Victron Smart Shunt fuse location

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hyxamp asked Dec 30, '22

Victron Smart Shunt fuse location

Hi,

we want to install a victron smart shunt in our RV to check the state of our aux battery. The installation seems to be simple. There is also one input to measure the voltage of the starter battery but im a bit confused about the location of the fuses.

Why are the fuses close to the smart shunt and not as close as possible to the batteries? I mean, the distance between starter battery and shunt is about 7 meters (23 feet) and it makes no sense to protect the wires at its ends. There are no additional fuses at the terminals of the batteries and I can not see any reason to use two fuses at each branch (battery terminal and smart shunt). What is the explanation for that? In my setup, I would use fuses as close as possible to the battery terminals and do not use any more fuses at the shunt or I am wrong?

Best regards

SmartShunt fuses

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Answer 1 · 2022-12-30T13:56:16Z

jkmann answered · Dec 30, 2022 at 01:56 PM

The fuse should be as close as reasonably possible to the battery. If that (+) wire is going to fault to ground, it's only protected after the fuse.

The Victron diagrams aren't meant to represent the physical layout of components as much as to show the electrical connections.

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Answer 2 · 2022-12-30T14:11:14Z

kevgermany answered · Dec 30, 2022 at 02:11 PM

Bear in mind that fuses are to protect the wiring.

The supplied red wires with the smart shunt have single built in fuses. These are generally adequate, and close enough to the battery.

Assuming your system has a negative earth, no need to fuse that leg.

Fusing the positive leg from the battery to the loads is really a design question. The risk is at the battery, so should be fused as close to the battery as practical. if there's a short, the battery will potentially output more than the designed current. At the charger end of this cable, current is limited by the charger, so fitting a fuse at the charger end serves no purpose. I expect you will take a feed to the DC loads from the positive battery feed. Use a busbar, from there to fuse boxes to the loads

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