Smart shunt (yes I know...)

[wireman]

Will the Victron Smart Shunt 300W one suffice for a single battery rated at 100amps?

 

[Cush]

I’d say yes as long as you don’t plan on pulling h more than 300 amps at any one time. More about draw than battery capacity.

 

[autorouter]

Will the Victron Smart Shunt 300W one suffice for a single battery rated at 100amps?

It's 300A not 300W. That means it will handle up to 12 x 300 = 3600W. I imagine that's quite sufficient, even for a large inverter.

 

[LithiumConvert]

Depends whether you like Bluetooth or not.

I prefer a dedicated display fixed to the 'van (or wireless - your choice).

One job - one unit. Simples.

 

[RogerIvy]

The 300A would be fine for your setup.

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[andyman]

Can someone explain this to me. Fitted the shunt on Wednesday and here is a screen shot from today. Why don't the in and out match.

 

[autorouter]

Do you mean the discharged energy = 0.4kWh, charged energy = 0.2kWh? It's not much of a difference, but maybe the shunt is not wired correctly, so that some of the charge or discharge is not being registered by the shunt. If the shunt is on the negative battery terminal, then no other wires should be connected to the battery side of the shunt. Only the link wires between batteries are allowed on the battery side of the shunt.

Is the chassis ground wire connected to the load side of the shunt? It's a common mistake to leave it connected to the battery terminal.

 

[andyman]

I have 2 batteries, the 2 battery negatives go to a terminal block along with the chassis ground and the shunt terminal marked battery.
Hooe this makes sense.

 

[autorouter]

The chassis ground needs to be moved to the load side of the shunt. What's happening is that the shunt is supposed to measure all the amps returning to the battery negative terminal. However some of the amps are returning to the battery directly instead of going through the shunt. The shunt can only measure the amps that are passing between the load side and the battery side. You're not the first to make that mistake, it's natural to think the chassis ground needs to be connected directly to the negative terminal.

 

[Kannon Fodda]

My smartshunt is always out of sync between overall charge and discharge power. Not a massive amount, but a clear difference. It is wired correctly on the negatives, and fully reset when i fitted the Fogstar (did the same with previous small lithium). Overall however it seems fine and i believe the overall charge state is accurate.

I can only assume, somewhere, there is a small miscalculation error. Perhaps induced oddly by the victron 2 solar controllers and also B2B all on the same bluetooth network. Or does it ignore it's own, minor, power use?

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[andyman]

Just moved the ground over and the shunt didn't read and amps in or out. ???
Confused parked on a campsite in rural Leicestershire

 

[growly_bear]

This is interesting. I don't have an answer, but I see the same. My only hab -ve connection is to the shunt. Everything else is from the -ve busbar. Mine are discharged 8.6KWh and charges 9KWh

 

[andyman]

This is interesting. I don't have an answer, but I see the same. My only hab -ve connection is to the shunt. Everything else is from the -ve busbar. Mine are discharged 8.6KWh and charges 9KWh

One of life's mysteries. For the last 30 years if I turned the light on, my battery was good. Now I have something to look at and worry about.

 

[mikash]

This is interesting. I don't have an answer, but I see the same. My only hab -ve connection is to the shunt. Everything else is from the -ve busbar. Mine are discharged 8.6KWh and charges 9KWh

Battery round trip efficiency could result in numbers like that. Discharge 8.6kWh and then charge 9kWh back to full. That'd be about 96% round-trip efficiency which would suggest a lithium battery .With lead battery the difference would be bigger.

 

[autorouter]

Just moved the ground over and the shunt didn't read and amps in or out. ???

What exactly did you move? You need to move only the chassis ground connection, from the negative terminal block to the load side of the shunt. The negative terminal block, with its two links to the negative battery terminals, needs to stay on the battery side of the shunt.

The idea is that all returning amps are channelled through the shunt, and there's no way for any amps to bypass the shunt.

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[andyman]

This is how it's wired. Had to get a friend to fit and wire it as I still have a gammy hand.
But I have checked this morning and the diagram shows how it's wired. Al be it the joints are made at a buss bar not all direct to the shunt.

 

[autorouter]

I can't see the chassis ground connection on that diagram. It should be connected to the 'System -' shunt terminal (not the 'Battery - ' shunt terminal). Is it possible to post a photo of the shunt, busbar and battery negative terminal?

 

[andyman]

I thought the chasis ground was the earth that went back to the habitation electric controller. Do I need an additional earth.

 

[autorouter]

OK I misunderstood, I thought you meant there was a wire direct to the chassis at the leisure battery negative. There should be second negative wire at the habitation electrics box that comes from the starter battery negative, or maybe goes straight to the chassis ground, ie to a bolt on a metal part of the chassis. The starter battery negative will definitely be grounded to the chassis, it has to be for the starter motor and alternator to work. So if there's a negative wire connection from the starter battery to the habitation electrics box then everything should work OK.