voltage from retifier varied CA77

Greggie-e · Post by **Greggie-e** » Wed Feb 29, 2012 9:05 am

Hi,I have tried to search the forum with an answer to this but I have just gotten myself confused.
:{

My battery is not charging so I am trying to identify the problem.

I figured if I disconect the +ve and run the multimeter in series to the wires that then run to the battery then I should be able to read a nice steady positive current.

Unfortunately that is not what happened.

The current that I was reading was varying so much that I could not read a figure off the multimeter.
I tested the multimeter over the battery and got a nice 13.01v, so I think I had the setting correct.

Does this mean that my rectifier is no good, or is my alternator no good?

I have a solid state rectifier from Oregon M/C parts. I am pretty sure I have installed it correctly.
Red to the battery, yellows to the alternator and black to earth.

I have no heat sink mounted as per the Oregon instructions. My fear is that I probably should have used a heat sink and that I may of cooked the rectifier?

Anyone know what is going on here?

Cheers

Greggie-e · Post by **Greggie-e** » Wed Feb 29, 2012 5:52 pm

Could it be that one of the wires from the alternator has a break in it somewhere so i am only getting one half of the alternating current?

G-Man · Post by **G-Man** » Thu Mar 01, 2012 2:32 am

Although the rectifier turns AC into DC it is not necessarily 'smooth' DC. It will have ripples in the output which may be upsetting your meter.

Put the meter on volts and measure the battery volts as you rev the engine. Does the voltage change? If the volts go up then the charging system is working.

Are the battery terminals clean?

G

Greggie-e · Post by **Greggie-e** » Thu Mar 01, 2012 3:11 am

Thanks G-Man,
the terminals are sparkly clean, although my wiring is getting a little old and probably due for a bit of an overhaul.

I will give that test a go this evening (in about 4 hours) and let you know.

Cheers
Greg

brewsky · Post by **brewsky** » Thu Mar 01, 2012 7:00 am

That connector looks like the previous rectifier shorted, and may have melted some wires in the harness. I would definately check the section from the rectifier to the battery if you haven't already, and replace that connector.

As G said, if you are getting 13+ volts across the battery while the motor is running revved up you are probably OK.

If your rectifier is securely mounted to the metal tab it is probably acting as an OK heat sink. I robbed one out of an old computer just to make sure.

Greggie-e · Post by **Greggie-e** » Thu Mar 01, 2012 6:15 pm

I put the wires all back together and measured the voltage across the battery with the bike running.
I had much the same problem, the multimeter read like a mad womans diary.

It does look like there has been some previous damage to the alternator wires.

I assume that the multimeter is not supposed to read like this, so I can only assume that there is an issue.

Sounds like it is time to replace the wiring, something I wanted to avoid as I like riding this bike and it is such good riding weather at the moment!

Anyone know where I can get a new, good quality, wiring harness??

rzgkane · Post by **rzgkane** » Thu Mar 01, 2012 6:47 pm

Greggie-e wrote:I put the wires all back together and measured the voltage across the battery with the bike running.
I had much the same problem, the multimeter read like a mad womans diary.

It does look like there has been some previous damage to the alternator wires.

I assume that the multimeter is not supposed to read like this, so I can only assume that there is an issue.

Sounds like it is time to replace the wiring, something I wanted to avoid as I like riding this bike and it is such good riding weather at the moment!

Running new wires from the stator connectors to the rectifier is a piece of cake. Don't even sweat it.