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DIY Off-Grid Solar Power

mobile-solarpower.com

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Re: DIY Off-Grid Solar Power

#81

Post by rklaehn »

cfn wrote: post #77
rklaehn wrote: post #75

This is a nice resource. I am building an off grid / backup solar install for a house in rural Romania. I want it to be off grid capable, but also be able to use the grid when available. One thing I am curious about: do the all in one systems like Growatt or MPT also provide voltage stabilization? The grid here has really bad voltage stability. Sometimes the voltage drops down to 180V (should be 220V in Europe). Some…

Offgrid inverters either get the power from the batteries/charge controllers or they get the power from the grid (usually to charge the batteries - they are called charger-inverters, look at the Outback VFX series for an example). This means that either you get the unstable grid power or you get the stable solar/battery power. Maybe there are inverters that somehow compensate and correct the power but I doubt it sinc…

Maybe the all in one system is not good in that case. I was hoping that since they already have the AC-DC inverter built in they could also do voltage stabilization.

Maybe charge the batteries from either the grid or the PV panels, and always run the house off the batteries via a separate inverter. That way, you got the inefficiency of AC->DC->AC but always have stable voltage.

In the long run I want this to be mostly off grid anyway, with the grid as just an emergency option...

Re: DIY Off-Grid Solar Power

#82

Post by theshrike79 »

diamondlovesyou wrote: post #70
devwastaken wrote: post #66

Earlier quoted context omitted.

Hypothetically, for the lithium batteries, what if you made a big stainless steel vacuum wall insulated enclosure? Or just a metal box with r-60 value of foam around it? The amount of heat needing to be generated can then be calculated based on the average temp over a longer period of time, and those batteries I don't imagine have to be "warm" exactly.

What about summer? Those batteries also need to stay cool...

You can just dig a big hole for them, the earth stays cool enough when you go a meter or two down.

Unless you live in the desert, having the batteries too hot isn't as big of an issue as freezing them.

Re: DIY Off-Grid Solar Power

#83

Post by adrianN »

Epa095 wrote: post #79
Syonyk wrote: post #17

Earlier quoted context omitted.

> Still not sure how I’ll ultimately get around this. If it's portable, your option works well. For year round off grid use, there's something to be said for sealed lead acid, or flooded lead acid - they don't care about being cycled while cold (capacity is down and the voltage sags a good bit), and as long as they don't get too deeply discharged, they don't freeze. A single panel, facing south, absolutely vertical,…

Is 5kW not enough to heat the cabin? I guess it must be really cold where you are. Modern heat pumps should unproblematic handle -25°C (air to air), and provide 4-5kWh of heat for each kWh of power used.

Which heat pump reaches that kind of efficiency when the temperature differential is so high?

Re: DIY Off-Grid Solar Power

#84

Post by CorrectHorseBat »

Epa095 wrote: post #79
Syonyk wrote: post #17

Earlier quoted context omitted.

> Still not sure how I’ll ultimately get around this. If it's portable, your option works well. For year round off grid use, there's something to be said for sealed lead acid, or flooded lead acid - they don't care about being cycled while cold (capacity is down and the voltage sags a good bit), and as long as they don't get too deeply discharged, they don't freeze. A single panel, facing south, absolutely vertical,…

Is 5kW not enough to heat the cabin? I guess it must be really cold where you are. Modern heat pumps should unproblematic handle -25°C (air to air), and provide 4-5kWh of heat for each kWh of power used.

5kW of panels don't produce 5kW in winter, that's the issue I guess.

Re: DIY Off-Grid Solar Power

#85

Post by cfn »

rklaehn wrote: post #81
cfn wrote: post #77

Earlier quoted context omitted.

Offgrid inverters either get the power from the batteries/charge controllers or they get the power from the grid (usually to charge the batteries - they are called charger-inverters, look at the Outback VFX series for an example). This means that either you get the unstable grid power or you get the stable solar/battery power. Maybe there are inverters that somehow compensate and correct the power but I doubt it sinc…

Maybe the all in one system is not good in that case. I was hoping that since they already have the AC-DC inverter built in they could also do voltage stabilization. Maybe charge the batteries from either the grid or the PV panels, and always run the house off the batteries via a separate inverter. That way, you got the inefficiency of AC->DC->AC but always have stable voltage. In the long run I want this to be mostl…

Yes, that is a good idea. Get a separate charger and always run the house from the isolated side. This will be more expensive as a good inverter/charger runs in the 1k-2k Euros area and you would need two (unless you find a suitable battery charger which is not very easy). I lived offgrid for nearly a decade and built myself three different solar systems. I started with a small all in one and found out that they are limiting when you want to expand since you usually cannot add more charge controllers and/or panels (which are the easiest way to expand a system). I ended up giving it away and building the others from separate systems. My biggest mistake was starting with 24 volts instead of 48 volts. It is cheaper but it gets a bit dangerous as you step up the power usage and there aren't many options for breakers and such.

Re: DIY Off-Grid Solar Power

#86

Post by kwhitefoot »

adrianN wrote: post #83
Epa095 wrote: post #79

Earlier quoted context omitted.

