Ammeter question

[IaininTenbury]

Quick question, will an ammeter from a 6 volt car work on a 12volt car. 'tis the cause of some discussion at work and I need a 2nd opinion....

[autolycus]

Yes.

Just make sure it's adequately rated for current - what is it marked? 20-0-20 may be marginal, 30-0-30 should be OK for a fairly standard car.

Kevin

[bmcecosse]

Of course it will be suited - amps in a 6 volt system are TWICE those in a 12 volt system.......

[autolycus]

... for the same power.

But 6V systems used headlamp powers as low as 24W, and often only had one tail lamp and no brake lights originally. What were Series 1 and 2 Morris 8 ammeters rated?

Kevin

[IaininTenbury]

Thanks for that, it confirms what I thought, but was begining to doubt myself there. Both ammeters are from the same type of vehicle, one a 1935 6volt version and the other a year later running on 12volt - the requirement being to convert the older one to 12volt. I think both are +-30amps. I made the point that the hefty cables onthe 6v car are more than ample for the 12v conversion which seemed ok.
Now what about fuel gauge and sender units...

[bmcecosse]

Probably a fixed resistor in the fuel gauge sender feed will do the trick. But the value will be determined by trial and error - I suggest starting with 2 X 5 ohm - you can then use them (in series) as 1 X 10 ohm, or 1 X 5 ohm, or (in parallel) = 1 X 2.5 ohm.

[IaininTenbury]

Thanks, I thought it may need something like that. I'll start with those figures and experiment waggling the sender unit about and see what happens!

[adam8]

Spam spam spam spam...

[bmcecosse]

Sorry - question not understood - please explain. An ammeter records instantly whtever current is flowing......

[rayofleamington]

it wasn't a question, it was an advert...

[bmcecosse]

Yes - I did wonder - but was giving out some more line.......