Battery dead? alternator?

[but bandit]

hi guys, i was wondering if you could help me out. basically i hadnt been riding my bike (400 bandit) for about a week or two and the other day i decided to go for a ride. i tried to start it on the electric start and it didnt have enough power to get going, so i bumped it and off i went. i thought by the time i'd got to my destination the alternator wouldve given the battery enough juice to start off the button when i left, but i had to bump it again. i had to bump it off whenever i used it after that, but it hasnt had too much use in this cold weather! but i took the battery off and charged it so i could at least start it ok if i did want to go for a ride. it seems fine now, since ive charged the battery, the lights are bright and i've had no trouble startin, ive been out maybe 4 times since i charged it and i started it just now to make sure it would be ok because i have to go out on it this afternoon. i know its a bit vague, but do you think it could be the alternator broken? would the battery have run down by now if it was? or just a knckered battery? or neither? hmmmmmm

any feedback appreciated

[interfuse]

Download the shop manual from the members section and run the tests on the generator, rectifier and battery. My "guess" is it's a bad battery, but unless you run the tests there's no way of knowing. If it is a bad battery, make sure you test the R/R to make sure that didn't smoke your battery or else you'll end up with the same problem again and another 10 lb lead acid paper weight.

[rkfire]

If the alternator was bad, it wouldn't bump start.

The battery was obviously discharged if the starter did nothing before, now after a charging it works fine.

It could very well be that the battery cables were either a little loose, or some corrosion on them, or both. In that case the battery wouldn't get a full charge while running the last time. Removing the battery and reinstalling it may have scuffed the corrosion off, or the connectors got tightened better this time.

[pmackie]

Before you spend too much time on anything else:
1. clean the battery posts & connections
2. make sure that there is still fluid in the battery (IE mostly full)
3. fully charge the battery.

Normally running the bike is great for keeping the charge up, but I have found on my 600, that a low battery does NOT come up to full charge on the bike, unless I keep the revs really high, and/or go far a multi-day ride.

Obviously, something caused the battery to loose some of its charge. I would bet the posts are corroded and the fluid is low. You can take the battery into a battery store after charging to have it load checked.

[gsxr400 racer]

Before you spend too much time on anything else:
1. clean the battery posts & connections
2. make sure that there is still fluid in the battery (IE mostly full)
3. fully charge the battery.

Normally running the bike is great for keeping the charge up, but I have found on my 600, that a low battery does NOT come up to full charge on the bike, unless I keep the revs really high, and/or go far a multi-day ride.

Obviously, something caused the battery to loose some of its charge. I would bet the posts are corroded and the fluid is low. You can take the battery into a battery store after charging to have it load checked.

Your always full of splendid info mate i dont think the time off has effected you at all lol
cheers

[but bandit]

hey guys. the bike seems fine now, left it for a few days and hopped on it yesterday and it started up a beaut! even in this horrible cold weather. im thinking it could have been the connections. thanks for all the info.