Author Topic: why would a fuse be battery powered ?  (Read 1218 times)

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Offline 3roomlabTopic starter

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why would a fuse be battery powered ?
« on: November 27, 2023, 02:17:27 am »
I am obviously not an expert here
but why would a fuse (or this fuse in particular) be battery powered ?
any ideas ?

some search reveals that owners will be prompted to replace the fuse


munro live teardown actually shows that it is powered by a (smaller sub*) battery (15:44)
https://youtu.be/eYvjVXGBWXQ?t=944

*my bad, the wording of the question is a little weird
it appears that a tiny battery powers the fuse circuit which would blow the bigger battery circuit
« Last Edit: November 27, 2023, 05:18:52 am by 3roomlab »
 

Offline Someone

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Re: why would a fuse be battery powered ?
« Reply #1 on: November 27, 2023, 02:42:06 am »
Fuse for battery, not battery for fuse.

Where is the battery in the screenshot you posted? Looks like ceramic fuses to me.
 

Offline moffy

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Re: why would a fuse be battery powered ?
« Reply #2 on: November 27, 2023, 02:46:19 am »
It might sense the voltage drop across the fuse, hence it needs a supply i.e. battery, and provide a health indication, just a guess. :)
 

Offline retiredfeline

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Re: why would a fuse be battery powered ?
« Reply #3 on: November 27, 2023, 02:46:55 am »
Hopefully you'll never "power" the fuse. If you do it'll be time for a new one. :-DD
 

Offline Phoenix

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Re: why would a fuse be battery powered ?
« Reply #4 on: November 27, 2023, 02:59:46 am »
According to the tear down guy there are a couple of lithium batteries in the removable fuse part. They must power some sort of local sensing circuit that needs to be isolated from the main power and/or able to operate without power.
 

Offline ejeffrey

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Re: why would a fuse be battery powered ?
« Reply #5 on: November 27, 2023, 03:28:39 am »
Fuse for battery, not battery for fuse.

Where is the battery in the screenshot you posted? Looks like ceramic fuses to me.

It's the fuse for the battery and it has its own battery.  At least some Teslas have a pyrotechnic fuse for the traction battery.  It has a small lithium primary cell to activate it should the need arise.
« Last Edit: November 27, 2023, 02:33:21 pm by ejeffrey »
 

Offline uer166

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Re: why would a fuse be battery powered ?
« Reply #6 on: November 27, 2023, 03:53:32 am »
Fuse for battery, not battery for fuse.

Where is the battery in the screenshot you posted? Looks like ceramic fuses to me.

this is confidently incorrect.. Older Tesla pack fuses have a small lithium cell to provide an independent power source for the pyrotechnics of the fuse. Newer ones have energy harvesting design that steals energy across the main sense shunt.

The ceramic small fuses you see are very small "arc-taking" fuses after the main  >500A or whatever pyro fuse blows (which cannot take the HV arc).
« Last Edit: November 27, 2023, 04:02:11 am by uer166 »
 
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Offline uer166

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Re: why would a fuse be battery powered ?
« Reply #7 on: November 27, 2023, 03:56:27 am »
It might sense the voltage drop across the fuse, hence it needs a supply i.e. battery, and provide a health indication, just a guess. :)

This forum would have a much higher quality if people didn't speculate about something they're clueless about..
 
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Offline floobydust

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Re: why would a fuse be battery powered ?
« Reply #8 on: November 27, 2023, 04:50:37 am »
See: Pyrotechnic High Voltage Battery Disconnect  US Pat. 20130154352
 
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Offline Someone

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Re: why would a fuse be battery powered ?
« Reply #9 on: November 27, 2023, 07:12:09 am »
Fuse for battery, not battery for fuse.

Where is the battery in the screenshot you posted? Looks like ceramic fuses to me.
this is confidently incorrect.. Older Tesla pack fuses have a small lithium cell to provide an independent power source for the pyrotechnics of the fuse. Newer ones have energy harvesting design that steals energy across the main sense shunt.

The ceramic small fuses you see are very small "arc-taking" fuses after the main  >500A or whatever pyro fuse blows (which cannot take the HV arc).
Thanks for the better photo, on the backward screen language sure is.
 

Offline BradC

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Re: why would a fuse be battery powered ?
« Reply #10 on: November 27, 2023, 07:13:35 am »
The internet in general This forum would have a much higher quality if people didn't speculate about something they're clueless about..

FTFY
 
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Offline coppercone2

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Re: why would a fuse be battery powered ?
« Reply #11 on: November 27, 2023, 09:51:53 am »
what is the problem if someone hypothesizes about something. i think that's a good guess
its like getting upset someone did not research patents for you
 


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