Hey all,
Wiring up an Ammeter. Instructions are crap. Says to "disconnect the smaller wire from the solenoid (starter motor) terminal where the heavy battery (+) cable is terminated, and connect one of the ammeter wires to it and insulate the joint. Connect the other ammeter wire to the solenoid battery terminal post."
The schematic shows the ammeter wire connected to the same post as the heavy + battery wire, yet the instructions say leave that alone and isolate the smaller wire that goes from the solenoid to the starter and install the ammeter between the solenoid and the starter motor. I took a look at the starter removed from the car, and there is a small uninsulated wire from the solenoid to the starter. So Q is, do I break that wire and install the ammeter there?
I'm not sparky by any means and know that some pretty high current run via these heavy wires to the start so don't want to blow my ammeter or better still start a fire.
In dumb mans language what do i need to do?
Edit: I searched and could not find anything re ammeters.
Ammeter wiring
1st need to know what kind of ammeter it is, eg is it
but as you note, the cable is thick for carrying current, ammeters used like this haven't been used for decades in vehicles....(did once have a Zepher for a while...
)
the modern implementation is either of 2 methods depicted...
That first conductor act as a shunt, even though its a thick cable a voltage drop still exists across it, the meter actually measures that rather than the current directly.
the main problem usually is that the + to battery is not typically that 1 wire,but starter and other leads join at the + terminal - that would have to be changed.
For 2. it is probably just measuring the current out of the alternator,
the uninsulated wire (strap) you talk of is the ground connection for the solenoid.
- ah I might be wrong here, it could be the +from solenoid to the starter - hey its just memory recall as i don't have a Lwagon to look at.
I suspect you may have type 2 meter, and it sounds like the instructions given with it are indeed crap.
- a centred needle type,showing direction of current?
- needle rests at LHS, so 1 direction of movement.
but as you note, the cable is thick for carrying current, ammeters used like this haven't been used for decades in vehicles....(did once have a Zepher for a while...
)the modern implementation is either of 2 methods depicted...
That first conductor act as a shunt, even though its a thick cable a voltage drop still exists across it, the meter actually measures that rather than the current directly.
the main problem usually is that the + to battery is not typically that 1 wire,but starter and other leads join at the + terminal - that would have to be changed.
For 2. it is probably just measuring the current out of the alternator,
the uninsulated wire (strap) you talk of is the ground connection for the solenoid.
- ah I might be wrong here, it could be the +from solenoid to the starter - hey its just memory recall as i don't have a Lwagon to look at.
I suspect you may have type 2 meter, and it sounds like the instructions given with it are indeed crap.
The ammeter is the centered needle type that will show a negative or a positive draw of current. I feel a volt meter is next to useless as its prob too late once the aircon and stereo and the spotties and UHF and the short that I had not detected after rewiring the fuel pump (hypotheticaly) caused the battery voltage to drop low enough for the dash idiot lights to turn on.
So if I have an ammeter i will be able to see/monitor the "live" effectiveness of my charging circuit taking into account the current draw at that exact moment.
Anyway, I'm a little scared to install the ammeter between that massive + battery cable from the batter to the starter solenoid. Its big for a reason, also the ammeter is 60-0-60, surely the draw would be far bigger to crank the engine? like 100 or so... I would think that would fry the meter.
There is a smaller 3mm ish uninsulated wire, not sure of the gauge numbers (i have read that I should use gauge 10 or bigger) going from the starter solenoid to the actual starter, that the one where I need to install the meter I think?
So if I have an ammeter i will be able to see/monitor the "live" effectiveness of my charging circuit taking into account the current draw at that exact moment.
Anyway, I'm a little scared to install the ammeter between that massive + battery cable from the batter to the starter solenoid. Its big for a reason, also the ammeter is 60-0-60, surely the draw would be far bigger to crank the engine? like 100 or so... I would think that would fry the meter.
There is a smaller 3mm ish uninsulated wire, not sure of the gauge numbers (i have read that I should use gauge 10 or bigger) going from the starter solenoid to the actual starter, that the one where I need to install the meter I think?
leave the starter cable alone,
you won't then measure the current draw to that.
Its the other cable(s) you need to look at.
So does your meter come with an external shunt or built in?
you'll have a wire going to the alt, and more going to the fusible links and
whatever else hooked direct to +bat, maybe aux lights etc.....
your shunt will need to go between +bat terminal and those wires.
The big starter cable+clamp remains at the +bat post as it is now.
I still would prefer monitoring the volts though, measuring current like your intending is useful for testing/checking, but after that i'd rather just keep an eye on volts, as anything above 13.2V means the battery is getting charge, and thats useful to know at all times. and over ~14.5V means busted regulator.
Jaycar has/had a LED bargraph type voltmeter, thats what I used.
you won't then measure the current draw to that.
Its the other cable(s) you need to look at.
So does your meter come with an external shunt or built in?
you'll have a wire going to the alt, and more going to the fusible links and
whatever else hooked direct to +bat, maybe aux lights etc.....
your shunt will need to go between +bat terminal and those wires.
The big starter cable+clamp remains at the +bat post as it is now.
I still would prefer monitoring the volts though, measuring current like your intending is useful for testing/checking, but after that i'd rather just keep an eye on volts, as anything above 13.2V means the battery is getting charge, and thats useful to know at all times. and over ~14.5V means busted regulator.
Jaycar has/had a LED bargraph type voltmeter, thats what I used.