Tom:
in a typical 12VDC system, it actually doesn't matter much which way you 
disconnect, or reconnect the battery terminals.
You may get less sparking by connecting the ground first when reconnecting 
the terminals, but you will still get a bit of sparking either way when 
reconnecting.
I say it doesn't matter much because from both personal experience, and from 
knowing and learning from various auto mechanics over my life time, that the 
ground last, ground first concept when disconnecting and reconnecting 
battery terminals in a 12volt auto system is a standard way to do it, but 
that it doesn't make any electrical difference to anything on the system if 
you do it the other way.
Remember, once one side of that circuit is broken, it doesn't matter what is 
still connected, the circuit is broken and there is no longer a posative or 
negative path in the circuit.
So, you and your YL were both right at the end of the day.
Now, if anyone has any theoretical info on which is the better way to do 
this, chime in...acording to a good friend who has been a mechanic for 40 
years and who holds four red seal tickets the order in which you connect or 
disconnect a vehicle battery is not important.

73
Colin, V A6BKX
--------------------------------------------------
From: "Tom Behler" <[log in to unmask]>
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
>
>
>
>
>
>