Headlamps relays

Nigel T · 1 Headlamps relays - mounting point? Sat Feb 13, 2016 5:04 pm

Nigel T

Silver member

Number of posts : 64

Hi,
I have bought all the components, as recommended by this Forum, to protect the switches, improve the headlamp wiring and light output on my K100RS. I bought the RS for its fairing so have no intention of removing it while I own the bike!
I am proposing to mount the relays in the fairing on the black moulding panel shown in the centre of the photo below:

Headlamps relays - mounting point? PhotoChooser-e19786aa-4f44-42be-910a-11af9e3e5fc2

Seems like a dry and protected location, with ample space to install the set up. Anyone see a reason why this would not work or anything I need to be aware of?
Many thanks!
Regards
Nigel

indian036 · 2 Re: Headlamps relays - mounting point? Sat Feb 13, 2016 8:11 pm

indian036

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Number of posts : 1465

I can't see any problems with that location.

To be aware of:

wiring heavy enough to carry the load from power source to relay and relay to light. A 100W bulb (as I use) draws a shade over 8A. The wire roll should indicate current capacity. I'd go for a safety factor and use wire of 12-15A+ capacity
Routing of wire where it won't be subject to excessive heat or chafing from steering movement
A fuse somewhere in the supply line, whether you take it from a fused source or put in a separate one. I used separate relays for high and low beam, each with an integrated fuse. (You can get a combined relay, but 2 separate is easy and cheap.) I installed them outside the relay box under the left side cover, either side of the main fuse block. That way all my fuses are together.

You probably have all the above covered, but just in case, and in case someone else is researching the use of light relays.

I chose to solder as well as crimp my connections, but others said plain crimp is better, due to possible wire fatigue breakage where the solder starts. Good routing and wire support should avoid that problem, and I have seen crimped wire connectors go high resistance and let go as well. Belt and braces for me!

Relay(s) is definitely a good move. Replacing burned out light and high/low switches is expensive. In the unlikely event you burn out a relay, its cheap.

Bill

duck · 3 Re: Headlamps relays - mounting point? Sat Feb 13, 2016 9:15 pm

duck

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Number of posts : 4462

I usually just leave them loose in the relay box. If you have an early relay box it will have some additional empty relay mounting spots for some of the early electrical options.

All of my bikes have an auxiliary 4 fuse block mounted next to the factory one. I really DESPISE in-line style fuses and having all of the fuses mounted together makes sense to me.

Headlamps relays - mounting point? Auxfus3

Headlamps relays - mounting point? Auxfus3

Holister · 4 Re: Headlamps relays - mounting point? Sun Feb 14, 2016 12:20 am

Holister

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Number of posts : 2491

I just bought a plug 'n play kit off ebay for $17 delivered. H4, ceramic connector, fused, 40A relays.
Its for a car but I figured I could use it for a dual headlight or run the LED spots of the other. I'll also shorten the leads so its a bit neater.
My machine is naked so I was going to locate the relays in the electrical box, probably just loose. Obviously the closer you can get the relays to the lamp the better.

indian036 · 5 Re: Headlamps relays - mounting point? Sun Feb 14, 2016 12:33 am

indian036

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Number of posts : 1465

Kaptain Holister wrote:
My machine is naked so I was going to locate the relays in the electrical box, probably just loose. Obviously the closer you can get the relays to the lamp the better.

Actually, power needs to come from battery or fuse/relay box to lights via the relay. A fairly direct shortest line between power source and headlight is best - easily done with the tank off, but the relay can be anywhere along that line. Site it for convenience of installation.

Bill

Holister · 6 Re: Headlamps relays - mounting point? Sun Feb 14, 2016 12:46 am

Holister

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Number of posts : 2491

Quite correct Bill, now I think about it.
Cheers

Nigel T · 7 Re: Headlamps relays - mounting point? Sun Feb 14, 2016 4:39 am

Nigel T

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Number of posts : 64

Thanks for all your comments and advice.

Cable is 33A, and I have a fuse holder and ceramic headlight connector in the bag too. I am going to crimp and solder, and have wasted a number of old connectors and scrap cable over the last weekend practising!

