Topic: Cb550 charging system issues

[ScottmSmith75]

1974 cb550 with m-unit

I have tested stator and field coils all are within spec as far as resistances.
Tested stator while running getting proper AC voltages. I have using a shorai ltx battery and and r/r have tried connecting black wiring to aux2 and 12v switched power  confirmed field coil is working. Wrech on stator cover is sticking so magnetic field is good. My battery goes from 13.5v when not running down to 12.7v when running increasing rpm does not do anything. Everything else on the bike works great just can't charge the battery. I have the rr for lith battery I should be running around 14.4v when running. Any ideas? Any help would be greatly appreciated been wanting to ride this bike more than a couple of block before battery dies.

Scott

[calj737]

“ and r/r have tried connecting black wiring to aux2 and 12v switched power”
And when you had the RR BLACK connected to switched power or AUX, what was the stator output?

You posted that you tested everything but did not post your actual voltage results from those tests. Please do so.

[ScottmSmith75]

It was the 12.7v volts checking voltage from the red wire when field coil is power is 12.5v
I have double checked all my connections even swap swapped the green wires on r/r just incase no change. I'm at my wits end not sure if I go a bad r/r. This is a new build ieven got a used stator just in case. When I check a/c voltage at idle I'm sitting around 24v and will increase with idle. So that tell me stator is good right? If I run the bike and test voltage coming off red wiring (not connected to anything) I get around 12v. I have tried some many options nothing giving me 14v I even wired the black and red straight to battery to see if that made a difference. (I didn't leave it like that as not to drain battery) Should I reach out to Rick's and see if it is a bad r/r?

Scott

[calj737]

You need to be specific with voltage measurements. “around 12v” means nothing useful.

Provide the specific voltage for the following tests:
DC voltage directly from battery, engine and key OFF-
Same as above with key ON, engine OFF -
Voltage at AUX2 with RR Black connected and key ON -

After you do this, we will move on to AC readings.

[scottly]

Hi Scott. The red reg/rect wire should be connected to the battery plus terminal, and all solid green wires should be connected to ground/battery minus, not just each other.
Also, the Rick's lithium reg/rect limits the voltage to about 13.9 instead of the optimal 14.4 Shorai states.

[ScottmSmith75]

Thanks for the responses guy I found the issue pinched wire in the harnessing I removed the chain cover I would get 14v at battery. Found 2/3 of the yellow wire had been pinched along with the white. Replaced the wires and we are good to go.  That was my first post here and glad there is a community like this. Thanks again

Scott

[ScottmSmith75]

Update managed to get 13.7-14.8v when riding the bike lights on. I ended up a new stator from Rick's and using Rick's R/R with the m-unit I can monitor voltage while riding everything is great then about 15-20 min into ride voltage drops from 13.7-14v down to 13.1-13.2 which is battery voltage. No charging. Now if I stop let the bike cool down and start it up again I'm charging  for another 15-20 min. Resistances on new stator are obviously good field coil is 5ohm. I tried putting in another field coils I had from parts bike which test 4.5ohm will charge up wrench sticks to cover when charged. Don't get any charging when running. Any ideas on what I can check or test to pinpoint what  maybe overheating and failing?

[calj737]

It’s possible that the “recharging” has stalled because at that time, the battery has been fully recharged while riding. If you don’t have a great deal of draw on the system, the regulator should slow down the recharge rate. Plus lithium batteries operate quite differently. They are quick to charge up to 85% but the remaining 15% of recharge takes as long as the first 85%. Personally, I wouldn’t worry (based upon your description) unless I saw a voltage below 12.8 while riding or an inability to restart the bike after a ride and it’s cooled down for 30+ minutes.