Volt Meter

[rogerguzzi]

Hello All

            Over the winter I have upgrade my radiator to full width(1500 Spitfire) and rebuilt the alternator(new bearings and brushes and a skim of the commutator.

 

I have also fitted two 9" fans controlled by a twin thermostat in the bottom of the radiator and over ride switch(2 postion = 1 or 2 fans)

 

Now the get to the topic? I have been thinking of battery drain when fans etc are on(going to Spain in June) I was thinking of fitting a Smiths volt meter into the dash.

 

As I looked about at prices I came across these and I thought at that price it will do the job and I can use it in any other car to test the alternator or dynamo.

 

http://www.amazon.co.uk/gp/product/B00B58VNZW?psc=1&redirect=true&ref_=oh_aui_detailpage_o00_s00

 

I have tried it against 2 good multi meters (retirement present if they only knew) and it is within 0.1 to 0.2 volts (minus) which is good enough for me and I suspect a lot more accurate than a Smiths voltmeter.

 

Roger

 

ps you do have to wait about 2 weeks for delivery but at that price I have  patience.

 

Photo of fans set up and switch and leds(just above blue pencil) that is with both fans on the switch is center off and left for one fan, right for both and the leds work when fans switch from the thermostat also(1 or 2)

 

extra ps just found these they will be free with cornflakes next? and I have wasted £0.43 !!!!!!!!!!

 

http://www.amazon.co.uk/Cigarette-Lighter-Voltage-Voltmeter-BuyinCoins/dp/B0092KVYGI/ref=pd_sim_ce_2?ie=UTF8&refRID=10M5PQMV85406F892ZGD

[Guest]

Roger.

 

If your alternator is working efficiently (your overhaul suggests that it now is) and has the correct output, I'm sure it will cover the demand of the 2x fans. 

 

Only when the alternator is punching above its weight will there be a problem.

 

Are your fans running live with the ignition off or do they work only when the ignition is on ??

 

Additionally, if your battery is spot-on, then you will be surprised how long it can keep providing power to electrical units; without instantly receiving charge from the alternator.

 

On a personal note, I would go for the Smiths gauge as I find they are accurate enough and look correct for the era of a classic car - IMHO !! 

 

Basically, I reckon you will be fine.

 

Regards.

 

Richard.

[rogerguzzi]

Hello Richard

                     I only got one of these as I did not want to make another hole in the dashboard.

 

I have carried out power consumption tests on all the electrical equipment to see if a Lucas 15acr alternator would cope and I would have to be sitting at tick over with every thing switched on? which is not likley to happen? you would turn off the headlights and heater and wipers as not needed when stationary and it balanced the fans out,

 

The charge rate at about 1500RPM balances everthing, so I can not see the need for a high output alternator unless you have heated windows and lots of extra electrical equipment.

 

So no worries when driving

 

Roger

[Cookie]

Plenty of Smiths Voltmeters around secondhand that are an exact match for the Spitfire 1500 guages as the Dolomites, Stags and Saloons of that age had then fitted. You should be able to get one for £5-10 at a Triumph Autojumble.

[Cookie]

Plenty of Smiths Voltmeters around secondhand that are an exact match for the Spitfire 1500 guages as the Dolomites, Stags and Saloons of that age had then fitted. You should be able to get one for £5-10 at a Triumph Autojumble.

Here's one on a 1500HL Dolomite

[dougbgt6]

I had a modern where a connector to the fans got corroded and they stopped working. Garage estimate £300 to repair  . I put a switch on the dashboard and ran a wire to the fans. Sorted. I ran on the motorway, around town and slow moving traffic. I only needed to turn the fans on when stationary in traffic for more than 15 minutes. Hope this gives you confidence in your system and how it's going to work.

 

On my Triumph I have both Ammeter and Voltmeter they tell you different things. The Voltmeter is sometimes correctly described as a battery condition meter. If the voltage starts to fall you can deduce that there may not be enough charge going in however, an Ammeter tells you instantly the condition of you charging device.