Blowing fuses

[slug]

Today my dear beast decided it likes the taste of 15 amp headlight circuit fuses. I've already put in an emergency order for new GEI relays from Dan, so that is covered. I can't find any obvious shorts around the headlight... A new fuse will last about 10 minutes, and seems to blow (or maybe just coincidence) when I go in to some harder engine braking. Going to hook up the 'ol voltmeter tomorrow to get a better idea of what's going on with the charge circuit.

 

Any hints, tips, experience?

 

Mucho Thanks!

[dlaing]

 

Any hints, tips, experience?

 

Mucho Thanks!

Checking the charging is the number one thing to check.

Check for over voltage and for resistance between regulator and battery.

Try riding with headlight disconnected (DISCLAIMER Don't do it if it is illegal )

Look for a loose horn wire.

Look for bad tachometer ground.

Look for bad brake light circuit.

Look for loose battery connection

[tikkanen]

Hi Slug,

 

I know how you feel as my Scura kept blowing fuses for the starter engine.

 

It turned out that the wires from the dashboard was scrubbing against the steering stem thus creating this malfunfunction. I simply took some gaffa tape (I think you guys call it duck tape or something like that) and gave the wireharness a good wrapping and presto! No more blown fuses.

 

Good luck

 

Søren

[slug]

Checking the charging is the number one thing to check.

Check or over voltage and for resistance between regulator and battery.

Thanks, you know the specific numbers (hi/low voltage, ohms, flux capacatance) off the top of your head?

[slug]

Found the problems:

 

1. Tail light wires were pinched against a sharp corner of the fender eliminator, and wore through the insulation.

2. Two of the three legs of that stupid reflector thing inside the headlight had broken, and one of the free legs was intermittently shorting out the circuit for the little pilot lamp in the headlight. I ended up using aviation shears to cut that little bastard up and get it out of the headlight.

 

I also found that the 30 amp fuse for the charging system has been getting super hot, practically melting, just like Enzo has experienced recently. Not sure what's causing that yet... Enzo, if you're reading this, did you ever figure this out?

 

To make life even more fun, while troubleshooting, I discovered a 1 1/2 inch cut/chunk torn out of the outer edge of my rear tire (right down to the cords ) Bummer is that I only had 2000 miles on them. Grrrr.

 

Thanks for the help everyone!

[dlaing]

Found the problems:

 

1. Tail light wires were pinched against a sharp corner of the fender eliminator, and wore through the insulation.

2. Two of the three legs of that stupid reflector thing inside the headlight had broken, and one of the free legs was intermittently shorting out the circuit for the little pilot lamp in the headlight. I ended up using aviation shears to cut that little bastard up and get it out of the headlight.

 

I also found that the 30 amp fuse for the charging system has been getting super hot, practically melting, just like Enzo has experienced recently. Not sure what's causing that yet... Enzo, if you're reading this, did you ever figure this out?

 

To make life even more fun, while troubleshooting, I discovered a 1 1/2 inch cut/chunk torn out of the outer edge of my rear tire (right down to the cords ) Bummer is that I only had 2000 miles on them. Grrrr.

 

Thanks for the help everyone!

I did the aviation shear method, too....but then I found out the glass face pops off the reflector pretty easilly and pops back on, too!

I would be concerned about the 30amp fuse.

Unfortunately I don't have good advice about how to deal with it.

You could run a heavier gauge bypass line, directly to the battery from the regulator.

Check all your connections, clean and lube with dielectric silicone or better.

Check the battery and charging system.

 

 

Thanks, you know the specific numbers (hi/low voltage, ohms, flux capacatance) off the top of your head?

You should get the shop manual, http://www.angelfire.com/weird2/v11/

 

Here is the excerpt for the regulator

REGULATOR The regulator has been calibrated in order to maintain the battery voltage at a value between 14÷14.6 Volts. The pilot light (illuminated when the engine is not running, but the key is inserted) will switch off when the generator begins to charge, (approx. 700 r.p.m.) REGULATOR CHECKS Normal work-shop tools are generally insufficient for regulator checking, however, listed below are certain operations that can be carried out in order to detect regulators that are defective. THE REGULATOR IS CERTAINLY DEFECTIVE IF: After having isolated it from the rest of the system short circuits can be detected between the earth (aluminum casing) and any of the output cables

alternator

ALTERNATOR AND VOLTAGE CONTROLLER WARNING If connections are inverted the regulator will be irreversibly damaged. Check that the regulator earth connections are efficient. Possible checks to be carried out on the alternator or regulator if the battery fails to re- charge or the power supply is no longer regulated. ALTERNATOR With the engine switched off, disconnect the two yellow generator cables from the rest of the system and then carry out the following tests with a ohmmeter: CHECK THE WINDING ISOLATION TOWARDS EARTH Connect one connecting point of the ohmmeter to one of the two yellow cables and the other connecting point to earth (laminar pack). The instrument should indicate a value above 10 MW. CHECK THE WINDING CONTINUITY Connect the two connecting points of the ohmmeter to the two yellow cables. The instrument should indicate a value of 0.2÷0.3 W. CHECK THE VOLTAGE OUTPUT Connect an alternate 200 Volt capacity voltmeter to the two yellow cables. Start the motor and check that the voltage output is included within the values indicated on the following tables

Table says
rpm		   1000	 3000	 6000
AC Volts	   15	   40	   80

[Ballacraine]

A few basic guidelines for vehicle electrics.

