Digital Voltmeter/Ampmeter fitting

[nesty]

https://club8090.co.uk/wiki/VW ... ging_cause" onclick="window.open(this.href);return false;

Hi

I brought one of the meters in the link above. However mine is the combined meter of Volts & Amps. The instructions ain't great. However, I understand the battery connection side of things. However for the Ampmeter connection I must connect a shunt (which I have); though I am unsure of the connections on the shunt.

The shunt has 4 terminals, 2 large and 2 small. The smaller connection I understand that gets connected to the meter. I am assuming for the large connections. I connect to the negative of the starting battery and other terminal the charging lead from altenator on the other terminal?

If anyone can shed some light who has install these meters.

Thanks

[toomanytoys]

Personally, I wouldnt be trying to measure amps.. the smallest alts fitted were 45 amps and thats a lot of power to be passing through wiring to and from the "gauge".. whats its rating?

[nesty]

I think the gauge is 70Amps. I did think of the power issue going to the switch. Though I am more intersted in what the 2 batterys are doing.

However looking at the set up. The power doesn't directly go to the meter, as it stops at the shunt by the battery. The switch remotely monitors the voltage at the shunt.

[tonytech]

The shunt is a resistor (probably about 0.01Ohms) it is connected between the battery and the van electrics.
The instructions should tell you which way round the shunt goes and if it should be connected in the Batterys +ve lead or the -ve lead.
The meter connects accross the shunt and measures the Voltage drop accross the shunt.
However by carefull chioce of the shunt value the meter appears to read the current.

[ghost123uk]

I too would not bother checking current (Amps)

However, if doing so and using a shunt powered meter, please make sure the shunt goes, not on the thick main cables at the battery, but on the thinner live feed cable on the battery. If you put it in the -ve (earth) lead or on the THICKER live +ve lead you will be feeding a couple of hundred Amps through it when you are starting the van - result will be smoke and fire

btw, the shunt should be right up close to the battery terminals and VERY carefully mounted and insulated as it is LIVE with the full power of the battery = dangerous The thin wires from the shunt then go off to the meter. They are often wildly inaccurate by the way.

imho = not worth the trouble.
Mind you, they were fitted as standard to the likes of E Type Jags and MGB's etc ! - these were not "Shunt" meters, but normal Amp meters connected in series with the thinner +ve lead from the battery. In those days, with Dynamos instead of Alternators, and much less electrical load, the average output was much less than a modern Alternator, so the meter and cable only had to deal with + and - around 25 Amps.

[nesty]

OK thanks for this. I might give the Amps a miss. I don't fancy having that current mixing like that right under my drivers seat! I am more intrested in the the state of the batterys. Just thought the meter was like the ammeter dials. Though sounds like a risk installing the Amps side of things.

[CovKid]

Its tempting to measure amps but voltage is all you need really. When the alternator is running, you'll know since its the highest voltage you'll ever see on the voltmeter and any problems with either battety become self-evident when parked and reading the voltage. Keep it simple - much like T25s.

Old analogue voltmeters were a bit vague and an ammeter was just another way to watch the charging but these digital ones are so sensitive, the ammeter just isn't needed if allyou want to do is keep an eye on things.

[nesty]

OK many thanks for the replies. Hopefully get the gauge installed next wek.

[bunnynogood]

Just thought I'd drop these here, as the most suitable place. Found on another forum..

An interesting blog about a T4 conversion with some useful electrical info

http://www.windowsmediapc.co.uk/t4/2007 ... meter.html" onclick="window.open(this.href);return false;

The WattsUP meter..

http://www.reuk.co.uk/Watts-Up-Meter.htm" onclick="window.open(this.href);return false;

[kevtherev]

I have an ammeter fitted, I find it very useful.
it told me when my split charge relay broke, it told me when my regulator brush pack went foo barr, it tells me when my leisure and starter batt is charging, it tells me when the starter and ignition circuit is OK

so I would recommend getting it to work

[CovKid]

Yeah, but what it DOESN'T tell you is.....

"LOOK UP YOU CLOWN YOU'RE ABOUT TO RUN INTO THE BACK Of THAT BUS AT THE ROUNDABOUT !!!!!!!"