I just added actual gauges to my '69 F100 to complement the factory "idiot lights" and was amazed to find that the stock alternator and regulator are putting out about 14.4V at the battery with headlights off, and around 13.6V at the battery with the headlights on. I even confirmed it with my test meter. Battery voltage is about 12.6V with the engine off.
My question is: Is this too high of voltage? Should I maybe change the voltage regulator? I just don't want to cook my new Optima battery by it being overcharged.
My personal opinion is that about 13.8V with accessories off and about 13.2V with all accessories on would be more ideal. Am I worrying for nothing?
Jason
"Where there's a wheel, there's a way!"
'69 F100 SWB in Lunar Green with built 351C & TKO-600 5-speed, 4.56 gears, and Eaton TrueTrac Posi.
Future plans: Maybe one day, fresh paint, though I've been told by some, "Don't touch it! It's done!"
'06 Mustang GT 5-speed
Sold: '77 F100, '72 Gran Torino, '76 El Camino with 454 & TH400
Put a known good digital meter on the battery posts to be sure. That seems a little high, may boil out the battery. I prefer mine to be below 14 volts. Also, the reading could be low because the battery is new and not fully charged and the charging system is trying to get the battery up.
It's got the factory square voltage regulator mounted next to the radiator. I never knew they were adjustable. How would I go about adjusting it? Remove the cover and turn a screw (like water well points) or something?
If so, I think high 13V's would be a better range to run in.
Jason
"Where there's a wheel, there's a way!"
'69 F100 SWB in Lunar Green with built 351C & TKO-600 5-speed, 4.56 gears, and Eaton TrueTrac Posi.
Future plans: Maybe one day, fresh paint, though I've been told by some, "Don't touch it! It's done!"
'06 Mustang GT 5-speed
Sold: '77 F100, '72 Gran Torino, '76 El Camino with 454 & TH400
The voltage regulator tries to keep the battery voltage between 13.5 and 14.5 volts. I wouldn't be worried about 14.4 volts at all, especially if you were checking it right after you started the truck and the battery was a bit low.
The regulator should shut down the alternator at anything above 14.5 volts. If you saw voltage above that level then it would be time to be concerned.
seattle67 wrote:The voltage regulator tries to keep the battery voltage between 13.5 and 14.5 volts. I wouldn't be worried about 14.4 volts at all, especially if you were checking it right after you started the truck and the battery was a bit low.
The regulator should shut down the alternator at anything above 14.5 volts. If you saw voltage above that level then it would be time to be concerned.
Yah 14.4 is fine, you want 1.5 - 2 volts above battery voltage while running, also you don't want it to dip more then 1.5 volts with all the accessories on. So at 14.4v with nothing on (except the engine) is bang on, try turning everything on and you don't want it below 12.9v running. Also you need 17 - 18v to boil a battery so don't' worry
Cool. I took a better look at my regulator and the cover is riveted on, so I doubt it could be adjusted anyway. Sounds like I was just worried for nothing then. Thanks again!
Jason
"Where there's a wheel, there's a way!"
'69 F100 SWB in Lunar Green with built 351C & TKO-600 5-speed, 4.56 gears, and Eaton TrueTrac Posi.
Future plans: Maybe one day, fresh paint, though I've been told by some, "Don't touch it! It's done!"
'06 Mustang GT 5-speed
Sold: '77 F100, '72 Gran Torino, '76 El Camino with 454 & TH400
