Battery replaced but alternator. not charging. Battery comes back to life after three days. The falling faults start showing on the display. Transmission fault, ABS etc

What is year--make--model of vehicle? I'd check alternator connections to and from alternator. Check battery and battery connections. Check for charging system trouble codes, see if any?

It could be the battery, yes, but it could also be an alternator fault.

If the alternator is faulty -( usually when the rectifier pack on the back of the alternator burns out) - the battery can run to earth and become flat within seconds, or it feels like a misfire when driving.

I once had a car that needed the battery charging every time just in order to start it. Once running, there was a misfire. Then the battery was too flat to restart the car. It was an alternator fault.

Disconnect the plug/wiring from the rear of your alternator FIRST. Charge the battery. Leave the plug DISCONNECTED from the rear of the alternator. Start your vehicle.

If your vehicle starts and runs ok with the alternator wiring disconnected - the alternator is suspect. The usual culprits are the diodes in the rectifier pack (the bit on the rear of the alternator). Burnt out, they can cause a battery to become flat within - literally - seconds.

Leave the alternator disconnected and try starting the car several times. Switch on your headlamps and try and restart the vehicle a few times over a 15 minute period.

If it continually starts even when the headlamps are on, your battery probably is ok.

Even better ... take your vehicle to an auto electrician. It would probably take 2 minutes for them to dignose the problem. this saves you 'guessing' and buying replacement battery/parts that aren't at fault.

It doesn't sound as though you have a big problem .. just one of the many 'irritations' that we motorists suffer...

If the problem is the alternator there's no need to replace the whole unit - you can replace the rectifier pack on the rear. If it is the battery at fault (an auto electrician will tell you within seconds) .. well, that's life.

Hi Les, I;m glad to help. There is an fusible link that runs off the battery cable pull on it and see if it comes apart, if it does replace it and see if everything is working properly. Hope this helps and have an awesome day Les.

Sounds like the alternator. Take it to any auto parts store to have it tested free.

either your battery is going bad or your alternator charging sistem is faulty, need to check, or one day your car wont start, or it will die runnig.

Well in order to check the alternator you must have a fully charged battery. I would try to charge battery and see if it will take a charge. If not, replace it then test the alternator.

Is the alternator charging it ? Do you have a light on in your dash : " ALT" or "BAT" ?
Check cables connections for corrosion also.
Please let me know.

maybe the alternator

Alternators are expensive parts, especially at dealerships. I'm inclined to agree with you, they should have got it right the first time. No shortage of tools with them, but in fairness to them, intermittent faults are the hardest to detect.
They might come back and say you need a new battery, although it does seem odd that a little testing the first time might have caught that.
Those are the two main items in the start circuit you are having trouble with. Well, the battery, the alternator, the starter and the ignition switch, those four items are the main parts of the start circuit. But with a good battery and an alternator to keep the battery charged up, it will crank over every time. Ideally, that means it will start and run.

Alternator.