Good advice on the relay box Duck, I will take a look at that later.

Regards
Nigel

duck · 8 Re: Headlamps relays - mounting point? Sun Feb 14, 2016 6:09 am

duck

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Number of posts : 4462

And what good is a headlight relay thread without a plug for my friend Jim Davis (former K100RS owner) who owns Eastern Beaver?

http://www.easternbeaver.com/Main/Wiring_Kits/H4_Kits/h4_kits.html

Jim is well known for selling quality MC electronics.

charlie99 · 9 Re: Headlamps relays - mounting point? Sun Feb 14, 2016 7:31 am

charlie99

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Number of posts : 11701

indeed ...highly recommended in here

duck · 10 Re: Headlamps relays - mounting point? Sun Feb 14, 2016 8:20 am

duck

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Nigel T wrote:Good advice on the relay box Duck, I will take a look at that later.

Here's some more detail on how I do that:

http://www.kbikeparts.com/classickbikes.com/ckb.tech/0.ckb.tech.files/auxfuse/auxfuse.htm

You need to do some relay reorganization to get the flasher relay out of the way but I like the end results.

92KK 84WW Olaf · 11 Re: Headlamps relays - mounting point? Sun Feb 14, 2016 9:55 am

92KK 84WW Olaf

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Number of posts : 7967

You can get 160W H4 bulbs which I have in the car, I tried one in the K100 and it was awesome. You can aim it low to avoid causing dazzle but its still very impressive.

I haven't got around to putting in the relays [one for low and ne for high beam] yet so did not leave the 160W in. Will do it soon. Otherwise it will burn out the handlebar switches. I decided on 2 separate relays with separate power supplies even though I could get one relay to do both. I felt two separate relays eliminate possibility of relay or relay supply fuse fault suddenly leaving me with no lights.

But if you upgrade you MUST use the ceramic bulb holder as mentioned. If you use your K like the rest of us on long distance night runs the high power bulb will heat up a cable if its too low capacity. 33A cable is good.

Nigel T · 12 Re: Headlamps relays - mounting point? Mon Feb 15, 2016 5:02 pm

Nigel T

Silver member

Number of posts : 64

I will go with Duck's suggestion to locate the relays in the Relay box, makes sense really...

Thinking through the wiring route it occurred to me that a new thicker gauge earth cable should be wired in down to the earthing point on the frame. I had previously thought the earth could be back through the original wiring but surely that goes back to the original problem of the wiring being too lightweight...?

Again comments to confirm thicker earth cable is required and where you have secured the earth cable would be appreciated.
Many thanks!
Regards
Nigel

indian036 · 13 Re: Headlamps relays - mounting point? Mon Feb 15, 2016 5:16 pm

indian036

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Number of posts : 1465

Heavier earth wire is indeed essential to not have higher wire resistance in that part. The result would be lower current through the bulb and some of the supply voltage being across the wire rather than all at the bulb. Not to the point of candle light levels, but why not take full advantage of the better wiring?

Smaller earth wire is not as serious as on the power supply side, as the switches are the potentially expensive weak point there. The fuse will prevent fried wire.

If you are using 33A wire for the earth as well, it won't make a lot of difference exactly where it is attached to the frame. Most important is to ensure there is a good connection - tight bolt, clean contact. Same applies to any/all earth connections.

Bill

88 · 14 Re: Headlamps relays - mounting point? Mon Feb 15, 2016 6:06 pm

88

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Number of posts : 3171

All of my bikes have an auxiliary 4 fuse block mounted next to the factory one. I really DESPISE in-line style fuses and having all of the fuses mounted together makes sense to me.

Very neat and the labelling is a great idea. Thanks Duck!

duck · 15 Re: Headlamps relays - mounting point? Mon Feb 15, 2016 6:39 pm

duck

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indian036 wrote:Smaller earth wire is not as serious as on the power supply side,

Sorry but you are just plain wrong here. The same number of electrons pass through both the positive and negative leads. Assuming similar lengths, the thinner wire will always be the weaker link.

robmack · 16 Re: Headlamps relays - mounting point? Mon Feb 15, 2016 7:18 pm

robmack

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Nigel T wrote:Again comments to confirm thicker earth cable is required and where you have secured the earth cable would be appreciated.

