4 ms·

No. It can't. My office has 5kW of panel hung, 10kWh of battery, and my Starlink terminal is on the house system (grid tied) because an extra 2.4kWh/day isn't

by Syonyk 5y ago

No. It can't. My office has 5kW of panel hung, 10kWh of battery, and my Starlink terminal is on the house system (grid tied) because an extra 2.4kWh/day isn't workable with my system in the winter, short of a LOT of generator time - I'm severely power limited during inversions, and the Starlink dish more than doubles my office's "idle power draw" (it's the property network hub, one of our internet connections, inverter idle, sleeping computers, etc). Yesterday, the 15.9kWh system on the house produced 78kWh for a "sun factor" of about 4.9, so a 400W panel would produce about 2 kWh. Whoops. That's not 2.4. In the dead of winter, the same system can produce 2.5 kWh - yes, 2.5 kWh on a 15.9kW nameplate system. A 400W panel won't even power on the charge controller in those conditions. To reliably power a 100W load, 24/7, in most areas, requires probably 1500-2000W of panel and 20+kWh of battery - or someone willing to light a generator, which is the far cheaper option. But "a 400W panel and batteries" (implied as a trivial thing to set up) definitely won't. It won't even run it 24/7 in peak sun most of the year. ... and that's before it tries to melt the snow off. From the blog post: > During the heavy snowfall, Dishy quickly spiked up to 125W, peaking at 175W towards the end of the snowstorm. Solar panels don't produce much covered in snow, either.

skellington 5y ago
You are probably technically correct, but most people don't need 24hr internet access, so that one 400 watt panel would provide high speed internet for let's say 12 hours a day and that's plenty for this odd scenario of living in a place with no power but still needing high speed internet.
- Syonyk 5y ago
  The claim was 24/7 powering with "a 400W panel and some batteries" - which is simply false. I deal with the realities of off-grid power in my office on a daily basis, and a vast majority of what's written about solar and batteries by people who don't have experience with them is simply wrong. I try to correct it where I can. With a 400W panel and a few kWh of batteries, you could reasonably accomplish 14-16 hours of access during peak sun in the summer, 8-12 hours in spring and fall, and 0-3 hours in winter, except for 5-6 hours on sunny winter days. Although I've heard that the newer Dishys use somewhat less power (50-70W), which does improve things.
dboreham 5y ago
Ah the joys of hiking 1000ft up a mountain in subzero temps through 4' drifts to clear ice off the panels. Although, for the most part I've found that provided you pitch the panels at 50 degrees or so, snow tends to slide off. The battery system has to be able to carry the load through 48h of zero panel output at least to let snow clear. In 20 years I've only had to physically clear ice off the panels three times.
- tigershark 5y ago
  48h is less than 5 kWh of batteries, one quarter of what the parent post proposed as the absolute minimum.
  - Syonyk 5y ago
    It will depend somewhat on the area, and you can trade panel area for battery pack capacity to a reasonable extent - but you either need a lot of panel area to power you on dark days, or you need a lot of battery to ride through those periods. Out here, at least, we'll have a week where my 5kW of panel on my office produces less than 1kWh/day, often rather significantly less. The problem is that after 48h, then... what do you have? You need to have either enough panel area to both run loads and charge the batteries, often in dim conditions, or you need a lot more battery. Doing reliable off grid power takes a lot more than most people who haven't dealt with it assume, especially if you're dealing with serious winters and don't want to light a generator. I'm basing my estimates off what it would require for me to run 2.4kWh/day, year round, without generator, on my office system - and it takes a LOT. I have 5kW of panel, 10kWh of battery, a typical winter day load of around 3kWh (base loads + minimal compute loads for a work day), and I still require a couple gallons a year of gas to run this reliably. Depending on the winter, I go through 3-5 gallons of propane for heat as well, though I've been trying to move to kerosene - more efficient, as I can run a lantern as a combined heat/light plant on my desk, and heat my hands, which are the only real constraint on cold temperature work in there. I know those numbers sound somewhat nonsensical for a 100W load, but I literally make a living in an off-grid office...
tigershark 5y ago
How on Earth you would need 20+kWh of batteries for a system that even run 24/7 uses 2.4 kWh? And absolutely doesn’t make sense to run it 24/7, even when no one is using it, if you are running it off grid.

by Syonyk 5y ago

skellington 5y ago

You are probably technically correct, but most people don't need 24hr internet access, so that one 400 watt panel would provide high speed internet for let's say 12 hours a day and that's plenty for this odd scenario of living in a place with no power but still needing high speed internet.

Syonyk 5y ago
The claim was 24/7 powering with "a 400W panel and some batteries" - which is simply false. I deal with the realities of off-grid power in my office on a daily basis, and a vast majority of what's written about solar and batteries by people who don't have experience with them is simply wrong. I try to correct it where I can. With a 400W panel and a few kWh of batteries, you could reasonably accomplish 14-16 hours of access during peak sun in the summer, 8-12 hours in spring and fall, and 0-3 hours in winter, except for 5-6 hours on sunny winter days. Although I've heard that the newer Dishys use somewhat less power (50-70W), which does improve things.

dboreham 5y ago

Ah the joys of hiking 1000ft up a mountain in subzero temps through 4' drifts to clear ice off the panels. Although, for the most part I've found that provided you pitch the panels at 50 degrees or so, snow tends to slide off. The battery system has to be able to carry the load through 48h of zero panel output at least to let snow clear. In 20 years I've only had to physically clear ice off the panels three times.

tigershark 5y ago
48h is less than 5 kWh of batteries, one quarter of what the parent post proposed as the absolute minimum.
- Syonyk 5y ago
  It will depend somewhat on the area, and you can trade panel area for battery pack capacity to a reasonable extent - but you either need a lot of panel area to power you on dark days, or you need a lot of battery to ride through those periods. Out here, at least, we'll have a week where my 5kW of panel on my office produces less than 1kWh/day, often rather significantly less. The problem is that after 48h, then... what do you have? You need to have either enough panel area to both run loads and charge the batteries, often in dim conditions, or you need a lot more battery. Doing reliable off grid power takes a lot more than most people who haven't dealt with it assume, especially if you're dealing with serious winters and don't want to light a generator. I'm basing my estimates off what it would require for me to run 2.4kWh/day, year round, without generator, on my office system - and it takes a LOT. I have 5kW of panel, 10kWh of battery, a typical winter day load of around 3kWh (base loads + minimal compute loads for a work day), and I still require a couple gallons a year of gas to run this reliably. Depending on the winter, I go through 3-5 gallons of propane for heat as well, though I've been trying to move to kerosene - more efficient, as I can run a lantern as a combined heat/light plant on my desk, and heat my hands, which are the only real constraint on cold temperature work in there. I know those numbers sound somewhat nonsensical for a 100W load, but I literally make a living in an off-grid office...

tigershark 5y ago

How on Earth you would need 20+kWh of batteries for a system that even run 24/7 uses 2.4 kWh? And absolutely doesn’t make sense to run it 24/7, even when no one is using it, if you are running it off grid.