1997 VL 125 Intruder

[Davie77]

This bike in 5 years has never let me down until recently.

I just had some heated grips fitted as my commuting miles are increasing. Oxford OF 692. and i still plan to keep the bike for some time

the grips are wired to the ignition so will switch off when the ignition is off.

however first time I used them i got a flat battery. The voltage had collapsed to 11.8V which was enough for lights and power but no spark. I got it going with a jump start and did a few tests. With the motor running the battery measured 13.8V. and even with full grips and lights the battery only drops to 13.5V.

Managed ok for a while but ive since struggled to start.

Most recently it was after a 2 hr run. So i woulda thought if anything the alternator would have given it a full charge

its a brand new battery only 2 months old. And i cant think of anything else.

[Davie77]

meant to add once it jump starts its ok for a couple of days then goes flat again

[Mr Fro]

Are you using the heated grips all the time?

[JRH]

The system should handle this. The rating for the genny is about 370W (30A)

But the battery voltage should be about 14V when charging @ 5000rpm.

Edit

Found another spec for the genny at 200W (16A) This might be getting close to not being able to charge the battery with everything running.

Do a voltage check at the battery with everything on and running @5000rpm.

Edited January 4, 2018 by JRH

[Davie77]

Yes last several times ive been out the grips have been on 50%

[JRH]

Yes last several times ive been out the grips have been on 50%

 

Do the voltage check as shown in above post.

[Davie77]

Battery showing 13.5 V with everything on full at 5000 rpm.

All that aside lowest my battery has ever been is 11.8V. shouldnt that still be enough to still start

[Tango]

Try running the bike for a few days without using the heated grips......my guess is that it'll be fine.......

[Davie77]

Put it on a full charge last night with an Optimate 4. tried to start this morning. not firing up. Put a voltmeter axross the terminals whilst trying to start. drops to 6V. duff battery ?

[JRH]

Sounds like it.

But check the level of the electrolyte. If it has been running down and then put on charge may have boiled off some of the water.

[Davie77]

Ok to resurrect an old Post,

Man is this bike giving me weird problems

Going through a period of flat batteries, having to charge them up every 2 weeks.

So I ran the bike for 2 weeks with no Lights or Heated grips (disconnected grips) and the battery was still going flat.

Tests at idle showed my alternator working.

the latest is the Main fuse. 20A blew. Couldn't find out what it was, so put in a 30A to get me home (all I had spare)

Which also blew the following morning heading out to buy more spares.

I'm sure all these problems are connected somehow but I cant work out what

fitted a new battery. same patterns

Test with a Current Clamp showed my lights only pulling 2A, and heated grips 4A. so should be well in the capability of the alternator

[megawatt]

Could be a phase gone down from the alternator. Test all three phases between phases and to earth.

[Grumpy Old Git]

main fuse (30Amp ) blowing - Most likely an intermittent short to earth (hard to find unless the wire insulation has actually melted).

Battery issues - You are certain that the grips are wired correctly? Disconnect (as Stu said) and run for a few days.

Alternator - Have you checked the coils (as mega said)?

If all OK so far, suggest you look at:

Rectifier.

ALL earth points on main loom.

Have you tried a new battery - uncertain from your posts?