Negative change over

drichards · Post by **drichards** » Fri May 01, 2015 2:10 am

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?

abowie · Post by **abowie** » Fri May 01, 2015 5:49 am

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.

drichards · Post by **drichards** » Fri May 01, 2015 7:05 am

Nice compromise! Any ideas on where I might source a Smiths volt meter preferably in Aus or possibly NZ.

abowie · Post by **abowie** » Fri May 01, 2015 7:32 am

Ebay is your friend!

drichards · Post by **drichards** » Fri May 01, 2015 7:34 am

So true, am on the case!

Post by **Heuer** » Fri May 01, 2015 9:55 am

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.

drichards · Post by **drichards** » Fri May 01, 2015 10:21 am

Wow, that is so very helpful. Many thanks. If my man in Queensland can't track one I will buy from Merlin.

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Negative change over

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