Alternator to shunt

[wazza]

I have installed a battery monitor so now I can see how much solar is giving me as well as a shore power charger, but not the alternator.
The alternator’s negative wire goes to the engine block which is of course normal but how do I run it through (or to) the shunt so to see the amps going into the batteries?
I have a bus bar with the - solar, shore power, load but don’t understand how to get the alternator’s output to my monitor:
Surely this must be a common issue as the engine generates amps for the batteries.

Thanks in advance for any tips & advice??

 

[ChromeDome]

On my boat the negative is common for engines and bus bar and then some.

If yours are the same any point of neg should do

 

[Tranona]

If you have wired your shunt and monitor correctly with the shunt on the negative house battery post (or immediately afterwards) then all current flows in and out will be measured, but it will not differentiate between the sources. charging from alternator, solar and mains will flow through the shunt.

You can see the shunt above the house bank in this photo. Note it is not yet connected to the negative bus bar or the monitor - work in progress!

 

[Daverw]

Sounds like you have run the solar and charger to the shunt and placed the shunt in the neg line see somewhere before house battery’s, the battery neg I assume has a second connection direct from your engine block somewhere as the alternator also sounds like it’s isolated neg

 

[PaulRainbow]

The engine battery cable and the cable going to the the block should both be connected after the shunt. The best way to do this is to fit a negative busbar or a terminal post, see the schematic below:

 

[wazza]

I’ll explain what I’ve done. I’m getting amps in and out fine with Solar and shore power & load, but nothing in when the engine is going.

Negatives from the solar and 220v battery charger go to a bus bar then from there to the shunt then on to the house batteries. That same bus bar has the negative to the fuse panel.

On the positive side I have a splitter/controller ( I don’t know the official word for it) which allows the start battery to be charged first.

Looking and the engine there’s a negative from the engine block directly on the the negative on the start battery. Is that an issue.

I feel dammed thick.

 

[wazza]

Can

The engine battery cable and the cable going to the the block should both be connected after the shunt. The best way to do this is to fit a negative busbar or a terminal post, see the schematic below:

Cant seem to see the schematic ?

 

[KompetentKrew]

Here's how the manual for the Victron Smart Shunt explains it:

1. Connect the negative battery terminal to the M10 bolt on the BATTERY MINUS side of the shunt.
   Note that there should be no other connections on this side of the shunt or on the negative battery terminal. Any loads or chargers connected here will be excluded from the battery state of charge calculation.
2. Connect the negative of the electrical system to the M10 bolt on the SYSTEM MINUS side of the shunt. Make sure that the negative of all DC loads, inverters, battery chargers, solar chargers and other charge sources are connected “after” the shunt.

The principle is the same whatever brand or model of shunt you have - it goes between the battery and everything else.

 

[PaulRainbow]

Can

Cant seem to see the schematic ?

My website is only available to UK users:

 

[VicS]

I’ll explain what I’ve done. I’m getting amps in and out fine with Solar and shore power & load, but nothing in when the engine is going.
Negatives from the solar and 220v battery charger go to a bus bar then from there to the shunt then on to the house batteries. That same bus bar has the negative to the fuse panel.
On the positive side I have a splitter/controller ( I don’t know the official word for it) which allows the start battery to be charged first.
Looking and the engine there’s a negative from the engine block directly on the the negative on the start battery. Is that an issue.
I feel dammed thick.

That all sounds correct.
I guess your "splitter/controller" is a VSR ?

Maybe the simple diagram below will help. All positive wiring and the battery monitor connections omitted for clarity

The monitor will show the house battery charge current only and only when your VSR closes to charge the house battery.
Perhaps your VSR is not operating ( is its negative connected )

 

[Tranona]

Looking and the engine there’s a negative from the engine block directly on the the negative on the start battery. Is that an issue.
.

That should go to the negative bus bar from the start battery and then to the engine as well

 

[roaringgirl]

I would combine the negatives of the engine and house batteries. Surely the VSR won't work unless you do this? Also, the VSR looks like it won't be powered by the alternator with this setup?

 

[PaulRainbow]

I’ll explain what I’ve done. I’m getting amps in and out fine with Solar and shore power & load, but nothing in when the engine is going.

Negatives from the solar and 220v battery charger go to a bus bar then from there to the shunt then on to the house batteries. That same bus bar has the negative to the fuse panel.

On the positive side I have a splitter/controller ( I don’t know the official word for it) which allows the start battery to be charged first.

Looking and the engine there’s a negative from the engine block directly on the the negative on the start battery. Is that an issue.

I feel dammed thick.

As you already have the negative busbar, all you need to do is to connect the cable from the engine block to the busbar and connect the engine battery negative to the same busbar. Job done

 

[wazza]

Thank you all so much for your help?️ I shall implement your advice??

 

[VicS]

I would combine the negatives of the engine and house batteries. Surely the VSR won't work unless you do this? Also, the VSR looks like it won't be powered by the alternator with this setup?

The two battery negatives must not be directly linked... . . .All connections to the house battery negative must be via the shunt.

For the VSR to work in the way Wazza wants , i.e. to link the batteries when charging from the alternator it must sense the engine start battery.
If he also wants it to link the batteries when charging from a single output solar controller or battery charger connected to the house battery it will have to be a dual sensing VSR.

We don't know what VSR he has. One aimed at the caravanning or motor caravanning market may be single sensing and connected the wrong way round so that it is not sensing the starter battery.

 

[wazza]

Sorted??? See the ALL the amps now, both in and out ?? even from the alternator.
Plus the charge controller is working as it should. No power dump from the start battery to the house bank.

Thanks again everyone for your advice. I knew I could rely on the ybw.com forum to find out what I needed ??️️