10 replies to this topic

[noeman]

I'm trying to help a friend wire up her amp gauge but it don't seem to be working. After reading several posts am I right in thinking one wire goes to the main brown terminal on the solenoid/starter motor and the other wire to the fuse box? Also does the engine need to be running for it to work? The manual that came with the gauge shows it needs to go inbetween the solenoid and alternator.
I want to get this right as I've read they can be quite dangerous and cause fired ?.
Thanks for any help.

[cal844]

I connect them directly to the battery, the amp is then triggered by the blue/white wire at the rear of the head unit.

[gazza82]

I connect them directly to the battery, the amp is then triggered by the blue/white wire at the rear of the head unit.

 

Amp GAUGE .. not amplifier!

[noeman]

I thought I was a little confused by cal844 reply.

[unburntfuelinthemorning]

The entire electrical current apart from the starter motor current needs to pass through the gauge.

 

This link should give you the gist of it:

 

https://www.classici...tion 012313.pdf

 

The S terminal shown on the diagram is where all the vehicle's electrics are supplied from.  If wired like this the gauge will register all current going to and from the battery with the ignition on and off.  The starter motor current isn't included as the current drawn by the starter is way higher than the gauge can cope with.

[noeman]

Thank you for the pdf. The wire going to the solenoid I understand. It's the other wire, looking at the pdf, 2 wires go to the 's' connection. 1 from the ignition, which I can get from the fuse box and the alternator has a plug, so I'm just wondering how to connect to that?

[cal844]

I connect them directly to the battery, the amp is then triggered by the blue/white wire at the rear of the head unit.

Amp GAUGE .. not amplifier!

Ah oops, my bad! My apologies for the confusion

[gazza82]

You are correct as well about the fire risk .. while fixing the wiring on a gauge on my car back in the 70s I dropped the end of a wire onto the ammeter terminal and it fried itself! ... Luckily I caught it in time but the ammeter terminals need properly insulating too ...

 

Why an ammeter? Voltmeters are safer.

[unburntfuelinthemorning]

I fitted an ammeter before in a Land Rover.  You need to do the wiring properly:  proper connections and insulated covers over the terminals as well as cable protection where they pass through the bulkhead and a gauge of cable which can easily handle the current.  Do disconnect the battery whilst carrying out the work too.  Done properly there is little risk.  A voltmeter is a lot easier to wire in though!

 

Looking at the diagram in the pdf, everything that is connected to the 'S' terminal would have been connected to the starter solenoid where it says '12V Post'. 

 

Run two heavy gauge cables from the ammeter to the starter solenoid.  Find the solenoid terminal with the main battery cable attached, remove all wires from that terminal apart from the main battery cable, connect one of the ammeter wires to that terminal.  Then join all the wires you removed to the other ammeter cable.

[Rorf]

Ammeters were used in the days of generators, with the newer alternators it is not necessary. You can however install a volt meter which will give the critical info needed to check the health of the system.

 

Ammeters poorly wired in can lead to burnt out wiring and fire hazards.

[noeman]

Run two heavy gauge cables from the ammeter to the starter solenoid. Find the solenoid terminal with the main battery cable attached, remove all wires from that terminal apart from the main battery cable, connect one of the ammeter wires to that terminal. Then join all the wires you removed to the other ammeter cable.

That makes sense thank you.
I have a voltage gauge in my mini that was easy to wire and comes in useful.
But I think she just bought a few gauges for her mini just to fill the 3 holes in her new dash. But I will also warn her of the dangers and non usefulness of the amp gauge.