[Healeys] Amp meter vs Volt Meter

[David Nock British Car Specialists]

You have to look at the amp meter and the volt meter differently.

  When the alternator or generator stop charging the ignition light  
should come on to warn you that there is a problem. The problem with  
the light is that you will not see it during the day.  So you need to  
have either a volt gauge or an Amp meter to tell the state of the  
charging system.

The volt meter acts like a fuel gauge. It is telling you how much  
electricity is in the battery. So when there is a problem with the  
charging system the voltage starts to go down. The problem here is  
the voltage from full charge to dead is not a very large span. So you  
will not get a warning right away.

Battery voltage is 12.77 volts = 100%
				12.61 volts =	75%
				12.44 volts = 50%
				12.22 volts = 25%
				12.00 volts =	Dead

The advantage to a Amp meter is that is will tell you the output of  
the charging system immedially. So if there is a fault in the  
charging system you will know as soon as there is a problem.

My personal preference is to install an amp meter this way if  
something happens i will know right away rather than wait to notice a  
1 volt drop on a volt gauge to tell me there is a problem with the  
charging system.


David Nock
British Car Specialists
Stockton Ca 95205
209-948-8767

www.britishcarspecialists.com

Please feel free to view an interview with the Nock's in 2009
	Enjoy	
www.youtube.com/watch?v=QOTTRYkbQzs
.
.

On Feb 27, 2013, at 11:26 PM, Oudesluys wrote:

> An ammeter is not really suitable with an alternator. Best to use a  
> voltage gauge instead.
> If you still prefer an ammeter fit it in the brown wire running  
> from alternator to starter engine/battery pole/starter relay/ 
> control box.
> If it reads the "wrong way around", switch over the wires on the  
> ammeter.
> Kees Oudesluijs
> NL
>
> Op 27-2-2013 17:22, Simon Lachlan schreef:
>> Another one for the guriest of the gurus....
>>
>> The car is a MkII BT7. (Negative earth, of course)
>>
>> So, let's do this stage by stage.
>>
>> 1)      When the car ran with a generator, I installed an ammeter. I
>> disconnected the brown wire that ran from A1 on the control box to  
>> the
>> solenoid at both ends. I ran a new wire from the solenoid, through an
>> ammeter and back to A1. This worked well.
>>
>> 2)      I bought a Lucas ACR17 alternator on eBay and installed  
>> it. You will
>> all doubtless know these Lucas alternators. There are three  
>> terminals. The
>> two large terminals are connected inside so that one can connect  
>> more than
>> one heavy duty cable for whatever purpose. For reference I used  
>> this:-
>> http://mgaguru.com/mgtech/electric/ac101.htm
>>
>> I have to laugh when I see his advice to just "physically mount the
>> alternator". (Almost as funny as the reference in the BMC manual  
>> to "gently
>> easing the gearbox rearwards". Me and Superman.)
>>
>> 3)      I bought an old control box on eBay and gutted it. I  
>> soldered a
>> large wire across terminals A & AI inside this control box. I then  
>> used the
>> control box as a junction box per the site's fourth diagram. (At  
>> this stage,
>> remember that the brown wire is still cut at A1 and the solenoid).
>>
>> 4)      Per the MGAgurus suggestion (safety first) I did install an
>> additional heavy cable from the alternator to the solenoid.
>>
>> 5)      I switched on and everything worked fine - I think -  
>> except the
>> ammeter needle which twitched about feebly. The dash charging  
>> light behaved
>> as it should.
>>
>> 6)      So, I suspect that the ammeter is wrongly hooked up.
>>
>> I suggest that I need to link both big wires from the ammeter  
>> together at
>> the solenoid, run a cable from the solenoid through the ammeter  
>> and back to
>> the joined terminals A & A1.
>>
>> I think that the brown cable remains disconnected, but that I  
>> could connect
>> it to the first feed from the alternator and use it to run the  
>> connection
>> down to the other feed at the solenoid.
>>
>> Am I right?
>>
>> I have no particular area of expertise in cars, but electrics  
>> would be at
>> the bottom of the list. And I don't want to wreck everything.
>>
>> I would be most grateful for some help,
>>
>> Thank you.
>>
>> Simon
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