powerlet outlet ground concern

[Wasabi]

I recently purchased and installed the Powerlet PKT-045 Front Panel Kit for my VStrom. After installation I found an article that caused some concern about the ground placement of the kit. The following is the correspondence I had with a Powerlet electrical engineer.

Email to Powerlet

FYI
Saw this at this site
http://motorcycleinfo.calsci.com/VStrom.html
Do I need to re-ground my power outlet ?

The VStrom electric system is designed with all grounds returned via wires to the battery ground. The frame should never be used as a ground return path on these bikes. Due to the fact that the frame is a mix of aluminum and steel, running current through these parts will result in an electrolytic reaction which will eat away at the frame. All added electrical accessories should have their ground current running through wires to the battery. Thanks to R.Cairns of Oz for pointing out this important fact.

Powerlet response

Hi Bill,

My name is John and I am one of the electrical engineers at Powerlet. I
understand you have some concern about ground current eating away at the aluminum/steel frame joints. In my opionion the statement is false.
Additionally the good news is it does not matter - the fix is simple.

First let me answer your question "Is the statement by the article
correct, "The frame should never be used as a ground return path on these bikes"?"

Theoretically... YES, the electrolytic process is certainly is happening.

Practiaclly... I dont think you could actually measure the frame decay
because the current is not high enough (or frequent enough) to cause
serious damage.

I have read the post on the Suzuki link you sent. In this case false
"inductive" logic may be causing unwarrented concern.

I believe the potential false logic goes something like this:
A. Suzuki used individual wires to return the grounds (factory wiring).
B. Flowing current through dissimilar metals create electrolytic reactions.
C. Therefore Suzuki does not use the frame for gorund returns because it
will weaken the frame.

A is TRUE
B is TRUE
A & B do not prove C.

There "may be" many reasons why Suzuki returned the ground wires seperatly at the factory. Maybe they are using fasteners that are coated for corrosion and these are not conductive. Maybe this was causing some bolts to "freeze" into the frame dus to a small amount of electrolytic action. The "maybes" here are endless, but most likely it is related to cost, not frame decay.

I will keep my eyes and ears open, I could be wrong.

The good news is that it does not matter the reason. If you are concerned about it, then you should terminate the black wire at the battery instead of bolt "E". The black wire in kit 045 is more than long enough to reach the battery.

I hope this helps, please feel free to post this info to any other
concerned Powerlet customer.

Ride Safe,
John

[Gilk51]

Bottom line is to run a ground wire to the battery. The electrolysis stuff is probably overstated but the main reason is - aluminum is a lousy conductor.

Copper is better! (no, not you 10-95)

[Squeaky]

Originally Posted by Gilk51

Copper is better!

See - someone finally agrees that my SV is 'da bomb!

[kurt]

I agree. Orange ones are bombs.

[Gilk51]

I just KNEW that reply was coming...

[Tx Rider]

Run the wire, electrolysis isn't something to fool with, a very very small current can eat a lot of metal quickly.

I don't buy powerlets and just use simpler plugs on my bikes but they are all usually grounded to the battery, and fed from the battery with a fuse inline.

[RobTx]

Originally Posted by Gilk51

Bottom line is to run a ground wire to the battery. The electrolysis stuff is probably overstated but the main reason is - aluminum is a lousy conductor.

Copper is better! (no, not you 10-95)

Actually, aluminum is a very good conductor of electricity. Best conductors are silver, copper, gold, aluminum, in that order. Aluminum is less conductive than copper (by 35%), but conducts plenty well to be used in antennas and other applications. On the other hand, steel, used as a ground path in lots of automobiles, is 97.5% less conductive than copper. I would have no problem grounding to the frame. I think you should wire directly to the battery though if you have any doubts. The peace of mind would be worth it.
Rob

[Gilk51]

Main problem with aluminum is that it is brittle and why they no longer use it for house wiring (can't see aluminum wire on vehicles at all). That 35% means a voltage drop in the frame/wiring that could be better used on your electic/electronic gear. Plus, frames are not built for good electrical pathways but for mechanical strength.

But all that just means that things run much better with a good, fat, copper wire ground (which probably has black insulation, Squeaky).

That goes for 4-wheeler frames, too. Better to wire to battery ground if you have something important. But not many auto-makers do that.

Best conductors are silver, copper, gold, aluminum, in that order.

Wouldn't have believed copper ahead of gold - those are always used to plate copper pins in connectors. Always heard that silver wire was best - if you could afford it.

[Tx Rider]

I think the point is a dissimilar metals contacting each other, and passing a current through it. I dunno if steel and aluminum will react poorly in this case, (any mechanical engineers?) but other dissimilar metal junctions do, and corrosion can be extreme.

I'd be safe and just wire it to the battery.

[RobTx]

Gilk, that 35% is conductivity in ohms/meter. In the case of the motorcycle frame it would mean a loss of less than a millionth of a volt. Nowhere near being measurable by any equipment an ordinary person would have at home. I would have no problem using the frame as a ground path for a single power outlet. The amount of current and time will not cause as much damage as mechanical fatigue in the same amount of time. As you correctly point out aluminum has a very low fatigue limit. I've owned several aluminum framed bicycles and the typical lifespan seems to be about 5 years. It will be interesting to see how far down the road we'll get before we start seeing aluminum motorcycle frames start breaking.
Rob

[VFRinAustin]

Been trying to remeber back to those classes but if I do remeber correctly, even if there is any carryover, it is from the steel to the aluminum, not the other way around, so the aluminum frame should be safe. Eiher way though, I cant imagine that there is enough big E transfer through the ground (epescially through the large mass of the frame) to cause any real siginificant corrosion. I agree with the Jastek engineer that just because Suzuki used wires and not the frane to run the ground does not establish that te reason was a concern over electrolytic corrosion, quite possible was to create and isolated ground to reduce the possiblilies of shorts.