Volt meters

[single]

Nothing better to do first thing today, so I thought I would fit two voltage displays for the boat.I plan to run a switched & fused wire direct to the engine start battery and a fused/switch wire to any circuit convenient for the domestics (aux) Is that the right way to do it? (ignore the readings, I just tested it with a knackered alarm battery)
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[Rigger Mortice]

Personally, I wouldn't want to wire either direct to a battery. I would wire them both to somewhere between the master switch and the switch panels. Those meters use so little power that I wouldn't bother switching them (unless it is necessary to be able to switch off the light at night)

I would also want to know why they are giving different readings. I would want more precision than your picture suggests.

 

[vyv_cox]

For a volt only display wire between the 1-2-both switch and the main panel. You can see the voltage in either battery by operating the switch. Amps is a useful value to monitor sometimes but it is normal to wire it to the earth return. Combined volt/amp meters are cheap from China on Ebay.

 

[VicS]

Nothing better to do first thing today, so I thought I would fit two voltage displays for the boat.I plan to run a switched & fused wire direct to the engine start battery and a fused/switch wire to any circuit convenient for the domestics (aux) Is that the right way to do it? (ignore the readings, I just tested it with a knackered alarm battery)

I'd wire both, via fuses, to their respective batteries. Perhaps direct, perhaps via the main isolator switches.

Like RM Id like to know why they read differently when connected to the same source ....... perhaps because their precision is only ± 0.05volts?

 

[William_H]

As said via a fuse to any part of the circuit that is switched off when you leave the boat.
Re different readings. Get a multimeter or better 2 meters and check compare to see if one of your mounted VM is inaccurate. If you can access the back of the printed circuit board of the bad meter you might find a little variable resistor. It will look like a small cylinder about 4mm high 5mm diameter with a tiny cross shaped hole in the top for a small phillips head screw driver. This is the adjustment for the voltage reference and will adjust the reading. You should be able to get them to read closer like .01 volt difference with long term accuracy of .02 volt. good luck olewill

 

[single]

They are reading the same now with a good connection and match the multimeter.