fuses for different systems. There are certainly several major fuses inside the PEM and ESS housings. The ESS fuses are only reachable by removing and opening the entire ESS (I learned this the hard way).

There is a service isolation for the ESS at the rear left side of the car.

I think he took out the "main shutter plug" It is on the left side of the battery pack and can be taken out to disconnect the power from the battery pack.

That seems pretty small to carry all of the current from the pack!

They told me to take it out to disconnect the pack. Think it is more or less the control power from the pack and that pack has it own relay that shuts off inside.

zack said:

That seems pretty small to carry all of the current from the pack!

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The ESS has a set of large relays. You can hear them engage when you open the car.

I believe the "main shutter plug" just controls power to those relays. Without the relays open, no power leaves the pack.

P.S. Tesla don't call them 'relays' but have some fancy name for them. Something like 'contracters'.

markwj said:

P.S. Tesla don't call them 'relays' but have some fancy name for them. Something like 'contracters'.

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"Contactors" would make more sense.

doug said:

"Contactors" would make more sense.

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Yep:

Roadster Technology - Power Control | Tesla Motors

The charge and drive modes are configured using a set of four large relays known as contactors. The contactors allow the semiconductor switches to be used to connect the battery to either the charge port or the motor. When the Roadster is turned on, a series of clicking sounds can be heard as the contactors close the connection to the motor.

smoothoperator said:

Reason I am asking is because in another thread a poster claimed to have removed the "main line" fuse as "directed by Tesla"

I was just wondering if this was bogus or true

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Perhaps the account of the removal event itself was not bogus, but I would say that removing any such main fuse or relay control is NOT going to "preserve the battery." The only way to preserve the battery is to leave the Roadster plugged in to power, ideally in Storage Mode for maximum preservation.

Doug_G said:

I suspect it will extend the life quite a bit if the car isn't plugged in. The car draws about 1% power a day to run the VDS etc. I expect pulling the plug will limit the drain to cell self-discharge, which could take a very long time.

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This is what I was told. The batteries in the workshop, not connected to a car, drain very slowly (although they do have a special maintenance rig to charge them outside the car, if necessary).

ernst said:

I think he took out the "main shutter plug" It is on the left side of the battery pack and can be taken out to disconnect the power from the battery pack.

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These photos look like the high voltage disconnect used in most, if not all, high voltage batteries to make them safer to service. It would be in series with the cells, and indeed it looks like it is designed for peak currents in the hundreds of amps. It's average or contineous current rating would be much less, about 1/5 of the peak rating or less, thus tricking zack's trained eye, which is probably accustomed to circuits designed to carry 80% of peak current on a contineous basis.

Also, don't forget that the cells will still slowly self discharge, even when completely disconnected.

GSP

In the case of a totaled Roadster, disconnecting the battery pack is probably more of a safety precaution than for preserving the battery.