What did you do to your Maverick or Comet today

oooooh shiny!

 

It means that when the fan kicks on, the voltage on the meter drops from 14.2 to around 13 or so, and unless the fan kicks off, the volts continue to drop. The battery is 6yrs old, but checks good, alt. is new, and the sensors and the fan have been replaced, and so have the relay and controller.

 

OK, in electrical speak it's drawing more current(amperage) than battery/alternator can supply. That in turn causes low voltage.

Does voltage climb with RPMs at 1500-2000? If not, the alternator is not supplying enough amperage to run fan and keep battery fully charged. Situation can be aggravated by a mediocre battery but is not really the whole issue.

You'll have to fill me in on what alt you are using.

 

What is rated amperage of the alternator? If not at least 90 amps. , that may be the issue. I have 130 rated amp., 8 year old battery, stero amp and can run headlights -- voltmeter never moves below 14.

 

Got another parts car today! I was busy with school so my dad made the 3 1/2 hour drive to go pick it up for me! 1976 four door comet with a 200.

 

found out I have no E-flashers or brake lights...

 

Ck , your fuses if they are ok then ck your turn signal switch , Good Luck

 

Well today I got the chance to work a little bit in the maverick rear end parts lot of work but very well worth the effort

 

nothing like a clean rear end...LOL

 

Alternator is new, 95amp 3G. It does not vary with rpm, and builds slowly, very slowly. If I turn the headlights on, it dips below 11 volts.

 

I am using a 95amp 3G alt from an F450 pickup truck. Should I go for a larger rated alt?

 

You really should be running at least 130 amps with a large draw electric fan and headlights.

 

I'm going to say a 95 amp should be plenty but extra head room(amperage) makes life easier for the alt.

If voltage drops with each accessory turned on, you have a classic case of weak alt. Headlights draw around 8 -10 amp for pair(at least anything reasonably stock). If voltage drops by a volt or more, no doubt you have a lazy alt. Most fans around 30 amps, heater-A/C blower 20-25 A(on high), much less at lower speeds.

I have a barely adequate 65A(at least when using electric fan) on my Comet and have seen voltage fall to under 12.5v idling in gear, but it always increases to 13.5/14v once car is moving again. This includes with lights on.

 

I'm thinking 95 should be sufficient if it's putting out near rated amps. I also think you may have a lazy/defective alt. I can run all electric accessories, including AC and have never experienced volt drop.

 

a good battery also helps.