Battery / Charging Problems

[JamesMio]

Hi Folks,

Hoping someone might be able to point me in the right direction with a problem I'm having.

2000 (W) Curvy was gradually getting less & less willing to start until eventually it refuses to turn over at all, flat battery.

Trickle charged it and all was well for a week until the same thing happened again, so replaced the battery last weekend. Perfect running for a week but today it's refused to turn over again and really sluggish, jump started Ok though.

If it was a car I'd have diagnosed it as a duff alternator - does this sound about right? If so what kind of job is involved in replacing it? I'm not very experienced mechanically but I'm more happy to have a go and follow my Haynes manual!

Is there anything else I should be checking for first do you think?

Not sure if this makes any difference but this has only started happening since it was serviced a couple of weeks ago. (I know he obvious response is going to be take it back to the garage, which I will if all else fails!)

it is probably the regulator/rectifier, do a search on here to find out more

Check voltage on the battery terminals with the engine started. You should read around 14-15volts. If you get less than your alternator is knackered, if you get more your regulator's gone. You need to get hold of a multimeter. A cheap one will be great for motorcycle maintenance, the expensive ones are for techno freaks like me. Still don't use half of the functions to be honest

Here's some more details:

Charging System

The charging system consists of the alternator (rotor/stator), rectifier, voltage regulator and the battery.

Here is a breakdown of what the parts do:

alternator: produces an alternating current by passing a moving magnetic field (rotor) through a nonmoving or static (stator) winding of wire. Gasoline is thus converted from a chemical energy to a mechanical energy (within the engine) to an electric energy (within the alternator). This energy is then sent to the rectifier.

rectifier: converts alternating current (AC) to direct current (DC). Early rectifiers simply took half of the energy (single wave), and sent it to the battery. Since alternating current travels in both directions, the early rectifiers simply grabbed the energy going in one direction and set it on. Later rectifiers use a diode group to grab both directions (full wave) of current and combine them into one direction and sent this on. Later rectifiers were much more efficient but more prone to failure.

voltage regulator: governs the amount of current coming from the alternator and limits it to about 14-15 volt. This is usually combined with the rectifier to make one piece of hardware. If too much current is generated, the regulator sends it to the ground or frame.

battery: stores energy and is the main place to dispense energy as needed, to plugs and lights. A sign of a bad charging system is when the headlight blinks or strobes at idle or when there is a marked increase in headlight intensity when you rev out the motor. All bikes show some increase in headlight intensity with higher RPMs but if it goes from dim to bright, it is probably the charging system.

Notes:

Make sure the battery is good! Use a volt/ohm meter to see if it is providing near 12 volts. If it reads 10 volts or less, replace it.

Originally Posted by zunkus

...If you get less than your alternator is knackered, if you get more your rectifier's gone. ...

That is not always true now is it!!

Oh and forgot to say in my first post, it can also be the wiring and/or a bad earth ....

[JamesMio]

Thanks guys, I'll get hold of a multi-meter & see what the results of that are...

Cheers
JM

c

Originally Posted by Blue_SV650S

(1)That is not always true now is it!!

(2) Oh and forgot to say in my first post, it can also be the wiring and/or a bad earth ....

(1) I've updated my post with some details.
If I'm in the wrong somewhere please clarify.

(2) That is a very valid point and should be the first thing to check actually.
Many faults are due to loose connections, mostly at the battery terminals or scraped wiring.

[JamesMio]

That's great, thanks very much - greatly appreciated!

[JamesMio]

Ok, borrowed a mate's multi-meter today and just tried it.

Got a reading of about 13.6ish from the battery terminals with the bike running - however the battery had been charged overnight, does this make any difference?

Typically I now can't find my Haynes book to identify what wiring I should be checking etc.

Sounds like a duff battey to me not holding its charge

[JamesMio]

Originally Posted by mototech

Sounds like a duff battey to me not holding its charge

Battery's a brand spanker - replaced it last weekend when this problem first started as I had the same thought....