MPP Solar + Batrium Design questions/thoughts

Hello guys,
have read threw this thread, and here are my questions / thought :
My project is to go solar + battery (very original around here ^^), 2 strings of solar PV East and West on the roof sides, and later a third one guess where . .. south on the flat roof of my house.
I get headaches thinking how I will configure this with the MPP inverters, I have studied the Victron solution, but it's too expensive for me.
Regarding power usage, I'll start easy, and increase capacity with time, and confidence in my skills. So let's say 1-1.5kWp on each side of the roof and 2-3 kWh battery to start with. In the end, I think 15kWh is what I need to run the house ...
Based on my solar potential, I would need 15kWp to have enough solar power during winter ! I'll propably never get so much, but I keep that in mind.
It will have to be grid tied just for times with battery + solar shortage, but with the ability to not feed anything to grid, my house is running on a single phase.

What should I do :
a- go with a big inverter single phase with 3 mppt charging my battery bank : 5048MST 180A 5kW : not Ideal to start with because it's not cheap, its made for 48V battery, also harder to increase capacity
b- go with three smaller inverter PIP MSX 2424 in parallele: not ideal either because it's for 24V battery only, has limited PV Power input of 1500W (so guessing Max 2kWp string), but I could built up my system as I progress, starting with a string, an inverter, and the battery, then add the second set, ...
c- go with multiple inverter 48v battery capable in parallele like the PIP 3248 or the pip 4848 MS ...
d- anyother option I havn't thought of

Last but not least, I also read a lot about BMS, and the Batrium system seems to be the best so far (not talking about price) : How do batrium and MPP Inverter talk together ? if they don't is it because they really don't need to share information, and if not, isn't it the down side of the couple MPP / Batrium?

Created new thread as it is more than just about MPP and moved to appropriate section. You can change title by doing full edit

Korishan said:

Created new thread as it is more than just about MPP and moved to appropriate section. You can change title by doing full edit

Click to expand...

Yup, I started just about MPP and then added more stuff to it !
Thanks

You can also do the charging and discharging with separated devices...
use "cheap" inverter(s) to take care of the loads, and expand or change them later in your build when needed.
For charging, use something like the PCM60 's, ie one for each string of solar panels.

Just another way to do things.

Batrium will not talk to MPP inverters ( for now ). Danil (Daromer) has done some work with batrium talking to a raspberry PIandhave the raspberrytalking tothe mpp inverter to quit charging... but i'm not sure ifit is a finished project.
Take a look at https://secondlifestorage.com/t-Esperyd´s-Raspberry-PI-project&highlight=solar+sis

@wim thanks for the reply ! Thats what I first thought, and thats the way I would do it with the victron solution but I can't find a "cheap" inverter that "just" invert, at least within the MPP Solar devices.

The only down side I can see with this solution, is that if its not "made for" like victron with an ESS supervisor, then I'm not so sure about battery life, battery management, and safety.
I think (but I might be wrong) you need something (a software) that will manage the energy. So taking a Inverter, and some MPPT that can't talk to each other ... I'm not convinced

Is it the way you went ?

As for "cheap" inverter i was thinking of something like this : https://www.benl.ebay.be/itm/3000W-...349551?hash=item212b0f636f:g:RWAAAOSwdjdaAwFD

I did not take that way, but used a hybrid inverter Mpp and the batrium bms.... they do not have to beconnected. The charger in the inverter stops charging when full voltage is reached, the bms keeps the packsbalanced and watch for high/low voltage, current and temp., when one of these values is getting to high or low, the bms disconnect the battery.
Safe? yes, perfect? probably not, but it's working for me

This is my build: https://secondlifestorage.com/t-Instant-powerwall

Not hard to get the Batrium to talk to the inverters either with a Raspberry in between as example

I just submited a pull request to Daniels' solar-sis project with implementation of several commands for settings in the PIP4048/5048:

-output_source_priority
-charger_priority
-bulk_charging (voltage)
-float_charging(voltage)
-utility_max_charging (current)
-max_charging(current)
-back_to_grid (voltage)
-back_to_battery(voltage)

This allows whatever scripting logic you want to control these kind of inverters based on batrium reported values.

https://github.com/opengd/solar-sis/pull/1

I hope Daniel will review and accept the changes, meanwhile you can use my fork of the project if you're in a hurry to get it working.