Topic: Dead battery???DIED ON HWY!!! I got lucky!!!BAD PLUG PIC!!!!2nd update

[scooter1]

I took the cb500 down to a friends shop to do some welding in the exhaust and the bike made it down there fine but on the way back it died...dead battery!!!
Could welding on the exhaust caused a problem with my charging system??

[Duke McDukiedook]

How old is it?

[scooter1]

the battery was brand new...as I drove up the hwy it was loosing power and just died....could not even kick start it, and there wasn't hardly enough power for the neutral light!!!
So the bike had been messed with before I got it and some of the wires from the bottom of the electrical box I think is the regulator/ rectifire three wires comong out of it had been replaced....and I assume that the battery might have been hooked up backwards in the past and melted the wires!!!

I now have the battery hooked up to the trickle charger, after I got it home I replaced the wires and boosted the bike and put a multi meter on it and I was just getting over 12v.....Would this be low because the battery was totaly dead?

[Duke McDukiedook]

12V with nothing happening is normal, below 12 after a charge and you have problems.

You need to check you voltage at different RPM settings- 2K, 3K, 4K and voltage should increase to 13 or 14 V max around 4K.

If it doesn't you could be having problems with your Regulator or stator. New batteries could have dead cells on them though.

TT detailed what to look for when a cell is dead on a battery, I forgot what the signs are. Search-fu will probably find it.

[TwoTired]

If they were electric welding with the battery connected, it is possible the voltage spikes blow up the rectifier diodes, or the electronics in a modern vreg.

Check the six diodes in the rectifier.

Cheers,

[Duke McDukiedook]

TT to the rescue, you'll have to test those diodes first.

[scooter1]

Thanks for the help guys!!!!
I just had the battery on charge all night and it was fully charged!!!

1. bike off= 13.6 v
2. key on/headlight off= 12.2
3. bike running @ idle= 12.4v
2000 rpm=14.0
3000 rmp=14.7
So I assume its working ok, I did clean some of the corrosion of the wires and re-soldered them....hope that did the trick!!!

I did make the mistake of not disconnecting the battery  and I was stick welding....my stupid mistake!!! I hope it was just a loose or corroded wire!!

[scooter1]

Took the bike for a little ride not too far...to the gas station , maybe 3km...I know its not that far but it seems to run good!!!
I let the bike sit and idle in the drivewaywith the headlight on  for about 5 min and checked the voltage at idle 1200rpm and its im getting 12.22v to12.60v is that good???

[Duke McDukiedook]

Yes, if the voltage climbs above idle to 13 or 14 max you are OK for now.
I am sure not disconnecting the electrics before welding fatigued your components though.

[tomsweb1]

Hey Scooter... I went to one of theose motorcycle madness things The Bear has on, and the same thing happened to me. It turned out that some of the wires to my stator had become disconnected. A poor connection could do the same thing. By those numbers, though, it sounds like you've got it.

[TwoTired]

There are two schools of thought about the electrical connections.  One is that the battery damps stray electrical impulses to protect the electric devices.  The other is that the battery provides a stable reference so any electrical spikes present maximum differential to any devices in the path between source and reference.

A diode doesn't care if both its connection rise to whatever voltage.  It is the differential voltage across it's leads that can kill them if the difference exceeds ratings.

Welding on the frame components, shifts the electrical potential of the frame.  Where the grounds connect, and the arrangement of devices on the bike determines the electrical stresses placed upon them.  Disconnecting the battery allows devices to "ride the wave" as it were.  However, if the welding currents don't use a path near the devices, the differential is not presented to them.

If you watched the show where Ewan McGregor rode new BMW's around the world, you remember they dumped the bike a broke a part off it, the local welder, welded it back on, and the bike wouldn't run anymore as the electronics were fried by the welder current.

Cheers,

[scooter1]

Good report...I GUESS I GOT LUCKY , Just tookthe bike on a 25 mile ride and all is well...thank god!!!  Checked it when I got back with the bike running and Im still getting 12.4 volts

Here is a pic of the plug coming from the rectifire what the PO HAD DONE!!....it was in bad shape so I cut it out and hard wired it!!!

[tomsweb1]

UGLY. 

[MJL]

There are two schools of thought about the electrical connections.  One is that the battery damps stray electrical impulses to protect the electric devices.  The other is that the battery provides a stable reference so any electrical spikes present maximum differential to any devices in the path between source and reference.

A diode doesn't care if both its connection rise to whatever voltage.  It is the differential voltage across it's leads that can kill them if the difference exceeds ratings.

Welding on the frame components, shifts the electrical potential of the frame.  Where the grounds connect, and the arrangement of devices on the bike determines the electrical stresses placed upon them.  Disconnecting the battery allows devices to "ride the wave" as it were.  However, if the welding currents don't use a path near the devices, the differential is not presented to them.

If you watched the show where Ewan McGregor rode new BMW's around the world, you remember they dumped the bike a broke a part off it, the local welder, welded it back on, and the bike wouldn't run anymore as the electronics were fried by the welder current.

Cheers,

You make it sound like the best thing to do is to pull both wires off the battery and put them together so both sides see 0 potential.

[tomsweb1]

Anything with no source of voltage has no potential difference.

[TwoTired]

You make it sound like the best thing to do is to pull both wires off the battery and put them together so both sides see 0 potential.

Certainly not a bad idea.

AC circuit dynamics are far more complex than DC circuit dynamics.  Welding dynamics fall into the AC effect category at every interruption/change/variation of current flow.

Cheers,

[tomsweb1]

I would not touch the leads together. If any electronic compent were to become enegrized during the welding process, it would have an unobstructed path to ground, allowing the full amperage of the welder to flow through them. Open circuit (no battery) is the best method.

[scooter1]

Well took the bike for a 2nd run tonight, rode about 45 miles and all is great!!!! I am so glad I bought this cb500.....dont get me wrong, I love my cb750 too...but the cb500 is so much fun to ride

cheers!!!