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I just upgraded the solar system at my family's off-grid cabin. It's incredible how much battery technology has improved over the last 10 years. Everyone is ge

I just upgraded the solar system at my family's off-grid cabin. It's incredible how much battery technology has improved over the last 10 years. Everyone is getting tired of me checking the panel to see how many watts we're bringing in. Next project, install a shunt and get a Raspberry Pi talking to it over USB. And then I'll be able to build a Grafana dashboard. :)

nonethewiser 4mo ago
Where is the cabin? Roughly speaking of course
- _whiteCaps_ 4mo ago
  The "Sunshine" Coast of BC. Right now we're limited by the charging capacity of the inverter/charger. It can only do 50A in from an external solar controller. In hindsight I should have gone with a 48V inverter/charger to get twice the power going in. On a sunny day we're maxing it out at 1200W for several hours at a time.
  - dghughes 4mo ago
    Hi, from the other coast. I wish I had solar maybe someday. Do you ever watch Artisan Electric from the UK? He tried to run his shop on 100% solar+battery. He ran into a problem where sunny day batteries full shop using power but the panels themselves were throttling. They had no where to send the extra power. He bought a bitcoin floor heater (lol), charged EVs, and some other stuff. https://www.youtube.com/watch?v=evkdqTcMbWM https://www.youtube.com/watch?v=evkdqTcMbWM
    - jvanderbot 4mo ago
      Yeah that's the point. Most systems are over producing on peak hours of peak days so they can average out to enough power on lower light days. You can buy more batteries, but if you don't have batteries it's waste.
ravedave5 4mo ago
I have a similar project, I'm so overpaneled I bought an electric heater so I could actually see how many watts I brought in during a nice summer day. The victron UIs have an excellent graph history.
- colechristensen 4mo ago
  The next step for people like you and things like nations: what do we do with this extra electricity we have laying around so often? What people figure out to do with actually free energy will be exciting. There are a lot of extremely "inefficient" things that might suddenly become commonplace. Proto-replicator technology where you dump your garbage into a barrel and it gets decomposed and recomposed into something similar to crude oil, blocks of metal, pure gasses, etc? Hydrocarbon fuel from air? Flying cars? You name it.
  - californical 4mo ago
    Generating hydrocarbons at home from their air with excess electricity is like the ultimate endgame in my opinion. It’d be so sick and enable a million new possibilities, essentially getting us into a net-zero emissions state without needing to use batteries for everything. I doubt that it ends up being actually better due to efficiency losses but it’d be really cool!!
  - Kaliboy 4mo ago
    I often daydream about electrolysing water to generate oxygen and hydrogen and store them to use for heating and like welding torches and stuff. To make electric energy I would have to make a small steam plant to run a turbine.
    - BobaFloutist 4mo ago
      >To make electric energy I would have to make a small steam plant to run a turbine. Or a hydrogen fuel cell: https://en.wikipedia.org/wiki/Fuel_cell https://en.wikipedia.org/wiki/Fuel_cell The round-trip efficiency is of course abysmal compared to batteries, but if the input energy is "free", the increased density could pay off.
Neywiny 4mo ago
Or an esp32 to not run Linux and whatnot off of an sd card. Should be more reliable in the long run
jphil529 4mo ago
Really curious about the difficulty of doing a self install with Solar. I'm moderately handy (built a Sauna from no plans) and confident with electrical. Any gotchas?
- soggybread 4mo ago
  I'm just getting into Solar myself and while it seems like a lot there are some things that you have to do math for. If you've got 10 panels you'll want to find out how to get all that energy to the inverter/mppt without going over the volt/amp limit on the device. This is probably the most difficult part and for everything else there's a huge solar community of people starting exactly where you are. I myself just bought an Anker solar battery and 2 panels that I bring out during the day to charge the battery and it runs my laptop and monitor for the evening after I get home from work. I want to do more but I'm renting so I'm just trying to find ways to do so. When my state legalizes balcony solar you bet I'm going to play with that too.
  - thrownthatway 4mo ago
    > without going over the volt/amp limit on the device. It’s not clear what device you’re referring to in this context.
    - _whiteCaps_ 4mo ago
      The MPPT solar controller. MidNite has a sizing tool for this: https://www.midnitesolar.com/sizingTool/ https://www.midnitesolar.com/sizingTool/
      - thrownthatway 4mo ago
        So the most difficult part is using a calculator to determine the charge controller capacity.
        cornstalks 4mo ago
amluto 4mo ago
For most purposes, I would avoid the shunt and use a current transformer (for AC) or a DC current sensor (conceptually the same thing but with a Hall effect sensor or other mechanism that works for DC). This way you don’t need anything to touch the potentially rather large voltages on a solar array.
- andyferris 4mo ago
  The OP mentioned modern battery technologies - generally the shunt sits between an LFP battery negative and the main circuit negative/ground, and the solar panels connect to MPPTs. So the voltage at the shunt is a nice consistent nominal 12.8V (~13.3V in practice) or a multiple thereof (for series battery setups). I just upgraded our hybrid caravan to 24V LFP (2x 300Ah 12V), roof solar + extra MPPT for external solar, shunt, inverter-charger, 24V->12V converter for existing circuity (lights, pump, etc), DCDC charger from car, battery balancer, a little touchscreen interface inside (all victron gear with renogy batteries). It was as a lot of fun and it's amazing how much power we have off grid now! The system would work excellent for a little cabin exactly how it is (minus DCDC).

