How can I test the output of my Alternator? I've been unable to identify which alternator I have, probably the stock one, and I want to get a reading on how much output it's giving. What equipment do I need? Do you know if the Alternator tester the auto parts stores have tell the output level or just if its working or not working? Thanks!!!! I want to get some electric fans from Troyer but I need to make sure I have enough power with all the other power drains I already have