The return wire has to be sized the same as the source wires, because the same current flows through it on its way back to the negative terminal of the battery.

I locate my return from the headlight to the ground connection under the tank. It's the nearest point to the headlight shell, resulting in the shortest length wire.

Last edited by robmack on Mon Feb 15, 2016 8:32 pm; edited 2 times in total

duck · 17 Re: Headlamps relays - mounting point? Mon Feb 15, 2016 8:30 pm

duck

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The frame ground under the tank is also the most convenient IMO.

Gaz · 18 Re: Headlamps relays - mounting point? Tue Feb 16, 2016 4:46 am

Gaz

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This post is not adding anything to the relay mounting discussion but while people are thinking about headlights maybe someone can answer this ..........

Is there any particular logic behind BMW's decision not to place a fuse in the headlight circuit?

and

Is it typical amongst other brands of bikes to not have a fuse in the headlight circuit?

Looking forward to hearing from the assembled brainstrust.

Thanks

indian036 · 19 Re: Headlamps relays - mounting point? Tue Feb 16, 2016 5:04 am

indian036

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Number of posts : 1465

duck wrote:

indian036 wrote:Smaller earth wire is not as serious as on the power supply side,

Sorry but you are just plain wrong here. The same number of electrons pass through both the positive and negative leads. Assuming similar lengths, the thinner wire will always be the weaker link.

Duck, I started my post with "Heavier earth wire is indeed essential".

The reference to smaller earth wire being not as serious only refers to the vulnerability of the switches to higher currents, vs higher currents in a smaller wire. In this scenario, I believe the switches are the weaker link.

Bill

Last edited by indian036 on Tue Feb 16, 2016 5:18 am; edited 1 time in total

indian036 · 20 Re: Headlamps relays - mounting point? Tue Feb 16, 2016 5:15 am

indian036

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Number of posts : 1465

Gaz80 wrote:Is there any particular logic behind BMW's decision not to place a fuse in the headlight circuit?

and

Is it typical amongst other brands of bikes to not have a fuse in the headlight circuit?

Looking forward to hearing from the assembled brainstrust.

Thanks

The only "logic" - somewhat questionable - is that the bulb itself could act as a fuse, but a fault between power source and bulb would have no protection. I don't think much of this logic, as the filament material and its inert gas environment mean it won't function nearly as well a a properly designed fuse.
Such design can get involved, such as the size of the hole an old fashioned household wire fuse goes through affects the current and blow characteristics of the fuse. As a sparky, you probably know this better than me.
No knowledge of other brand's practices.

Bill

Holister · 21 Re: Headlamps relays - mounting point? Tue Feb 16, 2016 7:44 am

Holister

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Number of posts : 2491

Gaz80 wrote:This post is not adding anything to the relay mounting discussion but while people are thinking about headlights maybe someone can answer this ..........

Is there any particular logic behind BMW's decision not to place a fuse in the headlight circuit?

and

Is it typical amongst other brands of bikes to not have a fuse in the headlight circuit?

Looking forward to hearing from the assembled brainstrust.

Thanks

I reckon it's a safety issue. If the fuse blows (and they can blow for no reason in particular) you are suddenly without lights.

This happened to me one night many many years ago on my little ducati. The battery bracket broke free. The battery moved to one side stressing the cable which snapped just as I was tearing round a r/h sweeper thru a cutting. Lights out... no engine... ended up in the ditch... unhurt thankfully.

robmack · 22 Re: Headlamps relays - mounting point? Tue Feb 16, 2016 8:42 am

robmack

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Headlight is protected with Fuse #2 -- trace the circuit (fuse 2-> grey -> ignition sw. -> grey/blue > headlight sw. -> white/yellow -> hi/lo sw. -> headlight -> ground).

