Ignition Switch Amperage Rating?

[sp838]

Hello all. I want to replace my keyed ignition switch with something simpler and more compact (no parking light position, not fork lock.)

 

Does anyone know what the switch rating is? How much juice runs through it during operation of the bike? I looked in the manual and couldn't find any specs for the switch itself. Tried to glean some info on it from the wiring diagram, but all I could see (if I read this correctly) is that it is on a circuit with a 10 A fuse...

 

I am looking at a waterproof switch that is rated up to 3A / 250VDC, would that be adequate?

 

Thanks!

[sp838]

Thanks docc. Question for the electrically literate (i.e. not me): if a switch is rated for 3A / 250VDC, shouldn't it be able to handle 10A at 14VDC? Ohm's law and all that stuff? Please pardon my ignorance... But if I do understand correctly, amperage, wattage and voltage are all related, so at lower voltage, shouldn't it be able to handle higher amperage? Or am I totally missing something here?

[docc]

Ah, sorry I didn't see the unique voltage. I was too busy revising my post, looking up bulb ratings, checking my math and squinting at the wiring diagram.

 

K_Roy is gonna get us straightened out on this and is definitely the best qualified to address the 250vDC question. My understanding is that as DC voltage goes up, wire size can be reduced. Not sure of that means the contact surfaces have been reduced similarly in your switch, but it would explain how it could be much smaller.

[Kiwi_Roy]

No as the Voltage goes up the current reduced for a certain wattage Watts = Volts x Amps but as the Voltage is fixed by the battery to 12 Volts the current stays the same.

Having said that often a switch contact has a higher current rating at a lower voltage

 

I think the normal current would be about 5 Amps, let me look at the schematic. Are we talking V11 Sport?

Most Guzzis including some V11 Sports pass the start solenoid current through the switch, that's about 40 - 50 Amps but only for about 1/10th of a second.

If you want to use a smaller switch you could add a relay somewhere between the battery and the loads using that to switch the heavy current, the standard Guzzi relays are rated at 60 Amps from memory.

The relay coils only draw 0.1 Amps

 

I looked at my 02 manual, it's quite unusual in the starter solenoid is not through the switch, the biggest load is the direction indicators and that's only intermittent.

 

If your switch is fed from a 10 amp fuse it's like mine, the start relay current bypasses the switch. the only steady current through it is the tail light, Electric petcock and a couple of relays, I think your 3 Amp switch will be fine.

Since you won't have a park light you can just connect the wires from 2 & 4 (J & L) together and use a single pole switch.

What was wrong with the original switch, they do need cleaning after 10 years at least mine did but 

 

A simplified schematic I based on the wiring of my V11, it doesn't show all the lighting detail, just the stuff that makes it run. Luigi got this one right IMHO, the heavy solenoid current (well over 40 Amps) goes through fuse 5, the relay and straight to the solenoid bypassing the switch. Fuse 5 also supplies the headlight, the other main load. The unusual feature of this wiring is the headlight current passes through 2 relays in series, other guzzis just switch the headlight relay coil with the start relay.

[sp838]

Kiwi_Roy, you are a gem. Thanks a lot. I am thinking I will go with the relay route just to be safe.

 

Thank you all, and best wishes for the holidays!

[helicopterjim R.I.P.]

Kiwi Roy's Global Guzzi Electric Call Centre ...... what would we do without him?

[docc]

Kiwi Roy's Global Guzzi Electric Call Centre ...... what would we do without him?

  I can see the classified ad:

 

Low mile V11, needs wiring harness, small undertank fire;  bike located some distance from here, but was pretty well hidden when I walked home . . .

[helicopterjim R.I.P.]

 

  I can see the classified ad:

 

Low mile V11, needs wiring harness, small undertank fire;  bike located some distance from here, but was pretty well hidden when I walked home . . .

 

 

 .... or even better .... tank located some distance from bike ...... I think it landed in some shrubs!!

[gstallons]

Kiwi_Roy, you are a gem. Thanks a lot. I am thinking I will go with the relay route just to be safe.

 

Thank you all, and best wishes for the holidays!

 

Kiwi_Roy, you are a gem. Thanks a lot. I am thinking I will go with the relay route just to be safe.

 

Thank you all, and best wishes for the holidays

 

Using relays to turn on a device is always better than using the switch to carry the current to power to the load .  A manufacturer should do this at all  opportunities but added costs factor into this . You know what wins = cost . 

  If you have enough time , resources, etc.... you should add the relays .