every few days, the batter stops charging and dies…
tested the alternator, and that provides a charge…tested the battery, and that takes a charge… the car runs off the battery or alternator…tested and replaced all wires between alternator and battery… cannot figure out what is wrong…there are a few forum posts on this, but no solution
Could be an intermittent alternator. Are you sure your batt terminals and clamps are CLEAN and greased and tight?
When the battery “dies” it’s drained? What’s the voltage?
Check battery voltage each day with engine off(should be 12.5-12.9V), then with engine idling and all accessories off (should be 13.5-14.5V).
Could be a parasitic drain, combined with insufficient charging (a 30 minute drive after a jump start doesn’t cut it).
they are brand new, cleaned, greased and tight
When the alternator fails to charge the battery then the charge warning light should turn on. It is also critical that the light work ok as it provides power to the exciter of the alternator. Perhaps there is a bad connection in the bulb socket which would keep the light from turning on while the alternator failed to charge the battery.
This is a 1993 Mazda. If this is the original alternator, chances are it is intermittent, probably due to worn brushes. If your car doesn’t have a voltmeter, it should have a battery light. This light should go on any time the alternator is not charging. Interestingly, a lot of Asian cars also have the brake light go on with the battery light. If this light has been going on and off, your problem is the alternator.
If neither light has been going on, check the battery lead to the alternator. This line includes a fusible link, and it may have fried.
The reason that the brake light can come on also is because it is in the same circuit circuit to the alternator as the charge warning light is. This is so the warning lights get tested when the key is turned to the ON position and engine not running. Current flows through the lamps and to the exciter field so the alternator can build a field up when it starts turning with the engine. When the field gets going there is a voltage generated on the field lead and that counters the voltage coming from the ignition switch so current then stops flowing and the warning lights turn off.
We’ve tried 2 or 3 alternators and the same thing…works on for a few days, then could cut out in the middle of driving…didn’t see any fusible links… just a wire
When the alternator cuts out does the battery warning light turn on? It is important that it works for the reason I mentioned earlier. If the light doesn’t come on then that needs to be checked out as to why and be fixed. It would also help to know if there is an external regulator for the charging system. I assume though it is built into the alternator.
The wire IS a fusible link. Designed to burn out anywhere along it’s length should a overload or short occur.