Most are common sense really:

 

1) Ensure all contacts are clean and tight. ( Important one this! )

2) Make sure that all wire routings are clear of snagging or chafing.

If you are adding to an existing loom for any reason, ( modification or repair ),

make sure you are a little generous when cutting length, so you don't get any tension on the wire during use.

3) Ensure wire insulation is in good condition.

4) Never defeat recommended fusing with metal foil or upgrade of fuse rating if the rest of the circuit is unchanged.

Fuse ratings are given for the load in a circuit. If they keep blowing there will be a good reason for it.

 

Specifically regarding your 30 Amp fuse.

 

It sounds like you may have excess resistance in the circuit. This will generate heat. I would do a check for dirty / loose connections for starters, if only to eliminagte this from the possible causes.

 

Hope this at least points you in the right direction.

 

Nige.

[docc]

I thought my very hot looking 30A fuse last year was a result of a bad regulator. But I find my current fuse has also been hot. I've been storing extra fuses between the fuses and thought that might be storing heat.

 

I've had all my connectors apart and greased but maybe it's time to go back through them all?

 

What else could it be? Should we all pull that 30A fuse and have a look?

[dlaing]

I thought my very hot looking 30A fuse last year was a result of a bad regulator. But I find my current fuse has also been hot. I've been storing extra fuses between the fuses and thought that might be storing heat.

 

I've had all my connectors apart and greased but maybe it's time to go back through them all?

 

What else could it be? Should we all pull that 30A fuse and have a look?

I think it is a good idea to check that and the wires coming out of the regulator.

I ended up with resistance between the hot line from the regulator and the fuse.

I don't know if that was cause or effect.

[callison]

I simply took some gaffa tape

 

Søren

 

That's interesting, I'll bet it was originally called "gaffer" tape for the guys in the movie industry (gaffers) that use it. Same with "duck tape" - it was duct tape used by the guys installing heating/air conditioning venting that used it to seal seams. That's probably why the most common color is silver. For where I used to work, it was called "explosive" tape - we used copious amounts of it to hold together virtually everything associatied with explosive experiments. Strong, lightweight, inexpensive and expendable and always black. We even had a guy repair his really torn up truck seat with the stuff. It took 2 rolls of tape. Then the sun came out... what a mess!

[luhbo]

It may look like some sort of technical overkill, but I'm really thinking about replacing these cheap hot wire connectors in the 30A thread with gold plated high current connectors, available in every R/C model shop. They cost not too much but stand 80 amps and more without any problem. The interesting thing: they do so also in winter, with dust, moisture and salt. They could at all be compatible with the ones actually coming out of the regulator, so any On-Road hot swap could still be possible.

 

Hubert

[docc]

Oh, yeah, it's getting hot allright. This fuse was only in for the sustained 750 mile 3 day ride. I'm taking the hot off my junction block and going straight back to the battery. It looks to be only about 16 guage wire ( maybe 14?) from the 30A fuse to the battery where it is twinned to the yellow/black which goes back to the fuses for the lamps and ignition switch. The red crosses from left to right and back to the positive terminal then the ylw/blk crosses back to the right and over left again to the fuse block. Maybe larger wire with a shorter run would minimize the resistance ?

[badmotogoozer]

If the fuse is physically hot (as is obvious from photo) the problem is always where the heat is. I would expect a poor contact right at the fuse holder. A poor contact has resistance. Add 20 amps of current and you have heat. There should be no resistance in a fuse or in the wire itself (OK there is but it is negligeble). This is a bad connection somewhere and I would sus the connections themselves.

 

Going to a larger gage wire or a shorter wire will not fix the problem unless you happen to fix the poor connection when replacing the wire.

 

Only one side of your fuse is melting - I'd start right there.

 

Rj

[luhbo]

When your fuse once was as hot as displayed on this picture you've probably lost the game already.

 

The fuse socket is made of cheap tinned brass and has lost now probably most of its hardness, due to to the excessive heat. This means no good conditions for contact resistance. Try to clean every part of the related surfaces, maybe some sort of agressive contact spray that removes oxide layers could help here.

 

Or go for gold. That'll be one of my next actions.

 

Hubert

[docc]

Thanks, Hubert and Ryan. I'll use some contact cleaner in the connection this morning.

 

 

 

EDIT: Well, I've cleaned them and tightened them up a bit. Hubert's concern about the softness of the metal seems likley. Also , the connections are slightly over 3mm while the fuse blades are 5mm. This hardly seems rated for 27amps. Is going gold enough or should the connectors be 5mm?

 

And to use larger connectors wouldn't the fuse have to be outside the fuse block?