charging voltage question

[MeestaSparkle]

Hello,
     Just got a 96 bandit 600, my first motorcycle.  It needs some work, but I got it cheap and the engine runs very well and is clean.  I have a question, and was hoping you guys could help me.

The battery was completely out of fluid after I got it home, I added distilled water to bring it back up to level.  Voltage read good on battery (12.7 volts).  Then I checked the voltage when the battery was hooked up.. at 1000 rpm it's 13.5 volts, at 3000 it's over 15.  All the service manual says is "voltage should be above 13.5".. but 15 seems very high at only 3k.

What should be the max voltage I should see across the battery when it's hooked up and running?  Do you think it could be overcharging the battery?


I have more questions, but I'll start with this for now.  Thanks!

[banditv]

if your voltmeter reads above 15 volts when you are giving the bike a rev, its prob a bit to high. high 14 volt range is acceptable.
if its above say 14.8 with the lights on, thats to much and you will end up boiling the battery dry. that suggests a faulty  reg/rect.
thankfully , the reg/rect is piss easy for average joe to replace. you'd prob find that much above 14.5 volts that the bulbs will blow on a regular basis, which is sort of a sign of charging problems. chuck a reg/rect at it and your probs will prob disappear.

[rider123]

You could try replacing the battery as well. Just get a cheap Canadian tire or Pep boys or whatever is in the States motorcycle battery. When the battery gets tired it will stop accepting more and more charge and hence the voltage will be higher than it should be. If you continue to ride it like that it will kill the regulator/rectifier eventually. Since the cost of a battery is around $30 and a regulator/rectifier if you buy new is $200 I would go with the $30 test first, if it still does it at least you know that the battery is new. If you have to buy a new R/R maybe try the wreckers in your area or you could do it jihadi style and fit another bikes  R/R as long as the connections are the same. I had a Yamaha Seca R/R on my GS650 for years after buying 2 Suzuki ones as the early eighties Suzuki electrics were notoriously crappy. It also had a stator from an unknown Kawasaki that me and my bike mechanic friend put on after it fried the stator a couple of times as well. Glad to see that Suzuki finally got it's act together as far as the electrics go.

[MeestaSparkle]

If you continue to ride it like that it will kill the regulator/rectifier eventually. Since the cost of a battery is around $30 and a regulator/rectifier if you buy new is $200 I would go with the $30 test first, if it still does it at least you know that the battery is new.

Thanks for the heads up about that, I didn't know.  I have no idea how long the previous owner had been driving it like that, so I hope nothing inside is fried!  I'll try the battery thing, looked them up and there are plenty of cheap batteries here to try.  This bandit has the regulator inside the alternator.. so there are no aftermarket direct fits that I could find.. and the oem parts are big $$.  Sure hope it's just the battery "fingers crossed".

Thanks guys!

[rider123]

Try www.bikebandit.com


They're cheaper than a dealership but it's still pretty damn rough! $190 for the regulator. If the whole alternator goes $885!!! Change that battery tomorrow!!! If you have to ride short shift it to keep the RPM's  low and fill the battery up to the top to soak up some of the excess voltage.

If you need to change out the regulator or the entire unit(I doubt it it's still pumping out power)you might want to check around for motorcycle wreckers.

Usually this happens when you get riders who buy a bike and have no phucking clue on what their doing so they don't even know you need to keep the battery filled with water so as the water evapourates the regulator/rectifier has to suck up all that juice that a full battery was supposed to absorb. So eventually it burns out. You're not too much off the mark so you may be ok with just a new battery. I've bought alot of bikes over the years and I've seen all kinds of crazyness that people do. When I buy a new bike I do this immediately no matter how the bike looks.

1. New battery no matter how good it looks($30-$40)
2. New oil and filter($30)
3. Fresh gas and a high rpm run in on the highway.($20)
4. Replace the brake fluid and bleed the brakes($20)


So for about $100 I covered most of the major systems on the bike. It's a good $100 insurance policy.


I bought a bike once that was basically brand new for $600 once because it wasn't running. The battery was dead and the fool didn't know it. All I did was replace the battery, clean out the carbs and got a bike with only 9000 kms on it for $600! The old battery looked like the original that came with the bike and the leads were rusted and there was not a drop of fluid in the battery. Not even moisture! You get all kinds of people riding bikes, alot unfortunately buy a bike for a summer or two to "look cool" and in the meantime they don't do shit to the bike and drive it until something breaks from lack of maintenance. It's a good way to pick up bikes from people who probably shouldn't have bought one in the first place but it's a bit of a gamble. Best to replace the cheap but important components to give yourself a piece of mind. All this stuff I suggested shouldn't cost you more than $100 and only take a few hours max. If the brake fluid looks ok you can even skimp on that step if you're unsure on how to replace brake fluid and bleed brakes.