Help understanding my Victron Smartshunt

[Ingwe]

Have recently had 2 110ah lithium batteries fitted under the passenger seat. Also fitted there is a Victron Smart Shunt and Victron B2B charger. I also have a Victron MPPT solar controller and a Victron IP22 mains charger. The Victron Connect works fine and I‘ve changed the default passwords and the listed names of the devices.

I’ve been reading the Shunt’s manual and, so far as I understand, it can monitor the leisure battery and, by way of the auxiliary lead, the vehicle battery. However, when I read the display on the app, it shows the state of charge etc of the leisure battery and right at the bottom of the display it shows a small voltage (less than 1 volt) as an input, to the vehicle battery. I wish that I had taken a screen shot of the of the display whilst I was at the van this morning. I should also mention that there is a Battery Master fitted (years before the lithium gear).

Anyway, my questions is this: as there are 2 leisure batteries, I assume the Shunt sees them as one battery so gives only one State of Charge (SOC). If that is right, shouldn't the auxiliary lead give the SOC for the vehicle battery? How, apart from accessing the vehicle battery by raising the carpet and cover and using a meter, can I monitor the SOC of charge of the vehicle battery?

I’ve assumed, perhaps wrongly, that the small input voltage was the Battery Master voltage going to the vehicle battery.

Thank you and apologies in advance if I’m being stupid in my assumptions/understanding.

 

[Bessy765]

We have a similar set up but no B2B. The two outputs are a main high amperage for the leisure side and a max 4 amp at a slightly lower voltage to take care of the starter battery. I have just been reading the book. As we have just had a 2kw Victron multi, 700 watts of Solar with a 60 amp controller and two 100 amp Transporter Lithium

 

[monzer]

If your batteries are wired like that then your shunt will take it as 1 battery as they are wired in parallel and voltages should continuously even out.

I too have the Aux display showing a tiny voltage and it classes it as the starter battery. No idea what this is telling me. The other options for this Aux setting in the menu are 'mid point', 'temperature' or 'none'. I'm guessing it would disappear if you selected 'none' but I'd also be keen on finding out why there is a small voltage showing there.

 

[cmcardle75]

View attachment 563717

If your batteries are wired like that then your shunt will take it as 1 battery as they are wired in parallel and voltages should continuously even out.

I too have the Aux display showing a tiny voltage and it classes it as the starter battery. No idea what this is telling me. The other options for this Aux setting in the menu are 'mid point', 'temperature' or 'none'. I'm guessing it would disappear if you selected 'none' but I'd also be keen on finding out why there is a small voltage showing there.

I would guess that the extra sensor probe is not fitted, so is just measuring static. Turn it off if you haven't attached a temperature probe or engine battery voltage sensor. If you do connect to the engine battery, it won't give SOC directly, but you can make a reasonable guess from the voltage.

 

[Ingwe]

I would guess that the extra sensor probe is not fitted, so is just measuring static. Turn it off if you haven't attached a temperature probe or engine battery voltage sensor. If you do connect to the engine battery, it won't give SOC directly, but you can make a reasonable guess from the voltage.

Can you turn it off using the Connect app? Is there a reason why the installer would not have connected the engine battery? The approximation of the engine battery’s SOC as you suggest would be pretty helpful in gauging the state of the engine battery.

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[steveh57]

Yes you can turn it off, just set it to none in the settings menu, misc , aux input.

I have an additional temperature voltage probe connected to that input, since the shunt and MPPT can link together with the V.E Smart Network. I think I’m correct that although the actual temperature is not critical for Lithium charging except when low i.e I’m set not to charge below 5C. The data from the shunt is fed back to the MPPT giving an accurate battery voltage and also will wake up the MPPT if the temperature rises above the cut off threshold .The MPPT does have a temperature sensor but I’ve read it only checks once at the start of the day??. So the MPPT stays off , more importantly the MPPT controller maybe be somewhere warm and cosy unlike the lithium batteries.

This is from the demo library in the VictronConnect app it shows the V.E smart network and the link between the MPPT and a smart battery sense, you can do the same with the smartshunt by adding the additional temp/voltage probe

Temperature Sensors [Victron Energy]

www.victronenergy.com

 

[Ingwe]

I would guess that the extra sensor probe is not fitted, so is just measuring static. Turn it off if you haven't attached a temperature probe or engine battery voltage sensor. If you do connect to the engine battery, it won't give SOC directly, but you can make a reasonable guess from the voltage.

I contacted the installers who fitted the Victron gear and batteries and they confirmed that they don't connect up the vehicle battery to the shunt because the van's control panel gives an adequate reading of the SOC of the vehicle battery.

They've asked me to send them a screen shot of the low voltage reading where on the Victron Connect app it reads Vehicle battery and will advise on that when they've seen it. I'll go to the van tomorrow and take a screen shot.

