Problem With Power Outlet

OK, here are the results of the tests.

With engine running, laptop plugged in and running in the rear outlet:
Battery: 13.5
Rear outlet (feed-through plug): 12.7
Front outlet: 13.5

Same as above, but with heater fan on full and headlights on:
Battery: 13.45
Rear outlet (feed-through plug): 12.5
Front outlet: 13.35

Chassis ground voltage drop test (with everything running as per above two):
0.057

With VM connected to battery positive and rear outlet fuse: 0.033

With VM connected to rear outlet fuse and center of inverter feed-through
plug in rear outlet: 0.69

With VM connected to shell of inverter feed-through plug in rear outlet and
body ground: 0.164

So, the results seem to be accurate, since the total of the four tests =
0.94, which is the same as the drop from the battery to the rear outlet.

What seemed strange to me, though, is that these tests don't show a big drop
to the front outlet. Yet I have intermittent problems with the inverter
staying on in the front outlet when the engine is off.

Plugging the inverter/laptop combination into the front outlet, with the
same conditions as above, I got:
Battery: 13.45
Inverter feed-through plug: 12.9

So, not as much of a drop as to the rear outlet, but still a drop (though it
didn't show up when I just tested the front outlet without the inverter
plugged in).

Anyway, thanks for your comments regarding the above!

Neil


<clare at snyder.on.ca> wrote in message
news
> On Sat, 18 Mar 2006 19:07:50 GMT, "Neil" > wrote:
>
>>> It is something else. DC likes to save money where it can and they
>>> probably
>>> didn't expect something that can draw 11+ amps and be sensitive to
>>> voltage
>>> drops to be plugged into that outlet and based the wire size on how warm
>>> they will get at full rated current, not on voltage drop. While there
>>> is
>>> a
>>> slight chance that replacing the battery will correct the problem, it
>>> will
>>> be a temporary solution. There could also be a voltage drop caused by a
>>> bad
>>> chassis to body ground but that is probably only adding to the
>>> undersized
>>> wires.
>>
>>I tend to think it's the latter. The front outlet is also problematic.
>>
>>> You are looking at it from the correct perspective and hopefully learned
>>> a
>>> little about electrical tracing as well.
>>
>>Yes, indeed! I appreciate everyone's help. I was able to do it with my
>>14-year old son, so we both learned a little and had fun (most of the time
>>:-) ) at the same time.
>>
>>> The problem IS in the wiring and
>>> rewiring the front outlet is really not that big of a deal and just
>>> about
>>> anyone that has installed a car stereo could do it. Good luck with
>>> whatever
>>> decision you make.
>>
>>If there are problems with both the front and the rear outlets, wouldn't
>>it
>>make sense that the problem is elsewhere besides the wiring to each
>>outlet?
>>
>>Neil
>>
>>
> Neil, are both outlets on the same fuse like on my Pontiac?
> If not, there is a simple way to find out if you have a common problem
> (affecting both) or whether it is simply a matter of both circuits
> having a problem. With the engine running, so HOPEFULLY the inverter
> will stay running, and with the inverter in the back plug, with the
> computer on, check the battery voltage at idle.
> Then check the voltage at the inveter feed-through plug, and then at
> the front plug. The front plug SHOULD read battery voltage, and the
> rear feed-through plug will read less.
>
> The difference between battery voltage and feed-through plug voltage
> is the total voltage drop. If the battery voltage and the front socket
> voltage are not the same, the difference is the voltage drop that is
> common to both circuits (could be ground resistance, could be power
> feed resistance to the fuse panel)
>
> Turn on the heater fan and / 0r headlights and see if the voltage drop
> increases. Make sure to recheck the battery voltage so you can
> accurately calculate the circuit voltage drop.
>
> Now do the chassis ground voltage drop test again (2 volt scale from
> battery post to the good chassis ground).
>
> Do this test with the same load (computer and headlights and/or heater
> fan). Subtract this drop from the total drop and you know how much
> drop you have un accounted for.
> To find out where the drop is occurring, connect a wire from the
> battery positive to one wire of the meter, and connect the other wire
> to the fuse in the fuse panel. You will need a "jumper" wire to extend
> the voltmeter leads from the battery back to the fuse box. Whatever
> the voltage reading is from the battery to the fuse is the voltage
> drop between the battery and the fuse block.
> Then you can go from the fuse to the center of the feed-through plug
> on the inverter. Any reading here is the voltage drop across the
> (thin) wire from the fuse to the inverter plug. Then connect the meter
> from the shell(ground side) of the feedthrough plug to a good body
> ground (can be any bright plated screw or bolt into the metal body -
> often the tailgate latch is as good and handy as any) ANY reading here
> is drop between the plug ground and body ground.
>
> Reply with the results of the test, or if you want to avoid the
> "circus" you can respond to me by e-mail. I think you can figure out
> my email address from the munged address shown.
>>>
>>>
>>> --
>>> If at first you don't succeed, you're not cut out for skydiving
>>>
>>>
>>
>
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On Sun, 26 Mar 2006 00:06:27 GMT, "Neil" > wrote:

