line side of charge controller diversion

Re: line side of charge controller diversion

Vic wrote: »

The venerable Outback Power CCs had a Aux output that would PWM-control PV voltage to a resistance element in a Water Heater, for example.
The MidNite Classic CC has improved this functionality.

The general term for this type of control process is often referred to as " Waste Not ".

You might use your favorite Search Engine to search this site, the MidNite Forum, or, perhaps the Outback Forum, using that Term. Perhaps " Diversion " as a Term might yield additional results.

You will want to isolate any MPPT CC's input from the diversion load with a diode, as the CC can be damaged by looking into the low Z diversion element.

Some who have tried PV side Diversion had not been too happy with the results, and had moved on to AC diversion from the Inverter ... FWIW Vic

Thanks Vic,

I am familiar with the classic being used to drive a SSR, but as you also know, the diversion is rarely done off the array. The reason that I am wanted to play around with this is that I have/will have a somewhat unusual system: I have a large PV array that overall greatly exceeds my electrical needs because I want a full charge on cloudy days. Its part of my "big array, small battery bank" philosophy (I think most people havent adjusted off grid design for .75/watt PV, but anyway thats a topic for another thread perhaps). I also want to heat water. Additionally, I have a poor site so the array will be far away requiring a 600 volt CC (expensive), thus adding multiple 600 V CC's just so I can then throw most of the electricity into water is expensive. Then add in the low voltage diversion controllers and elements and it gets more expensive. You mention diverting off the inverter which is a great idea, I was stuck on battery diversion and line side as the two options.

I am not too keen on PWM'ing the line side of the CC, it just seems like that could wreak havoc with the CC MPPT. According to my calculations, a constant load connected in series or parallel would most likely no result in the loss of MPPT, but without knowing the exact algorithm I cant know for sure. Ill some more research in the sources you suggested and see what I can dig up.