THEORY connector bounce problem due to engine vibration

Hello,

A recent gas mileage thread here included opinions that higher RPM
operation resulted in improved gas mileage so I have been cruising in
5th gear instead of 6 on my commute. Additionally, I have beem
practicing a lot on my favorite twisty/hilly road involving even more high
RPM running. In a recent post I commented about how quickly my VFR charging voltage drops off requiring cleaning
of the two R/R connectors. My frazzled brain managed to correlate
these two issues and recalled a website I visited when I first started
using a GPS on my VFR. And thus I offer this theory for consideration.

It is a simple extrapolation of the articles linked and excerpted
below: Certain frequencies of engine vibration cause the sping tension
contacts in the VFR electrical connectors (or any motorcycle) to bounce
and arc and over time a carbon residue builds up between the contacts
(making then "dirt") and causing resistance in the circuit.

The article talks about batteries and coil springs as well as
singles and and twins. I am suggesting that the higher vibration frequencies
of a 4 cylndar has the same effect on the spring metal contacts of
the male/female blade type connetors on a motorcycle as the lower vibration
frequencies of a single or twin have on the coil springs used in the
AA battery compartment of the GPS.

I own both a Garmin III and V and can attest that both are effectivly unuseable in battery mode
on the VFR due to the battery bounce phenomenon. I will additionally
comment that the failure can occur without residue buildup being
visible to the naked eye. However cleaning apparently "dead"
batteries with and eraser or emory cloth restores operation, although
only briefly.

I have excerpted the significant portions of two web pages that my
theory is based on and include the links as well.


"This discussion is for those trying to run a GPS on a motorcycle, on its internal batteries.
This is a battery bounce problem due to engine vibration, primarily on single cyclinder motorcycles, and some twins.
The battery problem usually disappears if the GPS is powered from the
motorcycle's 12v electrical system"

http://www.cycoactive.com/gps/gps_batteries.html



"

Notice the black deposits on the battery terminals. This is carbon buildup caused by engine vibration.
Inside the battery case, the batteries are suspended between two springs. At certain frequencies (RPMs)
the batteries jump around and lift off the terminals, creating a small spark each time they disconnect.
After thausands of sparkings, a black carbon residue builds up between the contact and the battery terminal.
Even though the batteries are not dead, the electricity can't get out thus the GPS thinks they're dead and
shuts down. You can scrape the residue off the battery, but it seems to return even faster, and it's difficult
to clean the contacts. For this reason we advise using external power right from the start if possible. At the
very least tape the batteries and put dielectric grease on the terminals to shut out the oxygen which prevents
a burning spark."


http://www.cycoactive.com/gps/GPS_ba...2and3plus.html



The major weakness in this theory that I see is that I don't know
for a fact that engine vibration is readily transmitted into the
wiring harness connectors since the connectors themselves are not in
direct contact with the frame but only loosely suspended from it by
the wiring?

Thanks for reading, comments welcomed,
Bob

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Bob Chappuis wrote:
> I am suggesting that the higher vibration frequencies
> of a 4 cylndar has the same effect on the spring metal contacts of
> the male/female blade type connetors on a motorcycle as the lower vibration
> frequencies of a single or twin have on the coil springs used in the
> AA battery compartment of the GPS.

Interesting theory, but it's a tough sell to me. I _might_ buy the theory as it
relates to batteries in portable electronics, since you have a (relatively) very
heavy battery between two lightweight spring contacts. But a blade connector?
Maybe if the connector was poorly made such that the metal was _barely_ in contact
in the first place - and the metal contanct can vibrate separate of the connector
housing. Maybe.


--
*********************************
Chris Merrill
cmerrill@xxxxxx
*********************************
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Some may not believe it, but that can happen in blade connectors. That
would be case of arcing causing the corrosion.
The reverse can also occur, where corrosion caused by harsh environments
results in arcing. In either case, the arc/corrosion cycle leads to
high resistance.
The problem can be solved by cleaning the contacts, confirming that they
are mating tightly, and packing them with di-electric grease prior to
assembly.
John Harrison
Birmingham


