Hello,
I'm about to add a Smartshunt on my installation in my campervan. I'd also like to add a general circuit breaker to be able to easily isolate the battery if necessary (i.e. working on the installation, winterizing, etc...)
So here is my question : is it ok/safe to place this circuit breaker between the battery and the Smartshunt ? Or should it be placed after the smartshunt (but in that case, the smartshunt is still powered) ?
Thanks !
Ideally nothing should be between the negative and the shunt.
The answer depends on if your battery can take the drain of the smart shunt over the expected time you are leaving it unattended.
You could always disconnect the positive power cable anyway if it is on the battery side.
If it is a good lithium it will likely go to sleep and stop the parasite draw. If lead acid you might return to a dead undercoverable battery.
Don't forget there is also battery self discharge as well.
Thanks for your answer. Ideally, it's to leave no consumer at all (it's a Gel Battery).
My concern - assuming I place it between the battery and the shunt - is the fact that in case of shut off/shut on, the smartshunt will be "wired" in the inverse order of the manual indications, i.e first battery minus, and last positive wire. Could it damage the shunt ?
I cannot speak for Victron of course, but I would be highly surprised if the Smartshunt could not handle that. Worst that could happen is it losses the time of day until you connect a phone again, so your history is off.
I agree with you, and after all, that is what would occur if I had to unplug the battery negative.
I guess the most careful way to switch off would be to first unplug the positive cable of the smartshunt, and then switch off the system.
Just a suggestion but if all you need is a way to disconnect the battery a disconnect switch such as this might be easier to install.
Thanks for your answer. I do not need to fully remove the battery : worst case scenario, I have an IP67 Victron charger onboard, and I can get the van near my appartment to plug it on 220v.
About the switch, that's exactly the kind I intend to install, although smaller because my circuit is simple and at low-power.
For instance :
Battery switch
So, you think it would be ok to place it between the shunt and the battery ?
@Reno As mentioned by Alexandra ideally there should be nothing between the shunt and the battery's negative terminal. I don't know the wiring details but if there is nothing between the load side of the shunt and the disconnect switch it should be fine. If you are doing any kind of repair work or installs disconnect both +/- wires at the battery before proceeding.
Thinking about it a bit further I should also add that if your camper has smoke and propane leak detectors a disconnect switch might also stop providing power to those devices.
Typically a switch like that would be placed in the positive cable. The shunt goes in the negative cable. Unless you're running 2x switches, which would be unusual.
Probably @Reno is considering the disconnect in the negative because that is classically how they used to be on old tractor and other farm equipment in the past. It is also still the normal mechanics advise when doing maintenance to first disconnect the negative terminal.
As to the why this is classically so, I always assumed these was for practical reasons:
- firstly, there used to be only one cable on the negative, and many on the positive, so on tractors it is easier to make a disconnect switch on the negative.
- secondly, when doing maintenance, given the chassis is negative, if you have a big wrench, and do the positive terminal first, it is easy to accidentally touch the chassis and make a short. But if you do the negative first, accidental shorts are nullified.
You're right, and it turns out that I intend to add a switch on the positive cable too, but just before the loads (the chargers will remain direct on the battery) and that's the one that I will use at will to limit consumption.
As said a little sooner (higher), the switch on the negative cable would be more an emergency/convenient switch.
Hi again !
So, on your advice - and my doubts - I went with the recommended solution, that is placing the smartshunt between the battery and the switch (reminder : negative circuit breaker in my case).
So far so good, I can live with that... BUT !! I then plugged the V.aux cable to monitor the main battery (starter battery), and I'm facing a new problem : when I switch off the circuit breaker, the Shunt is no longer connected to the common negative, and so the V.aux is something erratic (23v in the present case).
Do you think it's something to worry about ?
I wonder if the best solution was to place the switch between the battery and the Shunt actually...
Well, lets first remark that I was giving observations rather than advise. For a negative disconnect, I think I would have done it like you did, but I also did not think it would matter much.
But yes, it means you cannot read the aux battery (mine has a temp sensor). But had you place the shunt on the other side of the disconnect, you could read the aux, but not the main battery.
I guess if you want them both readable, you'd have to move the disconnect to the positive side. Like is more common nowadays, rather than the tractor example.
Next step is to add a switch before the loads on the positive side, so I won't have to use the main negative switch except for maintenance/emergency.
So far, I'm ok with this installation, but I just would like to be sure that keeping the Aux plugged while switching off is safe and harmless for the Smartshunt.
