blockpower
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| posted on 18/7/14 at 07:43 PM |
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Wiring Ammeter ?? help please.
I'm stuck trying to make my ammeter work. I thought it would be quite simple really take the neg side of the gauge to the feed off the
alternator and the positive feed from the starter main wire from the battery to the plus side of the gauge.
I have a ford zetec running a fiat alternator just a positive and neg terminal on the gauge so I'm assuming internal shunt but I can't
make it work any ideas please?
Many thanks..
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avagolen
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| posted on 18/7/14 at 08:58 PM |
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Hi,
Firstly you need to find out if the ammeter is the variety that requires wiring in circuit, or a shunt type that
needs to be wired in parallel with a 'shunt' that is wired in the cct.
The next step is where to wire it so that it displays the 'charge / discharge' current flow to / from the battery - which is why
if it is poorly wired can be a bit risky.
Normally, the ammeter goes in the wire that feeds all of the ccts of the car in the battery feed line.
If you have a main fuse in the circuit from the battery to the fuse box, this is the same wire that the ammeter
should be wired.
This must NOT be in the cct to the starter power line - way too much current for an ammeter.
Hope this helps.
Len.
[Edited on 18/7/14 by avagolen]
The Answer for everything, but never the last word....
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steve8274
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| posted on 18/7/14 at 09:21 PM |
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I purchased an ammeter for my mini and tried to fit it. Upon further investigation, I realised it couldn't be used. The smiths one I had was
designed for cars with dynamos.
The spade connectors on back where almost twice the size of a normal one. I was advised I would damage my alternator if I tried to wire it in. In the
end I just used a voltmeter.
Hope this helps.
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britishtrident
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| posted on 19/7/14 at 01:01 PM |
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Really best to forget it, with modern car with an alternator a voltmeter (battery condition gauge) will give more useful information and is a lot
easier and safer to wire.
If you really still want to fit an ammeter it must be a modern one that has a high enough current capacity to cope with the maximum output of a modern
alternator, this would normally require a meter that uses an external shunt
[Edited on 19/7/14 by britishtrident]
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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snowy2
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| posted on 20/7/14 at 07:06 AM |
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Q1; whats the power output of your alternator?
Q2; whats the scale maximum on your ammeter?
Q1 likely to be 45A+ Q2 is likely to be 30A.......are you seeing a conflict here?
old style smiths meters are usually in series with the alternator (errr.....dynamo....its very rare for alternator cars to have ammeters) but if you
must take the charge wire from the alternator and cut it then extend it to the ammeter and back from the ammeter to the other side of the cut wire,
and on to your battery.....oh and the charge wire will want up rating to much heavier gauge wire as it will cause a voltage drop over such a long run
and reduce the effective charging available. (possibly to near zero!)
if you have a shunt resistor for the ammeter, you cut the charge wire as above and connect the shunt between the two cut ends, the thinner wires at
either end of the resistor go to the ammeter......
personally i wouldn't bother, on an alternator it tells you almost nothing useful, much better to have a battery voltage gauge if you need to
have anything.
sometimes you are the pigeon, most of the time the statue.
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Angel Acevedo
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| posted on 20/7/14 at 04:24 PM |
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Another reason to fir voltage gauge instead of Amp meter is tat you have a smaller current going to the dash there for the risk of shorting and
causing a fire is reduced.
HTH
Beware of what you wish.. for it may come true....
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