Alternator and Ammeter

[chesney]

I finally got round to fitting an alternator to Maggie, but was very surprised to see a complete discharge on the in car ammeter with lights on etc.
Then I realised that the ammeter is built into the circuit through the brown wire right by the solenoid, ie the feed to the rest of the car electrics. My assumption is the ammeter works fine when a dynamo is fitted as the charge is carried back through the ammeter as it is connected up through the regulator, ie charge runs through the ammeter into the battery. The alternator is connected by a separate loom to the solenoid terminal with the battery, so pretty much bypasses the ammeter, and so the ammeter only shows a discharge of the current running through the brown wire.
Have I got it right, and if I have, can anyone recommend how best to connect the ammeter with the wiring system being used?
Thanks in advance.

[IslipMinor]

The three diagrams below show the transition from dynamo to alternator, and then to alternator + ammeter.

They are based on the 'sticky' at the start of this forum (thanks to Louise for the original).
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The original dynamo control box can either be left connected as shown in the second diagram, or disconnected and removed completely, as shown in the final diagram.

[bmcecosse]

As Richard shows - an ammeter needs to be connected in the main feed to/from the battery - with the alternator feed on the non-battery side ! Of course if you really want to glam up the dashboard -you could fit 3 ammeters! One on the alternator feed, one on the car supply feed, and one on the battery feed - which would hopefully show the net difference between the other two..... and a voltmeter too, of course...... :roll That's if you can squeeze them in beside the vacuum gauge ( ) the clock and the rev-counter..... Water and oil temperature of course and the only one you REALLY need - an oil pressure gauge !

[chesney]

Thanks Islip, I did browse the diagrams when I did the alternator change on my '58 a few years back, but didn't realise they included the wiring for an ammeter and alternator.
I hardly think three ammeters is necessary so I won't be doing that!

[John Naylor]

All the diagrams and instructions suggest that the earth connections can be removed from the control box and I blindly followed this and then wondered why my wipers had packed up! beware of snipping away your wiper earth.

[chesney]

Thanks John, I'll be keeping the regulator just in case I ever need to reinstate the dynamo

[IslipMinor]

suggest that the earth connections can be removed from the control box

Interesting - looking now at the wiring diagrams there is a note 'Earthed to the Control Box terminal 'E''. So if removing the control box the wiper motor earth needs to be maintained.

[chesney]

Thanks all, modified the alternator loom today and fitted it to the ammeter, works a dream

[bmcecosse]

Great success!