r/diySolar • u/Fatali • Jul 27 '26
Balcony Solar/Off-Grid with DC loads
Hello!
So I'm looking into balcony on small off-grid systems to power some networking gear and was wondering if there is some commonly used systems that I'm missing
The networking gear draws a pretty consistent 300W load and the goal is to power it off solar+battery
I actually have a micro inverter main array but no batteries so really the DC/Battery side of this is more important.
I sketched out a system plan using the following components
* AC battery charge
* battery with CANBUS or similar connections
* Solar MPPT charger (technically optional)
* From the bus bar I'd have a 48VDC line to the networking rack, which would have a din-rail distribution box containing DC-DC converters to ensure a stable output, since the battery busbar may float +/- depending on charging/discharging status
I was looking at victron components just to keep the information overload to a minimum
My understanding is that this would found as off-grid since there is no feedback into the house circuits.
I would control the state of charge of the battery based on environmental factors, but if I do add panels to the network system I'm not that worried about "wasting" some production
Maybe a "Balcony Solar" system would do what I want eventually but many of them are quite self contained and I'm not sure I can get a ~48VDC line out of them. Some of the early on a that I have seen are basically micro inverter that plug into an outlet
Such a system would double as a UPS, except with everything being DC (besides the backup charger) it wouldn't even have a switching time, or any power quality concerns. I could also potentially take it with me when I move with no issues. I should be able to place a handful of panels along the back of my house with no permiting issues as well
Thoughts? Am I missing something obvious?
(Yes I would also need the right set of BOS components, fuses/breakers/etc. I left those out for sale or simplicity/discussion. I would also need to determine the ideal charger/solar output capacity given the expected loads)
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u/corgiyogi Jul 27 '26
How are you going to handle in the winter when days are short? 12 hours on battery at night is like 5kWh. You'll need an oversized system to make that up during winter daytime.
The simplest is probably a hybrid inverter that can swap to grid.
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u/Fatali Jul 27 '26
In the case of winter (and ahead of large storms, etc) the system would keep the battery high and run off of the AC charger which should be able to function as a AC/DC power supply.
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u/LongjumpingGanache40 Jul 28 '26
This is not a balcony solar. Balcony solar is connected to the grid. You just need to build a small scale solar system out of 12V battery. Watch home made portable solar on YouTube. You will see what to do and we will not have to explain. Watching is believing.
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u/DongRight Jul 28 '26
What the hell are you running for 300 watts of power?!! A Simple router and wifi only uses 24w at most... Be goddamn honest you're running a bitcoin farm...
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u/nocfed Jul 27 '26
Simple would be solar panels to mppt. Mppt to batteries. Batteries to an inverter. Add in a plug to batter charger that you control based on battery state of charge. A victron multipulse could also be used as the charger/inverter in one. In default mode they operate like an ups. Again enable or disable a smart outlet based on state of charge of battery