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2002 Nissan xterra can not figure out battery problem

Abought six months a go I had the alt tested and told alt was good but batt was not so bought the right batt for the xterra now the batt dies I have to put a charger on it it charrges and I can run it for a.good wile then dies agian leaveing me stranded most the time just could use a little info abought it please

Ok, your alternator tested ok 6 months ago, but battery tested bad. You had a new battery installed. So now, 6 months later, sometimes when you try to start the car it won’t start, and you think the problem is the battery b/c it will start ok after you charge the battery with a battery charger. Is that correct?

hmmm … well, could be the new battery is no good, or the alternator has conked out, or there’s a wiring problem between the two, or there’s something else in the car draining the battery. First thing I’d do is make some voltage measurements at the battery terminals. With the engine off, after the car has been parked overnight, you should see 12.25 to 12.75 volts. Immediately after you start the engine (again, the car has sat in the garage overnight) you should see 14-15 volts. What do you measure on those two conditions?

Tried reading this 3x and my eyes began hurting…and then my head. Sorry…today I must take a rain check. Pretty hard for me to read in my weary state.


Check and see if fuse #36/ 7.5 amp in the under hood fuse box has blown.


It sounds like the alternator isn’t quite keeping up with the current demand on the battery. Check the alternator for a loose fan belt and also check the battery connections. Make sure the surface of the connections that make contact together are clean and the clamps are snug tight. Make sure the main alternator output lead is not burned due to a bad connection there. If you still have trouble then the alternator may have some bad diodes inside it and can’t produce the amount of current it is designed for. Have a load test done to check out condition of the charging system.