Is 5kW not enough to heat the cabin? I guess it must be really cold where you are. Modern heat pumps should unproblematic handle -25°C (air to air), and provide 4-5kWh of heat for each kWh of power used.

Which heat pump reaches that kind of efficiency when the temperature differential is so high?

None as far as I can tell. Some people I know here in Norway turn off the heat pump when the outside temperature is below -25°C, but those pumps were installed some years ago.

New ones do have a significant gain at that temperature. For instance this Samsung Nordic Home: https://www.elkjop.no/product/hjem-og-husholdning/oppvarming...

Re: DIY Off-Grid Solar Power

#87

Post by DyslexicAtheist »

Syonyk wrote: post #7
ctime wrote: post #2

Will Prose seems like a really great person. If you’re interested in what you see on this site, check out his YouTube channel: https://youtube.com/c/WillProwse

The problem with him, and people like him on YouTube, is that about 90% of what they say is fine, and 10% ranges from "iffy" to "This is a good way to burn your house down - at some unknown point in the future." The average viewer of that sort of material can't tell the difference, and by the time you can, you're not in need of handwaving entry level information, because you can read the design documents, spec sheets…

sounds a bit gate-keepy to me. People tell me that I shouldn't repair my own car for similar reasons. Instead I should go to the OEM and have it serviced there for 1000,- a pop. This assures I'm getting genuine OEM branded parts with a 800% profit margin while also reducing the time spent on diagnosing the issue because now whole modules get replaced since cost of human labor is expensive. If I would heed that advise, I'd still have no clue about how a modern diesel engine worked, how to reverse and flash a new ECU firmware, how to find and fix any problem without a mechanic ripping me off, or generally engage in things that (in the eyes of the vendor) are "very dangerous" to myself, my family, or others.

Yet I still make this choice because the alternative is a "John Deer no right to repair" future where we're ruled by chuckeducks and awful people who can't help but quote "rules and regulations" or can't wait to be up in everyone's shit. There is no way I could be convinced otherwise because this is the nature of those who fiddle and tinker in the first place. I'm sure many of the viewers on this channel think likewise because it's not about safety but about my own freedom to spend my weekends in the garage building something and being rewarded with self reliance. And also the freedom to make mistakes big enough to kill myself by accident without somebody going "uhm well ack-shually".

Re: DIY Off-Grid Solar Power

#88

Post by jrootabega »

kyleee wrote: post #19
Syonyk wrote: post #7

Earlier quoted context omitted.

The problem with him, and people like him on YouTube, is that about 90% of what they say is fine, and 10% ranges from "iffy" to "This is a good way to burn your house down - at some unknown point in the future." The average viewer of that sort of material can't tell the difference, and by the time you can, you're not in need of handwaving entry level information, because you can read the design documents, spec sheets…

"YouTube is simply the wrong medium to try to teach detailed" YouTube is literally just humans talking, so you are basically saying you don't think humans can teach complicated subjects?

"YouTube" can mean at least two things:

1. A theoretical space for someone with good ideas and good intentions to share those with the world.

2. The actual experience that viewers will have on YouTube if they were to open it today.

1. and 2. would be almost diametrically opposed these days. If YouTube provided ways for viewers to honestly and fairly discover, rate, filter, and share videos and channels, then the people in case 2 would be able to reliably find the people in case 1. And if YouTube didn't force video makers to pervert their personality and format into algorithm-pleasing parodies, then people in case 1. could continue to produce the content they actually want to produce as long as they were able to. But it's not possible today.

Re: DIY Off-Grid Solar Power

#89

Post by i_am_proteus »

Syonyk wrote: post #17
zoba wrote: post #8

I recently set up my own off grid solar system in a tiny cabin that I designed and had built. I used the Solar Controller+Inverter Combos recommended on this site (Growatt) but ultimately switched to ones by Renogy. The Growatt one I purchased has a wifi adapter and app - wifi requirement was a deal breaker when remote. The renogy one has a Bluetooth adapter and app, plus feels better designed (though actually I thin…

> Still not sure how I’ll ultimately get around this. If it's portable, your option works well. For year round off grid use, there's something to be said for sealed lead acid, or flooded lead acid - they don't care about being cycled while cold (capacity is down and the voltage sags a good bit), and as long as they don't get too deeply discharged, they don't freeze. A single panel, facing south, absolutely vertical,…

Yep. Unless you've got running water or a high cliffside for wind, the best off-the-grid heat source for cold climates is an acre of woods and an axe.

Insulation, too. A lot of sheds and cabins (and single-family homes) could do with more. Saves on cooling bills in the summer, too.

Re: DIY Off-Grid Solar Power

#90

Post by [deleted] »

zoba wrote: post #8

I recently set up my own off grid solar system in a tiny cabin that I designed and had built. I used the Solar Controller+Inverter Combos recommended on this site (Growatt) but ultimately switched to ones by Renogy. The Growatt one I purchased has a wifi adapter and app - wifi requirement was a deal breaker when remote. The renogy one has a Bluetooth adapter and app, plus feels better designed (though actually I thin…

[deleted]
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