Dead Battery?

Hi all,

So got out for a ride this morning all going well, rode for maybe an hour with no issues, was just poodling about. Get home into the back garden and the bike cuts out, no warning just cut out and now refuses to start.

Now the starter motor doesnt turn, or click, and every time I press the start button the alarm just kicks in.

Would a dead battery cause a bike to just stop? Wouldnt it just run but not charge the battery?

Anyhows, got it on charge now but thinking really it should be changed, I don`t know how old the battery is as it was in it when I got it last summer.

Could water/moisture cause this as well?

Any advice really welcome as Im hopeless and far too impatient for fault finding!

Cheers in advance

EDIT: Just tried it as it had been on charge for a bit and it turned so I would think the battery is discharged, Im just suprised it would cause the engine to cut out..........Anyhows need a new battery now, any recommendations?

[21QUEST]

Hi, it could be the battery but it could also be the rectifier or even the generator....if you are unlucky enough .

I'd suggest making sure the battery is fully charged and then checking how much voltage then rectifier is putting out and ALSO do the relevant tests on the generator.

Do you own a multimeter?

I'm in the process of changing the generator myself on a curvy.

edit: What year is your bike?

Oh, with a healthy battery, you can actually go a fair distance before you run out of battery juice....if you leave the lights off, don't use the indicators much and use the brakes as little as possible.

[21QUEST]

What part of Surrey do you reside?

Cheers for the reply, it is a 2000 curvy and I am in Epsom.

I put a multimeter on it and it was showing 11.7, that was before I put it on charge, it has fired up now and I`m hoping it just needs a new battery, will leave it on until it`s fully charged.

I was riding with the lights on etc and as it only gets used when it isn`t raining it`s not often at the moment!

[21QUEST]

Having a multimeter is a good start.

Once charged , do check it again but definitely check the alternator as well...see how much AC voltage its putting out and also check the resistance of the windings.

Battery should have about 13V fully charged
Rectifier should be putting out about 13.5 to 14.5V at 5000 rpm
Alternator should be putting out no less than 70V ac at 5000 rpm
The Haynes manual states, the resistance of the alternator winding should be between 0.2 to 0.55 ohms.

If you do need a new alternator, you can use one from any Curvy bar the K2 models.
The main difference is in the length of the wires. The K2 plugs into the loom on the left side(same side as the alternator is located) but up to K1, it plugs into the loom pretty much towards the rear of the bike, on the right side.

Cheers nice one, I will have a look when its finished charging

Yes, the battery should be charging when you're riding, not discharging. Best to find out why.

Cheers Wideguy, thats what I was getting at.

Say your battery had just enough to turn the bike over then surely riding it would put charge back, not stop the bike, wouldnt it?

I`ve just ordered a new battery but then hunting through the old paperwork found a receipt for a new one Dec 2012............bugger

Best get the thing started then check the rectifier and alternator

[jambo]

Generally it's worth being 100% sure of the issue before buying anything.

The best battery in the world will still go flat if it's being used but not charged.
The tests above given by 21Quest will help determine what's up.

When the bike is running, the engine turns the alternator which puts out ~70V AC on 3 phases. That would cook your wiring loom in quite short order so this goes to the regulator/rectifier. This takes the 70V AC input, and rectifies it to DC voltage. it then regulates the output to no more than about 14.5v. This is enough to top the battery back up, as well as running the bike's ignition, lights, etc.

Clearly if part of the above doesn't work it can end up not generating the power in the first place (alternator), not regulating it down to an appropriate voltage and cooking the battery, or not passing on any voltage at all, leaving the bike draining the battery down to nothing with use. When there is not enough power left to run the bike's ignition system it will stop.

Jambo