The battery warning lite on the dash is on but the voltage remains OK. Voltage varies with RPM. 11.5v at idle, 13v when driving. Changed voltage regulator, but, no change.

 

I think your volts are on the low side. Mine carries 14.1 at an idle and only drops to 13.6 with the lights on and both A/C units blowing. You might want to remove the alternator and have a reputable part house test it for you, they should do it for no charge.

alanscott


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I agree with alanscott, these diesel batteries 700 or more cold cranking amp batteries need to be charged around 14 volts. 11.5 is not acceptable.



1986 F-250 6.9 diesel,4x4,XLT Lariat,Ex Cab, 8'bed,etc...

 

I replaced the voltage reg and the alternator. The rebuilt alt is a 100amp model. The lite is now off on the instrument panel but the voltage, even after driving 6 miles to work today, the voltage is not 14.1v. It is just about 13volts. With the truck off, there is a VERY small amount of current flowing... probably the memories in the radio.. so there isn't a drain on the system somewhere. If I turn on the AC the voltage drops about another volt and stays there till it is turned off.

Since the voltage regulator is sealed, there really isn't any way to crank it up a bit is there.

Ken

 

What condition are your batteries in? I replaced the set in mine last march and it took a few hours of driving before the batteries were fully charged and it showed 14 volts. I think you should be good to go after you get the batteries fully charged again. At least I hope so

alanscott


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I would take the truck to a alternator shop and have them load test the batteries, and then trick the alt into thinking there is a big load on it and see what the output is. This take a special tester and they usually do it for free or a very small charge.


1986 F-250 6.9 diesel,4x4,XLT Lariat,Ex Cab, 8'bed,etc...

 

[font size="1" color="#FF0000"]LAST EDITED ON 10-Jul-01 AT 07:22 PM (EST)[/font][p]AlanScott,

The batteries are new this year. They are rated at 1000amps/900cca. I clean the terminals and coat them with a anticorrosion product. They are clean and should not be hi resistance.

 

I was thinking more along the lines of it might take a little while until your batteries are fully charged again. Sorry about the confusion.

alanscott


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