Can an alternator overcharge a battery?

[dom14]

I'm just wondering, can an alternator overcharge a battery on non-stop long trips?
By that I didn't mean a faulty voltage regulator.
So, the regulator controls the voltage at around 14V regardless of the speed the alternator spins.
Then I'm not sure whether it stops charging the battery or trickle charge the battery once it's fully charged. How does the alternator regulate the current once the battery fully charged or does it do that at all?
Is there a mechanism in the alternator to reduce the current it supply to the battery when it's fully charged?
Thanks.

[threedogs]

Yes an alternator can over charge a battery to the point it boils, very dangerous situation,
Its caused by brushes only contacting on their edges, well that's one cause

This was years ago on the way back from Bathurst in a HQ panelvan

[Yendor]

The regulator stops the alternator from overcharging by reducing the amount of field to the alternator's rotor.

[AB]

And the battery can look like this....My regulator died on a trip a couple of years ago and was left unnoticed for a few hours.

I think I read 15 volts when I found out.

IMG_0847.jpg

[threedogs]

One give away was the HQ headlights were very bright, but most modern sealed batteries have explosion caps built into the casing

[Rustyboner81]

Yes.
I had a different problem where the fusable link thars inline between the alternator and battery hsd deteriorated due to age or a previous overcharge condition. As a result minimal cahrge was getting back to the battery. All lights and acc. Would work fine while the car was running but bsttery would die...... volt gauge would read 15-16v

Put a new inline 60amp fuse in all has been good since.

Im just saying if you do get an overcharge dont condem your battery or alternator straight away

[NP99]

Yes an alternator can over charge a battery to the point it boils, very dangerous situation,
Its caused by brushes only contacting on their edges, well that's one cause

This was years ago on the way back from Bathurst in a HQ panelvan

HQ panel van......weren't they the ducks guts in their day

[Robo]

HQ panel van......weren't they the ducks guts in their day

The old sin bin !!

[Squalo]

I am not entirely sure about cars as they have slightly different set-ups in the charging circuit to bikes, but on a bike all excess current is dissipated by the regulator/rectifier as heat (which is why bikes experience reg/rec failure, especially Hondas).

Is this how a car charging system works?

[alfonso]

An alternator will not overcharge your battery on a long trip unless it is faulty . charge is usually 13.8 to 14.1 volts after battery is charged voltage will drop to around 13.5 to 13.7 which is float.Also you use power from battery such as radio and lights. If your vehicle is well maintained there shouldn't be a problem