Hi im having a nightmare and could really do with some help. I have a clk 230 komp/cab that is over charging the battery to the point where it has boiled over . I had problems with the alternator not charging the battery. I have changed the alternator and regular for a new one and now its sending too much power through and cooked the battery. Has anyone any ideas on what to do next? Could it just be a bad battery (its only a few months old) or the new alternator is a bad one or could it be that it just needs plugging in and resetting the system?

 

What is the resting voltage of the battery, what is the charging voltage from the Alternator.


These will provide your answer.

 

Thanks for responding......

Testing the voltage was the first thing I did. The battery is sitting on 13+ and with engine running it's pushing 15v

 

Ive gotten aftermarket alternators in the past, from Napa. 2 times to be exact, and one overcharged and one didn't charge at all.

 

It is either the Voltage Regulator or a bad ground.


See if there is any voltage between the shell of the Alt and the batter neg.


Not likely, but an easy test before you swap out the ALt.

 

Would a bad ground make it charge at upto 19v? Thanks

 

However much the alternator (or actually the Voltage regulator) floats above ground, that voltage can be added to the output.
It is not a real common problem, but so easy to check it is usually worth it when having weird charging problems.

 

I don't know if im being daft and missing something lol. What do you mean by floating? Sorry.