cleaning out some stuff i found a 1.5 farad capacitor i had used when i had a ridiculous 1600watt audio system in my car.
and i was thinking i could use this on my bike.

I have a relatively new battery in the bike, Scorpion AGM, and it works great.
but some cold mornings and evenings when i try to start up my bike, it takes a few attempts to get it started.
and a couple of times, i could hear the starter cranking slower and slower and would just barely start.

and sometimes when i'm at a red light i do notice the lights dim slightly when i'm at idle.

the idea of adding a 2nd battery has crossed my mind, but its heavy and bulky. but the capacitor is light and could quite possibly fit in the rear fairing of my 06 gs500f.  if i wire it in parallel it could give me a little extra juice for the times the bike is hard to start.  and it could help smooth out the voltage and take a some load off the stator and regulator, especially when i'm running my navigation, grip warmers, and charging my phone or ipod.

I'm by no mean an electrical engineer, so i thought i'd through out to see if the collective knowledge of the members could possible shed some light on this idea.

so is this a viable idea or am i just dreaming?

I believe its called a smoothing cap the way you want to use it now. Could work but batteries are supposed to be better than caps, smoothing caps are used for smoothing downstream of transformers and rectifier bridges. That's inherently more contaminated with ac. But well, your rectifier turns AC into DC. So it may work.
Cool.
Buddha.

Find the formula for energy stored in a capacitor and crunch the numbers. The answer will be expressed in joules (or watt/seconds) My math says in theory it would hold 108 joules. Thats enough energy to light a 55w headlamp for just under 2 secs or....power a 500w starter for about 0.2 secs...WOW 


Placing a cap in parrallel with a battery is not going to increase its abilty to deliver power and I hate to think what effect it would have on the reg/rect when it suddenly sees a capacitive load as well as a resistive load.

It wouldn't help. Caps help smooth out the peaks like Budda said. Peaks that last milliseconds. Turning the engine over would drain the cap in an instant.

Wiring your headlight through the starter switch (like most modern bikes do) will help you get additional starting power, since you won't be trying to power the headlight & the starter at the same time.  Here is a thread about it.

Switching to LED tail lights will help with issue of dimming at idle. You could check your idle speed, I haven't noticed dimming at idle and I wonder if yours is idling too low.

Ever thought of looking into a BATCAP? I used to run two of these in my competition audio car slash daily driver. I could rock my 3000 watt system hard for a good two hours off the power of just the two batcaps.. I wouldn't doubt that one would help you considering its way 200 times what your cap has.