The pilot of an amphibious C185 returned to his departure airport after suffering an apparent alternator failure.

Narrative

I was climbing my amphibious C185 and had been transferred from the Tower to Approach. I tried to raise the landing gear and it took much longer than normal. The main gear came up; but the bow wheels did not. I then extended the gear. They all extended. I then tried to raise them again. They all came up but it took 3 times longer than normal and the sequence was off. I then got an alert from the Garmin 600 that it had detected low voltage. The ammeter was now discharging. My thought was that I had an alternator failure. I called Approach and asked to return to my departure airport. They asked if I had a problem and if I needed further assistance. I told them that I had an electrical failure and that I was trying to deal with it. They cleared me to return to and to maintain 3;000 MSL. I turned back to the airport. At this point I was focused on trying to not make my situation worse. I wanted to get rid of high power users. I turned off the autopilot. I then lowered the landing gear. I wanted to get it down and locked before there was too little power. This created a lot of drag. I noticed that I had descended below 3;000. I was trying to correct this when Approach called and told me the same thing. I asked to cancel IFR and requested flight following so that I could concentrate on the electrical failure and not maintaining a fixed altitude.