Solar Controller Problems

Good sleuthing.    This could explain your issue - with the battery fuse blown, all the charge current was flowing through the load terminals - which means it was likely not being sensed by the MPPT controller correctly, which could certainly cause issues.    Before the fuse blew, you had a path through the load terminals from the main 12V bus back to the battery.   If you charge from either the truck or the on board converter, this could lead to reverse current to the battery though the load terminals, which definitely has the potential to cause damage. 

 

The easy way to fix this would be to disconnect the load terminals from the controller.   If you want to still use the load terminals, you need to find the other path by which the fuse block is getting power and disconnect that, so the fuse block is only powered through the load terminals.  You also want to make sure that any other charge sources (truck alternator, converter) are connected directly to the battery and not the fuse block. 

 

 Note you can only draw 15A or whatever you controller is rated for from the load terminals.   If you have higher current loads (eg and inverter) this won't work.  

PS it sounds like FWC owes overland solar a few charge controllers.   As mentioned earlier wiring is not FWC (or ATCs) strong point.

Thanks Rando.  I never paid much attention to "Load" wires option nor bothered to use them.  Good to hear more how they should work.

Funny thing is. Now that I’ve replaced the fuse at the battery, and left everything else the same I no longer get a ‘current’ reading in the battery or load output section of the app. Confused!

Funny thing is. Now that I’ve replaced the fuse at the battery, and left everything else the same I no longer get a ‘current’ reading in the battery or load output section of the app. Confused!

Like rando suggested, you need to simplify so you can troubleshoot more effectively.  That means not using the load connectors for now, and then opening circuits/connections until the fuse block loses power. 

The easy way to fix this would be to disconnect the load terminals from the controller.   If you want to still use the load terminals, you need to find the other path by which the fuse block is getting power and disconnect that, so the fuse block is only powered through the load terminals.  You also want to make sure that any other charge sources (truck alternator, converter) are connected directly to the battery and not the fuse block. 

Seems the fuse block may be intended to receive power directly from the battery and converter? Perhaps the positive wire from the load terminal of the controller to the fuse block should never have been installed,

 

This from the FWC Operation Manual:

When the camper is plugged into 120v shore power or a generator (electricity), the silver 12v master switch can be in either the “IN” or “OUT” position to operate the appliances in your camper. However, if you would like to have your camper battery(s) recharge from the 120V shore power electricity, the silver must be pulled “OUT” to allow for recharging of the auxiliary battery through the 30amp IOTA power converter

Not sure yet why the wire is going to the fuse block and why FWC wires it that way in the first place. Seems that once the fuse blew it only caused you grief and labor.

I would remove it, tape the end and see how it works from there on.

Seems the fuse block may be intended to receive power directly from the battery and converter? Perhaps the positive wire from the load terminal of the controller to the fuse block should never have been installed,

 

This from the FWC Operation Manual:

When the camper is plugged into 120v shore power or a generator (electricity), the silver 12v master switch can be in either the “IN” or “OUT” position to operate the appliances in your camper. However, if you would like to have your camper battery(s) recharge from the 120V shore power electricity, the silver must be pulled “OUT” to allow for recharging of the auxiliary battery through the 30amp IOTA power converter

 

OK, having never owned a built model of FWC, just shells, this is my first time hearing that whole quote.  Based on that, I think that this pic depicts what it says:

 

Does this look like what you expected?  If this is correct, then we can make some sense of what you are observing.  And if it is wired right, then all other stock campers should exhibit the same behavior.

 

Yeah, I can’t follow all the wires end to end to be sure there are no other connections. But your diagram reflects what I find.

Yeah, I can’t follow all the wires end to end to be sure there are no other connections. But your diagram reflects what I find.

OK, so then what do we know?  If the diagram is accurate:

 

1) With the camper on AC power, you will always have power inside the camper, no matter what position the kill switch is in.  Is that the case for you?  Is that the case for all FWC from the factory?

2) If you unplug the AC power, and leave the kill switch OFF (is that pushed in?) then if the LOAD setting in the MPPT is set to OFF, then you should have no power in the camper.  Is that the case for you?  Is that the case for all FWC from the factory?

 

3) With kill switch OFF and the LOAD setting in the MPPT set to ON, you should have power, even with no sunshine falling on the solar panels, you will have power because it goes from the battery through the MPPT to the LOAD terminals. (That sounds goofy to me.... because it means the KILL switch doesn't kill all power).  (Same questions).

 

4) Per your troubleshooting above, if you disconnect your LOAD terminals, and the KILL switch is OFF and AC is not plugged in, you should have NO power in the camper.  (Same questions)

 

Any other testing you can report on would be good.