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Discussion Starter #1
Hey All,

Anyone have a guess how many amps accessories can draw on a base k100?

Thinking about some heated grips and a heated vest. Might look into upgrading to the 50amp alt in the spring to add some more lights, but rather not do it right now.

Thanks
 

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what me worry

Luke Man

What makes you worry? I always thought amp lack was strictly a Japanese bike phenomenon. Other than ante farklemania airheads, I have not heard of watt starvation on BMWs. And all my beemerphiliac friends turn their Gerbings on high soon as it dips below 50, run their GPS, iPod, satellite radidio, Hellas, PIAAs, and every other kind of farkle as fast as they can buy them. Still never run out of juice.

For example: I have a 2007 Kawasucky KLR650 rated at a puny 180 watts. By the time you fire the engine and headlight, you got nuttin. Especially since that puny 180 is measured at just above redline. Horsepower and amps both are often rated at impossible spin on metrics. They like to inflate the numbers. I installed a volt meter on this bike and I can tell you that no more than heated grips and you are already at deficit sitting at a stop light. Bright headlights and heated grips together and you'd better be under way with your revs up. KLRistas install a second battery to run a heated vest, and charge that battery overnight in the garage.

Had a GL1200 same way. Rated a mere 340 watts even though lit up like a Christmas tree. Have a friend who distance tours with his wife aboard a GL1500 had to install a 500 watt alternator because the OEM would not fire their Gerbings.

By contrast, my K75 pumps an ample 460 watts. Don't know the RPMs at which it achieves that, but I bet they are in ordinary operating range, rather than the improbable stratosphere. I have a 2003 R1200CLC in the garage puts out a whopping 840 watts at a mere 3000 RPM. You could light a minor league ballpark with that and still have room for the pop corn popper, and all at a relaxed cruising RPM.

So I am curious what makes you worry? I am new to bricks and maybe I haven't heard the scoop. Have you slapped on a cheap volt meter to see what she reads?
 

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PsyKotic Waterfowl
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You should have enough extra juice to run the heated gear you want but once you start upgrading lighting and stuff it's pretty easy to outdo the 32A alternator. My 93 K11LT was fine with a 90W headlight and a pair of 35W aux lights but once I upgraded the aux lights to 55W my battery got drained (w/ heated grips off) so I had to do the 50A alternator.
 

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Discussion Starter #4
Mainly concerned with the fact that the later models got the upgraded 50 amp alternator while mine has the puny 32amp alt. Did BMW up the alternator because it just didn't make enough juice? Just didn't want to go for a long ride and end up with a dead battery.
 

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PsyKotic Waterfowl
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The 32A certainly had enough juice for the bikes. However, once you start adding aux lights and such it gets overtaxed. The first K with the 50A alternator was the 93 K1100RS, then in 94 the K1100LTs and K75s got the 50A alternator. Since production of K100 models had ceased by then the K100s never had the 50A alternator.
 

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Lukeman

The best way to get maximum performance from your stock alternator is to go with a 35W HID headlight upgrade.http://www.ddmtuning.com/product.php?II=105

You will drop your headlight power draw from 55W to approx. 42W (inc. ballast power). You will almost double your lighting output, maybe to the point of not needing aux. lighting.
By doing the HID conversion you can safely run heated gear, etc. for a under $50.00 investment.
 

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Hid

Only saves one amp. Do the math.

So what's burning up all the juice? All your tail and dash lights together maybe two amps. The headlight less than five. The fuel pump is a bunch -- maybe eight. Spark plug coils pump a bajillion volts, but only for a bajillionth of a second, so not much draw to speak of there. Does this radiator have a fan? You're still only looking at half the available juice. What's burning it up?
 

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Discussion Starter #9
Haha, yeah that was what I was asking. :) Like if the bike draws 25 amps during normal operation, i have ~7amps to fool around with. I just didn't want to buy a bunch of electric gear if it was going to burden the alt, but it looks like I should be fine with a couple things.

