I strongly don't recommend connecting 7.2 kW of panels to an inverter (any brand or model) that is rated for 4 kW of PV. I know it will only use what it needs in theory, but the Solar Charge Controllers assume rated panel power (or a little higher), and can overshoot and undershoot quite badly with severly "overclocked" PV. When the Pylontechs disconnect due to over-voltage, unusual and sometimes bad things can happen.
Also, the bifacial panels are quite new; I would call them an untested technology. Do you intend to mount them vertically to get east-west sun, or conventionally on a roof? I've not heard of the former before, and would not know how to mount them safely. The 6 mm thickness modules seem fragile to me (perhaps you are considering the ones with the frames, but those are only 10 mm wide at the top and bottom, and 30 mm wide at the sides). I note that I could not see any 300 W models; the lowest models I saw were 305 W (unframed) and 310 W (framed).
Those will be able to be charged at 37 x 3 = 111 A, which should be able to take the full power of your PV array (nearly 12 A per string, or some 96 A).
I will perhaps add a "SCC MPPT 3kW" to cover what the PIP can't
I would recommends this (or any other external MPPT). Or a second PIP in parallel to take half the PV strings (see below).
I will create 2 electrical cicruits in my house, one 48V and one 220V ... those circuit are pretty simple, i will step down the 48V circuit with transfomers depending on what is needed, 5V here .. 12V here...
By "transformer", I assume you mean a DC-DC converter, since your 48 V is presumably DC. This is an attractive idea in theory, but consider the problems:
- A completely separate wiring system, which should be physically separate from the AC system (not sharing the same conduits or channels, for example).
- The difficulty of switching 48 VDC at significant currents. Ordinary AC switches will not be suitable, as they will arc. I get away with AC switches in my house for a few lighting loads, because I use 24 V (makes a huge difference), and the loads are very low power (< 1 A). 95% of my lights, and 100% of my power, are 230 (or 240) VAC. The 24 VDC system is a legacy that I keep as an ultimate backup in case two other systems fail, or something trips the house Residual Current Device.
- The difficulty of fusing DC (fuses are larger and way more expensive)
- 48 V cables need to be some 5 times thicker for the same power level.
The goal is to switch the inverter off each night automaticaly, cause those 30W are way too much in my opinion and loss in transforming also add up while my 48V-12V transformers kind lose near nothing.
I note that if you have a charging source (PV all day, or you have utility AC-in at night), then PIP inverters don't switch completely off, even if you turn off the switch. If you don't have AC-in connected, then leaving the switch off will cause the inverter to switch off at sunset, but that's presumably not what you want. Turning off 230 VAC power at night means every clock in the house will lose power (apart from battery powered ones, of course). Personally, I find the clock in the microwave to be very useful.
I'm also planning on using the unused energy to power my water heater, for that i will use an arduino and a small decicated solar panel (or just a led if precise enough) which will inform me on how much energy is available(led will give me insolation, i will evaluate what is available on my 24 panels, i got a smart algorithm in mind.. well .. at least it seems smart to me ..

).. i will then switch my water heater resistors accordingly, i will use 3x48V resistors : (200W, 500W and 1000W) => 200W > 500W > 700W > 1000W > 1200W > 1500W > 1700W are possible. I'm planning to connect those resistors directly on the charging port.. does it sound stupid ? (to avoid the inverter loss) Or i could eventually connect them directly to the panels .. but this solution is kind harder to build, but could be even more efficient..
This is another idea that is attractive in theory, but difficult in practice. You'll need several DC rated contactors, and if you connect to the panel side, it's ~100 VDC, so those are different elements than ones suited for 50 V. Resistive elements draw 4x the power at 2x the voltage; you very likely can't overpower the elements by 300%. You can't ue the ordinary thermostat; it's only rated for AC, so you'll need a special thermostat, or some other sensor, and then there are safety concerns. It likely can be done, but it's very tricky.
My questions : What is the best voltronic / Pip to buy today, i need 5kW, i think i will not need parrallel capability cause 5kw is already plenty for me, and this would double the sleeping energy cost.
I thought that 4 kW would be enough for me (one PIP-4048MS). But now I'm running two in parallel. The main thing I didn't cater for is charging an electric car. You may not have one now, but in 5-10 years, that could well change. So I'd at least get a parallelable model, even if you go with only one inverter for now.
Are those with the High pv voltage (500V) more interesting then the 145V max pv voltage ? (PIP MS, MK, MG, GK ..?)
The 450 V or 500 V max SCC models make it easier to wire the solar panels, that's all. PIPs don't have insulation monitoring, so the higher voltage models aren't legal in Australia; I don't know about other countries. There is no patched firmware for the higher voltage SCC models, although there may be one or two lightly patched versions (just fixing the premature float bugs) in future.
One last question, for people that already tried both, would a victron system be really more efficient in terms of sleep energy cost, in term of inverter efficiency, in term of Mppt reaction time.. voltage start up .. ?
Total : 2900€ ... vs a PIP 5048MG that would cost me 650€... that a quarter of the price .. !
Wow. I haven't checked the price differential for years; it was something like that ratio back then. I thought the newish Multiplus II was supposed to be much more competitive.
Nissan Leaf 2012 with new battery May 2019.
5650 W solar, 2xPIP-4048MS inverters, 16 kWh battery.
1.4 kW solar with 1.2 kW Latronics inverter and FIT.
160 W solar, 2.5 kWh 24 V battery for lights.
Patching PIP-4048/5048 inverter-chargers.