What are the 2 meters for?

[Wandering Star]

My Dufour 2800 has these 2 displays factory iinstalled - neither appear to be connected to anywhere!

I’m not au fait with amps & stuff, I presume the first meter should display the battery state & the second one should display either the draw from the charge going into the battery?

So what info should they be providing me with and how do I rewire them (from where to where)?

 

[Sticky Fingers]

Are these charging status and current draw on shore power?

 

[Minerva]

One is state of charge from your battery - it's basically just a voltage meter. The other should be on the feed to the main busbar showing how much electrickery you're drawing.

 

[skipper021]

I had these gauges on my last Dufour 2800, I didn't have any confidence in the waggle needles, so I binned these gauges and fitted a Nasa BM-1 Compact Battery Monitor - a huge improvement!

 

[VicS]

My Dufour 2800 has these 2 displays factory iinstalled - neither appear to be connected to anywhere!

I’m not au fait with amps & stuff, I presume the first meter should display the battery state & the second one should display either the draw from the charge going into the battery?

So what info should they be providing me with and how do I rewire them (from where to where)?

The left hand one is as said basically a voltmeter scaled to show battery state of charge (SOC) . If the knob below it is a switch it could be wired to show SOC of either the starter battery or the domestic battery bank.

The ammeter could be connected to show the draw from the domestic battery bank or to show the charging current from the alternator. It might be associated with a remote shunt but the non-linear scale suggests it is a moving Iron or moving magnet type which may not involve a shunt

For some basic info and instruction on electrical stuff see the Boat electrical notes on Tony Brooks' TB training website
http://www.tb-training.co.uk/cover.html
In particular see the sections on voltmeters and ammeters
.

 

[William_H]

As Vic says volt meter and amp meter. If it is a moving iron amp meter it will require all current being metered to pass through it. It should have 2 big bolts on back. Possibly with heavy wires attached. I would suggest the amp meter could most usefully used as a meter to measure current from engine driven alternator. Firstly as a check of alternator charging but then an indication of decline of charge current with battery charge state. Very useful if you are running the engine just to charge batteries. Tells you when more engine running will not benefit much.
Unfortunately a moving iron type meter will require heavy wires from alternator to battery (bus). A moving coil type meter is much more sensitive taking very small current to actuate it. Thus we use a "shunt" in the main high current wire. This takes most of the current forcing only a small amount through meter hence light wires are good. The shunt might look like a block perhaps 10cms long with bolt connections for heavy wires plus 2 light wires leading one from each end. You could probably find a replacement moving coil meter to fit in place of existing amp meter but need a shunt.
The volt meter if not indicating means it is not connected or kaput. It should have 2 wires on 2 bolt type terminals. If it has measure voltage across them with multimeter. If there is volts there you have a bad meter. if not then wiring has been changed. As said the switch below may be used to select which battery you are metering. (might have a centre off position) could select engine or house battery to measure. Very useful. If not then house battery condition is most useful. ol'will

 

[Sandy]

I had something similar on my Gib'Sea. As I struggle to draw more than 10 amps the ammeter was as useful as a chocolate teapot and the battery thingy was a total work of fiction; both have been replaced. As @skipper021 has said a NASA BM-1 will do the job. I've stepped up from NASA to Victron system as that gives me even more detail.

 

[Wandering Star]

Well, thanks everyone for the education - seems the consensus is to scrap the meters and fit a BM1 which I had been considering doing anyway.