BMW K bikes (Bricks)

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1Back to top Go down   Dash switch current rating Empty Dash switch current rating on Sun Jun 14, 2020 4:57 am

Gaz

Gaz
Life time member
Life time member
Has anybody out there in this great forum ever found info on the current rating of our K bike dash switches?

I'm confident that Duck is the man to help me with this info - are you out there mate? ...... or anyone else.

Cheers


__________________________________________________
Gaz
1990 K75 6427509; 1987 R80G/S PD 6292136; 2010 G650GS ZW13381; 95 K1100LT 0232224
    

2Back to top Go down   Dash switch current rating Empty Re: Dash switch current rating on Sun Jun 14, 2020 6:42 am

Dai

Dai
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Life time member
Having dismantled a few and comparing them to the contact area of known Japanese switches, you're looking at a minimum of ten amps for the copper. What I don't know is if the heat of putting ten amps through them will affect the plastic. I'd stick to 5 amps (60 watts) as I'm reasonably confident that would be okay.

OTOH there's always a relay Very Happy


__________________________________________________
1983 K100 upgraded to K100RS spec, 1987 K100RT
Others...
1978 Moto Guzzi 850-T3, 1979 Moto Guzzi 850-T3 California,1993 Moto Guzzi 1100ie California
2020 Royal Enfield Bullet 500
    

3Back to top Go down   Dash switch current rating Empty switch on Sun Jun 14, 2020 8:09 am

daveson

daveson
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New member
I've used a switch from the car wreckers (I think it was from a Mitsubishi) for a hazard switch. It works, but I've never measured the current.

    

4Back to top Go down   Dash switch current rating Empty Re: Dash switch current rating on Sun Jun 14, 2020 9:49 pm

Gaz

Gaz
Life time member
Life time member
Thanks guys.

Dai, I'm normally a relay guy as well but I'm fiddling with my 650 and may want to switch some LEDs directly with a load of only 20 watts so much simpler to just use a switch. Like you I have disassembled and resurrected many of our K bike rocker switches and agree with your thoughts on their contact size/potential rating but just thought I'd look for some support of my thoughts from the forum.

Cheers


__________________________________________________
Gaz
1990 K75 6427509; 1987 R80G/S PD 6292136; 2010 G650GS ZW13381; 95 K1100LT 0232224
    

5Back to top Go down   Dash switch current rating Empty Re: Dash switch current rating on Sun Jun 14, 2020 10:31 pm

MartinW

MartinW
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Life time member
Wattage divided by voltage gives you amperage. So 20 divided by 12 equals 1.66666 Amps which is stuff all.
Regards Martin.


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K75s Hybrid
    

6Back to top Go down   Dash switch current rating Empty Re: Dash switch current rating on Mon Jun 15, 2020 6:19 am

92KK 84WW Olaf

avatar
Life time member
Life time member
On my K...

Hazard has a relay.
ABS has a relay.
Heated grips have relay.
Screen has relay ??

Design ratings may not be high.


__________________________________________________
1992 K100LT 0193214 Bertha Blue 101,000 miles
1984 K100RT 0022575 Brutus Baja Red 578 bought 36,000 now 89,150 miles
1997 K1100LT 0188024 Wotan Mystic Red 689 58,645 now 106,950 miles Deceased.
1983 K100RS 0011171 Fricka 606 Alaska Blue 29,495 miles Damn K Pox Its a Bat outta Hell Now 37,190 miles
1996 K1100LT 0233004 Lohengrin Mystic Red 38,000 miles.
    

7Back to top Go down   Dash switch current rating Empty Re: Dash switch current rating on Mon Jun 15, 2020 8:38 am

Dai

Dai
Life time member
Life time member
Screen has two relays: up and down. All those you've quoted, Olaf, aren't particularly high-current users. Off the top of my head:

Heated grips: 4 - 5 amps
Screen: 7 amps
ABS: deity only knows but it's a 15amp fuse, so probably somewhere in the region of ten amps
Hazard: just under 8 amps. Normally the K doesn't have a relay for this - it's just 'crossed wires'.

Yer standard headlight on full beam is 5 amps.

The biggest problem at those currents are contacts that are dirty or covered with copper oxide until it all just stops working. However, (with the exception of the grips) in their favour they are all intermittant loads with a cooldown period between loading, so overheating is not normally a problem. Having said all that, the inrush/surge current as the screen motor starts up definately needs a relay. Can't speak for the ABS (don't have it) but I'd guess that has an inrush problem too as the motors start up.


__________________________________________________
1983 K100 upgraded to K100RS spec, 1987 K100RT
Others...
1978 Moto Guzzi 850-T3, 1979 Moto Guzzi 850-T3 California,1993 Moto Guzzi 1100ie California
2020 Royal Enfield Bullet 500
    

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