Necessary change battery when I change a faulty voltage regulator?
 

So tech heads, is it necessary to change all the components of the charging system in one go when one element is faulty, or just advisable?
Had a faulty voltage regulator, with a battery pretty dry. Need to change the battery too, or just add some liquid and good to go?
Cheers

Not necessarily. A knackered regulator/rectifier can mean the stator will continue to sending charge to the battery and eventually frying it and burning out the stator. The R/R regulates the amount of current and rectifies and converts the current from the stator (AC to DC).

This is why it's often a good idea to replace the R/R when you replace or rewind the stator ie a burnt out stator is often caused by a faulty R/R. The stator can also just get old and burnt out with age and simply fail to provide sufficient power to keep the battery fully charged. Eventually when you're on the road the electrics on the bike will die.

My stator burnt out on my BMW F800GS a few weeks ago, it'd been going for a while but it has done 66k miles. I had the stator rewound and now it's good as new. It's not always necessary no change the battery, if it will recharge and hold it's charge it'll be fine. (It's usually cheaper to rewind a stator than to replace it - and it's usually rewound to a higher than OEM stadard).

If your tyre goes flat .. do you replace the rim?

Depends...
If the fault has damaged the other item/s then yes you replace them.

Rectifier/regulators going faulty usually damage the battery.. usually. If you want to play it safe - replace the battery. If don't replace the battery you risk being stopped beside the road again. With the information you have provided .. I'd replace the battery.

Has anyone added a voltmeter to their bike to monitor these situations and hopefully get warning before any damage is done?

Voltmeter
 

Many people have.
They were an option on some motorcycles e.g. BMW G/S

They range from the simple 3LED type - one for too low, one for OK and the last for too high, to Digital voltmeters (LED or LCD) to analog ones (as fitted to the BMW G/S)..

Google "motorcycle voltmeter" ...

I've bought a little voltmetre to fit to my GS to monitor the charging system but not fitted it yet. You can get them very cheaply on amazon or eBay.

Thanks heaps for the info.
We ended up changing the battery as well. Better not to risk it right?
Bit of a bummer the battery we replaced only lasted about a month, but what can you do?
Thanks and ride safe!