Capacitor ???'s

redlinedave

redlinedave

Been Around the Block
Any one tried using a large capacitor that normally is used
in car stereos' as a battery delete? i saw one at a pawn shop for cheap.
I think it was 24v and 50,000u
would it work?
 
I imagine it would, but you would have to run a beefy voltage regulator to keep any of your parts from getting more than about 16 volts. Anymore than 16 and you will do damage to your bulbs.

If I remember correctly, though, Car Audio caps are huge. The same size as a battery, right?

You can use a 50,000-mfd, 16VDC computer grade capacitor. If your stock Regulator is in good nick, it should handle the additional 4 volts without issue.
 
No, it won't work. Capacitors discharge in an instant, batteries over time. When starting you need power over time, when the brake light goes on you need power over time time.
 
Kong said:
No, it won't work. Capacitors discharge in an instant, batteries over time. When starting you need power over time, when the brake light goes on you need power over time time.
Click to expand...

True that a Capacitor is an instant Discharge device, but you also have to take into account the charging system on the motorcycle will be providing constant current. Obviously the Cap will not be able to start the bike, it will have to be kickstarted. You will also have no lights until the bike is running. The alternator will provide power for all lights (including brake, turn, running, etc). Some people wire in a kill switch for their lights. Kick the bike over, rev a bit to get Alternator/Cap going, flip on the lights.

Once running the Cap will limit the amount your headlight and tail light flicker.

Many people in the motorcycle community use a Large cap as a Battery Eliminator. Some run both a Cap and a small lawn mower style battery as a back up.
 
I would go for something smaller. The higher the uF rating of the cap, the more kicking that is required to get a charge and get the bike going. Something in the 15KuF - 25KuF range would work a lot better. I've actually for a 15KuF cap sitting ready to go onto my bike when I finish my build.
 
I did this. I used a 50 volt, 10,000 uF Panasonic capacitor (for car audio). Can't quite tell you if it works or not, since I haven't been able to start the bike yet (unrelated issues). But the capacitor itself is about 2 inches tall, 1 inch in diameter. Got it on ebay for cheap.
Here is the thread that convinced me it would work:
http://forums.kz650.info/index.php?topic=3677.0
 
Thanks guys, Im a cheap azz mo fo and want to keep costs down.
Im going to Active Surplus (in Toronto) tomorrow and will see what I can find.
Ill either pick up a small 12v gel cell or go the cap route. BTW my bike is an SR500. Kick start only. Ive seen caps on Fleacebay but way too much bread.
$50 is too much. I could find a genaric cap for under $10 Im sure. Just need to know what to look for. so Im guessing something under 50v and 15 to 25uF.
Ill keep you all posted
 
Keep an eye on eBay. Generic electronics-oriented caps come up every now and again. Stay away from the ones labeled or pushed toward audio usage. Way overpriced for the same damn thing.
 
I see car audio caps are 1 to 4 farad. Will they store more "juice" longer than a
25 to 50 uf cap ?
What is better?
this whole cap learning curve is beyond me
 
Anyone know if you can run a cap and a small ah battery at the same time? Would that allow you to run high powered headlights and electronic ignition and the like?
 
I went to the electronic nerd store and bought a cap off the shelf
for $3...figured I'd gamble....works so far
25vdc 20000mdf
 
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