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BMGraeme Flying Brick Rider
Joined: 14 Mar 2006 Posts: 373 Location: Marlborough, United Kingdom
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Posted: Mon Jan 17, 2011 4:49 pm Post subject: Too much for an earth? |
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Not having had to consider this before and realising it might be a daft question but here goes. I'm fitting a pair of fogs and spots to the K11RS., total draw about 20amps. In the process I thought I would make the wiring up front a little neater in readiness to install a simple fuse block somewhere up around the headlight area. A number of years ago I fitted a headlamp relay from Eastern Beaver and in the process of the tidying up stripped back the connections I made at the time, revealing an unused earth lead that I had forgotten all about. Now, I need to earth the fogs and spots and this earth is positioned perfectly where I could tap the 4 earths into. This would save having to route the cables up to the main frame earth under the tank. So my daft question is - is this too much to put onto one, not exactly huge diametre earth wire?
My logic is telling me this is fine but thought I had better ask the collective. Thanks in advance. _________________ 1980 CB900FA
1994 K1100RS
2008 R1200GSA |
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Scott_Anderson Site Admin
Joined: 05 Sep 2006 Posts: 3122 Location: Central Iowa, USA
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Posted: Mon Jan 17, 2011 4:57 pm Post subject: |
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Well, if your load is actually going to be in the 20A range you are going to want a wire at least 15AWG size or 12AWG size would be better.
I wouldn't try to tap them into the tail you have hanging there as most likely it's not big enough. _________________ Ride safe.
1995 K1100LT 0302044
2017 FLHTK Ultra Limited
Garmin StreetPilot 2820
Garmin Zumo 550
Garmin Zumo XT
"One who does not ask questions is ashamed to learn" Danish proverb
1997 K1100LT 0302488(R.I.P.)
1997 R1100RT ZC62149(sold) |
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BMGraeme Flying Brick Rider
Joined: 14 Mar 2006 Posts: 373 Location: Marlborough, United Kingdom
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Posted: Mon Jan 17, 2011 5:10 pm Post subject: |
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| Scott_Anderson wrote: | Well, if your load is actually going to be in the 20A range you are going to want a wire at least 15AWG size or 12AWG size would be better.
I wouldn't try to tap them into the tail you have hanging there as most likely it's not big enough. |
Yeah, having thought about it a bit more I'm thinking I should split the load. It's unlikely, but possible, that I could have the fogs and the spots on at the same time albeit briefly. _________________ 1980 CB900FA
1994 K1100RS
2008 R1200GSA |
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Scott_Anderson Site Admin
Joined: 05 Sep 2006 Posts: 3122 Location: Central Iowa, USA
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Posted: Mon Jan 17, 2011 5:15 pm Post subject: |
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Not sure about your road rules over there, but here where I am at we are allowed only 2 acc lights lit at any one time.
I have my driving acc lights and fog lights wired to a 3-way switch so I can only have one set on at a time. _________________ Ride safe.
1995 K1100LT 0302044
2017 FLHTK Ultra Limited
Garmin StreetPilot 2820
Garmin Zumo 550
Garmin Zumo XT
"One who does not ask questions is ashamed to learn" Danish proverb
1997 K1100LT 0302488(R.I.P.)
1997 R1100RT ZC62149(sold) |
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Flying Duck PsyKotic Waterfowl

Joined: 27 Jan 2005 Posts: 10102 Location: Bumf***, WA
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Posted: Mon Jan 17, 2011 5:16 pm Post subject: |
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You circuit may have a 20A fuse but I doubt your lights draw that much power. That would make them 120W each - which would be pretty dang bright. The wattage of the bulbs divided by the watts tells you many amps they are actually drawing.
I run a pair of 70W(140W total) aux lights on a 15A fuse. They came with a 20A fuse but that's overkill if you ask me.
If you use wire that's too small not only will it generate heat but you'll lose some voltage and hence some light.
