Auto Electric Experts

[Jerzy Woking]

HELP!

 

Having issues with charging. Revving the engine saw the voltage output drop by a volt or so.

 

I replaced the reg/rec, even wiring the earth to the chassis, but still this issue was there. Checked the stator to find it was black. Had it rewound but seems to be the same. Fitted a new, fully charged battery, but still the issue remains. The reg/rec tried on another bike and seems to work perfectly.

 

This is doing my bloody head in-anyone know what could be the issue? Although it's a bike (Suzuki SV650) electrical systems should all work the same, shouldn't they?

 

Thanks for any advice-got to be better than my guesswork.

[Guest Hooli]

It does sound reg/rec related. Have you checked all the wiring to/from it?

 

If you unplug the stator you get something like 60v AC out of that before the reg/reg, then check again at the reg/rec multiplug. From there I'd see if you can bodgerate temporary connections into the reg/rec to ensure 12v comes out & then follow that wiring to the battery, there's probably another multiplug & maybe a fuse inbetween.

[twosmoke300]

Voltage dropping as you rev on a bike is classic faulty battery symptom so i would be checking for corrosion on the wiring for the reg/ rec to the battery inc the fuse box

[Jerzy Woking]

Reg/rec been wired independent of the loom (initially suspected a break in the loom somewhere) just as you suggested Hooli. This was to the cheap Chinese one I fitted when this issue first arose, as all indications were that the original had burnt out. I thought it was ok, but after a few weeks tge battery slowly lost charge until not enough to spin the motor over.

 

New reg/rec (ok, secondhand but genuine Suzuki one) fitted, no change. Stripped out stator, which was black as coal. Had it rewound, fitted it, same issue. Fitted the new and fully charged battery from my KTM. No difference.

 

Was going to try another reg/rec (Suzuki V-Strom - known to be good) but wiring slightly different so best not to try. All wiring checked and checked again, before being checked once more. I do have the original reg/rec, but it's in a small box in the garage roofspace (somewhere!), but will have to take the eight bikes out of the garage to search for it. Bear in mind I still cannot find the Guzzi end can I put up there two years ago.

 

Looks like Thursday will be spent pulling all the bikes out from hibernation so I can look through everything and tidy the garage up a bit ( it looks like Dollywobbler's at the moment) UNLESS another thing to try can be suggested. Please see if you can save me from a long day in the garage.

[Bren]

As said earlier I would be looking at the connections if the battery is healthy. Was it a brand new one? If not I would get it tested.I have had mainly suzukis, the electrical system can be a PITA.

[twosmoke300]

I’ve got a genuine Sv Manual on cd somewhere if it’s any help

[DodgeRover]

New stator, new reg/ rec, all new inpendendant wiring, new battery.

Must be a bad wire or connection somewhere.

What hasn't been renewed?

[Jerzy Woking]

New stator, new reg/ rec, all new inpendendant wiring, new battery.

Must be a bad wire or connection somewhere.

What hasn't been renewed?

My patience and my understanding of electrics.

[DodgeRover]

Is it possible to run an earth wire from the stator coil mount to the battery negative and on to the reg/ rec body?

[Jerzy Woking]

Good suggestion DR-I'll give that a go.

[tul66]

Have you checked the brushes?

[Guest Hooli]

Have you checked the brushes?

 

What brushes? most bikes use solid state alternator tech so no brushes are involved.

[red5]

How do you know the voltage drops?

 

I assume a multi-meter? 

[Jerzy Woking]

This is doing my fucking head in.

 

Multimeter shows that the rewound stator is at 60 ohms as it should be, and is constant (before tje rewind it wasn't stable). Had a go at wiring it up independently of the bikes loom., and showing 13.4 volts at tickover, then at 5000 pm showing 14.6v which it should.

 

However, switch on the lights and voltage is all over the place before settling at 13.6 v at tickover, and then 13.2v at 5000 rpm. Lights off and goes up to 14.4 v

 

Think a box of matches and a can of petrol beckons-just can't work out what's going on. All wiring checked is good. Will try another reg/rec later but not today, as thoroughly pissed off by it all now

[twosmoke300]

Has the reg / rec got a good earth ? Was it let to get hot without it bolted to the frame ( heat sink )

[red5]

Reg/rec then. Assuming you've check the earths for high resistance etc as twosmoke mentioned ?

[MikeR]

I know its being said before

 

and it may sound daft , but are the earths ok , try measuring for a voltage drop between the chassis earth and the batt earth  and the Alternator earth ..

 

that extra volt might being lost over a earth connection , and it the earth is bad it might be causing the regulator to bounce around before settling as it does not have a good earth to reference to ,

 

ie , you switch on the lights , so the earth rises , the regulator ref then goes up as well m causing it to wobble ..

 

dont just trust a resistance check , put the lights on etc and check for a volt drop , anything will look good before you start shoving some amps throu it and it heats up

[Jerzy Woking]

Thanks again for all the suggestions. Going to leave it tomorrow and have another go on Monday. I'll go through EVERYTHING suggested here. Used a brand new battery and a known (ie working) reg rec. It's the putting on of lights that screws things, so ALL wiring and earths will be gone through. Bike is pretty much stripped now so should be easier to do.

[Jerzy Woking]

Right, this is now kind of sorted. Every connection and connection block the loom was disconnected, cleaned and put back together. Ignition switch checked and cleaned up, and a visual inspection of the loom was made.

 

Battery is good, ANOTHER (genuine Suzuki) reg/rec fitted and wired independent earth.

 

Bike charging at tickover (13.4v) and 14.5v at 5000 rpm. However, switch the lights off and it goes up to 15.6v.

 

I figure that as long as I ride it with the lights on, it won't be overcharging, but will keep a regular check on the charging voltage over the next few weeks.

Hoping this won't damage anything, as the price of a new loom is just not worth it.

[MikeR]

when you switch the lights off the residual magnetism in the rotor could be generating the 15 volts despite the regulator saying "off"

 

as it works better under load ,,,

 

fit some handle bar warmers for the winter ?

[Jerzy Woking]

Oxford grips already fitted. It was when they weren't working (a light flashes on the control panel when they are getting enough power) even when the bike was at 8000 rpm was when I knew something wasn't right.

[DodgeRover]

Just out of interest what does it do now with the first reg/ rec unit fitted?

Maybe check the temperature of the battery after a 20 minute run to make sure it isn't cooking it.

Voltage may drop after a while with the lights switched off.

[Jerzy Woking]

It did the same- got a bit confusing but both the Suzuki ones do the same, but didn't test the cheap Chinese one that was on there (although still have it).

 

Good idea about running the bike for a while to check it is ok. Weather looks good tomorrow so will go for a thrash on it to check out all is good now.