Victron SmartShunt 500A problem (blowing fuses)

J.P.

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Oct 9, 2020
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25
Several months ago I purchased a Victron SmartShunt 500A off Amazon. About 6 weeks ago I finally installed it. It worked the day I installed it just fine. I was able to connect with the app and look at the settings. Weekend before last I went to the building and tried to connect with the shunt and the app could not locate it. I finally figured out that it had no power, the fuse was blown. I purchased new 1 Amp Slow Blow fuses (glad I got more than one) and tried to replace it last Saturday but it kept blowing the fuse immediately. I tried 3 times with the same result. I even turned the entire system (panels, charge controllers, and inverter) off including the batteries (Smart BMS's), replaced the fuse and then turned just one battery pack back on. The fuse burned through immediately.

I went to the Victron site and put in a Support Request detailing just what I said above. They forwarded my request to a dealer. Below is his response.

"I’m responding to the issue you're having with a blown fuse. That fuse is in line before the power gets to the smartshunt. Something from the battery must be causing it to blow. Its there to protect the smartshunt from a battery surge. A quick way to test this would be to take another battery and hook the smartshunt power cable to it and see if the fuse blows. Let me know what you discover."

Does this make sense to anyone? The battery is somehow surging too much amperage into the shunt and blowing the fuse?

Has anyone else experienced this problem?

Anyone have any ideas?


Thanks,
J.P.
 

mikefitz

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May 28, 2020
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The cable with the small fuse feeds power to the shunt electrics from the battery positive pole. The fuse value is one amp.
For it to blow there is a path to the battery negative either with a cable fault or faulty circuit in the Smart Shunt.
The dealer response is rubbish.
Is the wire at the Smart Shunt correctly inserted into the fast connect?

Mike
 

J.P.

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Oct 9, 2020
Messages
25
The cable with the small fuse feeds power to the shunt electrics from the battery positive pole. The fuse value is one amp.
For it to blow there is a path to the battery negative either with a cable fault or faulty circuit in the Smart Shunt.
The dealer response is rubbish.
Is the wire at the Smart Shunt correctly inserted into the fast connect?

Mike
IMG_3627c.jpgIMG_3630c.jpg
The Inverter is to the left. The Battery is to the right.
 
Last edited:

Sanwizard

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Is this a 48V system? You may have surge going on if so. The Blue Sea switches are only certified UP to 48V. Also, those flat chinese breakers are known to have issues.
 

J.P.

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Oct 9, 2020
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Is this a 48V system? You may have surge going on if so. The Blue Sea switches are only certified UP to 48V. Also, those flat chinese breakers are known to have issues.
It is a 48V system.

Are you saying the Blue Sea Switch is only certified to an ABSOLUTE 48.0V and not a nominal 48V system that might reach 57V?

Since the switch and breaker are both downstream of the Shunt (which is hooked directly to the cable coming off the batteries) , what would be the mechanism where they could be causing the problem of forcing too much current into the shunt and blowing the fuse?

What kind of issues are you referring to?
 

Sanwizard

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It is a 48V system.

Are you saying the Blue Sea Switch is only certified to an ABSOLUTE 48.0V and not a nominal 48V system that might reach 57V?

Since the switch and breaker are both downstream of the Shunt (which is hooked directly to the cable coming off the batteries) , what would be the mechanism where they could be causing the problem of forcing too much current into the shunt and blowing the fuse?

What kind of issues are you referring to?
I have no idea where your short is, but there is a short or a surge somehwere causing the fuse to blow. Yes, the Blue Sea is not rated for above 48V, especially under load. I had bought one myself, and called their support line about that, as when we charge, the voltage is up to 58V at times. Their rep was very up-front, and indicated the switch could arc when switched if volts were above 48V DC.
Also, others have been complaining of shorts in those flat chinese breakers.

I would start by disconnecting loads( remove the load side cable on the shunt) and then then connect the pos shunt wire directly to battery positive. Also try the aux port on the shunt, and see if the fuse blows. If it does, the shunt is bad. If it does not, remove one load at a time with the load wire connected until it stops blowing. You may want to stock up on 1amp fuses😊
 

cinergi

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I see nothing wrong in your installation - it does seem like a faulty shunt. Other people's suggestions of removing loads has *nothing* to do with the shunt itself being powered and blowing its fuse. I used the same shunt on a 48v nominal (56+v) system without issue. It's rated for at least 60 volts. Give this same information to your reseller (include a picture of the battery in the same picture as the shunt, if possible, so the wire from "to battery minus" is clearly going to the battery). If your battery voltage is actually < 60v (show a DMM with this, too) then it's the shunt; there's no such thing as a "battery surge" when connecting the shunt. Devices PULL current ... batteries don't PUSH current. The shunt is PULLING too much current. Something is wrong with it.
 

Sanwizard

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I see nothing wrong in your installation - it does seem like a faulty shunt. Other people's suggestions of removing loads has *nothing* to do with the shunt itself being powered and blowing its fuse. I used the same shunt on a 48v nominal (56+v) system without issue. It's rated for at least 60 volts. Give this same information to your reseller (include a picture of the battery in the same picture as the shunt, if possible, so the wire from "to battery minus" is clearly going to the battery). If your battery voltage is actually < 60v (show a DMM with this, too) then it's the shunt; there's no such thing as a "battery surge" when connecting the shunt. Devices PULL current ... batteries don't PUSH current. The shunt is PULLING too much current. Something is wrong with it.
I was not saying the shunt is not rated for over 48V, I said it was Blue Sea support that said that. I agree, the shunt may be bad, but I was trying to "shorten the bus" to troubleshoot it. Old trick from years ago on PDP11 Digital Equipment Computer systems.
 

Tecnodave

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Mar 22, 2021
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Little late but......I have never seen a shunt in the battery positive.....MidNite, MagnaSine and Bogart Engineering Trimetric and Pentametric all place the shunt in the battery negative.......But i do not have Victron equiptment, that may be the way that they do it.....worth verifying that.....

UPDATE.......the Victron manual does show the shunt in the negative cable........
 

Sanwizard

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Mine is also in the negative path, with a power input from the positive.
 

RickP

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I don’t see any issue in the wiring. Simply disconnect it from the shunt and see if it blows under power, and if not, it is almost certainly the shunt itself. That wire only powers the shunt data and comm operations as far as I’m aware, and draws very little In operation.
 

SniperR27

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Jun 8, 2021
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Is this Smart Shunt installed in the Negative line?
Some people are suggesting it is installed on the positive feed, if it is, then it is wrongly installed.
See; https://www.victronenergy.com/media/pg/SmartShunt/en/installation.html
The Shunt must be in the negative line with the small power cable connecting from the positive line to the quick connect.
Check the contact tightness with the quick connect as they often don't grip the cable very well.
 
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