Date:         Wed, 22 Sep 2004 14:12:28 -0500
Reply-To:     Bruce Nadig <motorbruce@HOTMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Bruce Nadig <motorbruce@HOTMAIL.COM>
Subject:      Re: Q: Battery Disconnect Sequence?
Comments: To: refisher@MCHSI.COM
Content-Type: text/plain; format=flowed

Hydrogen gas can escape from a damaged or leaking battery. The damage may
not always be visible. One sign that it might be around is excessive
corrosion around the battery terminals, but that is by no means the only
indicator. Where batteries are concerned, it is best to play it safe. Assume
that there is hydrogen gas. No open flame or sparks around any batteries,
especially ones that are on chargers (that is when most of the chemical
reaction takes place that creates the hydrogen {I think I remember that
right from chemistry}).

Play it safe. No flame or sparks around batteries. Always connect the
negative terminal last, and disconnect it first on negative ground vehicles.
When jump starting a vehicle, do not connect the negative leads to the
battery. Connect them to a good bare metal spot on the engine or frame of
the car.

Safety First!
Bruce
motorbruce
motorbruce@hotmail.com




>From: Robert Fisher <refisher@MCHSI.COM>
>Reply-To: Robert Fisher <refisher@MCHSI.COM>
>To: vanagon@GERRY.VANAGON.COM
>Subject: Re: Q: Battery Disconnect Sequence?
>Date: Wed, 22 Sep 2004 05:09:07 -0700
>
>Re: The hydrogen gas- is it that there's a very small amount so that it
>sort
>of forms a 'halo' just in the immediate vicinity of the battery? Every time
>I read about this, I get this image of somebody in the passenger seat
>lighting a cigarette... well you get the idea.
>
>What's the scoop?
>
>Cya,
>Robert
>
>----- Original Message -----
>From: "Bruce Nadig" <motorbruce@HOTMAIL.COM>
>To: <vanagon@GERRY.VANAGON.COM>
>Sent: Tuesday, September 21, 2004 6:46 PM
>Subject: Re: Q: Battery Disconnect Sequence?
>
>
>>The answer below is close to the truth, but not right on.
>>
>>True, the body of the vehicle is negative. Chances are that any tool (such
>>as a socket or box-end wrench) you would use to loosen the battery
>>terminal
>>would be metal. If that metal tool was being used to disconnect the
>>positive
>>terminal first and it hit the body while doing so, things would get real
>>exciting real quick. I have heard stories of mechanics even having their
>>rings (ie. wedding rings) getting "welded" between a positive and negative
>>connection.
>>
>>If you take your metal tool and disconnect the negative side first, you
>>won't have a problem if your wrench touches the body because the body is
>>just an extension of the negative side of the electrical system. If your
>>negative is still connected and you are attempting to disconnect the
>>positive terminal and that same tool contacts the negatively charged body,
>>at a minimum, you will get a large spark. Being so close to the battery,
>>that spark could very well ignite any hydrogen gas that has been
>>discharged
>>from the battery (that is why you don't connect your negative cable on
>>your
>>jumper cables to the battery).
>>
>>What is stated below isn't quite true. Once the positive cable is
>>disconnected from the battery terminal it no longer has a charge in it, so
>>it doesn't make any difference if it hits the negatively charged body
>>(which
>>is no longer negatively charged, by the way, because there is no longer a
>>complete electrical circuit). You could, in fact, safely put that positive
>>terminal to the negative terminal to the battery and nothing would happen
>>so
>>long as there is nothing connected to the positive terminal of the
>>battery.
>>
>>Make sense?
>>
>>Be Safe.
>>
>>Another electrical tip: When giving someone a jump start, make sure that
>>the
>>vehicles that are involved in the jumping process are not touching in any
>>way.
>>
>>Cheers,
>>Bruce
>>motorbruce
>>motorbruce@hotmail.com
>>
>>
>>
>>>From: Jim Felder <felder@KNOLOGY.NET>
>>>Reply-To: Jim Felder <felder@KNOLOGY.NET>
>>>To: vanagon@GERRY.VANAGON.COM
>>>Subject: Re: Q: Battery Disconnect Sequence?
>>>Date: Tue, 21 Sep 2004 19:56:31 -0500
>>>
>>>It's not the sequence.
>>>
>>>On any car but old english ones, the negative is the ground, and it's
>>>strapped to the car frame somewhere. So you could say that everything
>>>on the car is "negative" that is connected to the frame by even a
>>>fastener. If you take the positive cable loose, it stands every chance
>>>of hitting one of these negative frame or body members (engine too,
>>>everything) and you'll get a big hot spark in the best-case scenario.
>>>
>>>Letting the negative cable hit anything but the positive terminal, and
>>>nothing will happen.
>>>
>>>Jim
>>>
>>>On Sep 21, 2004, at 8:46 PM, Jack wrote:
>>>
>>>>Ok, I need help.
>>>>
>>>>In several manuals, including a Ford Owner's manual (forgive me) and a
>>>>Haynes repair manual, I've noticed that they specify that the negative
>>>>battery cable must be removed first when disconnecting the battery.
>>>>Why???
>>>>
>>>>What possible difference can it make which terminal is disconnected
>>>>first???
>>>>  When I first ran across this, I ignored it as a harmless error by
>>>>someone
>>>>who didn't understand electrics, but now I find it in "professional"
>>>>references.
>>>>
>>>>Help!  What am I missing?
>>>>
>>>>//Jack
>>>>