I know it could be any of a number of things... but I'm having a charging problem.

This morning (very wet weather) I stalled (not enough gas!) and she wouldn't restart. Pushed her half a mile to the car park, where I managed to start her rolling down ther ramp. I rode for 30 seconds and parked, revved her up a few times, turned off the ignition. Then she started fine. She started fine after sitting for nine hours too. But at the end of my ride home tonight the battery was down to 11.4 volts. (it's an AGM Absorbent Glass Mat battery).

I've just forked out £120 for a Lithium Iron Battery. It came today, measuring 13.25V. I put it in the bike just now and at the battery I'm getting over 12 volts at idle, 14v at 2,000 rpm, well over 14v at 3,000 rpm.

This means my reg rec is OK, right? What else should I be checking?

 

Sounds like the old battery was no good. Your new battery fixed it.

How much over 14V at 3k is it?

 

Hi 74demon,

It's about 14.5V I think. Too late to try again - babies next door and across the street trying to sleep!

Problem is, I'm not sure the new battery will fix it. The AGM battery was 12.7V this morning, but only 11.4V this evening. It was lent to me by a guy who parks his bikes in the same car park as me. (He has a VFR750 and a CBR600F parked down there - and 6 or 7 Bimotas! Recently he lent me a Lithium Iron battery from one of his Bimotas. It cranked my bike over real easy that's why I bought one. If I use that one tomorrow and it goes flat, I'll have to spend another £60 on a special charger - which I can't really afford.

 

14.5V is fine. If it was 15V or higher then it would be too much.

Those are good charging numbers and a good battery. If it goes flat after 1 night, you have an electrical draw somewhere. Your bike should be able to sit for 2 weeks or more without any trouble. Trickle chargers are for keeping them up in long term storage.

 

Thanks again Demon.

As I said, the new Lithium Iron battery was over 13.25V when I received it in the post. I'll measure it again in the morning.

I'll also take a spare battery with me... the AGM one is half the size and half the weight of the Lead Acid one. The new Li Fe battery is about the same size as the Lead Acid one - but only weighs about 1KG.

 

Charged two batteries overnight. Both were 12.5v this morning, so I used my old sealed motobatt, expecting it to be discharged by the time I got to work. However after I arrived it was still 12.5v and she started on the button first time. Ditto when cold 4 hours later.

So, some days the battery loses charge, some days not.

Anyone any ideas? Damp? Cold? Generator bushes?

 

Intermittent draw or charging system. Maybe just a poor connection somewhere.

Keep your voltmeter on it and watch it while you ride.

 

Check the plug contacts in the harness at your left knee going to the R/R

 

12.5v is only about 40-50% charged, I have a new Motobatt that I charged a few days ago and it is now sitting on 12.98v.


I would say your 12.5v just charged batteries are at the end of their useful life (as starting batteries, alright for running led camp lights for a while longer though)

 

Did a bit of monitoring today. At the battery I get 14v at 3,000rpm, but when I put the headlamps on it drops to 12.5v. Suppose this won't charge the battery?

Jarvid - I take your point, but could the above happen even with a good battery (i.e. something wrong with charging circuit)?

Sprock - do you mean the yellow ones from the generator? If so, I think they're OK (had to make my own connectors after reg/rec caused meltdown a couple of years ago).