Solar recommendations?

[CathyInBlue]

Vocabulary Nazi time.

Many (hundreds of) solar cells go into making a single solar panel.
Many (dozens of) solar panels go into making a single solar array.
Many (dozens of) solar arrays go into making a single solar field.

Okay, the field term may be largely my own idiosyncrasy, but it's appropriate. You do not just take a bunch of individual 3.5" silicon photo cells and plug them into a Trace inverter and start making power. There's beau coup infrastructure that stands between the lowest level, where the photons meet the silicon, and the highest level, where the plug meets the socket. When you confuse the terms, you are implying that some infrastructure has been handled, where you may not have meant to indicate that at all.

 

[Sailor]

PLEASE don't hijack the thread. Keep this to OFF GRID since it is in the survival section. And system for both on/off grid is a good topic for a different thread.

Want to find an inexpensive ( or rather least expensive) way to give power to an 100% off grid location. Powering some lights, fridge/Freezer to keep food items from spoiling.. not for ice production. (I plan to further insulate the fridge Freezer to minimize power consumption), and a few fans for some cooling. Will have wood heat.

So far sound like DC system (have not bought a fridge yet so that is still an option) is the way to go. Although I imagine that also means I will have to make sure lights and fans are DC powered.
DE-0061/EV-0061 is an option.. power use 12/24v=3.2-2.2 amp

Any ideas on cost? (panels, batteries, wiring, etc) not including appliances etc..

Most people use propane for off grid refrigeration, because of the cost and issues of solar for this. If you insist, then look at marine fridge freezer made for this use. Remember back in the day they had an ice chest? That's what the ice is for.

You wanted cheap. Harbor Freight solar panels will run LED's forever for a small cabin. $160 tabletop ice maker makes 28 lbs of ice a day. Run it off your car if you have to. It's quieter than a generator anyhow.

 

[shibumiseeker]

Most people use propane for off grid refrigeration, because of the cost and issues of solar for this. If you insist, then look at marine fridge freezer made for this use. Remember back in the day they had an ice chest? That's what the ice is for.

Propane and kerosene fridges cost more to run than a regular 120v ac fridge with inverter, batteries, and solar panels.

High efficiency 12v fridges will not pay back the extra cost over their lifetimes.

I'm not speaking out of my ass here, I've been living it my whole life.

 

[NomadS]

I have been off-grid for the last 2 decades. Do a search on my username and "solar" or "off-grid" and you can find a bunch of stuff I have written on this site about my system and giving other people advice about their systems.

Will do.. Thanks

 

[Sailor]

Propane and kerosene fridges cost more to run than a regular 120v ac fridge with inverter, batteries, and solar panels.

High efficiency 12v fridges will not pay back the extra cost over their lifetimes.

I'm not speaking out of my ass here, I've been living it my whole life.

Ok, but for a back up cabin, not his house would you not agree that an ice maker and a marine cooler would accomplish the task with less power requirements and cost?

 

[NomadS]

Most people use propane for off grid refrigeration, because of the cost and issues of solar for this. If you insist, then look at marine fridge freezer made for this use. Remember back in the day they had an ice chest? That's what the ice is for.

You wanted cheap. Harbor Freight solar panels will run LED's forever for a small cabin. $160 tabletop ice maker makes 28 lbs of ice a day. Run it off your car if you have to. It's quieter than a generator anyhow.

Yes but who knows how long propane will be available if the grid goes down for a prolonged period. Solar will be around, or, if it is not, we won't be either. Wood gas is an idea too.

I do suppose the ice maker could be sufficient for the ice chest method refrigeration but it does take another layer of convenience out off the table. Any idea of DC ice makers are available and what their amp draw is?

 

[shibumiseeker]

Ok, but for a back up cabin, not his house would you not agree that an ice maker and a marine cooler would accomplish the task with less power requirements and cost?

Depends on the end expectations. For a weekend getaway, sure. For a BOL, not really.

Power requirements really are a TANSTAAFL situation. Insulate the hell out of a regular inexpensive 10-12cu ft fridge that has external coils and you can run it on 300-400 watts a day. Run that fridge at 50f inside instead of 35f and you can get even lower. Set it on a timer so that it only runs during the day and you can lower the battery requirements.

You want x amount of cooling and the power requirements are affected by the efficiency of the system and the amount of heat transfer that occurs from the outside environment to the cooled area, it doesn't matter if that's ice cubes or freon. You have 2 choices, increase the efficiency of the cooling system (difficult) or decrease the heat transfer (easier).

 

[inxs]

Maybe you should investigate some old technology. There was a packing house in St Louis nearly a hundred years ago that had solar refrigeration. Its pretty simple really if you think about ammonia charged systems..... and it could be backed up by either propane or electric.....