nonethewiser 4mo ago

Where is the cabin? Roughly speaking of course

_whiteCaps_ 4mo ago
The "Sunshine" Coast of BC. Right now we're limited by the charging capacity of the inverter/charger. It can only do 50A in from an external solar controller. In hindsight I should have gone with a 48V inverter/charger to get twice the power going in. On a sunny day we're maxing it out at 1200W for several hours at a time.
- dghughes 4mo ago
  Hi, from the other coast. I wish I had solar maybe someday. Do you ever watch Artisan Electric from the UK? He tried to run his shop on 100% solar+battery. He ran into a problem where sunny day batteries full shop using power but the panels themselves were throttling. They had no where to send the extra power. He bought a bitcoin floor heater (lol), charged EVs, and some other stuff. https://www.youtube.com/watch?v=evkdqTcMbWM https://www.youtube.com/watch?v=evkdqTcMbWM
  - jvanderbot 4mo ago
    Yeah that's the point. Most systems are over producing on peak hours of peak days so they can average out to enough power on lower light days. You can buy more batteries, but if you don't have batteries it's waste.

ravedave5 4mo ago

I have a similar project, I'm so overpaneled I bought an electric heater so I could actually see how many watts I brought in during a nice summer day. The victron UIs have an excellent graph history.

colechristensen 4mo ago
The next step for people like you and things like nations: what do we do with this extra electricity we have laying around so often? What people figure out to do with actually free energy will be exciting. There are a lot of extremely "inefficient" things that might suddenly become commonplace. Proto-replicator technology where you dump your garbage into a barrel and it gets decomposed and recomposed into something similar to crude oil, blocks of metal, pure gasses, etc? Hydrocarbon fuel from air? Flying cars? You name it.
- californical 4mo ago
  Generating hydrocarbons at home from their air with excess electricity is like the ultimate endgame in my opinion. It’d be so sick and enable a million new possibilities, essentially getting us into a net-zero emissions state without needing to use batteries for everything. I doubt that it ends up being actually better due to efficiency losses but it’d be really cool!!
- Kaliboy 4mo ago
  I often daydream about electrolysing water to generate oxygen and hydrogen and store them to use for heating and like welding torches and stuff. To make electric energy I would have to make a small steam plant to run a turbine.
  - BobaFloutist 4mo ago
    >To make electric energy I would have to make a small steam plant to run a turbine. Or a hydrogen fuel cell: https://en.wikipedia.org/wiki/Fuel_cell https://en.wikipedia.org/wiki/Fuel_cell The round-trip efficiency is of course abysmal compared to batteries, but if the input energy is "free", the increased density could pay off.

Neywiny 4mo ago

Or an esp32 to not run Linux and whatnot off of an sd card. Should be more reliable in the long run

jphil529 4mo ago

Really curious about the difficulty of doing a self install with Solar. I'm moderately handy (built a Sauna from no plans) and confident with electrical. Any gotchas?

soggybread 4mo ago
I'm just getting into Solar myself and while it seems like a lot there are some things that you have to do math for. If you've got 10 panels you'll want to find out how to get all that energy to the inverter/mppt without going over the volt/amp limit on the device. This is probably the most difficult part and for everything else there's a huge solar community of people starting exactly where you are. I myself just bought an Anker solar battery and 2 panels that I bring out during the day to charge the battery and it runs my laptop and monitor for the evening after I get home from work. I want to do more but I'm renting so I'm just trying to find ways to do so. When my state legalizes balcony solar you bet I'm going to play with that too.
- thrownthatway 4mo ago
  > without going over the volt/amp limit on the device. It’s not clear what device you’re referring to in this context.
  - _whiteCaps_ 4mo ago
    The MPPT solar controller. MidNite has a sizing tool for this: https://www.midnitesolar.com/sizingTool/ https://www.midnitesolar.com/sizingTool/
    - thrownthatway 4mo ago
      So the most difficult part is using a calculator to determine the charge controller capacity.
      - cornstalks 4mo ago

amluto 4mo ago

For most purposes, I would avoid the shunt and use a current transformer (for AC) or a DC current sensor (conceptually the same thing but with a Hall effect sensor or other mechanism that works for DC). This way you don’t need anything to touch the potentially rather large voltages on a solar array.

andyferris 4mo ago
The OP mentioned modern battery technologies - generally the shunt sits between an LFP battery negative and the main circuit negative/ground, and the solar panels connect to MPPTs. So the voltage at the shunt is a nice consistent nominal 12.8V (~13.3V in practice) or a multiple thereof (for series battery setups). I just upgraded our hybrid caravan to 24V LFP (2x 300Ah 12V), roof solar + extra MPPT for external solar, shunt, inverter-charger, 24V->12V converter for existing circuity (lights, pump, etc), DCDC charger from car, battery balancer, a little touchscreen interface inside (all victron gear with renogy batteries). It was as a lot of fun and it's amazing how much power we have off grid now! The system would work excellent for a little cabin exactly how it is (minus DCDC).