Conext XW6848 issue?.

cz7gdmcan

I serviced my three year old off grid Cummins C13n6h generator yesterday (oil, oil filter, air filter, check valve lash). It is connected to a Conext XW6848, 2x MPPT60 and 24kwh batteries plus 7kw solar.  With snow covered solar, I ran the generator, but saw that it was not charging continuously., instead it was charging for three or four seconds then no charge for a minute before repeating.  I can sometimes get it to charge by setting max charge percent to half of normal. Sometimes I see the mppt icons flash red on my app, but no error message. I have done several system reboots and powered off and on the XW. 

The multitude of settings look as they have been for the last three years, apart from charge percentage above.

Any suggestions?

mike95490

half of normal charge rate may indicate that the RPM's ( frequency ) of the generator may be off, and when it loads down from the charger, it slows too much, then get's dropped.
 Any stickiness in the governor could cause this, or something with air intake.   Were the valves very far off of adjustment?

ELYNN4

You might check your fuel supply to make sure the generator isn’t starving.  Is this NG or propane?  If the weather is colder than normal and you are running on propane with a small tank you may have a vaporization issue.

cz7gdmcan

Thanks, Guys.  I rechecked the valve lash and one was off.  As suggested, the charging was dropped when the motor slowed too much under load and dropped below the minimum hertz at the inverter. I have corrected the valve and all runs sweet.

RCinFLA

Two things are critical.  First is rpm's to produce freq within range.

More important is stability of frequency.  If generator governor control is slightly unstable causing rpm to vary the inverter will release from generator.  Inverter phase tracking has very slow tracking rate.  No more than 0.3 Hz per second of wobble.  A DVM with freq capability will not pick this up.  Best to listen for constant, smooth even sound with no 'wah-wah' variance in sound.

Also if you have a sudden heavy load it can pass through inverter to generator causing it to bog down, dropping freq and causing disconnect by inverter.