Factory alternator 61 or 80 amp

[NOS118]

Hey folks so I been done a bit more driving since the weather has going very pleasant. But I have notice that when I have might light on my voltage drop well into 11.6-12.5 range when at idle. I notice that I have 61 amp alt. Would upgrading to an 80amp fix that small problem? Or is it that my alt is just about to expire?? I do drive at night with heavy loads. lights and ac on.

 

[melsg5]

Is your idle speed too low?
Is your belt tight?
Have you confirmed accuracy with a hand held gauge?

 

[NOS118]

Idle is on point. I do need to check the belt but I doubt it loose. I haven’t check with a hand held but the dash gauge seem to be at 14.3 when no accessories are on including lights

 

[NOS118]

Just check my belt they have great tension

______________________________

 

[melsg5]

Check with a hand held.
How old is the battery?

 

[NOS118]

So I had my alternator rebuilt but I notice that with light and ac with foot on the brake the voltage drops to 12 but now charges back up instantly back to 13.7-13.9 is it that normal. Battery was test and it was good per the tester

 

[melsg5]

Yes, you have a heavy load and low engine speed.