Battery Monitor: Positive Amp from solar?

[Tim Good]

Simple question:
Why does my battery monitor seem to recognise amps incoming via a PMW solar controller whilst it ignores amps from an MPPT controller?

More detail
You may recognise this battery monitor? It’s a Heart Link2000 which is also link to a big Heart Freedom system.

Anyway it records all sorts of stuff but at its most basic it has an amps and amp hr monitor. Very useful.

The 3 sets of batteries all go via a Victron Argofet isolator. Into that goes the alternator, small solar panel via a simple dual PMW solar controller connected to bow and engine battery battery. Then a larger 360w solar array via an MPPT controller goes to the house bank. Also connected to the Argofet.

If I run the engine you see the positive amps going into the batteries on the amps. Likewise I can see positive amps going into the Bow and Engine batteries from the PMW solar controller. However it doesn’t record any positive amps from the main solar array. And that’s really what I need.

I can obviously monitor the incoming amps via Victron app but what is useful is it working on the battery monitor and showing the amp hrs used during the night and then being replenished and going back to zero during day when the solar is working. It gives a much better picture of how full the batteries are or how close your are to being full.

Why might the monitor not pick up the amps from the Victron controller?

 

[Boater Sam]

Because there is no charge going into the batteries! Do you know that it is really working? Check with a meter.

 

[Pete7]

Then a larger 360w solar array via an MPPT controller goes to the house bank. Also connected to the Argofet.

What does the Victron app say? can you post a screen shot?

Does the connection for the MPPT go after the Argofet and the link system to the batteries?

As Sam suggests, check with a meter to see what the output of the MPPT is and then what are the batteries actually seeing.

 

[Sandy]

Where is the MPPT connected to the system?

The negative wire should be on the non battery side of the shunt.

 

[VicS]

Simple question:
Why does my battery monitor seem to recognise amps incoming via a PMW solar controller whilst it ignores amps from an MPPT controller?
>
Then a larger 360w solar array via an MPPT controller goes to the house bank. Also connected to the Argofet.

As Sandy suggests check that the negative connection from the MPPT controller does not bypass the shunt. It should be connected to the same place as the negative connection from the PWM controller.

.

 

[Tim Good]

Where is the MPPT connected to the system?

The negative wire should be on the non battery side of the shunt.

Negative connected to shunt… what do you mean “non battery side of shunt”?

 

[Tim Good]

As Sandy suggests check that the negative connection from the MPPT controller does not bypass the shunt. It should be connected to the same place as the negative connection from the PWM controller.

.

Thanks. Ok it is connected to shunt but not to the same place as the PWM. Perhaps I need to understand the shunt more and the various connections to it. It’s something I’m quite ignorant about. Care to summarise for me?

 

[PaulRainbow]

Negative connected to shunt… what do you mean “non battery side of shunt”?

If you have the positive from the MPPT controller going to the Argofet input, it won't reliably work, connect it to the domestic battery terminal of the Argofet.

 

[Tim Good]

Duplicate. Ignore

 

[Tim Good]

If you have the positive from the MPPT controller going to the Argofet input, it won't reliably work, connect it to the domestic battery terminal of the Argofet.

The Argo has 4 posts. Battery 1, 2, 3 and alternator. The MPPT positive is connected to the battery 1 post (house bank)

 

[PaulRainbow]

Thanks. Ok it is connected to shunt but not to the same place as the PWM. Perhaps I need to understand the shunt more and the various connections to it. It’s something I’m quite ignorant about. Care to summarise for me?

One end of the shunt connects to the battery negative, nothing else should be connected to this end of the shunt or the battery terminal.

Everything else, loads and charging, connect to the other end of the shunt. Best way is to connect a busbar to this end of the shunt and then connect all loads and charging sources to the busbar.

Does the Victron Connect app' definitely show that there is a charging current from the MPPT ?

 

[PaulRainbow]

Because there is no charge going into the batteries! Do you know that it is really working? Check with a meter.

In post #1 the OP states "I can obviously monitor the incoming amps via Victron app"

If that is the case, the controller is charging, but it doesn't show up on the battery monitor, almost certainly because the negative from the MPPT is incorrectly connected.

 

[VicS]

Thanks. Ok it is connected to shunt but not to the same place as the PWM. Perhaps I need to understand the shunt more and the various connections to it. It’s something I’m quite ignorant about. Care to summarise for me?

The shunt is a very, very low value resistance . Current flowing through it produces a very small voltage across it ( a few mV). The voltage is proportional to the current ( Ohm's law and all that stuff) and its polarity depends on the direction of the nett current flow ( charge or discharge ) . The monitor measures this small voltage and displays the result as amps charge or discharge.

All current to and from the battery being monitored must pass through this shunt. One end (the battery end ) is connected to the battery negative. All other connections, ( loads, charging sources and other batteries must the connected to the other end ( the "system" end).

The diagram below comes from the installation instructions. All loads and charging must be connected via the negative connection shown on the left hand side. There should be no other connections to the battery negative or the "battery" terminal of the shunt ( which I have marked with red asterisks).

* The "main battery" will be your house/domestic battery bank. The "auxiliary battery" will presumably be your engine start battery( but it could be your bow battery if you wanted the monitor to display its voltage).

The positive connection from your MPPT controller appears to be correct but the negative seems to be connected to the wrong place.

 

[Tim Good]

Ok thanks guys. I’ll rewire the negative on the shunt and report back!

 

[Tim Good]

@VicS @PaulRainbow

Ok so this is my shunt. Top right is the main house bank negative. I’m not entirely sure where the others go but I do have a 1, Both, 2, off switch. Off is house bank whilst 1 is Bow and 2 is Engine. It’s always been like this.

Where is that snake pit would you say the solar negatives should go?

Note: the wiring diagram I’ve added was from a long time ago before the boat was mine. It does not appear to be wired like that any longer.

 

[PaulRainbow]

@VicS @PaulRainbow

Ok so this is my shunt. Top right is the main house bank negative. I’m not entirely sure where the others go but I do have a 1, Both, 2, off switch. Off is house bank whilst 1 is Bow and 2 is Engine. It’s always been like this.

Where is that snake pit would you say the solar negatives should go?

Note: the wiring diagram I’ve added was from a long time ago before the boat was mine. It does not appear to be wired like that any longer.

The top two bolts should only have the two wires that are screwed to the sides of the shunt, these go to the display.

There should be no other wires going to the top of the shunt or to the battery negative terminals. You have an additional black wire going to the top right bolt. I suspect this could be from the MPPT, it needs to be moved to the bottom busbar, you can use one of the bolts, or one of the centrally located slotted brass screws.

 

[simonfraser]

Are we looking at vertical shunt on the left
-ve horizontal bus bar at the bottom, part of the shunt, with two lower big connector and some further small connection
top right ? What’s that ?

 

[PaulRainbow]

Are we looking at vertical shunt on the left
-ve horizontal bus bar at the bottom, part of the shunt, with two lower big connector and some further small connection
top right ? What’s that ?

It's a dual shunt Simon, left vertical monitors battery one, right vertical monitors battery 2. The horizontal bottom bar is the common negative to all loads and charging sources.

 

[VicS]

Where is that snake pit would you say the solar negatives should go?

 

[simonfraser]

It's a dual shunt Simon, left vertical monitors battery one, right vertical monitors battery 2. The horizontal bottom bare is the common negative to all loads and charging sources.

Tnx, dual shunt, first one I've seen