Post by Admin on Sept 15, 2018 14:43:45 GMT
Jun 30, 2018 1:48:46 GMT Guest said:
I recently bought a windynation 200 watt system that came with a PWM controller which happened to be a positive ground controller.
I decided to hook it up anyway in my bus even though I had to run extra ground wires from a new truck fridge I installed. I have other negative ground equipment such as my sinks water pump-I decided to stop in my tracks and buy the Rover 30A mppt that works with a negative ground system.
But now I'm a bit confused. On my windynation controller, I ran my load wires through the controller so I could monitor my power consumption, instead of coming straight off the battery. With the Renogy controller, I still need to run a load negative wire to it. So will I run the ground wire from my fridge to the load negative port as I did with my positive system. If so, then what about my sink pump! It seems like I would still have a positive system if I have to run all my negative load wires back to the controller (which is why a bought the renogy negative system to AVOID this extra wiring)
What am I missing here!!
Another reason I wanted to change back to a negative ground system is i couldn't charge my house battery off of my alternator through a relay when the house battery was not grounded to the chassis any longer since the battery ground went to the controller. Living in the Nw, where sun is not always present, I like the idea of charging the house battery when needed.
I hope someone can unfreeze my brain freeze!!!
Thanks
Jun 30, 2018 13:03:17 GMT @rabird said:
Grounding is to the earth.
A positive 'ground' controller has the PV+. BATT+ and Load+ tied together internally (grounding to earth in one spot grounds all to earth), controller regulation, load timer, low voltage cutoff is done on the negative. If the battery is tied to the chassis and loads use the chassis to complete the circuit then the timer/low voltage/current monitor etc does not function. Running a negative back to the load terminal neg allows the controller's timer/low voltage cutoff etc to work correctly. No grounding is needed and the battery negative can be tied to the chassis as a common but loads need to complete their circuit through the controller's load terminal (not via the common) for the timer and current monitoring to work correctly.
Is Rover negative 'ground'? lots of E4 over current errors on this forum with the Rover & load terminal use.
So a negative 'ground' controller should be the reverse of above, again no grounding to earth is needed. Controller positive would control regulation/timer, I am unaware how current is measured ie does it need measured loads negative to return to the load terminal or is common chassis back to the battery acceptable?