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The news is pretty good unless you're a V-Strom owner. Our charging system has little excess capacity, so you have to calculate your electrical additions carefully. This article from CycleNutz.com presents an easy to understand explanation.

One interesting observation was the effect of the fuel filter on electrical capacity. A dirty fuel filter causes restriction that makes the fuel pump on a fuel injected bike work harder. This increases electrical draw and accelerates wear on the pump and charging system. Makes me want to change my fuel filter!
 

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FORUM GODFATHER.....R.I.P. PAT
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That's a good point. When I see people totaling up the electrical draw on the system, I don't think I've seen the fuel pump included. A motor is a big ticket item.
 

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<snip>
One interesting observation was the effect of the fuel filter on electrical capacity. A dirty fuel filter causes restriction that makes the fuel pump on a fuel injected bike work harder. This increases electrical draw and accelerates wear on the pump and charging system. Makes me want to change my fuel filter!
My (very limited) understanding of impeller type pumps is that they actually draw less power (speed up) when the pumped volume decreases? (similar to closing down the outlet of a centrifugal fan causes it to speed up). As well, the fuel filter is on the low pressure side, and should it be restricted the pump would spin easier? The output of the pump goes to a regulator which dumps the fuel back into the tank when the pressure exceeds the set point, so the pump normally has a constant load set by the regulated fuel pressure? Wouldn't the filter have to be almost completely plugged before it would cause a noticeable increase in current draw? (the friction of the fuel on itself is the only real "suction" to the system). Just curious....
(picture from service manual)
 

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That image is of Regenerative turbine pump. These are pumps designed for low flow and high pressure. You can find more detail here: http://www.lytron.com/ToolsTechReference/ApplicationNotesDetail.aspx?id=692The power demand from a regenerative turbine pump increases with back pressure at pretty much the same rate. In other words, double the backpressure, double the power required.

Centrifugal pumps behave differently and the power curve depends heavily on the specific speed of the impeller. However, your typical impeller pump (swimming pool or spa pool for instance) will have a best efficiency point (BEP) where it draws maximum power. If the backpressure increases from BEP, the power required will drop.

Now if the motor is variable speed, and the FI brains tell it to maintain both flow and pressure it will have to speed up and the power really jumps.

Troy
 

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This article was written by John Swiatek, president and founder of Powerlet Products. It's been widely reprinted and that's a good thing. It's not something everyone considers. I had the pleasure of dining with John in Indiana one evening. He's a genuinely great guy and super hard worker. He's done us all favor with the great line moto-electrical hardware he manufactures. I for one, have a lot of his stuff on my bikes. Powlerlet sockets, tankbag power kits, iPod charger, cell phone charger, all kinds of stuff.

Sadly the Strom, in the finest tradition of marginal electrical components from Suzuki, has a minimal-capacity charging system. Newer DL 1Ks are just 400 watts and earlier units are 360 watts. I don't know about wee-Stroms.

I can however run two each 35 watt PIAA 510s and my Widder vest at the same time. If I am running the heated grips too, I usually shut off the PIAAs. I am thinking about putting a stealthy, weatherproof switch somewhere handy to turn off one headlight for daytime running or one 510 driving lamp as I choose. That would allow me much greater power management options especially useful in very cold weather.

Heat Trollers are good for your heated gear as they are not resistive devices. That way you can use heated gear/grips at lower that full heat settings while not wasting the "unused" portion of the current draw.
 
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