 

[steveh57]

I do recommend playing around with the VictronConnect demo library, you get a virtual representation of the device and it's settings which you can then change as you wish and see the effect of this changes.

 

[Ingwe]

I do recommend playing around with the VictronConnect demo library, you get a virtual representation of the device and it's settings which you can then change as you wish and see the effect of this changes.

Is the demo library on the Victron site? Had a quick look but didn't see it.

 

[cmcardle75]

Is the demo library on the Victron site? Had a quick look but didn't see it.

It's on the phone app. You can add pretend devices as well as real ones!

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[Ingwe]

It's on the phone app. You can add pretend devices as well as real ones!

Ok. will have a play. Hopefully can't stuff my settings as van's 5 miles away.

 

[TCG]

I contacted the installers who fitted the Victron gear and batteries and they confirmed that they don't connect up the vehicle battery to the shunt because the van's control panel gives an adequate reading of the SOC of the vehicle battery.

They've asked me to send them a screen shot of the low voltage reading where on the Victron Connect app it reads Vehicle battery and will advise on that when they've seen it. I'll go to the van tomorrow and take a screen shot.

my fitters said exactly the same thing so fitted it myself. i find it is more accurate that the sergeant panel

 

[Ingwe]

my fitters said exactly the same thing so fitted it myself. i find it is more accurate that the sergeant panel

View attachment 564305

Did you simply connect the 2nd red cable with the 1amp in-line slow-blow fuse to the auxiliary input on the shunt?

 

[TCG]

Did you simply connect the 2nd red cable with the 1amp in-line slow-blow fuse to the auxiliary input on the shunt?

yes

 

[Ingwe]

It would have been better had it been connected during the installing. I may just leave things as they are.
But thanks all.

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[Ingwe]

Just had a look at our van’s manual and it would appear that the control panel only let’s you monitor the leisure battery. So currently (no pun intended) the only way I can measure the vehicle battery is by putting a test meter on the battery’s terminals.

 

[the1andonly]

The obvious method is to connect to the 2nd battery location on the shunt.
if this is too much grief try one of these
bm2 battery monitor as initial suggested by Richard n Ann

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This can be just added to the SB and read by a Bluetooth ap

 

[andyjc]

Just a thought, you haven't inadvertently pressed the red button (if you have one) when removing the ignition key thereby disabling the vehicle battery - if so it would show a minimal voltage as you describe.

 

[Googlebot]

I had an issue with mine where it was alarming low volts on vehicle battery.

It was showing just 2 volts and on checking, it was fine. I located a dodgy fuse connector on the original Victron wire to the chassis battery. Replaced fuse connector and all has been good since.

 

[Ingwe]

Just a thought, you haven't inadvertently pressed the red button (if you have one) when removing the ignition key thereby disabling the vehicle battery - if so it would show a minimal voltage as you describe.

No red button near the ignition key.

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[Ingwe]

As the van’s control panel does not monitor the vehicle battery and I don’t want to run a lead from that battery to the shunt, I was thinking about the role of the Battery Master.
As I understand it, this works by sensing the difference in voltage between the leisure and vehicle battery. Once that difference is .8v (the leisure battery is higher than the vehicle battery by .8v or more) the BM allows a trickle of current to the vehicle battery. So if the shunt tells me the leisure battery is at 12.8v and the BM light is green, then I can assume that the vehicle battery is 12.8v or around there or else the red light will be on the BM?
Make sense?

 

[Richard J]

My understanding is that the leisure battery shunt can only measure the SOC of the leisure battery. The wire to the starter battery will measure voltage from which you can infer an approximate SOC, but to get that more accurately you need a shunt on the starter battery as well and I imagine that opens a whole new can of worms. I have a BMV 700 so it cannot monitor starter battery voltage but a £5 gizmo plugged into the cab 12V cigarette lighter socket seems to do the trick.

 

[Nirvanauk]

Ok I give in. Why is a shunt needed? As far as I am aware I have a solar panel connected to a MPPT controller that feeds into the leisure battery that has a B2B installed somewhere to provide my engine battery with any excess sun power. So, what is this shunt thing that you speak of?
many thanks.

 

[Ingwe]

Ok I give in. Why is a shunt needed? As far as I am aware I have a solar panel connected to a MPPT controller that feeds into the leisure battery that has a B2B installed somewhere to provide my engine battery with any excess sun power. So, what is this shunt thing that you speak of?
many thanks.

I believe the shunt is necessary only for monitoring the leisure battery not for charging it. Don’t believe that the B2B does anything with “excess sun power”. It charges the leisure battery (and the vehicle battery) using the alternator. It is the Battery Master that diverts “excess current” from the leisure battery to the vehicle battery either when on hook-up or when receiving solar.