Victron Smart Shunt

Irie308

Well-Known Member
May 28, 2013
2,577
CT
Boat Info
2004 420 DB, GHS Hydraulic Lift
Garmin 8600/Garmin 1222 plus
AB Mares 10 VSX with 30 hp Tohatsu
Engines
Cummins 450C 8.3 L Turbocharged
Not looking to make a massive investment in replacing my battery chargers as they work well for us and with the way we use the gen there really is no need for an inverter. However since we have replaced our batteries last season I'm curious about the victron smart shunt to monitor all the batteries. Current setup is a 24v bank for the bow thursters and 2 12volt 260 Amp hour banks for the port and starboard\house. Looking for some feedback and photos of anyone that has installed the smart shunts. Seem easy enough and I know the wiring diagram victron provides for working with battery banks however I have some heavy cabling connected to the negative terminals on both 12v banks. I think i would need to have the cables reterminated to fit a neutral mounting block to remove the load from the negative stud and route all through the shunt. Does anyone have pics of their install?
 
A good battery monitor system is money well spent and the smart shunts are not very expensive for what they give.
As you have two separate banks for port and starboard which are charged and discharged independently you should install two separate shunts. So, remove the negative battery cable from the common grounding block for each battery bank and install shunts on each one then make up a cable to route from the shunt to the grounding block. That's all there is to it. As these battery banks are also for engine cranking the shunts must also handle that cranking current. My cranking current is 325 amps but the locked rotor current is much higher. You may get away with a couple of 500 amp shunts for your boat.
As far as the bow thruster system, unless you are having trouble keeping those batteries charged I wouldn't worry too much about monitoring. But that's me....
 
Ok that part I understand, but I'm not clear on the best method of moving the cables on the - terminal in the pic to the shunt on the load side as they consist of 4/0 cabling. Should I use a terminal block (appropriately sized) to connect them to the shunt? If so, should the cable from the shunt to the battery mount to the large post on the battery? I want to make sure I'm not under sizing my terminal connections when I introduce the shunt.

P.S I had the terminal covers off as I was doing work on the battery. They are normally covered.

Port Batt Bank.jpg
 
Ok that part I understand, but I'm not clear on the best method of moving the cables on the - terminal in the pic to the shunt on the load side as they consist of 4/0 cabling. Should I use a terminal block (appropriately sized) to connect them to the shunt? If so, should the cable from the shunt to the battery mount to the large post on the battery? I want to make sure I'm not under sizing my terminal connections when I introduce the shunt.

P.S I had the terminal covers off as I was doing work on the battery. They are normally covered.

View attachment 118441
Interesting setup there. I've never seen that configuration before...
It seems there is the negative cable that is attached with lug clamps and another negative cable attached with a bolt to the battery, two separate negative connections.
What I would is this -
The cable that is attached using clamps follow it to where it is terminated and disconnect there (it may ground on the engine block). That cable will be the battery side of the shunt. If it does go all the way to the engine block you may want to cut it to size and use the other half for the load side of the shunt. Make up another cable (4/0) and route from the shunt load side to where the original cable was connected.
The negative cable and small wire attached to the battery bolted connection remove and move that to the load side of the shunt with the new cable you fabricated.
So in the end you have only the batteries on the battery side of the shunt then all others on the load side.
 
Interesting setup there. I've never seen that configuration before...
It seems there is the negative cable that is attached with lug clamps and another negative cable attached with a bolt to the battery, two separate negative connections.
What I would is this -
The cable that is attached using clamps follow it to where it is terminated and disconnect there (it may ground on the engine block). That cable will be the battery side of the shunt. If it does go all the way to the engine block you may want to cut it to size and use the other half for the load side of the shunt. Make up another cable (4/0) and route from the shunt load side to where the original cable was connected.
The negative cable and small wire attached to the battery bolted connection remove and move that to the load side of the shunt with the new cable you fabricated.
So in the end you have only the batteries on the battery side of the shunt then all others on the load side.
Ok, i see what you're saying. Will trace it back more than likely it is running to the motor. The other 4/0 on the smaller terminal is the stern thruster negative.
 
Last edited:
Victron has an app that runs on the Raymarine Axiom products, but you need to get data to it via ethernet.

I was sold on getting shunts for my system instead of replacing the charger right away. It looks like I would need either a venus GX or possibly a raspberry pi to integrate between the smart shunts and the axiom.

According to mercruiser, the 8.1L engines with DTS, need 850-1000cca batterys to start, so I'm looking at going with the 1000A Smart Shunt. I suspect the 500A model can handle the job, but I'm also powering a 12V bow thruster off of this circuit.
 
