- Hacker minded Solar power setup
I have been really fascinated about idea of producing your own electricity and being a bit more self sufficient.. We live in pretty much middle of nowhere and because of that and long/old electric line, grid outages have been pretty normal here (during first few years there has been few even over 12h outages) . To over come those we build UPS backuped electric sockets to every room to our house (and garage) when we build our new house.
Now as old UPS device looks like it could need a replacement, i was wondering could i merge these two things together.
I created simple list what i wanted:
- work as a replacement for current UPS system
- solar input has to work even on cases when grid goes down ( grid tied AC inverters will go down)
- most of the work will be done by me
- reasonable starting costs, but have to be extendable easily
- in future ability to handle lifepo4 etc batteries (example powerwall)
- EMI, i am a also HAM, so no need for additional radio pollution
- extra points from opensource / ability to hack
When i was searching this kind of system i found out that there is thing called "energy storage for solar", and it is getting pretty big.. idea behind is that you could store your surplus solar energy to battery and use it when solar production is going low, so you are increasing your self consumed part of your solar production.. I instantly found out that this type of system could full fill most of my needs..
When compared different vendors and systems one stands up on many ways.. Victron. Company has started by building power system to naval systems, and is now doing also many kinds of solar related products and systems. one of the coolest thing is that they are truly making most of system open source and there is already community around victrons opensource things. they are example releasing full code for their "control unit", and actual image to run that software on rasberrypi if wanted.. All protocols and interfaces are well documented and some sample codes also in python! awesome!
I was also really lucky when i was asking products / prices on finnish suppliers, that one of the suppliers technical guys was A. Really got into deep on Victron world B. I did know guy from another hobby as well
So, with helping hand from suppliers guy, we did some specifications for upcoming system.
victron ESS system
(inverter+charger(multigrid)/controller(venus)/dc solar controller(mppt)
about 2kw of solar panels
big cheap 48v set of batteries (12kwh)
(i did have source for lightly used ones)
So with this setup i could full fill all my planned features
plus it allows few extra:
- selling surplus energy back to the grid
- acting as solar energy storage, so actively using some percentage of battery capacity for ess
Actual list we ordered:
1 Kpl ?MultiGrid 48/3000/35-50 PMP483024000
1 Kpl VenusGX BPP900400100
1 Kpl VE.Direct Cable 0,9m ASS030530209
1 Kpl ?BlueSolar MPPT 150/35 SCC020035000
1 Kpl 48Vdc 125A Mega CIP136125000
2 Kpl Fuse holder for Mega. CIP000100001
1 pc Energy meter ET340 REL300300000
6 kpl Recom 270 Poly panel + mounting gears
cables for connecting panels to MPPT
Cables for batteries
some AC cable and fuses
few MC4 connectors
safety switch outside (this is needed if connected to public grid in Finland)
Actual installation was pretty straight forward.
On software side i did want to integrate all relevant data feed to my emonCMS system what i have used since we moved to our new house.
There was indeed good selection of apis and different interfaces to gather data and modify settings etc..
- Victron vms web portal (venus os controller can send data here)
- - here is good proper rest api, i do read some kwh related data from here (self made python script)
- venusOs offers mqtt and TCP-modbus
- - both offers pretty much all of the data well documented fashion - did select MTTQ for my data gathering, i do read most of the values this way to emoncms (self made python again)
There is also easy way to alter settings thru modbus or MQTT, there is example relays on both venuxgx and multigrid you can use further automation..
Sample pictures are from 16.11.2017, when snow has already covered panels.. let see on next summer what the real production will be.
All in all I am really satisfied for solution, it turns out to be much more than i even think on first place
costs were pretty reasonable if you count that this is actually working as a UPS (that was something i was replacing on first place)
All gears did costs pretty much 3500e (did get those batteries almost for free)
Size of the UPS i was planning will cost easily more than 1000e, so 2500e for getting 2kw of good quality solar+inveverter is not bad at all..
Tho it was not biggest nor only goal for this project, from any calculations it should be decent investment too, and will pay it self off on a reasonable timescale.
I did most of the work by myself as planned
(some helping hand from licenced electrician)
it is quite likely that we add a another set of solar panels to our roof next summer, which is pretty easy and cheap (need only panels and cheap mppt controller at this point)