90 Galant -Alternator not charging to battery

we have a 90 galant and the battery keeps getting drained. the alternator tests good. fuses and relays are good. tried doing a direct wire from the alternator to the battery and still can't get a good charge from alt to battery. HELP! out of ideas....

Reply to
Justsam
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What voltage do you detect at the battery with the alternator running (engine running). Should be above 13.8 volts. If after you stop charging the battery the votage drops below 11 volts, check the battery liquid level if you can, you may need to replace the battery. How do you charge the battery, if the alternator isn't doing it. Does the battery hold a charge after it's been charged.

How old is the battery?

Reply to
Nirodac

the battery is good. we keep draining it and recharging it. the battery isn't the problem, keeping it charged up seems to be the issue. we can run the car until it is completely drain then we are out of luck. hence why we are looking into the alternator. something is going on with the charging system. the alternator isn't recharging or keeping the battery charged like it should.

Reply to
Justsam

Mitsu alternators have a wire attached to the "S" terminal on the alternator. This sense wire actually goes directly back to the battery, and is used by the alternator to measure the battery voltage, which determines whether the battery gets charged or not. If this wire is open, the alternator will not output a charge voltage. Check the alternator wiring, and all the connectors to the battery. Check for opens and especially corrosion on contacts. If you have a voltmeter, measure the voltage on the "S" lead, it should be exactly the battery voltage. The "S" is usually embossed right on the alternator.

Reply to
Nirodac

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