Battery Problem

[f250ghost]

My buddys 2002 7.3 F350 keeps discharging the battery after it sits for about 24hrs or more...sometimes though it goes 2 or 3 days with no problems. Both batteries are brand new Opitima Red tops...alternator is new (6mos)...and we can't figure out what the problem is. Any ideas???

Thanks in advance

-Ben

[f250ghost]

[Diesel Freak]

OLD SCHOOL :
Disconnect both batteries. Re-connect one positive lead; just touching battery post. If there is a considerable amount of spark ... You have a short. Remove fuses one by one. Checking that battery lead each time. Hope this helps.
P.S. any added power leads disconnect first

[The_rook]

Trying to figure out a battery drain over the internet is next to impossible. A DVM and removing fuses is the only way I know. Did he have this problem before he got the new batteries ? Good luck this can be a tough one.

[The_rook]

Originally Posted by Diesel Freak

OLD SCHOOL :
Disconnect both batteries. Re-connect one positive lead; just touching battery post. If there is a considerable amount of spark ... You have a short. Remove fuses one by one. Checking that battery lead each time. Hope this helps.
P.S. any added power leads disconnect first

A short would show its ugly head IE.. ( burnt wire , fried electronics.). I would think something is running that is not supposed to be. Optima batteries are not the best choice current wise. For the price they are low on Amp. hours.

[Diesel Freak]

Originally Posted by The_rook

A short would show its ugly head IE.. ( burnt wire , fried electronics.). I would think something is running that is not supposed to be. Optima batteries are not the best choice current wise. For the price they are low on Amp. hours.

Not Always will a wire be burnt. Low amp draws sometimes dont even pop fuses

[korterman1]

any new goodies recently installed? I once had a battery draining problem it turned out being a dime stuck in the cigarette lighter was an S.O.B finding.

[choctaw]

Originally Posted by korterman1

any new goodies recently installed? I once had a battery draining problem it turned out being a dime stuck in the cigarette lighter was an S.O.B finding.

Someboby must have had it in for you.

That had to be a b-tch to find.

[The_rook]

Originally Posted by Diesel Freak

Not Always will a wire be burnt. Low amp draws sometimes dont even pop fuses

A low amp draw is not a short. A short is current to ground and at that point something is going to give. A short and a open are different.

[sevenmalards]

I think he should start with the basics, and use a volt meter at the back of the Alternator to see if it is putting out the right amount of volts. Do it at Idle, then do it at 2K RPM with everything on, headlights, high beams A/C EVERYTHING and the voltage shouldn't drop below the number that was recorded at idle, but it should be higher. Then dissconnect each battery and test them with a volt meter.

Just because an Alternator is 6mo. old, doesn't mean it's good! I've seen plenty of brand new junk parts that are bad, and they are usually alternators or starters.

And the Optima batteries are not good at all for these rigs. I just replaced both of mine (and a new alternator) and I went with the 850 cc amps from Motorcraft (ford replacement batteries, and alternator)
If everything checks out okay I would point to the stereo system first, if there is an aftermarket amp installed, some brands are notorious for not shutting down and drawing power all night.