>OK, here are the results of the tests.
>
>With engine running, laptop plugged in and running in the rear outlet:
> Battery: 13.5
> Rear outlet (feed-through plug): 12.7
> Front outlet: 13.5

OK, You have a 0.8 volt drop - which IS excessive.
>
>Same as above, but with heater fan on full and headlights on:
> Battery: 13.45
> Rear outlet (feed-through plug): 12.5
> Front outlet: 13.35

And your drop increases with other loads by 0.15 volts, which is also
excessive, This is "common" circuit voltage drop - which could be
body ground, or could be between the battery and the fuse.
>
>Chassis ground voltage drop test (with everything running as per above two):
>0.057

This indicates roughly 1/3 of this "common" drop is on the body
ground.
>
>With VM connected to battery positive and rear outlet fuse: 0.033
And 0.030 volt drop is on the live side between the battery and the
fuse.
>
>With VM connected to rear outlet fuse and center of inverter feed-through
>plug in rear outlet: 0.69
Which indicates the wire between the fuse panel and the socket has a
large voltage drop. Either a bad connection on the back of the socket
or severely undersized wire.
>
>With VM connected to shell of inverter feed-through plug in rear outlet and
>body ground: 0.164

And the wire from the socket to ground also has excessive resistance,
for the same reasons.
>
>So, the results seem to be accurate, since the total of the four tests =
>0.94, which is the same as the drop from the battery to the rear outlet.
>
>What seemed strange to me, though, is that these tests don't show a big drop
>to the front outlet. Yet I have intermittent problems with the inverter
>staying on in the front outlet when the engine is off.

The drop to the front will only show up with the inverter plugged into
the front,
>
>Plugging the inverter/laptop combination into the front outlet, with the
>same conditions as above, I got:
> Battery: 13.45
> Inverter feed-through plug: 12.9

Which indicates a total drop on the front plug of 0.55 volts - which
is still excessive.
>
>So, not as much of a drop as to the rear outlet, but still a drop (though it
>didn't show up when I just tested the front outlet without the inverter
>plugged in).

Voltage drops ONLY show up under load. The front and rear are separate
circuits.
>
>Anyway, thanks for your comments regarding the above!
>
>Neil
>
I would pull the rear socket and check the connection there, and run
another wire, at least as heavy as the current wire, and preferably
more like a #14 or better wire from the fuse box to the socket, and
from the socket to ground, in parallel with the existing wire.

I would also still put an extra ground from the battery to the body -
#6 preferred - or a standard ground braid if you can find one.
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> I would pull the rear socket and check the connection there, and run
> another wire, at least as heavy as the current wire, and preferably
> more like a #14 or better wire from the fuse box to the socket, and
> from the socket to ground, in parallel with the existing wire.

Thanks for your comments! I assume that this running of the new wire to the
socket is something that I would have a professional do. Is it something
terribly difficult/complicated? Any idea about what it might cost?

>
> I would also still put an extra ground from the battery to the body -
> #6 preferred - or a standard ground braid if you can find one.

When you previously said, "add a new body ground," I thought you meant to
replace the existing one. But here you're saying to add an extra body
ground. So I must have misunderstood.

You note above to run a new wire from the fuse box to the rear outlet. Since
the front outlet also has a drop under load and is on a separate circuit, I
assume I would need to do the same for the front outlet?

Also, as noted previously, the headlights sometimes flicker when in use. You
said previously that that was probably due to a bad body ground. Would
adding the second ground from the battery to the body resolve that, or do I
need to some something else?

Thanks again!

Neil

On Sun, 26 Mar 2006 08:17:09 GMT, "Neil" > wrote:

>> I would pull the rear socket and check the connection there, and run
>> another wire, at least as heavy as the current wire, and preferably
>> more like a #14 or better wire from the fuse box to the socket, and
>> from the socket to ground, in parallel with the existing wire.
>
>Thanks for your comments! I assume that this running of the new wire to the
>socket is something that I would have a professional do. Is it something
>terribly difficult/complicated? Any idea about what it might cost?

If you were close to Waterloo Ontario we'd do it in less than an hour
in the driveway. It's RELATIVELY simple, if you know what you are
doing.
>
>>
>> I would also still put an extra ground from the battery to the body -
>> #6 preferred - or a standard ground braid if you can find one.
>
>When you previously said, "add a new body ground," I thought you meant to
>replace the existing one. But here you're saying to add an extra body
>ground. So I must have misunderstood.

I never remove the existing - adding a second ground, even of equally
poor quality,cuts the voltage drop in half.
>
>You note above to run a new wire from the fuse box to the rear outlet. Since
>the front outlet also has a drop under load and is on a separate circuit, I
>assume I would need to do the same for the front outlet?
>
>Also, as noted previously, the headlights sometimes flicker when in use. You
>said previously that that was probably due to a bad body ground. Would
>adding the second ground from the battery to the body resolve that, or do I
>need to some something else?
>
>Thanks again!
>
>Neil
>

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Thanks for the reply, Clare. Not sure if you noticed the last couple of
questions I had, so thought I'd repost them here.

