Fuse problem, What would cause this? - Page 2 - PeachParts Mercedes-Benz Forum

Oracle12345 · #16 06-22-2009, 03:59 PM

guys he doesnt have an SDL, look at the sig.

whatever is one that circuit is drawing too much, so brushes are worn out or getting there.

copper fuses are better since they are better conductor. thats why wires are made out of copper because its better conductor than aluminum.

ah-kay · #17 06-22-2009, 07:13 PM

You can use gold plated fuses for all I care. Copper and Aluminum ( aluminum alloy ) fuses are all the same.

BTW: there are aluminum wires, they are thicker to make up the loss of conductivity. Most tranmission wires are made of aluminum for light weight and costs and is very successful.

snookwhaler · #18 06-22-2009, 08:44 PM

Well, I cleaned the contacts up with a bronze wire brush and put "D" grease on the tips of the fuses. I went for a quick ride and the fan still works as it should (it never quit working). It was dark when I got back. I used a plastic/aluminum fuse. I'll have a look at it tomorrow and see how it looks.

Jeremy5848 · #19 06-22-2009, 11:27 PM

Quote:

Originally Posted by ah-kay

You can use gold plated fuses for all I care. Copper and Aluminum ( aluminum alloy ) fuses are all the same.

They are built to have the same amperage rating, yes, but the metals act differently under severe (i.e., real world) conditions. Both metals oxidize but aluminum oxide is an insulator while copper oxide is still a fair conductor.

Quote:

Originally Posted by ah-kay

BTW: there are aluminum wires, they are thicker to make up the loss of conductivity. Most tranmission wires are made of aluminum for light weight and costs and is very successful.

Quite true, and connections between aluminum and any other metal have a special grease put on them so the aluminum-to-whatever junction doesn't turn into a crude diode. Since people don't usually take that precaution in fuse boxes, problems result. A copper alloy fuse is a better galvanic match to the copper alloy contacts in the fusebox. For the few cents difference, it just isn't worth the risk.

In the 1970s there were a lot of homes built with all-aluminum wiring and a few had serious problems ("fire"). Nowadays we know to use a copper pigtail and special grease to prevent corrosion but that had to be learned the hard way.

Jeremy

ah-kay · #20 06-23-2009, 02:29 AM

The max rated fuse inside the MBZ fuse box is 30A in my cars, i.e. 'Real world' condition is 30A or 360Watt ( 30Ax12V) max.

The interface between copper and aluminum in a transmission line is Mega Watt. That is why they use special grease. It is chalk and cheese compare to a car. I would sleep well/drive well using aluminum fuses. As I have said, one can use gold plated stuff but it is not necessary.

rrgrassi · #21 06-23-2009, 10:00 AM

If aluminum was so great, don't you think the auto industry would have used it for wiring instead of copper? It is lighter weight. It also expands and contracts differently.

Blade and glass fuses are aluminum. I agree about the amp ratings, however, since our fuse panels are under the hood, not in the passenger compartment, copper is a better choice for our cars.

Alastair · #22 06-23-2009, 10:26 AM

Moisture is the biggest issue for Ally fuses...

They corrode at the point of contact and there you go...

Keep 'em dry and greased, and they'll be fine, But given a choice, I would use Copper types...

toomany MBZ · #23 06-23-2009, 10:58 AM

Quote:

Originally Posted by Jeremy5848

Quite true, and connections between aluminum and any other metal have a special grease put on them so the aluminum-to-whatever junction doesn't turn into a crude diode. Since people don't usually take that precaution in fuse boxes, problems result. A copper alloy fuse is a better galvanic match to the copper alloy contacts in the fusebox. For the few cents difference, it just isn't worth the risk.

In the 1970s there were a lot of homes built with all-aluminum wiring and a few had serious problems ("fire"). Nowadays we know to use a copper pigtail and special grease to prevent corrosion but that had to be learned the hard way.

Jeremy

I couldn't have put it any better. If you want a good electrical connection, use copper.

tangofox007 · #24 06-23-2009, 11:18 AM

Quote:

Originally Posted by ah-kay

I would sleep well/drive well using aluminum fuses.

That's because you don't undertstand that the issue is not with basic conductivity so much as it is with the potential for galvanic corrosion. Depending on the particular alloy, aluminim has a galvanic index 2-3 times that of copper. Any suggestion that aluminim and copper are equal as fuse material is nothing short of preposterous.

ah-kay · #25 06-23-2009, 12:00 PM

Quote:

Originally Posted by tangofox007

That's because you don't undertstand that the issue is not with basic conductivity so much as it is with the potential for galvanic corrosion. Depending on the particular alloy, aluminim has a galvanic index 2-3 times that of copper. Any suggestion that aluminim and copper are equal as fuse material is nothing short of preposterous.

Why don't you write to the manufacturers and MBZ requesting them to stop manufacturing aluminum fuses. Tell them your 'experience' with aluminum fuses and that they are hurting your MBZ. That would do everybody a favor and stop our acrimonious, sometimes personal debate.

Look at the facts.

ah-kay · #26 06-23-2009, 12:03 PM

Quote:

Originally Posted by toomany MBZ

I couldn't have put it any better. If you want a good electrical connection, use copper.

I would use gold for conductivity. But this is fuse, the speed the fuse will break in abnormal conditions.

"Speed The speed at which a fuse blows depends on how much current flows through it and the material of which the fuse is made."

If some members are so keen on copper fuses then I challenge you to replace the blower, glow plugs fuses with a copper one.

Jeremy5848 · #27 06-23-2009, 12:46 PM

Quote:

Originally Posted by ah-kay

. . . If some members are so keen on copper fuses then I challenge you to replace the blower, glow plugs fuses with a copper one.

In fact I would do that if they were available. When I first installed an external 30A aluminum strip fuse for the blower in my '87 300D Turbo (W124, OM603) -- it was an early model and didn't get it installed at the factory -- the fuseholder melted! Apparently corrosion built up at one end, where the fuse contacted the plated steel screw. When I replaced the fuse holder, I used conductive grease to seal the connection and have had no repeat of the problem.

ah-kay · #28 06-23-2009, 01:04 PM

Quote:

Originally Posted by Jeremy5848

In fact I would do that if they were available. When I first installed an external 30A aluminum strip fuse for the blower in my '87 300D Turbo (W124, OM603) -- it was an early model and didn't get it installed at the factory -- the fuseholder melted! Apparently corrosion built up at one end, where the fuse contacted the plated steel screw. When I replaced the fuse holder, I used conductive grease to seal the connection and have had no repeat of the problem.

It goes to show aluminum fuses has NO issue. It is your inferior fuse holder had issues.

I challenge you again to look around for ANY Mercedes ever manufactured and see whether they have put 'conductive grease' to seal the GP relay, blower fuses from factory. I support what you are doing with the grease though I would not do it myself. I take exception that aluminum fuses are inferior. They are made for a purpose.

toomany MBZ · #29 06-23-2009, 03:04 PM

Quote:

Originally Posted by ah-kay

I would use gold for conductivity. But this is fuse, the speed the fuse will break in abnormal conditions.

"Speed The speed at which a fuse blows depends on how much current flows through it and the material of which the fuse is made."

If some members are so keen on copper fuses then I challenge you to replace the blower, glow plugs fuses with a copper one.

I'll agree gold is even better, yet cost does play a factor. The Concorde can fly fast enough across the ocean, but they have been retired due to cost constraints.
The fuses I have are either brass or copper.
Aluminum seems to oxidize faster than the above mentioned metals, again, cost is a factor.