It should be mentioned that fuses protect wiring, not necessarily loads. The fuse should be sized to blow at a current draw that is below the maximum designed value for the size of wiring used in the circuit. Loads are designed to normally draw less than the fused current, but sometimes circuits are over-committed (ie. designed with loads that, if all used, could draw >100% of the fused current).

Dai · 23 Re: Headlamps relays - mounting point? Tue Feb 16, 2016 8:53 am

Dai

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Gaz80 wrote:Is it typical amongst other brands of bikes to not have a fuse in the headlight circuit?

No it's not. I was almost shocked to find BMW taking this route. Then again, IMHO some of the decisions BMW made when designing the wiring loom are very questionable; so much so that when I rewired LFB I very nearly succumbed to redesigning the loom from scratch.

Inge K. · 24 Re: Headlamps relays - mounting point? Tue Feb 16, 2016 11:30 am

Inge K.

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robmack wrote:Headlight is protected with Fuse #2 -- trace the circuit (fuse 2-> grey -> ignition sw. -> grey/blue > headlight sw. -> white/yellow -> hi/lo sw. -> headlight -> ground).

It's the other way around....from the ignition switch the grey wire goes to fuse #2............and protects tail lamp and park lamp, not the headlight.

robmack · 25 Re: Headlamps relays - mounting point? Tue Feb 16, 2016 12:56 pm

robmack

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Oops.

Nigel T · 26 Re: Headlamps relays - mounting point? Tue Feb 16, 2016 4:42 pm

Nigel T

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Number of posts : 64

Many thanks! Good advice all! I will be going for Relays in the relay box, using decent gauge cable throughout with the earth point under the tank.

Just got to find that earth point, if anyone can provide a picture of where it is that would be gratefully received, but this also seems like a good excuse to get in and clean up all the connectors under the tank with some contact cleaner.

Regards
Nigel

Inge K. · 27 Re: Headlamps relays - mounting point? Tue Feb 16, 2016 5:17 pm

Inge K.

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Nigel T wrote:Just got to find that earth point, if anyone can provide a picture

Look in the start of the troubleshooting diagram at the portal.

Holister · 28 Re: Headlamps relays - mounting point? Tue Feb 16, 2016 7:31 pm

Holister

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Number of posts : 2491

Earth connection is just under the main spar here...

Headlamps relays - mounting point? Under_10

My $17 headlight relay harness (post #4) arrived yesterday. Not bad quality. Very easy to install but I'll need to tidy it up when I get back from the Snowy Run this weekend. Works a treat. Very Happy

Needed to get that in as I've just installed a higher wattage headlight and my hi-beam switch has been playing up occassionally.... another job to do.

duck · 29 Re: Headlamps relays - mounting point? Wed Feb 17, 2016 12:48 am

duck

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Oh my, that sure is a clean frame. Do you ever actually take the bike out and ride it? Laughing

Point-Seven-five · 30 Re: Headlamps relays - mounting point? Wed Feb 17, 2016 1:21 am

Point-Seven-five

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duck wrote:Oh my, that sure is a clean frame. Do you ever actually take the bike out and ride it?

I thought I was the only one who noticed how clean that frame looked.

Holister · 31 Re: Headlamps relays - mounting point? Wed Feb 17, 2016 3:12 am

Holister

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Number of posts : 2491

Point-Seven-five wrote:

duck wrote:Oh my, that sure is a clean frame. Do you ever actually take the bike out and ride it?

I thought I was the only one who noticed how clean that frame looked.

10,000km over the past 3 months. Most of that was late Nov thru to mid Jan. I'll clock another 3,000km over the coming week and a half.

Pretty sure I wiped it down before I snapped that photo anyway.

Cheers

Point-Seven-five · 32 Re: Headlamps relays - mounting point? Wed Feb 17, 2016 10:03 am

Point-Seven-five

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How would you like to borrow one of my bricks for a couple thousand klicks? The RT could use a bit of detailing..

Nigel T · 33 Re: Headlamps relays - mounting point? Wed Feb 17, 2016 5:32 pm

Nigel T

Silver member

Number of posts : 64

Kaptain Holister wrote:

Point-Seven-five wrote:

duck wrote:Oh my, that sure is a clean frame. Do you ever actually take the bike out and ride it?