 

[2ADMNLOVER]

China's solar situation may prove useful to us soon .

http://www.nytimes.com/2012/10/05/b.../business/energy-environment/index.jsonp&_r=0

Seems like they now have more than they can use .

 

[CathyInBlue]

Power requirements really are a TANSTAAFL situation.

I see so many people make the mistake of ignoring this simple fact. It's not just a monetary budget you have to worry about. You have to figure out your power budget as well. It does no good to spend just 20% of the cost of a professionally assembled and installed grid intertie system to roll your own solar power system from scratch, when you can only power 5% of the things you need to power with that DIY set up that the professional set up would manage just fine. If it was the other way around, spend 5% of a professional rig to achieve 20% of the same benefits, that would be great. Then, you'd just need to spend 1/4 of the price of a professional rig to get 100% of the same benefits. It never works out that way.

And then there are the comparisons to other energy delivery systems. Straight grid use like most people (electric and gas), wind instead of solar, wind and solar mixed, passive technologies, and on and on. I admire the people who think they can start from scratch and roll their own and achieve all of the same benefits. I just don't believe most of them are going to come out the better on the other end.

 

[remauto1187]

Many (hundreds of) solar cells go into making a single solar panel..

Huh? A solar cell makes .5vdc or so (assuming the sun is out) If "your" system is 12vdc then you will need 24 SOLAR CELLS. I use 6"x6" because they yield double the power (Current) that a 3"x6" makes. A 24vdc system would need 48 Solar Cells and a 48vdc would need 96 solar cells. There are other ways to parallell the panels and even the solar cells to get different amounts of dc output and even current output.

Many (dozens of) solar panels go into making a single solar array.

The amount depends on how much wattage your system rquires. Then of course the voltage output the system needs AND whether they are hooked up in series, parallel, etc.

Many (dozens of) solar arrays go into making a single solar field.

Now you are really splitting hairs.

Okay, the field term may be largely my own idiosyncrasy, but it's appropriate. You do not just take a bunch of individual 3.5" silicon photo cells and plug them into a Trace inverter and start making power. There's beau coup infrastructure that stands between the lowest level, where the photons meet the silicon, and the highest level, where the plug meets the socket. When you confuse the terms, you are implying that some infrastructure has been handled, where you may not have meant to indicate that at all.

Nothing was implied....its called simplified. Didnt figure the conversation needed every little wire, ground and battery lug mentioned. If some is going to dive in then they will be able to find a system diagram and schematic online with ease.
I'll post pics when I get my sytem completed. First I am putting my garage on solar. It is going to be my project BEFORE the house. The house will have solar and a wind turbine generator. While it does work out better in the end to have a home purpose built for solar, it is not necessary. Costs are cut dramatically if solar panels are built by the owner. Less than .50/watt vs. $3/watt. Here is a vid that shows how a panel is home made. [ame]http://www.youtube.com/watch?v=_PpV32jSDi8&feature=related[/ame] Not necessarily the best but there are a million of them on youtube so people can see what they are getting themselves into.

 

[yaquindn]

I have 2 sets of harbor freight solar panels that I paid $135.45 after tax. I also bought four 6 volt gc-2 golf cart batteries and rewired the panels to produce 24 volts and wired the battery bank for 24 volts also ( 24 volt produces more usable power) then reduce it back down to 12 volt to run inverters and lights. Each battery has 206 amp hour or 75amp @ 115mins X 4 so this is more than enough for the small set up to run emergency equipment(TV radio frig lights etc...)

 

[Valvestate]

Search youtube for aluminum conversion for batteries. Increases lead acid battery efficiency/power density. I saw a guy draw an amp out of a plastic party cup with a shammy and a light acid like vinegar or citric acid for over an hour.

 

[remauto1187]

I have 2 sets of harbor freight solar panels that I paid $135.45 after tax. I also bought four 6 volt gc-2 golf cart batteries and rewired the panels to produce 24 volts and wired the battery bank for 24 volts also ( 24 volt produces more usable power)...)

How many watts are the panels rated for? 24 volts produces more usable power? HUH? (6) 12v 100ah batteries produce 600ah wired in parallel. (6) 12v batteries wired in series/parallel to yield 3 strings of 24v in parallel with each other...yield 600a/h. With same amount of batteries you get the same amount of a/h rating.

then reduce it back down to 12 volt to run inverters and lights. Each battery has 206 amp hour or 75amp @ 115mins X 4 so this is more than enough for the small set up to run emergency equipment(TV radio frig lights etc...)

Anytime you regulate a voltage down you will waste power in the voltage regulation in the form of heat. Thats how the voltage gets lowered. Its bled off typically in a resistor.