Wiring chart - I'd go a size or two bigger(smaller gauge number) just because)
http://www.rallylights.com/hella/SensibleWiring.aspx _________________ 93 LT (x2)
94 RS
86-97 K75F(K75/100/1100 Frankenbrick)
86 K75C w/paralever, hi perf cams,TURBO!
91 & 92 K75Ss
91 K1
86 custom K100
14 WR250R
IBA #17739 (SS1K, BBG, 50CC)
Buy parts HERE |
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BMGraeme Flying Brick Rider
Joined: 14 Mar 2006 Posts: 373 Location: Marlborough, United Kingdom
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Posted: Mon Jan 17, 2011 6:08 pm Post subject: |
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| Flying Duck wrote: | You circuit may have a 20A fuse but I doubt your lights draw that much power. That would make them 120W each - which would be pretty dang bright. The wattage of the bulbs divided by the watts tells you many amps they are actually drawing.
I run a pair of 70W(140W total) aux lights on a 15A fuse. They came with a 20A fuse but that's overkill if you ask me.
If you use wire that's too small not only will it generate heat but you'll lose some voltage and hence some light.
Wiring chart - I'd go a size or two bigger(smaller gauge number) just because)
http://www.rallylights.com/hella/SensibleWiring.aspx |
I have 2 x fogs @ 55w each = 110watt
plus 2 x spots @ 55w each = 110watt
In theory this is just under 20A. I wouldn't have both sets on together by choice, but could forget, so the safest option is to run to the frame as seperate sets. Strangely, I seemed to have answered my own question. As an afterthought, I could take the switched power for the fogs relay from dipped beam so if I hit the hi beam switch, the fogs would automatically turn off.
I think I will just run seperate earths and be done with it. Sometimes elegance has to lose out to brute force. _________________ 1980 CB900FA
1994 K1100RS
2008 R1200GSA |
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whyoldbill Flying Brick Rider
Joined: 12 Jun 2006 Posts: 440 Location: in the boonies, northwest of Columbus, Ohio
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Posted: Wed Jan 19, 2011 12:36 am Post subject: |
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| BMGraeme wrote: | | Sometimes elegance has to lose out to brute force. |
Over-engineered circuits don't let the magic smoke out, either.... _________________ '02 - GL1800
The desired effect is what you get when you improve your interplanetary funksmanship - George Clinton |
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Ernie-NH Flying Brick Rider
Joined: 14 Oct 2009 Posts: 982 Location: Bristol, New Hampshire
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Posted: Fri Jan 21, 2011 7:14 pm Post subject: |
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Hi guys...
I know I'm being petty to point this out :
"" The wattage of the bulbs divided by the watts tells you many amps they are actually drawing. ""
OK ???? P= E x I so I = P / E
Best regards all...........// Ernie in NH _________________ AMA,, American Deaf Bikers
Airhead Beemers Club
'11 G650gs
'95 K1100LT
'76 R100/7 |
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Flying Duck PsyKotic Waterfowl

Joined: 27 Jan 2005 Posts: 10102 Location: Bumf***, WA
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Posted: Fri Jan 21, 2011 8:35 pm Post subject: |
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Oops, I meant watts divided by volts.
Wattage divided by watts would always be 1.  _________________ 93 LT (x2)
94 RS
86-97 K75F(K75/100/1100 Frankenbrick)
86 K75C w/paralever, hi perf cams,TURBO!
91 & 92 K75Ss
91 K1
86 custom K100
14 WR250R
IBA #17739 (SS1K, BBG, 50CC)
Buy parts HERE |
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merlin geikie Flying Brick Rider
Joined: 26 Dec 2008 Posts: 343 Location: Lismore far north coast nsw australia
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Posted: Fri Jan 21, 2011 9:14 pm Post subject: |
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Ha ha we knew what you meant
I have heard you mention the K12 RS as being value and a good bike.
Flying Duck, you have K11s but what do you seriously think of the K12RS for the shade tree wrench with not a lot of loot?
They're big and expensive looking, but apart from that are they full of glitches and bmw do'hs... ??
Seen a heap of em on the market here and the early ones, before servo, look OK, eat tyres, engine oil seals and clutch slave cylinders, but seem to be OK, but not so much of a work-horse camper as the K11.
What you reckon please Sir?