I thought I was the only one who noticed how clean that frame looked.

10,000km over the past 3 months. Most of that was late Nov thru to mid Jan. I'll clock another 3,000km over the coming week and a half.

Pretty sure I wiped it down before I snapped that photo anyway.

Cheers

Kaptain!
I reckon you have even been polishing the rubbers that the tank sits on! Out of sight out of mind as far as I am concerned... Many thanks for the image, spot on!
Regards
Nigel

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1 Headlamps relays - mounting point? Sat Feb 13, 2016 5:04 pm

Nigel T

2 Re: Headlamps relays - mounting point? Sat Feb 13, 2016 8:11 pm

indian036

3 Re: Headlamps relays - mounting point? Sat Feb 13, 2016 9:15 pm

duck

4 Re: Headlamps relays - mounting point? Sun Feb 14, 2016 12:20 am

Holister

5 Re: Headlamps relays - mounting point? Sun Feb 14, 2016 12:33 am

indian036

6 Re: Headlamps relays - mounting point? Sun Feb 14, 2016 12:46 am

Holister

7 Re: Headlamps relays - mounting point? Sun Feb 14, 2016 4:39 am

Nigel T

8 Re: Headlamps relays - mounting point? Sun Feb 14, 2016 6:09 am

duck

9 Re: Headlamps relays - mounting point? Sun Feb 14, 2016 7:31 am

charlie99

10 Re: Headlamps relays - mounting point? Sun Feb 14, 2016 8:20 am

duck

11 Re: Headlamps relays - mounting point? Sun Feb 14, 2016 9:55 am

92KK 84WW Olaf

12 Re: Headlamps relays - mounting point? Mon Feb 15, 2016 5:02 pm

Nigel T

13 Re: Headlamps relays - mounting point? Mon Feb 15, 2016 5:16 pm

indian036

14 Re: Headlamps relays - mounting point? Mon Feb 15, 2016 6:06 pm

88

15 Re: Headlamps relays - mounting point? Mon Feb 15, 2016 6:39 pm

duck

16 Re: Headlamps relays - mounting point? Mon Feb 15, 2016 7:18 pm

robmack

17 Re: Headlamps relays - mounting point? Mon Feb 15, 2016 8:30 pm

duck

18 Re: Headlamps relays - mounting point? Tue Feb 16, 2016 4:46 am

Gaz

19 Re: Headlamps relays - mounting point? Tue Feb 16, 2016 5:04 am

indian036

20 Re: Headlamps relays - mounting point? Tue Feb 16, 2016 5:15 am

indian036

21 Re: Headlamps relays - mounting point? Tue Feb 16, 2016 7:44 am

Holister

22 Re: Headlamps relays - mounting point? Tue Feb 16, 2016 8:42 am

robmack

23 Re: Headlamps relays - mounting point? Tue Feb 16, 2016 8:53 am

Dai

24 Re: Headlamps relays - mounting point? Tue Feb 16, 2016 11:30 am

Inge K.

25 Re: Headlamps relays - mounting point? Tue Feb 16, 2016 12:56 pm

robmack

26 Re: Headlamps relays - mounting point? Tue Feb 16, 2016 4:42 pm

Nigel T

27 Re: Headlamps relays - mounting point? Tue Feb 16, 2016 5:17 pm

Inge K.

28 Re: Headlamps relays - mounting point? Tue Feb 16, 2016 7:31 pm

Holister

29 Re: Headlamps relays - mounting point? Wed Feb 17, 2016 12:48 am

duck

30 Re: Headlamps relays - mounting point? Wed Feb 17, 2016 1:21 am

Point-Seven-five

31 Re: Headlamps relays - mounting point? Wed Feb 17, 2016 3:12 am

Holister

32 Re: Headlamps relays - mounting point? Wed Feb 17, 2016 10:03 am

Point-Seven-five

33 Re: Headlamps relays - mounting point? Wed Feb 17, 2016 5:32 pm

Nigel T

34 Re: Headlamps relays - mounting point?

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