Ammeter and Voltmeter (gauges) Install

[korn3172]

Does anyone know how to install the ammeter?
I have heard that there is always a current in the car, so installing one can be dangerous. Thinks like it catching on fire, etc (BAD).

They said that i should install it onto my amps so i know how much they are draining, could someone give me a idea how to do that?

[danja]

Disconnect your battery first, you should be right.

[nicko]

sure u no this but an ammeter fills in a break you make in the circuit. If you instal it across the circuit it will cook a fuse and show no ohm readings

[danja]

Yeah, install in series.

[Tasmaniak]

question, do you know what an Ampere is? If not then why bother?

[commsirac]

Installing ammeters is problematical and typically ends up in tears for the average DIY(burnt out wires/fires) with limited electrical knowledge. Depending how it is connected up, it may not give you readings that are sensible, especially with all the devices triggered by relays. They were simple enough on older cars where all the electrics came off the fuse panel that mades it way inside the car and the whole power supply was put through the ammeter gauge on the dash.
There are more sophisticated ways of doing it now, but the after market ammeter that you buy would still require it to be done like this.

You can establish how well your system is working from good resolution voltmeters. to 0.1V.

The one advantage of an ammeter is it can give you a very good idea of the exact state of charge of the battery and/or condition. If the battery has been flattened and on jump starting and subsequent driving of the vehicle where the ammeter shows it charging for a few hours then it is a sign that the battery is in good nic. If however, there is no charge happening immediately after the jump start, then it shows a battery that isnt accepting charge. This can be read on a voltmeter with a bit of reasoning, but there are other variables with alternator/regulator output that can cloud the issue.

On a modern car an ammeter would need to be able to show readings of +/- 100A, the instrument is going to be of no use in finding small leakage currents when the car is switched off etc.

[danja]

I assumed he wanted to have one just to see how much current draw his amplifiers were using, not so much for monitoring charge state or in general for the car.

Presumably if you wired one on the power wire between the fuse in the engine bay and the amp it would work. Not sure where you'd get a 4GA ammeter though...

[Tasmaniak]

stinger make plenty of fuse blocks that have built in volt and ammeters

[korn3172]

Installing ammeters is problematical and typically ends up in tears for the average DIY(burnt out wires/fires) with limited electrical knowledge. Depending how it is connected up, it may not give you readings that are sensible, especially with all the devices triggered by relays. They were simple enough on older cars where all the electrics came off the fuse panel that mades it way inside the car and the whole power supply was put through the ammeter gauge on the dash.
There are more sophisticated ways of doing it now, but the after market ammeter that you buy would still require it to be done like this.

You can establish how well your system is working from good resolution voltmeters. to 0.1V.

The one advantage of an ammeter is it can give you a very good idea of the exact state of charge of the battery and/or condition. If the battery has been flattened and on jump starting and subsequent driving of the vehicle where the ammeter shows it charging for a few hours then it is a sign that the battery is in good nic. If however, there is no charge happening immediately after the jump start, then it shows a battery that isnt accepting charge. This can be read on a voltmeter with a bit of reasoning, but there are other variables with alternator/regulator output that can cloud the issue.

On a modern car an ammeter would need to be able to show readings of +/- 100A, the instrument is going to be of no use in finding small leakage currents when the car is switched off etc.

Yeah i got the +/- 100 ampmeter, and just want to read how much the amps are drawing, if its 100 then i know that i need to turn it down a bit cause the car would also be draining.

[rcnugget]

it would only most likley hit 100a on bass notes, check the fuses on your amps arnt exceeding 100a or you run the high possiblility of blowing your gauge up,

as above said I have a stinger termination block with built in 250a meters per channel and volt meter, they are over the alternators 120a output quite often but not long enough to drain the battery flat .....

I only have the because it came with my huge install kits and I wouldnt bother with buying them on thier own as part of an install they really give me no valuable information for day to day running

[commsirac]

it would only most likley hit 100a on bass notes, check the fuses on your amps arnt exceeding 100a or you run the high possiblility of blowing your gauge up,

If its just for the amps, and they are 100A+, then a cheap and safe way would just to measure the voltage drop from the battery to the amp and calibrate this against a known load going through the same wire. The voltage drop is proportional to the current. This eliminates the problem of having to wire extra lengths of heavy duty cable to the ammeter and have that cabling routed through the dash etc(assuming you want to be able to read this all the time), all of which will compromise the system by causing further transmission losses.
So if you put a 60W test lamp on the end of the wire and measured a voltage drop of 0.05V, then 0.05V represents 5A or 1V/100A.
You could use cheap multimeters for this task, or purpose built car digital voltmeters that are accurate to 0.1V should provide enough resolution.

[kopper69]

If its just for the amps, and they are 100A+, then a cheap and safe way would just to measure the voltage drop from the battery to the amp and calibrate this against a known load going through the same wire. The voltage drop is proportional to the current. This eliminates the problem of having to wire extra lengths of heavy duty cable to the ammeter and have that cabling routed through the dash etc(assuming you want to be able to read this all the time), all of which will compromise the system by causing further transmission losses.
So if you put a 60W test lamp on the end of the wire and measured a voltage drop of 0.05V, then 0.05V represents 5A or 1V/100A.
You could use cheap multimeters for this task, or purpose built car digital voltmeters that are accurate to 0.1V should provide enough resolution.

Nice work commsirac, thats what I would suggest. Dick smith sells little voltmeters that are simply a LCD screen. I would knock one of them up and you can calibrate it to any reading you need. You can then use tiny wires to make the measurements. Depends on how you go with electronics though. But putting a ammeter in for that much current doesnt sound like a good idea to me.