2006 Escape weird electrical problem

just finished doing a paper route. It's been raining all night. About 50 degrees out. I had everything electrical running. Fog lights on. Defroster on. Fan on #2. Radio on. Using xm radio portable with light socket plug. Passenger dome light on. And front wipers on. Rough night, LOL. All of a sudden, I pull into a delivery spot and I notice the headlights dimmed a bit and my wipers slowed down incredibly. I shut off the radio, defroster, fan, pulled the lighter socket plug and the wipers. Tried the wipers again and they were still very slow. The fast position was even slower than the regular wiper setting. The rain had subsided a bit so I rolled the window down to keep the windshield clear. (Heavy breathing I guess due to me moving around so much). I continued on my route with most electronics off. Further down the road, I tried the "mist" one-time wiper selection and it seemed normal. A little later, I tried the regular wiper setting and it seemed to be normal. No further dimming of the headlights as I drove on. As it got chillier, I turned the foot/defroster back on and turned the radio back on. Tried the wiper again and it was slow again. Luckily it had quit raining so I stopped using the wiper all together. I plugged my xm radio cord back in too and everything seemed to work fine again. My first thought was the alternator. I bought this back in late 2014. Don't know how old the battery is, but it's very clean and looks new. No corrosion on the terminals. I'll check all this again later today. Could water have gotten in the wrong place and caused a problem?  I know this is a long post but I wanted to give as many details as I could.  Any help would be appreciated. Thanks!