Fusebox upgrade

[Dark Skies]

I've been getting a number of dud glass fuses recently - poorly soldered where the wire joins the end caps. I've tried a couple of sources but I'm guessing they get them from the same supplier because a number in these packets are scrap too. This coupled with the fact that you don't find glass fuses in garages these days prompted me to consider updating my fusebox to one that accepts the commonly found plastic cartridge type as found on modern bikes.

The only problem I can see with this is selecting the equivalent fuses.

Glass fuses are usually rated at the current that will cause them to fuse. So a fuse rated 10 amp will blow at 10 amp.

Cartridge fuses are usually rated for the current they will continually pass and will generally blow at double that rate. So a 10 amp fuse will actually blow at 20 amp.

Apart from one fuse rated at 30 amps all the rest of my glass fuses are rated at 10 amp. If I replace them all with cartridge type fuses then to get them to blow at the same rate I'd need one rated at 15 amp and the rest at 5 amp. Given the wiring in the harness they protect is a little over 8 amp and 17 amp plus some heavy duty stuff on the starter side of things does this sound about right to any electricians on this board?

Anyone else carried out this mod?

Cheers.

[tlc]

Sounds spot on to me.

Don`t forget though that any resistance in the circuit will cause the amperage to increase.

Also that a low battery voltage will have the same effect.

Can you check with the 10A setting on a multimeter what the various wires are drawing under load ? It may be that you don`t need to change the fuses rather change wires or connectors to reduce resistance !

[Taffus]

I am about to do it, I think you are talking about tolarences for the blow. some fuses are "slow blow" others are quick acting
datasheet here https://www1.elfa.se/data1/wwwroot/webroot/Z_DATA/6afa7f00-75a4-11dc-b309-005056c00008.pdf

I 'll have a deeper look over then next .......after I find my self induced carb fault

[Dark Skies]

Sounds spot on to me.

Don`t forget though that any resistance in the circuit will cause the amperage to increase.

Also that a low battery voltage will have the same effect.

Can you check with the 10A setting on a multimeter what the various wires are drawing under load ? It may be that you don`t need to change the fuses rather change wires or connectors to reduce resistance !

I investigated along these lines but found the problem lay with the fuses themselves. The wiring is all good. Connections all clean. Battery charged. But if you grasp one of the newly purchased fuses by the metal end cap you can lift it off as easily as you would take a cap off a Biro. Looking inside the cap I find oxidised fuselink that was only just hanging on to the cap end where it had been crapily sweated on. I bought about thirty from various sources and at least half are crap.

[Taffus]

Sounds like the fuse caps have "dry joints". This when solder crystalises , you can get round it by resoldering the connection. A good soldered connection should be shiney or bright not dull grey

Made a fortune in the 80 's repairing TV's and videos with these faults....

[Dark Skies]

I am about to do it, I think you are talking about tolarences for the blow. some fuses are "slow blow" others are quick acting
datasheet here https://www1.elfa.se/data1/wwwroot/webroot/Z_DATA/6afa7f00-75a4-11dc-b309-005056c00008.pdf

I 'll have a deeper look over then next .......after I find my self induced carb fault

A very useful link. Cheers. Quick blow are the ones we'd need for bike systems. Slow blow fuses are intended for items that are expected to occasionaly take a bigger draw than they usually do and therefore have a bit of leeway before actually blowing. Things like fuses for electric windows for instance. Mostly the draw will be within normal spec. However, every now and then a motor might have to work harder - like when a window is frosted to the frame in cold weather. The slow blow fuses will cut a little slack if the draw exceeds the usual momentarily and only go if you continue to lean on the switch if the window sticks.

The only thing that makes me think my rough and ready reckoner might be slightly out is the fact that the modern fuses in my Triumph's system are rated so much higher for like for like circuits such as the rear and front lights. I'd expected them to be within the same ballpark figure - roughly half the rating of my old glass tube fuses. I have so many fuse standards and electrc theorems running round my head that I actually feel less certain as to how to go about it. My wife suggested the most sensible (albeit laborious and expensive) approach. "work out what you think is about right and then stick in a lesser fuse by a few amps. Keep blowing them until you reach your original figure and hopefully don't blow any more fuses."

It has to be said that my wife also seems to employ this approach to parking her car too. Keep trying gaps until you find a space where you don't scratch the panels .

[Taffus]

Ah , my wife does "contact parking" don't ask

But back to fuses, these old bike are relatively simple electrically eg my kettle had 1 fuse! my gpz has five though this could be a bad example as it has had a carb conversion and the electrical work is somewhat "interesting"

I have bought a 6 way blade fuse box I'll try and do some testing by connecting up to power supplies ( I was an electronics engineer in a former life!)

[Dark Skies]

Sounds like the fuse caps have "dry joints". This when solder crystalises , you can get round it by resoldering the connection. A good soldered connection should be shiney or bright not dull grey

I could try but it's a bit fiddly and it'd be difficult to be sure it really took. What I've been doing is pulling the end off the tube, chucking the fusible link, punching a small hole in the caps, popping them on the tube, passing some 10 amp fuse wire end to end and soldering in place. But it's a total pain when they should just work right out the box.

[Dark Skies]

Ah , my wife does "contact parking" don't ask

But back to fuses, these old bike are relatively simple electrically eg my kettle had 1 fuse! my gpz has five though this could be a bad example as it has had a carb conversion and the electrical work is somewhat "interesting"

I have bought a 6 way blade fuse box I'll try and do some testing by connecting up to power supplies ( I was an electronics engineer in a former life!)

Five seems to be about right for Kawas of our era. My CSR has five fuses in the main box plus two unused spare fuse holders on a rubber mounted block for accessories. I suspect that's because the very similar US police bikes share the same wiring harness.

[Taffus]

Yes, been toying with the idea of getting a 1000j harness and losing the b1 one but I am pretty far into sorting it now, can't help just enjoying working on it

[tlc]

It has to be said that my wife also seems to employ this approach to parking her car too. Keep trying gaps until you find a space where you don't scratch the panels .

I think I`ve seen her

[compo z1r]

D-S have you got a jet ski club or shop near you being a jet skier my self
jet skis have glass tube fuses as the engines run in water and cannot use cartrige type for that reason they are of top grade and makes .will be more cash than bike fuses but hay