Component Suggestions (especially all-in-one inverter/SCC/charger) for 48V cabin system

[Wineguy]

Hey there, new to this forum and looking for some advice on system components. I plan to install a 48V system on a remote cabin accessible only by boat with no grid power and no cell coverage. Read here, it's hard to get to and has no connectivity for troubleshooting so I would like to minimize connectivity issues between battery and inverter. I have an existing cheapo 12V PV system with 235W of PV, a small charge controller, FLA golf cart batteries and an inexpensive 500W inverter to mostly power lights and chargers for cell phones and power tool batteries. I shut off the inverter when the cabin is not in use.

I am looking at installing an additional (or just new) 800W to 1000W of PV, a 2kW or 3kW all-in-one inverter/SCC/charger, and a single 48V 100ah LFP battery. I think I have settled on an SOK 48V 100 ah pro server rack battery (unless I can get by with the cheaper non UL listed version) and will probably buy 4 used Santan Solar 250 W poly panels (VMP 30V) or 3 new Qcell 365W panels (VMP 39V). I am a little stuck on the all-in-one. I was looking at the MPPSolar PIP 3048LV-MK 3kW versus the EG4 3kW off grid (3000 EHV-48). The EG4 looked interesting until I found out I need 120V PV input for any charging to initiate. I don't have a lot of extra room for mounting PV panels on the roof so I am kind of locked in to around 1000W of PV.

As always, trying to keep the cost down and the uptime and maintenance/troubleshooting to a minimum. It does get cold at the cabin but for the most part would stay above freezing in the cabin at the mounting location. I will have to drop the 48V down to 12 V to run an RV pump and the brains of my RV fridge that I have in the cabin. Secondarily, I am wondering out loud if I could keep this new system running constantly and power a Starlink device so I could install cameras and monitor remotely. The cabin is in a high wildfire potential area so would have major concerns about keeping everything powered up when we aren't there. Any thoughts on system compatibility and system components would be helpful. We use the cabin every month but winter stays are typically 2 to 3 days and summer stays can be 2 weeks or longer. Thanks

 

[DIYrich]

If it gets below freezing, you are likely to have times when the battery can't charge.

You will have to do a load calculation to see how long a 5kWh battery will last. Turning off pump and fridge is helpful to keep starlink running when you are not there.

BTW: if an inverter needs 50 watts to run, that is 1.2kWh per day. If you can run stuff directly off dc battery power, that will help the battery to last longer. That also means you should get a component system so you can turn off the inverter and keep the charge controller working.

Starlink and one camera is about 100 watts. If you disconnect everything else and just run those two things off battery, you could run it for about 2 days without sun.

 

[Wineguy]

Thank you. I think I need to rethink the all-in-one or find one that can charge batteries while the inverter side is off (don't know if they exist) because in my existing cheapo system my batteries stay charged when we are away so I always have a full bank of batteries when we get there and they last 2-3 days in overcast weather in the winter.

If I continue to run my fridge on LP then my summertime use is about 2.4kW/day (max) (without Starlink) and we have good reliable sunshine for 5 hours most days. In the winter load demand is less than half of summer so I think I should be good with 1000W PV.