 

[shibumiseeker]

How many watts are the panels rated for? 24 volts produces more usable power? HUH? (6) 12v 100ah batteries produce 600ah wired in parallel. (6) 12v batteries wired in series/parallel to yield 3 strings of 24v in parallel with each other...yield 600a/h. With same amount of batteries you get the same amount of a/h rating.

Yeah, that one had me scratching my head too. The ONLY advantage to going to higher voltage is lesser I^R losses in wiring and interconnects, but that only works if the inverter is also a higher voltage inverter.

And as far as the Harbor Freight equipment goes: it's the gun equivalent of buying a Highpoint. Yes it will work, but the quality and longevity is lacking.

Anytime you regulate a voltage down you will waste power in the voltage regulation in the form of heat. Thats how the voltage gets lowered. Its bled off typically in a resistor.

Actually voltage conversion in this case is usually digital and reasonably efficient, but your basic point is still valid: it makes no sense to wire everything for 24v only to convert it back to 12v use.

 

[downzero]

it makes no sense to wire everything for 24v only to convert it back to 12v use.

It'd seem having the wire be half the size might make sense if the current draw was enough.

 

[shibumiseeker]

It'd seem having the wire be half the size might make sense if the current draw was enough.

Right, which is why high powered systems drawing tens of thousands of watts use higher voltages like 48 volts and up. But a system where the maximum current draw is only going to be a few hundred watts AND the user is only going to convert it back down to 12v for sole end use, it makes no sense. It's different if the primary draw is going into a 24v inverter and the user also wants to power a few 12v loads, but that's not what was said.

 

[remauto1187]

Using the higher voltage setup is only logical IF the wire runs are very long. That is the only purpose of say 120vac stepped up to 240vac then ran 1000ft to a stepdown transformer 240vac:120vac. But we are dealing with DC and while resistance of the wires is very important to prevent substantial voltage drop across the wires...it best to just go alot bigger than the min. recommended. If you arent running your leads from solar panels to your regulator much more than 50ft then 12vdc system with large wire will be fairly cheap and provide minimal voltage drop.
(100ah batteries for example) When you have a 12vdc system if you have a battery go south on you, you lose 100ah's of capacity. You just yank the battery out of the parallel string. With a 24vdc system you have strings of (2) 12vdc batteries that are parallel with each other and if one battery dies, you loose 200ah's of capacity because now (2) batteries are useless. This is of course until you manage to replace the bad battery. Hopefully it isnt the middle of winter and your system is powering your heat source and you HAVE the $$$ for the replacement batteries.
This is why I am going with a 12vdc system for my garage anyway. Now most larger watter inverters, especially the ones that can output 240vac will run on 24vdc or 48vdc only. I dont believe they make a 12vdc/240vac inverter unfortunately, which is what I would like for my house.
The larger you make your wires the more efficient your system will be. You want to be able to deliver the max amount of current from the solar panels that you can with the least amount of voltage drop possible(afford). So the larger wire is really an investment that will pay for it self over time.

 

[longbow]

Depends

I priced out a 15,000 watt system and was going to convert my home over to propane. I have an all electric house. The battery bank was sized for three days of no sun and I had a generator sized to charge the system.

It ranged between $90,000 and $120,000 depending the battery brands, inverters and controls. My plans died because the costs kept rising. My insurance company wanted to insure the items under an equipment floater and were not happy about me wanting hail and wind damage coverage for roughly half of that expense. That coverage also included electrical surges and breakdown. They also told me the generator could not be inside the house, and the fuel tank had to be above ground. That forced me to move it 200 feet to the barn and the additional wire costs alone were a shock,

The change over to propane heat, water heat, clothes dryer and stove were salty. Within that cost was a 1,500 gallon underground propane tank.

There are some great tax breaks, tax credits and other things utilities can do. I was told they would repurchase back up to 10KW of power from the system when it produced excess power.

FYI-the initial quote from the company was about $60,000. You can save about 25% if you do all the work on your own.

 

[shibumiseeker]

Switching over everything all at once can be expensive, especially when you have to hire everything done which is why it is always easier to do it in pieces.

When I was running my AE consulting business I would start with asking the client what they wanted to spend and what their expectations were. Then I'd work up a matrix of what kind of system they could get with what tradeoffs and work with them until they had a system they could be happy with. I'd map out three pricing structures including costs if they completely DIY, did some of the work and equipment sourcing, and if they hired a contractor to do it all.

I made my money in the consult and the recommendations of equipment and contractors and system design, NOT in doing the contracting itself, so I didn't have a lot of incentive to try to sell the biggest system I could which seems to be the model that's more common today.