Quick Charging Question

[blown240]

Does heat affect the amount an alternator charges?

The alternator in my truck is about a year old. Its a basic stock 3 wire. 63 amp I think? It charges real strong when the truck us cold, but once it warms up, it the voltage gauge is much lower. Its still in the green, but a lot lower. Truck runs at 180 most of the time. Gets up to 210 when its real hot out.

My stereo has multiple amps if that matters....