Date: Sat, 21 Dec 2013 16:43:33 -0800
Reply-To: Stuart <ve3smf@YAHOO.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Stuart <ve3smf@YAHOO.COM>
Subject: Re: Van Dies while in motion
In-Reply-To: <52B461C7.8010606@comcast.net>
Content-Type: text/plain; charset=iso-8859-1
OK, I am willing to go out on the limb for this one.....
First some background. Any device such as headlights, heater fans, blowers, etc will draw a fixed amount or power. P=I*E where Power in watts = Current times Voltage. The problem is, when voltage drops, the device still draws the same power, and the amount of current required (ampre) will go up.
ref: http://www.sengpielaudio.com/calculator-ohm.htm
The second issue is the ability of any wire to conduct and not melt depends on the ampres, not on the voltage. A given wire can carry high voltage, and low ampre, but not high ampres, at low voltage.
ref: http://www.engineeringtoolbox.com/amps-wire-gauge-d_730.html
In the case where either a battery in a vehicle is failing and/or the alternator is failing, under high power load (such as headlights on high beam, heater fan going and air circulation fan going), the voltage will drop. When an alternator fails, it will still be possible for a vehicle to drive for a while, until the voltage from the battery drops to the point that the coil will not provide sufficient spark to the engine. The other issue is the electrical circuits through the ignition switch are designed to sustain a maximiun current (ampre) flow at 13.8 VDC. When the voltage in the system goes down, the ampres go up (P=I*E). With the higher current flow, and the inherit internal resistance of the wiring, the wires and the switch will heat to the point that the copper and switch will melt.
In the case of a battery and/or alternator failure (cause) under high power demands, you will get circuit wire and switch failure (sysmptoms).
In this case, I hope that several fuses melted before damage happend to the wires. Tracing and replacing burnt wire harness is not fun. The ignition switch may have also failed, but has been pointed out, this is easy to replace. As far as the actual cause of the failure, I would look at both the battery and the alternator. This will likely be a multi-point failure.
In terms of monitoring the state of health of a vehicle electrical system, one of those cigarette plug in voltage monitors would have given diagnostic information as the system was failing. The fact that the high beams were required to be on, as well as the heater fan and front fan pushed the system over the edge. The unit that I have will monitor the battery voltage when every thing is turned off, and the system (alternator voltage) when everything is running. This is very valuable information. The best system would look at both the battery and the alternator at the same time. On Youtube is a project that was done with a focus on the Arduino-based power monitoring system.
http://www.youtube.com/watch?v=0gS6RaVO8po
I hope things work out, and you can share the final results.
Stuart
86 Vanagon GL 2.1L
________________________________
From: Ken Wilford <kenwilfy@COMCAST.NET>
To: vanagon@GERRY.VANAGON.COM
Sent: Friday, December 20, 2013 10:27:03 AM
Subject: Re: Van Dies while in motion
Tony,
Sounds like the ignition switch as Jim has stated. Or it could be an
alternator/battery issue or both. I would get a new battery and a new
ignition switch. You can drop the lower column cover, unplug the old
ignition switch from the harness and plug the new one into the harness
without installing it. Use a small screw driver to turn it in the slot
that is on the side that is away from the plug just like you would be
turning the key in the ignition normally. If the van starts right up
and is back to normal then that is the problem, get it home and install
the new switch. If not, install the new battery (group 41 from
Wal-mart). Now try starting it. Even if the alternator is toast it
should start up and be able to be driven for an hour before getting so
low that it kills the engine again (try not to run any other lights or
fans if you can help it). Use a volt meter at the battery to see if the
alternator is putting out. It should be doing at least 13.5volts. You
may have to rev the engine above 2000 rpms to get it to kick in.
Let us know what you find out.
Ken Wilford
John 3:16
www.vanagain.com
PS
Welcome to the Vanagon List!
On 12/20/2013 1:46 AM, Anthony Boscolo wrote:
> Hi all,
>
> This is my first post so I will try to be as clear as possible. I have an
> 1986 Syncro GL.
> Driving up to the mountains tonight the head lights went out...about 20
> seconds later the engine died...the key is stuck in the ignition and if i
> turn it the dash lights (bat,ox, etc...) don't respond. There is no noise
> at all if I turn the key.
>
> At the time I had the rear heater on full, and was running the
> high-beams...and I may have had the front heater/fan on as well.
>
> Any thoughts on what went wrong? fuse? if so I can't figure out which one.
>
> In the meantime, the Van is on the side of the road on SR 410 just before
> the turn up to crystal mt. If you see her, wish her good thoughts.
>
> Thanks for the help
>
> --
> Anthony Boscolo | 206.794.1727 | abosail@gmail.com
>
>
> -----
> No virus found in this message.
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>
>
--
Thanks,
Ken Wilford
John 3:16
www.vanagain.com
Phone: 856-327-4936
Fax: 856-327-2242
| 
