Tom,
Our friend Mr. Google gave me back ten citations about your 
question.  And damned if they don't say negative first.  A new one on 
me - I have always gone positive first.  They say reconect the 
negative first as well.
My new thing for the day!!
Pat, K9JAUAt 03:58 PM 10/24/2014, you wrote:
>Ed:
>
>Interestingly, my XYL looked up the proper procedure on the internet, and
>the correct procedure according to the web site she checked  is in line with
>what she suggests.
>
>Don't worry:  our discussion is still very amicable.  Remember, she's a ham
>too, and we've been married for 39 years!  (smile)
>
>Tom Behler: KB8TYJ
>
>
>-----Original Message-----
>From: For blind ham radio operators [mailto:[log in to unmask]]
>On Behalf Of Ed Malmgren
>Sent: Friday, October 24, 2014 4:52 PM
>To: [log in to unmask]
>Subject: Fw: Best procedure for connecting and disconnecting a 12-volt
>battery
>
>Tom, your right this time but don't tell your Y L that I said she is wrong.
>
>
>Oh well I don't have to live with her hi hi 73 ED K7UC -----Original
>Message-----
>From: Tom Behler
>Sent: Friday, October 24, 2014 2:37 PM
>To: [log in to unmask]
>Subject: Best procedure for connecting and disconnecting a 12-volt battery
>
>Hi, all.
>
>
>
>I am sure that, to some, this question might seem to be very elementary,
>especially for someone like me who holds an Extra class license.  So, please
>bare with me, and understand why I am asking the question.  As a college
>professor, I always try to teach my students not to simply memorize
>procedures or concepts just for the sake of doing so.  I tell them that real
>learning involves understanding the procedures and/or concepts and the
>reasons behind them.  I also stress that true learning involves being able
>to apply what you have learned to real life situations.
>
>
>
>Anyway, here's my question:
>
>
>
>Earlier this afternoon, my XYL and I were in the process of getting our
>summer camping trailer winterized for the season, and taken to a local
>facility for winter storage.  As we worked, it came time to disconnect the
>house battery from the unit, so that it can be put on a trickle charger
>during the winter months.
>
>
>
>Before we disconnected the battery, we were discussing the best and/or
>safest procedure for doing so.  We never worried about this with the
>drivable RV we used to have, because it was always kept in our driveway and
>plugged into our main house power all winter.
>
>
>
>Anyway, my proposed approach was this:
>
>
>
>When disconnecting the battery, disconnect the positive side first, and then
>the negative.  The idea here is that you always have the negative or ground
>connected when you're working with the battery.
>
>
>
>When re-connecting the battery, I proposed connecting the ground terminal
>first, once again, to give you a ground to start from, and then connect the
>positive terminal last.
>
>
>
>My XYL's approach was the opposite:
>
>
>
>She argued that when disconnecting the battery, disconnect the negative
>terminal first, and then the positive.  . When connecting, connect the
>positive first, and then the negative.
>
>
>
>As a smart person who has much faith in my XYL's judgment, I decided to go
>along with her proposed approach, and happily, we are both still here to
>talk about it.
>
>
>
>However, I know that I have connected and disconnected many a battery using
>my initial approach, and I've survived that as well.  Perhaps I just got
>lucky, but I always thought I was proceeding with care, and with the correct
>procedure.
>
>
>
>Once again, I hope nobody minds this question, but I consider everyone here
>to be knowledgeable on many things, and I trust that you will all be able to
>go with the idea that the only stupid question is a question that goes
>un-asked.
>
>
>
>Your wisdom on the topic would be most appreciated.
>
>
>
>Thanks for listening.
>
>
>
>Tom Behler: KB8TYJ