Flat battery

[tdi-man]

fitted a new alternator just in case that was faulty as it had done a few miles.

voltage would drop to 11.60 volts over night with new battey on but would start car.

sent battery back to shop and tested ok but would test it after the weekend to see if voltage drops and they are now sending me a new battery out.

so wondering if old alternator might of been faulty and damaged battery ,

 

[Johnny Bravo]

I don't see how the alternator can damage the battery.
At most it would not charge enough.

 

[tdi-man]

They can discharge your battery when left over night , but will charge fine .

Think it's a internal resistor