1998 XV250 s Battery? Or reg/rec? (United Kingdom)

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roxburd
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1998 XV250 s Battery? Or reg/rec? (United Kingdom)

Post by roxburd » Sun May 01, 2022 9:03 am

Hi all,

1998 XV250 S, UK

Symptoms: After leaving the bike on charge for hours it starts fine.

If I stop the engine after a 10 minute run the battery then struggles to restart it - solenoid clicking on and off.

If I replace the battery when it's struggling with a known good one the bike starts 100% fine. So at that point in time, at least, it's just the battery that's the problem.

But if I leave it for an hour WITHOUT putting it on charge the battery revives and can start the bike!

The fault has worsened quickly - it's so bad that now during a ride, just switching the lights/indicators on can cause the ignition to fail.

I've ordered a new battery but I'm concerned that the battery may not be the root cause - could it be the regulator/rectifier? I say that because if you leave the bike for an hour the battery revives itself - if the battery were just duff I wouldn't expect it to revive.

#Confused

When I put a voltmeter across the battery with the engine running, sometimes it shows 15v, sometime 12v.

Any ideas for further tests? Any common issues I should look out for?

Cheers,
Dave

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ViragoJoe
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Re: 1998 XV250 s Battery? Or reg/rec? (United Kingdom)

Post by ViragoJoe » Sun May 01, 2022 10:05 am

roxburd wrote:
Sun May 01, 2022 9:03 am
Hi all,

1998 XV250 S, UK

Symptoms: After leaving the bike on charge for hours it starts fine.

If I stop the engine after a 10 minute run the battery then struggles to restart it - solenoid clicking on and off.

If I replace the battery when it's struggling with a known good one the bike starts 100% fine. So at that point in time, at least, it's just the battery that's the problem.

But if I leave it for an hour WITHOUT putting it on charge the battery revives and can start the bike!

The fault has worsened quickly - it's so bad that now during a ride, just switching the lights/indicators on can cause the ignition to fail.

I've ordered a new battery but I'm concerned that the battery may not be the root cause - could it be the regulator/rectifier? I say that because if you leave the bike for an hour the battery revives itself - if the battery were just duff I wouldn't expect it to revive.

#Confused

When I put a voltmeter across the battery with the engine running, sometimes it shows 15v, sometime 12v.

Any ideas for further tests? Any common issues I should look out for?

Cheers,
Dave
========================

Rox,

Take your battery to an auto parts store and have it load tested. That will tell you if it has the punching Power to start the bike.

As for voltage readings on the battery.
When taken directly off the charger you will get a False Surface Charge reading.
Let it sit for 8 hours. The voltage shown then will be the true voltage that it can maintain. A fully charged battery should maintain 12.6 voltage a tad higher for AGM Batteries.

Although, you may get the correct voltage reading doesn't mean the battery will have the punching power (AMPS DELIVERED) to start the bike. However, you will get a lot of clicking from the starter solenoids and relays.

REGULATOR/RECTIFIER TROUBLE SHOOTING and TESTING [INFO] & NEW VERSION

viewtopic.php?t=772
ViragoJoe 🇺🇸
1996 XV1100SH Virago Special
"Never ride faster than your Guardian Angel can fly!!"
;)


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roxburd
Posts: 7
Joined: Thu Apr 21, 2022 5:30 pm
Location: United Kingdom
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Re: 1998 XV250 s Battery? Or reg/rec? (United Kingdom)

Post by roxburd » Thu May 05, 2022 3:55 am

Thanks ViragoJoe,

After my initial post on this thread, my Optimate trickle charged said the battery was weak. Also, using the good battery from another bike had seemed to resolve the problem. So I replaced the battery with a new one (out of the box, 15v).

After a 10-mile test (average speed ~50mph) all was perfectly fine - battery voltage at 14v. Bike started again no problem.

I went straight out on another 20-mile test (average speed ~40mph) all was perfectly fine - battery voltage at 14v. Bike started again no problem.

I went straight out on a 5-mile ride to get petrol (average speed ~60mph) and the bike was right back to square one - clearly an electrical issue preventing starting. Clicking, wheezing/whirring but the engine not being strongly turned over.

The battery was still showing 14v.

At the end of a 3-mile stretch at 70mph on that final ride to get petrol, I slowed down and got a faint whiff of a weird smell (but couldn't be sure where it came from, obviously - could have been my pants). I'm now wondering if the regulator/rectifier is allowing over-voltage to the battery and frying it. I plan to rig up a voltmeter so I can watch it as I ride at speed. I can also do a bench-test on the rectifier diodes.

Just posting in case it's a common / known thing. I have a starter solenoid on order as I was optimistic that was the faulty component but I'm actually now suspecting the reg/rec. The only way it could be the solenoid is if it's an intermittent fault that just comes and goes.

Argh, this has been an arse-ache of a saga. And it's not over yet, clearly.

Cheers

roxburd
Posts: 7
Joined: Thu Apr 21, 2022 5:30 pm
Location: United Kingdom
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Re: 1998 XV250 s Battery? Or reg/rec? (United Kingdom)

Post by roxburd » Tue May 10, 2022 4:04 pm

So, after some simple testing with a multi-meter, I'm pretty sure it's the regulator/rectifier. The alternator was putting out the same voltage across each pair of the three connections - between 5v and 30v AC, depending on engine speed.

But the voltage across the battery was rock-solid whether the bike was started or running and regardless of the engine speed.

On further reg/rec testing, one of the diodes in the rectifier had low resistance (around 5 ohms) where it should have been open-circuit (reverse bias?).

So, replacement reg/rec should be here tomorrow.

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ViragoJoe
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Re: 1998 XV250 s Battery? Or reg/rec? (United Kingdom)

Post by ViragoJoe » Tue May 10, 2022 5:31 pm

roxburd wrote:
Tue May 10, 2022 4:04 pm
So, after some simple testing with a multi-meter, I'm pretty sure it's the regulator/rectifier. The alternator was putting out the same voltage across each pair of the three connections - between 5v and 30v AC, depending on engine speed.

But the voltage across the battery was rock-solid whether the bike was started or running and regardless of the engine speed.

On further reg/rec testing, one of the diodes in the rectifier had low resistance (around 5 ohms) where it should have been open-circuit (reverse bias?).

So, replacement reg/rec should be here tomorrow.
=============

Yup rox,

It only takes one diode to make it a bad Reg/Rec!
ViragoJoe 🇺🇸
1996 XV1100SH Virago Special
"Never ride faster than your Guardian Angel can fly!!"
;)


NOTE TO ALL:
:arrow: Please edit your profile with location (State/Country) & Bike Information. It will aid us in assisting you!


All topics are archived by vehicle families for easy perusing and to find answers.

Also: If this website was helpful, please consider donating to help keep this site here for yourself and future Virago owners.

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