Battery Is Not Charging

[mattpatt]

I've just done a bit of work on my new (SP3033) SPF Cobra's electrical system trying to trace out what might/might not be a problem. What I've learned is: The alternator output voltage should show up at the battery - so you definitely have a disconnect between the alternator and the battery. The Optima (red top) battery can only handle 15.0 volts max charging voltage - make sure, when you get the charging circuit fixed, the voltage at the alternator is 15.0 volts or less (not the 17.5-18.0 you mentioned) - maybe under load it will drop into range.

As for fuses, I found that my car is wired different than Blas' wiring diagram (a real good investment, by the way). On my drop down fuse panel the unfused post ONLY has one wire which is connected to the amp meter. The alternator is wired to the fused post (6 wires to this post - post has an 80 amp fuse between it and the unfused post)) which, I think, is a factory miswire (do you know, Blas?). If yours is wired like mine and that 80 amp fuse is blown you will have an open charging circuit. Note that if your ignition is powered from the unfused post circuit you'd probably have trouble on a long ride because you'd be using the battery to power your ignition.

Blas - I added a 60 amp fuse between the amp meter and the battery supply - I assume my alternator should be re-wired to the unfused post to protect the alt/battery circuit from a short on the fused side. The 60 amp fuse just adds protection between the alt and the battery. What do you think? By the way - I'll post where I am with the Optima "problem" under the thread I originally started after I get the battery tested later this week.

Gil - good luck. Let us know what you learn.

Matt