All the very best in flood-free riding  |
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ljjohns Flying Brick Rider
Joined: 21 Oct 2006 Posts: 263 Location: El Paso
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Posted: Fri Jan 21, 2011 9:57 pm Post subject: |
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Merlin:
While there's not much commentary on the K12 series on the BMWMOA site, I think you'll find some useful info on the BMWLT.com site; while focused on the LT series, the other K12 models get their share of attention and substantial amounds of info apply to the whole K12 series.
I'd suggest you check it out.
Larry Johnson _________________ 1993 K1100LT (Washington)
1995 K1100LTSE
1996 K1100LTSE (parts)
2003 K1200LTC
1991 K75RT |
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BMGraeme Flying Brick Rider
Joined: 14 Mar 2006 Posts: 373 Location: Marlborough, United Kingdom
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Posted: Sat Jan 22, 2011 5:27 am Post subject: |
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Finally, the Condura weather proof rocker switch has arrived for the fogs. It's a bit bigger than I had thought so need to find a place to mount it. I had thought about the dash on the RS just left of the ignition switch area but I think thats out now. The obvious area now is the left hand fairing panel just below the plastic louvered infill - anyone had experience of cutting a small reactangular hole here and what worked best to do it? _________________ 1980 CB900FA
1994 K1100RS
2008 R1200GSA |
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Flying Duck PsyKotic Waterfowl

Joined: 27 Jan 2005 Posts: 10102 Location: Bumf***, WA
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Posted: Sat Jan 22, 2011 10:20 am Post subject: |
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| merlin geikie wrote: | | Flying Duck, you have K11s but what do you seriously think of the K12RS for the shade tree wrench with not a lot of loot? |
I honestly don't know. I've ridden one though and it was plenty fun. Always liked the "taxi cab" paint job.
 _________________ 93 LT (x2)
94 RS
86-97 K75F(K75/100/1100 Frankenbrick)
86 K75C w/paralever, hi perf cams,TURBO!
91 & 92 K75Ss
91 K1
86 custom K100
14 WR250R
IBA #17739 (SS1K, BBG, 50CC)
Buy parts HERE |
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BMGraeme Flying Brick Rider
Joined: 14 Mar 2006 Posts: 373 Location: Marlborough, United Kingdom
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Posted: Sat Jan 22, 2011 12:53 pm Post subject: |
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| BMGraeme wrote: | | Finally, the Condura weather proof rocker switch has arrived for the fogs. It's a bit bigger than I had thought so need to find a place to mount it. I had thought about the dash on the RS just left of the ignition switch area but I think thats out now. The obvious area now is the left hand fairing panel just below the plastic louvered infill - anyone had experience of cutting a small reactangular hole here and what worked best to do it? |
In the end it does fit left of the ignition switch with plenty of clearance underneath - works a treat. Have also wired the SatNav into the alarm connector so this is now switched power. _________________ 1980 CB900FA
1994 K1100RS
2008 R1200GSA |
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Flying Duck PsyKotic Waterfowl

Joined: 27 Jan 2005 Posts: 10102 Location: Bumf***, WA
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Posted: Sat Jan 22, 2011 1:23 pm Post subject: |
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Square hole: Drill a starter hole and then use a jig/reciprocating saw. Like a power outlet in your house.
Note that there is metal sandwiched in the middle of the knee panel so you'll want to use a saw blade capable of cutting metal. _________________ 93 LT (x2)
94 RS
86-97 K75F(K75/100/1100 Frankenbrick)
86 K75C w/paralever, hi perf cams,TURBO!
91 & 92 K75Ss
91 K1
86 custom K100
14 WR250R
IBA #17739 (SS1K, BBG, 50CC)
Buy parts HERE |
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Scott_Anderson Site Admin
Joined: 05 Sep 2006 Posts: 3122 Location: Central Iowa, USA
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Posted: Sat Jan 22, 2011 3:50 pm Post subject: |
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A small dremel works good too.
That's what I have used for some of my switch modifications. _________________ Ride safe.
1995 K1100LT 0302044
2017 FLHTK Ultra Limited
Garmin StreetPilot 2820
Garmin Zumo 550
Garmin Zumo XT
"One who does not ask questions is ashamed to learn" Danish proverb
1997 K1100LT 0302488(R.I.P.)
1997 R1100RT ZC62149(sold) |
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