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#1 Negative change over

Posted: Fri May 01, 2015 2:10 am
by drichards
I have changed the polarity of the wiring and the company which built the new loom said I needed to bridge the ammeter due to the higher output from the alternator. I am no electrician but understand that bridging across the back of the ammeter actually bypasses it. As a result you will not get any readings on battery charging. Advice from another expert has suggested 2 things. Firstly bridge the ammeter (as it is a fairly crude device anyway) and mount a volt meter somewhere in the dash. Alternatively live with the ammeter but get a "shunt" made which reduces the output flowing through the ammeter. How have others dealt with this issue?

#2

Posted: Fri May 01, 2015 5:49 am
by abowie
Or remove the ammeter and replace it with a voltmeter. Bridge the old ammeter terminals, INSULATE THEM WELL.
Install a Smiths voltmeter. Connect one side of it to the B side of the voltage stabiliser and the other to earth.

#3

Posted: Fri May 01, 2015 7:05 am
by drichards
Nice compromise! Any ideas on where I might source a Smiths volt meter preferably in Aus or possibly NZ.

#4

Posted: Fri May 01, 2015 7:32 am
by abowie
Ebay is your friend!

#5

Posted: Fri May 01, 2015 7:34 am
by drichards
So true, am on the case!

#6

Posted: Fri May 01, 2015 9:55 am
by Heuer
If not you can buy new ones here: https://www.merlinmotorsport.co.uk/p/sm ... meter-cb-v

Full fitting instructions here: viewtopic.php?t=166&highlight=voltmeter

Depending on the type of alternator you have fitted you may not have to do any modifications. The original alternator output about 45amps and the wiring will handle almost double that. Check your alternator specs - ideally they should be around 60amps. Anything higher is pretty pointless as an E-Type with all electrical items on (cooling fan, heater motor, wipers, headlights, ignition, alternator energiser etc) draws about 39 amps.

#7

Posted: Fri May 01, 2015 10:21 am
by drichards
Wow, that is so very helpful. Many thanks. If my man in Queensland can't track one I will buy from Merlin.