I wish raymarine would have integrated the phone app into the mfd. Lots of extra cost in the ethernet set up.
 
I know. The axiom has bluetooth and is running a version of android anyway. You might be able to load the app with a SD Card. I've seen somewhere that it would run standard android apps. Just not sure if the app will run if it determines it's on a MFD.

Thinking back to my shunt size. I should probably check the size of my isolating solenoid and match it.
 
I can't imagine a 500 amp wouldn't work.
 
... Thinking back to my shunt size. I should probably check the size of my isolating solenoid and match it.

Your "isolation solenoid" has nothing to do with starting capacity. I would match you battery capacity for the starter. In short what Merc stated for amperage.
 
I can't imagine a 500 amp wouldn't work.

The initial current draw (instantaneous - mili-seconds) is quite large on any gas V8 and why most electronics will reboot if on the same current path.
 
Your "isolation solenoid" has nothing to do with starting capacity. I would match you battery capacity for the starter. In short what Merc stated for amperage.
Yeah, I realized that as I was looking through the schematics just now. The starter wiring bypasses that circuit completely. There’s no fuse in the circuit either, so that leaves me with the 850cca battery requirement from mercruiser.


Bow thruster is fused at 250A, so that isn’t an issue.
 
The initial current draw (instantaneous - mili-seconds) is quite large on any gas V8 and why most electronics will reboot if on the same current path.

I have 500 amp and have never had a issue.
 
I agree with Craig, I have two 500 amp smart shunts installed one on each battery bank. I’ve never had an issue with my 8.1’s starting. I would also agree with some of the earlier posts that I wish they would connect to my axiom MFD without the added cost of purchasing something like a Victron cerbo GX and connecting the shunts to the cerbo and the cerbo to the mfd. just a bunch of added cost. The other thing that kinda sucks, and I know I’m knit picking here, is with two smart shunts, you have to connect to each shunt separately via the app to see what’s going on with that bank then disconnect and log on to the other bank to see what’s happening on the other bank. The app doesn’t connect to both shunts at the same time and show a side by side. With that being said, it was worth the investment and provides valuable information in battery conditions. It’s really helped me to understand how much power each system utilizes
 
I have setup the Victron Venus OS on a pi and there is a N2K board that can be added to make a bridge to the N2K network and on to about any display. Works well, not very expensive. If serious about it, a Victron product would be a more robust solution.
 
Can you guys help me figure out where to put the smart shunt? The installer put it where the yellow box is in my drawing (he basically replaced the bus bar with the shunt back on the transom) but I am showing amps as + instead of - when using DC power. He mentioned that the battery bank had two grounds and as you can see the negative cable runs to both batteries and off both sides. How do I do this properly?
AFAF45EB-98CC-4420-BA85-E2CDDDB93B18.jpeg
 
Last edited:
Originally the battery negatives went to a common buss bar. If you have a single shunt then both the battery negative cables terminate on the shunt battery side. Then the Shunt load side gets a cable of appropriate size landed on that buss bar. That's it. If the Shunt is reading charging when in fact the system is discharging it is installed backwards. Simply swap ends on the shunt. You really want the shunt in this configuration as close to the negative buss bar as possible so the cable size and length is reasonable.
 
Originally the battery negatives went to a common buss bar. If you have a single shunt then both the battery negative cables terminate on the shunt battery side. Then the Shunt load side gets a cable of appropriate size landed on that buss bar. That's it. If the Shunt is reading charging when in fact the system is discharging it is installed backwards. Simply swap ends on the shunt. You really want the shunt in this configuration as close to the negative buss bar as possible so the cable size and length is reasonable.

I took a few pictures last night. The negative cable runs from the charger to a bus bar then over to the batteries. There it connects to the first battery and then the next (same cable) then routes over to another junction area back on the transom. The installer replaced this junction with the smart shunt. Does this work? What’s strange to me is that the battery side is going to the batteries so it doesn’t seem installed backward. However, my readings shown inverse of what they should. Is the shunt isolated like it should be? D8507F79-8D44-4DB3-AA7C-0BF7247C27EA.jpeg187E8DD9-0507-421D-A4A8-498425FB23F5.jpeg234FF9FC-C1E2-4DF7-BD07-9430519BA39E.jpeg14544854-A069-4A94-9B27-E3E50BA4E81A.jpeg
 

Forum statistics

Threads
112,942
Messages
1,422,701
Members
60,927
Latest member
Jaguar65
Back
Top