Capri Ammeter

[Guest Fred2b]

I have just bought a set of Capri clocks from a fellow Hoodie and well pleased I am. I have cut off the four smaller clocks to be mounted under the two bigger ones. Eveything works and looks good except I don't know how to wire up the ammeter. Ian said to put the yellow wire on the positive side of the battery and the red wire on the alternator output but this does nothing. Is this right? or is the guage kaput?

I am no sparks but to me that is just like putting both wires on the +ve side of the battery and will not work.

So how is it done?

 

Fred

[Guest Ianz]

Fred

 

This topic has been covered in detail before,but with no

satisfactory outcome,do a search under Capri clocks and you will

see what I mean!!!!!

By the way I believe their is a "shunt" wire that needs to be removed

from Capri wiring for the ammeter to work properly,as an ammeter needs

to be connected in series from battery to load, ......if you were to put all the starting current through the ammeter it would probably cook it.

 

Cheers Ian

[niduncan]

Hi Fred,

 

"Fellow Hoodie" here. When I had the clocks fitted the ammeter was definately connected to the battery and the alternator. I know it looks as if you are connecting both wires to the battery but the ammeter is actually measuring the voltage drop across the main feed wire between the battery and the alternator. To test the ammeter turn on the headlights without the engine running, this simulates an alternator failure. The ammeter will show a negative (downwards) reading. During normal running the ammeter would very rarely show a positive reading.

Do not put the ammeter in series as you would a normal after-market ammeter as this would burn it out.

 

Hope this helps.

 

Nigel.

[Guest boggie]

Hi Fred,

The ammeter is actually a millivoltmeter designed to measure small changes in voltage difference. The Capri wiring connects the ammeter across the fuseable link (a short length of wire designed to burn out when there is a major short circuit in the power supply from the Capri battery to the car's electric components - not used in the Sierra loom). Get a Capri F-Link from a breakers, insert it into the Sierra battery output ( but NOT including the connection to the starter) and connect the ammeter to either side of it and you will get the correct results.

Hope that helps, Boggie

[Guest Fred2b]

Thanks Boggie

Can I just use a length of thick wire like something used in a house ringmain about 1000mm long. Does the length matter? I am sure a Capri fuse link wire is going to be impossible to find at my local breakers yard!

Fred

[Guest Ant]

A house ring-main usually has a 15 Amp rating, 30 Amp if you're talking about the line to an imersion heater or cooker. A car can draw significantly more than that if the rad fan, heater, wipers, fuel pump etc are all going at the same time. The fusable links in a Sierra Ghia EFi loom are 40 Amps each and there's two of them. 15, or even 30 Amps is simply not enough.

 

Power=Volts x Amps. In a mains circuit volts is 240 so Amps can be quite low. In a car volts is only 12, so to get a decent amount of power the currents are significantly higher. DON'T use any cable which is rated (in Amps) for a lower current than you put through it, otherwise you'll end up with a vehicle fire.

 

Regarding the Ammeter, the "fusable link" has a rated resistance (very small, but rated all the same). The ammeter measures the voltage drop across this known resistance using volts = amps x resistance. If you use anything with a different resistance to the "fusable link" then all the current measurements will be incorrect. Doubling the length of wire doubles its resistance, increasing the thickness reduces the resistance, changing the material (eg copper to nickel or gold plate) makes a difference, etc etc etc.

 

Ant

[Guest boggie]

Hi Fred,

You can get a Capri fuseable link from HERE. the guy's name is Mark Ackers. He wont sell you it on its' own - you will have to get the whole loom but he only wants around £30 so it is worth it.

Let me know how you get on as this is still on my 'To Do' list!

Boggie