Victron Shunt connections

PeterCarole29

PeterCarole29

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Renault Master Fleetwood
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I have in the past been given good advice but think i have misunderstood it
I am about to replace the trojan still good lead acid batteries with a Fogstar 460ah.
If i understand correct everything has to go through the Negative on the shunt and the shunt connects to the negative on the battery and the negative on the Battery also connects to the chasis

The positive feed from the
Solar controller MPPT inverter charger and Battery to Battery go dirrectly to the positive on the battery

Please advise and thanks in advance
 
Hi should have said advice was a while ago and i cant find the posts
 
Yes...imagine it this way...all your neg items always come from the shunt...only the shunt connects to the neg on the battery with a suitable thickness cable..

All POS connect to the POS on the battery...or the bus bar that may be connected to the POS with a suitable sized cable
 
Everything needs to go through the shunt. If the battery is earthed and any devices are also earthed the flow will bypass the shunt.
 
Pausim said:
Everything needs to go through the shunt. If the battery is earthed and any devices are also earthed the flow will bypass the shunt.
Click to expand...
So do you earth to the chasis on the load side of the shunt or not at all

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Pausim said:
Everything needs to go through the shunt. If the battery is earthed and any devices are also earthed the flow will bypass the shunt.
Click to expand...
Thanks thats very clear now i have read it several times and is also clear electrics arent my best subject I was just confused because i am so used to the battery haveing to go to the chasis somewhere
 
The battery side of the shunt connects to the battery negative terminal. If you have more than one battery, and they are linked, then the link wire goes to the battery negative terminal too. Everything else goes to the load side of the shunt, including the chassis connection.
 
If you have a lot of cables going to the battery terminals I would recommend using a bus bar for the positive and one for the negative, run all you negative connections into the bus bar and run one cable to the shunt then from the other side of the shunt to the negative battery terminal. With the positive cables run them into the bus bar and one cable from the bus bar to the positive side of the battery, it’s also a good idea to put a battery cut off switch between the positive cable between the bus bar and battery.
 
image.jpg

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I’ve just changed my Inverter to a 2000w Victron one and that recommended 70mm cable, it fitted fine I just had to cut a small bit of the plastic casing out but besides that it worked fine

IMG_2602.jpeg IMG_2601.jpeg
 
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I think it was from Amazon £29 I think if you hunt about you can get them for £20

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treblid said:
Is it me or do people not read other posts...... :unsure:

I feel invisible!!!
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You could change your user name to “The Invisible Man” and have a plain white avatar. 😀
(am I talking to myself or is there someone there?)

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Anyone else read this stuff about shunts etc and haven’t got a bloody clue ? 🤪
 
UptheGas said:
Anyone else read this stuff about shunts etc and haven’t got a bloody clue ? 🤪
Click to expand...
I think Revolvor's link is a full explanation, but covers many aspects that are not relevant to the shunts used in a motorhome for measuring amps.

A shunt resistor is one of the technologies used to measure the flow of electric current around a circuit, in amps.

A known length of thick wire of known cross-sectional area will have a known resistance. For example, a 1 metre length of 16mm^2 copper wire will have a resistance of about 1 milliohm (= 1/1000 of an ohm).

If you send a current of 1 amp through it, the voltage drop across is will be about 1 millvolt. For 2A it will be about 2mV, and so on. If you had an accurate voltmeter that could measure the voltage across that piece of wire, you could calculate the current in amps flowing through it.

If you wanted to do this accurately, you would first get a length of metal that had a definite very accurately known resistance, and that's what a shunt resistor is.

A shunt resistor is a resistor that has a very small but very accurately known resistance. Typically it might be a tenth of a milliohm. Such a resistor would produce a voltage drop of a tenth of a millivolt for a current of 1 amp. It might have a maximum current of 500A, which would produce a voltage drop of 50mV.

The standard Victron shunt is 50mV at 500A, which is 0.1 milliohms, although others are available for higher currents if you need them.

This resistance is small enough that it is negligible in terms of the total voltage drop around the circuit path, but it is large enough for a very accurate voltmeter to measure voltage drop, and work out the amps flowing through it.

Once you know how it works, you can see that a shunt resistor can only measure amps that are flowing through it. Anything that bypasses the shunt resistor doesn't get measured.
 
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autorouter said:
I think Revolvor's link is a full explanation, but covers many aspects that are not relevant to the shunts used in a motorhome for measuring amps.

A shunt resistor is one of the technologies used to measure the flow of electric current around a circuit, in amps.

A known length of thick wire of known cross-sectional area will have a known resistance. For example, a 1 metre length of 16mm^2 copper wire will have a resistance of about 1 milliohm (= 1/1000 of an ohm).

If you send a current of 1 amp through it, the voltage drop across is will be about 1 millvolt. For 2A it will be about 2mV, and so on. If you had an accurate voltmeter that could measure the voltage across that piece of wire, you could calculate the current in amps flowing through it.

If you wanted to do this accurately, you would first get a length of metal that had a definite very accurately known resistance, and that's what a shunt resistor is.

A shunt resistor is a resistor that has a very small but very accurately known resistance. Typically it might be a tenth of a milliohm. Such a resistor would produce a voltage drop of a tenth of a millivolt for a current of 1 amp. It might have a maximum current of 500A, which would produce a voltage drop of 50mV.

The standard Victron shunt is 50mV at 500A, which is 0.1 milliohms, although others are available for higher currents if you need them.

This resistance is small enough that it is negligible in terms of the total voltage drop around the circuit path, but it is large enough for a very accurate voltmeter to measure voltage drop, and work out the amps flowing through it.

Once you know how it works, you can see that a shunt resistor can only measure amps that are flowing through it. Anything that bypasses the shunt resistor doesn't get measured.
Click to expand...
I should have known that autorouter would give a succinct, sensible explanation! :giggle:

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