Generator doing something weird...

[Teancum10]

My Onan 5500 onboard generator is surging up and down about 9 amps every few seconds. Up and down and up and down.

I have "fixed" it a couple of times by resetting the battery cables, or by just using one battery at a time, but it only works as a solution until the next time I turn the generator on.

There is a clicking noise in my battery compartment that initiates the surge or the power down. Nothing in the trailer itself is turning on and off, so it seems like it is something having to do with the batteries.

Anyone have any experience with something like this?

I did recently replace two of the batteries that had gone dead, but changing to just one, or two, or just the old battery doesn't seem to help much.

Last bit of information--when it is doing it's surging trick, when I turn off the generator, it also shuts down the control panel and everything in the trailer. It starts right back up again a moment later. When I can get it cycling correctly after playing with the battery cables, it works correctly.

[Jim_HiTek]

Corroded main ground cable? If it's not making good contact, that could be an issue. So find and remove the big ground cable from the generator and clean up the surface metal where it's connected and the connector too maybe?

[Skibane]

Originally Posted by Teancum10

My Onan 5500 onboard generator is surging up and down about 9 amps every few seconds.

Are you referring to the AC output current from your generator changing by 9 amps, or the DC battery charging output?

Or perhaps you mean "volts", rather than "amps"?

[Teancum10]

I'll look at that!

[Teancum10]

I do mean amps. I have a display that tells me how many amps the system is drawing. It jumps up, the generator surges to compensate, and it does it over and over again.

[donr103]

When is last time you cleaned armature slip rings ?

[Teancum10]

Never. The clicking is coming from the relay sitting under where the positive wire goes into the trailer from the batteries. There is also some heat in that wire three inches down from that side that attaches to the trailer.

[Teancum10]

The clicking is coming from the relay sitting under where the positive wire goes into the trailer from the batteries. There is also some heat in that wire three inches down from that side that attaches to the trailer

[777 Driver]

Is the engine RPM varying concurrent with the Amp variation?

Fuel filter obstruction can cause the engine RPM to vary.

Take care,
Stu

[Teancum10]

It is, certainly. We did have some lower octane gas in there a bit ago, so a fuel filter issue could be there. Would it continue for days, and randomly go and come back, though?

And would it cause a relay to click?

[donr103]

Then clean or inspect them.. they should be nice and shiny .. then check amps and volts.. clean main jet and make sure adjusted for altitude.. or run carb cleaner through it..

You ask about hot wires.. please post pictures of your concerns and where you believe wires are getting hot?
Good luck and keep us posted

[donr103]

Do you have a transfer switch ? Is that where you hear clicking ?
Good luck and keep us posted

[Teancum10]

The clicking is coming from right under where the hot lead attaches to the trailer. If I grab hold of that wire I can feel it click. Also if I put my finger up against it I can feel and hear the click.

[Teancum10]

Wasn't the main ground cable. All cables checked with multimeter and are good. Batteries all good.