PaulRainbow
Well-Known Member
It effectively works the same as a diode, without the big voltage drop.
Suddenly...the battery isolater won't isolate
- Thread starter salar
- Start date
It effectively works the same as a diode, without the big voltage drop.
VicS
Well-Known Member
maybe one of the alternative positions for the shunt shown in this diagram will be more appropriate. The trouble will always be the starter current when the domestic battery is used for emergency starting. Separate ammeters for charge current and load currents has some merit
salar
Well-Known Member
Do you have to have a different type of ammeter/shunt if it is fitted to the negative side? It is a Wema 150amp ammeter, installation instructions here showing positive installation: https://www.furneauxriddall.com/acatalog/amperpometer.pdf
VicS
Well-Known Member
Very probably has to be fitted in the positive but I am not making a great deal of sense of the wiring "instructions"
Why does the shunt In the battery positive lead have an earth connection ?
Will it work if powered from the same power source that it is measuring .... or does the battery shown in the wiring diagram indicate a separate power supply.
I' a bit doubtful if it is suitable for what you want to do.
What bollox see #45
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Lon nan Gruagach
Well-Known Member
Mebby a wild guess, but a "shunt", more likely a sensor, with 5 connections: Load, battery, +v gnd and output is almost certainly an active, non contact current sensor. In which case it matters not where its placed.
along the lines of: https://cpc.farnell.com/honeywell/csnp661-002/current-transducer/dp/SN36592 it has a second large contact on the other side...
VicS
Well-Known Member
You're right..... that's why they call it a sensor, it's not a shunt at all.
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salar
Well-Known Member
This is a Wema marine ammeter and shunt. Two spade connectors go to the ammeter itself, shown as the plug in the back of the instrument on the diagram, the other to ground. It has worked pretty well for the last 5 years and was still working up to the point I disconnected it to see where the diode was connected. I'm happy with the ammeter I have, I just want to make sure it is wired up in the best way with the diode.
VicS
Well-Known Member
salar
Well-Known Member
That's good to know! Thank you. I assume it says Shunt all over the packaging because that is what people expect and there is a shunt at the heart of it with the sensor around it. I'll try it on the negative circuit.
PaulRainbow
Well-Known Member
I don't agree that you can fit it "anywhere". You still need to have all loads and all charging sources connected to the load terminal, or they don't get measured by the shunt/sensor.
Ordinarily, you would connect the ArgoFET to the battery side of the isolator, but that would not allow the charging to be sensed by the ammeter, as Vic said. You could put the shunt prior to the isolator, connecting the ArgoFET to the battery terminal of the isolator and the loads to the load side, that would sense everything. But, doing that would mean that if you used the emergency combine switch to start the engine the current to the starter would have to pass through the shunt. That would very likely be too much for the shunt to carry, so i would leave it as it is in your diagram and remember that in order to charge the domestic battery, the isolator must be switched on.
Do not fit it to the negative side of the circuit.
PaulRainbow
Well-Known Member
In this case, no doubt for the electronics in the sensor. But, it's not uncommon to have such a connection. The Victron negative shunts have a positive connection, then they just have a data cable from the shunt to the instrument, which also carried power for the instrument. Handy when installing, as you only need the single cable to the instrument.
salar
Well-Known Member
The new Argo FET is in place at last. For some reason known only to Yanmar and the sparky that set it up, the alternator and domestic battery both need to be connected to the same post on the diode for the engine to start. I'm assuming that post would be the Alternator IN post as it was on the original diode (earlier photo)?
PaulRainbow
Well-Known Member
Something clearly amiss here, that needs looking into. Alternator goes to the INPUT terminal, domestic and engine batteries go the the OUTPUT terminals. Nothing else goes to the Argofet, other than ground and possibly energise.
VicS
Well-Known Member
Sounds very wrong... Needs sorting out and wiring as PR says
Diagram from Victron literature below ( Shows 3 battery version but the two battery version is the same with one battery and one terminal on the Argo-FET less)
salar
Well-Known Member
Wiring the Argo FET is simple enough. The need for power to the domestic circuit to start the engine is the puzzle, maybe the engine control panel positive feed is coming from a single positive feed from the domestic to the cabin area, instead of having two independent feeds so the engine control panel could be fed from the starter battery.
PaulRainbow
Well-Known Member
Something is very wrong here. There should be a cable from the alternator B+ to the Argofet (it isn't a diode) input, there should be nothing else connected to either the input terminal, or the alternator B+. I suspect you may have a +VE connection at the B+ terminal of the alternator.
You then have a cable from each output terminal to a battery bank, and finally, the negative connection.
All loads then come from the respective isolator switches. I suspect you originally had a 1-2-b switch and the person who fitted the separate switches has moved the starter wiring to the new engine switch, leaving the control panel on the domestic circuit., Not the first time i've seen this, it needs changing.
I also suspect there is an incorrect positive connection at the alternator, as i said previously. This must be removed. You may find that when you do remove it you don't get an output from the alternator, if that is the case connect a switched positive to the "energise" terminal of the Argofet.
salar
Well-Known Member
Paul you may well be right, there was a 1-2-b switch which was swapped out for the three individual switches. I have traced the alternator feed wire back to the alternator but not checked exactly what else is connected there. I have also messaged the sparky who did the work, that may throw a bit of light onto it. I wish the boat was nearer so I could more easily pop down for more investigations. I think moving the engine panel onto the starter circuit will be a good step forward.
VicS
Well-Known Member
Surely the engine control panel should be fed from the engine, and thereby from what ever battery is connected as the engine start battery, via the wiring harness..
The wiring diagram in the Service manual I'm looking at is a load of poo but there are good diagrams in the Owners manuals.
VicS
Well-Known Member
I have attempted to highlight the feed to the panel in the diagram below.
The wire to which the red arrow points should be disconnected from the starter and re-routed from the alternator to the input terminal on the Argo FET ( previously it should have been re-routed to the common terminal of the diode splitter)
A connection from the "AC" terminal on the starter switch to the "energise " terminal on the Argo FET will almost certainly be needed too ( this is the "switched supply" to which PR refers)
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salar
Well-Known Member
One would think so but the power is coming from the Domestic circuit somehow. More wire-tracing I suppose. But hey, this is why we have Februarys. Many thanks for the diagram too.