> -----Original Message-----
> From: vfr-bounces@xxxxxx
> [mailto:vfr-bounces@xxxxxx] On Behalf Of Chris Merrill
> Sent: Thursday, May 18, 2006 9:58 AM
> To: vfr@xxxxxx
> Subject: Re: THEORY connector bounce problem due to engine vibration
>
> Interesting theory, but it's a tough sell to me. I _might_
> buy the theory as it
> relates to batteries in portable electronics, since you have
> a (relatively) very
> heavy battery between two lightweight spring contacts. But a
> blade connector?
> Maybe if the connector was poorly made such that the metal
> was _barely_ in contact
> in the first place - and the metal contanct can vibrate
> separate of the connector
> housing. Maybe.
>
>
> --
> *********************************
> Chris Merrill
> cmerrill@xxxxxx
> *********************************
> _______________________________________________
> Vfr mailing list
> Vfr@xxxxxx
> For subscription and delivery options:
> https://lists.cs.wisc.edu/mailman/listinfo/vfr
>

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Hi Bob,

I can and do accept that this is a possibility where a relatively heavy
battery is made contact to by quite light springs, but the connectors used
on the bike are very different.

The forces exerted by the spade connectors (that's what we call the flat
vehicle connectors in the UK) on the sides of the spade is very high when
compared to the weight of cable which can vibrate. I would also accept that
if these have been removed and refitted several times perhaps becoming loose
in the process, that they can then become subject to vibration, poor contact
and over heating.

There is one effect of heat and vibration worth mentioning, as perhaps some
of you have not come across it....

If you solder tin bare wires, then insert then into brass or other metal
terminal with a screw to tighten - then the solder can over time, heat and
vibration creep out from under the securing screw. Thus it becomes loose,
generates heat through its resistance and the deterioration accelerates. So
never tin wires before use in a screw terminal, just twist the bare wires or
one of those tubular sleeves designed for the job.

-----Original Message-----
Hello,

It is a simple extrapolation of the articles linked and excerpted
below: Certain frequencies of engine vibration cause the sping tension
contacts in the VFR electrical connectors (or any motorcycle) to bounce and
arc and over time a carbon residue builds up between the contacts (making
then "dirt") and causing resistance in the circuit.

The article talks about batteries and coil springs as well as
singles and and twins. I am suggesting that the higher vibration
frequencies of a 4 cylndar has the same effect on the spring metal
contacts of the male/female blade type connetors on a motorcycle as the
lower vibration frequencies of a single or twin have on the coil springs
used in the AA battery compartment of the GPS.
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So have you seen an increase in gas mileage?
I don't care if the engine is more "efficient" at the higher rpm, I don't
see how it can give you better gas mileage.
The wheels, transmission, and engine are in a simple mechanical ratio. For
each mile that the wheels turn, the engine revolves a number of times
depending upon the ratio, and a certain amount of fuel goes into the
cylinder for each cycle. What, less than 80% as much fuel goes into each
cylinder at 7,500 rpm as what goes in at 6,000 rpm?
Ed
1998 VFR800

> -----Original Message-----
> On Behalf Of Bob Chappuis
>
> A recent gas mileage thread here included opinions that higher RPM
> operation resulted in improved gas mileage so I have been cruising in
> 5th gear instead of 6 on my commute. Additionally, I have beem
> practicing a lot on my favorite twisty/hilly road involving even more
> high RPM running. In a recent post I commented about how quickly my VFR


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No! I have not see any significant increase in gas mileage. If
anything it down a half a mile per gallon.


Cheers,
Bob
Friday, May 19, 2006, 10:11:27 PM, you wrote:
> So have you seen an increase in gas mileage?
> I don't care if the engine is more "efficient" at the higher rpm, I don't
> see how it can give you better gas mileage.
> The wheels, transmission, and engine are in a simple mechanical ratio. For
> each mile that the wheels turn, the engine revolves a number of times
> depending upon the ratio, and a certain amount of fuel goes into the
> cylinder for each cycle. What, less than 80% as much fuel goes into each
> cylinder at 7,500 rpm as what goes in at 6,000 rpm?
> Ed
> 1998 VFR800

>> -----Original Message-----
>> On Behalf Of Bob Chappuis
>>
>> A recent gas mileage thread here included opinions that higher RPM
>> operation resulted in improved gas mileage so I have been cruising in
>> 5th gear instead of 6 on my commute. Additionally, I have beem
>> practicing a lot on my favorite twisty/hilly road involving even more
>> high RPM running. In a recent post I commented about how quickly my VFR
>

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