Alternator wont stay charged.

Either the alternator is not being energized with the key on, or the main wire from the alternator to the battery/starter is bad.
Have you checked output on the back of the alternator with the engine running ?

possible a bad regulator. Some alternators have the regulator as part of the alternator and others have it separate. If you did not have the alternator bench tested but simply used a multimeter to check voltage then it is possible that the alternator is not good as you can have 14.5 volts out put but it could be ac current as a rectifier is bad.

either that cable going to the battery is shorted to ground somewhere (maybe on the body of the alternator) or the alternator is defective. there is a chance that you put one of the wires wrong on the alternator and you are forcing it into full field mode. that is a mode we use to test the full output of an alternator. if an alternator stays on full field too long (more than ten seconds) it could fail.

Does the engine spin over and not start? Or turn the key and nothing happens?
New spark plugs and wires won't have anything to do with the starter and battery keeping the engine from spinning when you turn the key.
Need more specific explanation. Thanks,
Scott

who put in the alternator and battery. when you rev up the motor the alternator is push more volts. are the wires all hooked up right. there is a starter relay . but i think a wire is touching or is not hooked up right

There are few things that you will have to check. 1) Is the battery properly charged. 2) Are you getting spark at the spark plugs, when you crank the car to start. 3) Is there proper fuel in the car. ---------------- If the battery is not charged properly the car will not start.Check the voltage of the battery .It should be exact 12volt. If there is no spark coming when you crank the engine then its the problem of either the spark plugs or the coil pack.the spark plugs gets power to spark from coil packs.Also check the fuel pump and fuel filter.If the fuel pump and fuel filter are worn out then it will not supply the fuel properly to the engine and this results in no-start problem. If all battery, fuel pump and spark plugs checked out OK then its time to check the wiring connections between the battery to starter and battery to alternator.This will help. Thanks. you can rate this solution and show your appreciation.

Check all cables to the starter and the ground or negative cable from the battery to the engine or frame. They get old and break down between the insulation and you wont get enough current to start the car

Does it crank well and all that but with no spark or is the battery just dead? If the battery is dead, it either won't charge while alternator is spinning or the alternator doesn't charge well enough to keep the battery charged well. If it jumps and runs indefinitely, battery is done. If it jumps and dies, alternator is done. If battery and alternator are fine, and you have no spark, you may need a new coil, new spark plug wires if they are worn out and too resistant, pick up coil inside of distributor, or you may have some other ignition system issue.

Most times when an alternator fails, it starts charging less and less till the car won't keep running or it won't start the next time. If the alternator hasn't failed, the battery needs replacing. If your battery is 5 or more years old this is a very good possibility. If your alternator failed and you have killed your battery many times before replace them both. Each time you drain a battery to dead you lose about 10% of its current capacity.

If the battery is fine and engine will not turn, starter may need replacing. Hope I helped.

keep in mind, your engine use both source of power to run, one from the battery and one form alternator. If the alternator is good, your engine should stay running regardless if the battery is good or bad, the alternator should keep the engine running. It sound like to me the alternator is faulty not charging your battery or keeping your engine running, even though the alternator is brand new does not mean is good. My guess I would take the alternator back and get another one. the reason why your car ran for 25 min and die it has no source of power to keep the sparks going although the alternator should keep the engine running and at the same time charging the battery but is not.

Q1. Engine will not start or is hard to start (Cranks OK) A1 -Ignition lock switch faulty -Ignition coil faulty -Power transistor faulty -Spark plugs faulty -Ignition wiring disconnected or broken -Spark plugs faulty Q2, Engine will not crank A2. Battery discharged Battery cables loose, corroded or worn out Transaxle range switch faulty (Vehicle with automatic transaxle only) Fusible link blown Starter motor faulty Ignition switch faulty Ignition lock switch faulty REMEDY Charge or replace battery Repair or replace cables Adjust or replace switch Replace fusible link Repair starter motor Replace ignition switch Replace ignition lock switch