mystery squeal

[el Miguel]

I just had a new a/c compressor, drier, expansion valve, pressure switch, and belts put on my 380 SE. At start up there is no squeal and the a/c blows cold but after getting on the road and the compressor switches from on to off and back there is a bad squeal for a few seconds until it engages again. It really sounds like a belt but it hasn't done it while idling and cycling the a/c. Recently my battery has started dying and I thought the squeal came from the alternator. In fact I am certain I needed a new alternator belt and heard the squeal in the alternator area. This has been happening since way before the a/c work. Can it be that when the compressor kicks in that extra current is being drawn and the alternator is going bad? Frustrating because now it only seems to do it while moving down the road so I can't pinpoint it. Thoughts???
1985 380SE 207K