The ddm kit is a good idea, i threw the 55w in my old 525 with projectors and it made an amazing difference. Anyone have experience with those bulbs that move to switch between hi-lo beam?
 

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If you stick with stock headlight, and use low-energy conspicuity/fog lights, then you should have plenty of power for the vest. A low-power solution for consipicuity lights is to use a pair of MR16 fog lights, then put-in some 5W MR16 LED bulbs. That would keep your lighting needs to 55+10W.

If you need the extra light to see more distance the road, you could use the 35W low-beam DDM kit, then rewire the high beam switch to a relay on some HID driving lights (2x 25W?). That could keep lighting needs to 35W+50W.

I think where people run into trouble is raising the headlamp to 90W, then adding 2x 55W driving lights... then adding the heated gear.
 

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Kay said:
Only saves one amp. Do the math.
Lets do the math on saving 1 amp and using 14 volts(alternator output voltage) as a constant.
The OP figures he has about 7amps to fool around with: 7A *14V = 98Watts.
That 1A(actually 13 W) saving on the HID equals around a 13% constant power savings.
I figure that's not a not too bad saving and lighting improvement for 50 bucks.

Another place to save, is installing LED lamps where possible(parking and stop/tail best bang for the buck) :http://www.superbrightleds.com/cgi-bin/store/index.cgi?action=DispPage&Page2Disp=/led_prods.htm
Also eBay has good LED prices, if you want to wait a couple weeks for shipment from Hong Kong.
 

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not at all

Bruce, I don't see where he's saying anything of the sort. All he said is "Like if..." Nor do I see where you can get any significant savings out of a standard tail light which only burns eight watts anyway, much less from a turn signal which only flashes on briefly when you are at a turn.

So who HAS added up all the little juice suckers to see what the total juice draw really is?

55 W headlight
8 W for a standard 1157 tail light bulb
something small for the CDI -- after all, puters run on peanuts
Your coils may take on the order of forty watts. It's hard to google up a definitive answer; probably because this is the one item where current increases as engine speed increases; unlike a light which is constant. At any rate, the twin coils on my big oilhead boxer which each spark on the exhaust as well as on the power stroke, thus equivalent to a four banger, are said to require 40W.
Fuel pump in my K75 I just googled, it said 28 W
Of course, you have to have a surplus to replenish what the starter drew. And you are not making much at idle, so you have to replenish that.

But so far, we are still drawing under a buck and a half. Specs say you have 460W to play with. What else am I missing here? What draws so much juice that you even need to think about it? Heated grips on my KLR are like 15W. GPSes and such not draw next to nothing. Aux lights could suck some juice. Grips and aux lights together might run you top half the capacity. Still no worries. Amy I missing something?

Or is the juice box just more than ample without worrying.
 

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Kay said:
Bruce, I don't see where he's saying anything of the sort. All he said is "Like if..." Nor do I see where you can get any significant savings out of a standard tail light which only burns eight watts anyway, much less from a turn signal which only flashes on briefly when you are at a turn.
Key
I took the 7 amp comment from the OP's post #9 of this thread.
My only point in this thread is to say the conversion to HID headlight is a worthwhile mod with a savings in power and increase in light. And any savings you get must be from something that runs all the time.
That's it!
You apparently disagree, so fine, lets go on to something else.
 

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PsyKotic Waterfowl
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There's a few problems with HIDs:

1) Since your headlight isn't designed to run an HID bulb you can get light scatter that will blind other drivers at night. This is not good for your safety and it's pretty rude as well. Several people have tried them in K bikes only to have to go back to normal lighting.

2) Because of #1 they are illegal and you can get a ticket for it, Google "HID ticket."
 

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Discussion Starter #15
You can't put in one of those hi-lo beam HID bulbs that I see on DDMtuning? The ones that actually move to direct the light either downward or full.

Also had the douche bags that put HID bulbs into standard housings, its like a spotlight in your eyes.
 
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