>>You note above to run a new wire from the fuse box to the rear outlet.
>>Since
>>the front outlet also has a drop under load and is on a separate circuit,
>>I
>>assume I would need to do the same for the front outlet?

>>Also, as noted previously, the headlights sometimes flicker when in use.
>>You
>>said previously that that was probably due to a bad body ground. Would
>>adding the second ground from the battery to the body resolve that, or do
>>I
>>need to some something else?

Thanks for the reply!

Neil



<clare at snyder.on.ca> wrote in message
...
> On Sun, 26 Mar 2006 08:17:09 GMT, "Neil" > wrote:
>
>>> I would pull the rear socket and check the connection there, and run
>>> another wire, at least as heavy as the current wire, and preferably
>>> more like a #14 or better wire from the fuse box to the socket, and
>>> from the socket to ground, in parallel with the existing wire.
>>
>>Thanks for your comments! I assume that this running of the new wire to
>>the
>>socket is something that I would have a professional do. Is it something
>>terribly difficult/complicated? Any idea about what it might cost?
>
> If you were close to Waterloo Ontario we'd do it in less than an hour
> in the driveway. It's RELATIVELY simple, if you know what you are
> doing.
>>
>>>
>>> I would also still put an extra ground from the battery to the body -
>>> #6 preferred - or a standard ground braid if you can find one.
>>
>>When you previously said, "add a new body ground," I thought you meant to
>>replace the existing one. But here you're saying to add an extra body
>>ground. So I must have misunderstood.
>
> I never remove the existing - adding a second ground, even of equally
> poor quality,cuts the voltage drop in half.
>>
>>You note above to run a new wire from the fuse box to the rear outlet.
>>Since
>>the front outlet also has a drop under load and is on a separate circuit,
>>I
>>assume I would need to do the same for the front outlet?
>>
>>Also, as noted previously, the headlights sometimes flicker when in use.
>>You
>>said previously that that was probably due to a bad body ground. Would
>>adding the second ground from the battery to the body resolve that, or do
>>I
>>need to some something else?
>>
>>Thanks again!
>>
>>Neil
>>
>
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On Mon, 27 Mar 2006 05:08:16 GMT, "Neil" > wrote:

>Thanks for the reply, Clare. Not sure if you noticed the last couple of
>questions I had, so thought I'd repost them here.
>
>>>You note above to run a new wire from the fuse box to the rear outlet.
>>>Since
>>>the front outlet also has a drop under load and is on a separate circuit,
>>>I
>>>assume I would need to do the same for the front outlet?

Yes.
>
>>>Also, as noted previously, the headlights sometimes flicker when in use.
>>>You
>>>said previously that that was probably due to a bad body ground. Would
>>>adding the second ground from the battery to the body resolve that, or do
>>>I
>>>need to some something else?

If it is a body ground issue, the additional ground will fix it.
>
>Thanks for the reply!
>
>Neil
>
>
>
><clare at snyder.on.ca> wrote in message
.. .
>> On Sun, 26 Mar 2006 08:17:09 GMT, "Neil" > wrote:
>>
>>>> I would pull the rear socket and check the connection there, and run
>>>> another wire, at least as heavy as the current wire, and preferably
>>>> more like a #14 or better wire from the fuse box to the socket, and
>>>> from the socket to ground, in parallel with the existing wire.
>>>
>>>Thanks for your comments! I assume that this running of the new wire to
>>>the
>>>socket is something that I would have a professional do. Is it something
>>>terribly difficult/complicated? Any idea about what it might cost?
>>
>> If you were close to Waterloo Ontario we'd do it in less than an hour
>> in the driveway. It's RELATIVELY simple, if you know what you are
>> doing.
>>>
>>>>
>>>> I would also still put an extra ground from the battery to the body -
>>>> #6 preferred - or a standard ground braid if you can find one.
>>>
>>>When you previously said, "add a new body ground," I thought you meant to
>>>replace the existing one. But here you're saying to add an extra body
>>>ground. So I must have misunderstood.
>>
>> I never remove the existing - adding a second ground, even of equally
>> poor quality,cuts the voltage drop in half.
>>>
>>>You note above to run a new wire from the fuse box to the rear outlet.
>>>Since
>>>the front outlet also has a drop under load and is on a separate circuit,
>>>I
>>>assume I would need to do the same for the front outlet?
>>>
>>>Also, as noted previously, the headlights sometimes flicker when in use.
>>>You
>>>said previously that that was probably due to a bad body ground. Would
>>>adding the second ground from the battery to the body resolve that, or do
>>>I
>>>need to some something else?
>>>
>>>Thanks again!
>>>
>>>Neil
>>>
>>
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>> *** Encrypt your Internet usage with a free VPN account from
>> http://www.SecureIX.com ***
>

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