Topic: CB550 regulator current draw?

[middletons]

Troubleshooting some electrical gremlins and in the process noticed that the main 15amp fuse was a bit warm (engine off, key on). Decided to measure the current draw across that fuse and got 2.4amps.  Disconnected everything at the front of the harness and got the same number. Narrowed it down to the regulator.  As soon as I disconnected that, the draw went to nothing. Is it normal to have that amount of current draw from the regulator (again, engine off, key on)?  Seems high.

[Erny]

when key is on, regulator feeds field coil. Coil shall have 4.9Ohm (+/- 10%). So taking reference 12V, current is around 2.44A static (engine does not run).
looking at service manual, current should be 1.6Amp, but I assume they assume engine running - attached

All in all , I think your case is normal

[middletons]

I see now, thanks for the explanation. I did not catch that later in the manual it gives 4.9r as the field coil resistance. 👍 on with the troubleshooting...

[maxheadflow]

If you fuse is getting warm at only 2.4 amps, you probably want to clean the fuse contacts and make sure the wire connections to contacts are good.

Beside the resistance of the field coil the looks to be additional 36 ohms to ground through the regulator. Additional load can come from indicator lights, and running lights.

[middletons]

yep, getting a new fuse block.  The current one is a bit melty.  In this situation, everything is disconnected from the harness but the regulator, so no additional draw.

[RAFster122s]

HondaMan makes a nice pre-wired modern blade fuseblock.