RT-31S Shunt installation Question

[Sea-X]

I've purchased a Victron BMV-712 monitor and looking for guidance on connecting the shunt to the load side. Has anyone connected the shunt next to the battery or did you go next to the bus bar which is in the opposite side of the boat, meaning that I would need an extension to the positive/temp wires to the battery. Cruising Elvin Rey on his Ranger Tug 23 installed an additional bus bar, is that necessary on the RT 31S 2020? Thank you.
Alain
Sea-X, Sidney BC

 

[watson1987]

The shunt must be installed on the negative or ground side of your battery. Typically the positive side is referred to as the load side of a circuit, so just making sure we are talking about the same thing. I assume the bus bar you are referring to is the ground one in the SB laz, with the house bank being in the port side laz, which is where you are talking about needing it on the opposite side of the boat.

You should install the shunt as close to the battery as possible, meaning in the port side laz. You shouldn't need another negative bus bar for the installation, but you will need an extra 12-18 inch cable (I think it is 3/0).

 

[Sea-X]

Thanks for your input watson1987. Yes, you are correct with your assumption. I should disconnect the negative lead out of the battery bank and connect to the load side the shunt then use the 12-18 inch cable to connect to the end of battery bank negative daisy chain. I'll get back to you next week after I have time to install.

 

[Sea-X]

Ok, I installed the shunt as I understood from the manual and comment above but not getting the shore power input from the charger. The negative out of the battery bank is connected to the battery side of the shunt and the load side of the shunt is using the lead to the busbar. The positive wire of the shunt is connected to the positive of the battery bank.

 

[watson1987]

What you described seems correct. Is your battery already charged? What load do you have on the system right now, does the BMV show negative current flow but not positive?

Can you disconnect from shore power, turn on your inverter, run the microwave for a few minutes (with a cup of water or something inside of it), and then reconnect your shore power to see if you now see current flowing to your batteries?

 

[Sea-X]

Yes, the battery bank is fully charged.
Can't tell the load exactly as I'm not aboard but the BVM showed negative current flow with the shore power connected and charger/inverter indicating battery full.
I will get back to the boat tomorrow and try drawing some power without the shore power connected, thanks.

 

[SKing]

Did you disconnect ALL negative leads from the battery bank and run them through the shunt? My bank had 2 large negative cables (C30).

 

[Sea-X]

Did you disconnect ALL negative leads from the battery bank and run them through the shunt? My bank had 2 large negative cables (C30).

No but will have a look at it, from the R-31 Power Distribution diagram, it looks like one of the negatives exits the house bank to the engine battery. Thanks for the suggestion.

 

[shontm]

Let me know where you land because I have the same wiring in my R-29 and plan to install the battery monitor with shunt. If I stick with the 4 AGMs (I am contemplating going lithium), I figured I would need to install a negative bus bar near the batteries because there are 3 different negative lines to capture (inverter/charger, engine battery, and house loads - to ground bus bar).

 

[Sea-X]

Let me know where you land because I have the same wiring in my R-29 and plan to install the battery monitor with shunt. If I stick with the 4 AGMs (I am contemplating going lithium), I figured I would need to install a negative bus bar near the batteries because there are 3 different negative lines to capture (inverter/charger, engine battery, and house loads - to ground bus bar).

Will do, I'll try to get out to the boat tomorrow.

 

[Sea-X]

Shontm, you were correct and all worked fine once I gathered the negatives together on the load side of the shunt. I'll get a busbar to tidy up.

 

[Sea-X]

Did you disconnect ALL negative leads from the battery bank and run them through the shunt? My bank had 2 large negative cables (C30).

Yes, I did and thanks for the suggestion, all works fine now.