Solar Charge Port vs Alligator clips

Michael_Godshall

I have a T@B320 Boondock.  

100AH renogy LI battery. 

105 solar on roof
victron controller 75/15
200 ah Renogy suitcase. 

Voyager controller 20Amp 

when I connect suitcase to battery with clips - 12% battery.  Time to full charge 6hr31mins 

when I connect through SAE charge port - 
12% battery - time to full charge. 33 hours. 

What am I doing wrong with the charge port?  

Grumpy_G

You're probably not doing anything wrong but check where the SAE port connects to. It either doesn't connect to the battery at all, or maybe it is connected to the victron controller in which case you don't need the Renogy controller. Note though that 300W total exceeds the capacity of the Victron which is 220W so you can't connect both panels even if you remove the Renogy controller. 

Michael_Godshall

The port is directly wired to the battery. 

Horigan

Weird.  One of the wires between the solar port and the battery may have high resistance/port connection.  I would measure the resistance of each wire with a multi-meter.  Each should be well below one ohm.  For 20A, the wire should be 12 AWG or thicker.

Grumpy_G

Ok, check the "polarity" of the SAE connectors. SAE connectors are somewhat non-deterministic which pin is positive and which one is negative. 

pthomas745

I'm going to vote for polarity, too.  Have a multimeter?  The cable from the solar controller to the SAE port on the trailer must be wired (in the vast majority of the trailers) with the positive output from the controller wired to the "shielded" part of the cable....not that big metal part.  Most likely, the "top" input of your SAE port is wired to the positive posts of the battery. See the picture below.  When you are just hooking up with a easy to see properly wired set of battery clamps....you get it correct and you get good charging.  This would indicate your solar panels are correctly wired, but, whatever you are using to the port is not.

And, fuses at the battery: check to make sure the fuse for the solar port hasn't blown if this is a case of reverse polarity.

A multimeter can answer this for you quickly, as far as the SAE port goes.  This shot shows the "top" section of the port, where the "protected" part of the SAE cable attaches.  You can either wire your cable from the controller to make this happen, or use one of the little adapters to make it right.

Sharon_is_SAM

@Michael_Godshall - how long and what gauge are your extensions?

Michael_Godshall

12 gauge , 20ft. 

Michael_Godshall

Thank you.  Hoping to pick up a multimeter tomorrow-   I will let you know.