I will try to expand and stay on subject…….. DamonHD may need to translate a bit as I do wonder around a bit, sorry.
I do have wind turbines on my system that DC charge the batteries, but dump to 8kW of independent air heaters 100 meters away in the main house.
However, some reasons why I have gone down particular concepts may need further explanation.
The readily well priced heating matts need a constant voltage, the element wire does not want to burn out, or your digging up the tiles. So dump loading is a NO NO, and direct feeding from the PV is inefficient.
The PV panels I use are the industry standard. Each is 250w with a VOC of 37.8 volts, (its max the panel puts out when in a working system). About 1.6 meters by 1 meter.
The manufacturers I use are good quality but not the Rolls Royce like LG, Panasonic etc, and what's at a good price when I want them, including taxes no more than £150 GBP each.
I have Sharpe, PV, Yingli, Eurosolar, Renosolar, Rensu, Knive etc. All at that 37.8v VOC.
Now to get that 10% in murky gloomy days, I use Controllers that are MPPT, that takes a high DC voltage and converts it down to a 48v DC battery voltage, 180vdc max with the Midnite Classic controller or 120vdc max with my Tristar MPPT controllers. However these controllers are expensive, rarely come up second hand, but they are good and their battery charging regimes excellent.
Or,........... and what I am now using is Solar Inverters that are GTI's Grid Tied Inverters that take a higher DC voltage about 550vdc and MPPT, get it down to match the Normal Grid. But I fool these GTI machines by running them from my OzInverter, 48vdc to 230vac, created Mini Grid to function.
The power can be directly used at my buildings without having to go through the batteries or the Inverter.
Which means for my large system, I No longer need to increase my 1300ah battery bank in size.
These GTI's are now cheap as chips here in Europe, as Houses with PV installed for receiving the Government FIT grants etc, want the Max 4kW install, so under 3kW they are sometimes as little as £160 GBP, for brand New solar GTI SMA 2.5kW. Or even cheaper if a Used replaced from a enlarging installation.
I did purchase, very expensive, what I thought was one of the best manufactured battery Inverters, 48vdc to 230AC, a SMA Sunny Island 6kw, but sadly the manufacturer has done some odd things with the control software so it does not DC couple and AC couple, (what I am doing), without you spending vast amounts of money on just there manufactured interface equipment. What they have done is to allow the machines Frequency to climb so high that normal household equipment/appliances fail.
I kicked the machine out and its on it way back, and I made my Own OzInverter from Oztules remarkable endeavours.
That's basically it.
Depends on how big you are going, how cost effective you want, and your sustainable philosophy.