Hi All,
Here’s my setup for our off grid cabin that we recently completed. Goal was to have enough battery and solar to basically (almost) never have to run the generator. The cabin consumes more electricity in the winter than the summer, due to having to run the furnace, and of course there’s less solar hours in the winter. On an average winter day, we consume 12 to 17 KWh. With the setup below, I can run 5 to 6 days before the generator will have to kick in, which is plenty of time. It hardly ever is cloudy for that long in a row over here.
The cabin has only one 220V load, and that is the well pump (about 11A @ 220V). In the future there will be an electric vehicle 20A or 30A 230V outlet as well.
I started out with Full River AGM batteries and an Outback inverter/mppt/mate system, but I didn’t like either enough to keep them. The long tail to get the AGM batteries fully charged is a waste of solar hours, and the (pretty extreme) capacity degradation in the cold, plus the fact that to get the optimal amount of cycles you should not discharge to about 60% SOC, made the AGMs less than ideal. The outback system simply isn’t as cool or flexible as a Victron setup, so that had to go as well.
So this is the setup:
Be happy to answer any questions!
Barthold
The full setup in one picture.
The five Trophy 304Ah batteries, with an interesting wiring setup as per Trophy's recommendation. I built an insulated box around the batteries, as it does get cold here. The box is two layers of R13 rigid foam, for a total of R26. There's also a lid with the same insulation (not shown).
Midnite solar panel with 250A breaker to the inverter on the left, and the 175A solar controller breaker on the right. The top breakers are not used.
Four of the 11 panels on one pole. Rest not shown.
Looking down into the cistern where you can see the Flowline Echopod measuring water level. The cistern is about 300 foot away from the Victron GX Tank 140. Works like a charm!
Screenshot of Victron VRM in action. This was a cloudy day, not a lot of solar produced.
Here’s my setup for our off grid cabin that we recently completed. Goal was to have enough battery and solar to basically (almost) never have to run the generator. The cabin consumes more electricity in the winter than the summer, due to having to run the furnace, and of course there’s less solar hours in the winter. On an average winter day, we consume 12 to 17 KWh. With the setup below, I can run 5 to 6 days before the generator will have to kick in, which is plenty of time. It hardly ever is cloudy for that long in a row over here.
The cabin has only one 220V load, and that is the well pump (about 11A @ 220V). In the future there will be an electric vehicle 20A or 30A 230V outlet as well.
I started out with Full River AGM batteries and an Outback inverter/mppt/mate system, but I didn’t like either enough to keep them. The long tail to get the AGM batteries fully charged is a waste of solar hours, and the (pretty extreme) capacity degradation in the cold, plus the fact that to get the optimal amount of cycles you should not discharge to about 60% SOC, made the AGMs less than ideal. The outback system simply isn’t as cool or flexible as a Victron setup, so that had to go as well.
So this is the setup:
- Five Trophy 304Ah lithium batteries, for a total of 1520 Ah @ 51V, or about 77 KWh. Love those batteries!
- Victron MultiPlus-II 48/10000/140-100/100 inverter (230V model)
- Victron 100A Autotransformer to feed a standard electrical panel for my 110V needs
- Victron Smartsolar MPPT RS 450/200
- Victron CerboGX with GX Tank 140 (super cool! I can monitor the amount of drinking water in my 3000 gallon cistern that way)
- Relay 1 of the CerboGX is used to control the well pump, when the water level in the cistern is getting low
- Two Victron BMV 712 battery monitors. One is hooked up to the CerboGX to provide SOC, and battery temp. The other is just there so I can ALSO see the SOC in the cabin, on the display of the BMV 712.
- Whenever I get the Trophy batteries to talk to the CerboGX, one of them can go. Working with Dan @ Trophy on making this happen, but so far no luck.
- The main BMV 712 is also used to start the generator on a low SOC of the batteries. I couldn’t use the CerboGX for this, as the relay on the CerboGX controls the well pump.
- 11 Silfab 490 solar panels. These things are amazing, Although officially rated at 490W, I have drawn 670 Watts per panel out of an array of six of these panels. Being at 9300 foot altitude, and a nice sunny cold winter day, gets the best out of them. I put them in a string of 5 and a string of 6 panels, and use two out of the four MPPT controllers in the Victron MPPT RS (so far).
- Midnite solar MNE250STSLT E panel, which is used to house a 250A breaker for the inverter feed, and a 175A breaker for the MPPT controller feed.
- Flowline Echopod UG-6 acoustic water level sensor to measure the water in the cistern
- Some odds and ends like the well pump protector, well pump remote controller, generator on/off/auto switch, and temperature monitor and heater inside the batter box.
Be happy to answer any questions!
Barthold
The full setup in one picture.
The five Trophy 304Ah batteries, with an interesting wiring setup as per Trophy's recommendation. I built an insulated box around the batteries, as it does get cold here. The box is two layers of R13 rigid foam, for a total of R26. There's also a lid with the same insulation (not shown).
Midnite solar panel with 250A breaker to the inverter on the left, and the 175A solar controller breaker on the right. The top breakers are not used.
Four of the 11 panels on one pole. Rest not shown.
Looking down into the cistern where you can see the Flowline Echopod measuring water level. The cistern is about 300 foot away from the Victron GX Tank 140. Works like a charm!
Screenshot of Victron VRM in action. This was a cloudy day, not a lot of solar produced.
Nice! I attached a heating pad to each battery, and tied that to a thermostat, so that I can control the temperature inside my insulated battery box, and keep it at 55F. The control logic for that is in the far-right of my first picture. I know the batteries have an internal heater, but two reasons I don't want to rely on them as the only way to keep them warm. 1) By the time the heater kicks in, the battery will be quite cold inside and that is going to come at the cost of capacity. 2) The battery heaters only works when there is sun, so if the battery ever drops below its cutoff temp of -14C during the night, because the heaters do not kick in, that would be really bad. Because if it is that cold, then I would likely need power the most to keep the cabin heated.
