[budbrew]

Given the battery-power nature of the RWA products a natural extension of this design is recharging the SLA batteries via solar. Has anyone looked into this? Imagine a high-end audio system totally off the grid I plan to look into this. My audio system is right under a south facing window so I could get good light most days. It looks like all you would need is a simple panel and controller rated for the correct 12v battery.

[Jampot]

A system for an RV or boat will probably work straight out the box

[woodsyi]

I thought about that too.  Good idea if you can do it.  I have a camara battery pack that has solar recharger -- comes in handy for shooting in remote places.  I believe you need to recharge only when you are not listening as charging battery has unstable voltage.  Since most people listen in the evening, this probably would not be an issue. 

[Vinnie R.]

Hi Guys,

I never tried a solar charger, but I just did a quick search online and found this one:
http://www.siliconsolar.com/shop/catalog/12v-Solar-Battery-Charger-p-133.html



For the Signature 30 or modded Olive, please make sure that the charger is designed to work with a 12V SLA battery AND that the output current does not exceed 2,500mA.  The charger in the link about says it is 15W, so you are looking at a little over 1,000mA so that should be fine.  You also should make sure that you can't overcharge the batteries with the charger.

Here are some more links:

http://www.batterystuff.com/solar-chargers/

http://www.batterymart.com/battery.mv?c=Flat+Solar+Panels

            

[EDS_]

Bad idea guys. I haven't researched this topic in a year or two. However, photovoltaic solar cells almost always fail before converting energy equal to that required, likely from hydrocarbons, make the cell. Restated; photovoltaic solar fails the Second Law of Thermodynamics test.

Research in this area is great. However, photovoltaic solar, as sold today, is a non-green way to produce energy.

[woodsyi]

Bad idea guys. I haven't researched this topic in a year or two. However, photovoltaic solar cells almost always fail before converting energy equal to that required, likely from hydrocarbons, make the cell. Restated; photovoltaic solar fails the Second Law of Thermodynamics test.

Research in this area is great. However, photovoltaic solar, as sold today, is a non-green way to produce energy.

I don't get it.  I don't see what the 2nd law of thermodynamics has to do with it.  In the right weather condition, there is unlimited solar energy.  How ever "inefficient" it is, photovoltaic cells have unlimited free photons to work with.  Even one molecule of hydrocarbon has to be paid for and produces undesirable waste product. Which is "greener?"  The only problem that I see is the original cost -- how may cycles of recharging from the wall socket would it take to equal the cost?  Also, how much sun do you have access to?  This product can probably do the job. http://laliquidators.net/2501BN.html But is it cost effective?

[EDS_]

Bad idea guys. I haven't researched this topic in a year or two. However, photovoltaic solar cells almost always fail before converting energy equal to that required, likely from hydrocarbons, make the cell. Restated; photovoltaic solar fails the Second Law of Thermodynamics test.

Research in this area is great. However, photovoltaic solar, as sold today, is a non-green way to produce energy.

I don't get it.  I don't see what the 2nd law of thermodynamics has to do with it.  In the right weather condition, there is unlimited solar energy.  How ever "inefficient" it is, photovoltaic cells have unlimited free photons to work with.  Even one molecule of hydrocarbon has to be paid for and produces undesirable waste product. Which is "greener?"  The only problem that I see is the original cost -- how may cycles of recharging from the wall socket would it take to equal the cost?  Also, how much sun do you have access to?  This product can probably do the job. http://laliquidators.net/2501BN.html But is it cost effective?

One must think of these things more like an economist and less like an accountant or consumer.....It's more about opportunity costs and efficient use of scarce resources and less about how  does x-product perform after purchase.



Let's say 5,000,000 BTU are required to manufacture a photovoltaic array of x-size. That cell array will fail long before it has produced 5,000,000 BTU of energy. Ergo it is a net energy loser. The net yield is that you, me,  and the world are better off not using photovoltaic solar. Certain circumstances excepted.


It's like putting money in the bank and the bank charging points for the privilege.

[woodsyi]

Okay,  I understand where you are coming from.  Does this mean all the solar panels that are used to augment power in the so called "Eco friendly" houses are not really green?  What about wind or water turbines?  Geothermal?  What resources are "green" in this sense?  If we don't use them for the reasons you give, how do we improve the manufacturing process to eventually make the equation "green?"

[samplesj]

Ummm, No.  What kind of agenda are you pushing EDS_?  Would you care to provide some research material to back your point?

Just to provide a counterpoint here is a faq entry from the National Center for Photovoltaics
called What is the Energy Payback for PV?


It states anywhere from 1-4 years based on what type of module and how recent the technology

Jeremy

[JeffB]

No system is 100% efficient either.  Just because the panels do not give out as much energy as was put into making them does mean that they are not competive with other means of producing energy.  If you burned the 5,000,000 BTUs to create energy you would not get 5,000,000 BTUs of energy for use.
I have no clue what is best, but a comparison to something else is required here.

[EDS_]

Ummm, No.  What kind of agenda are you pushing EDS_?  Would you care to provide some research material to back your point?

Just to provide a counterpoint here is a faq entry from the National Center for Photovoltaics
called What is the Energy Payback for PV?


It states anywhere from 1-4 years based on what type of module and how recent the technology

Jeremy

Funny how that link reads like an advertisement.

That said-I will find the "models" by Dones and Frischknecht. I know nothing about their work....I have read studies in the past that bundle every possible direct, indirect and tangential energy cost for fossil fuels and only strict and direct manufacturing energy costs for PV. I'll be on the lookout for this.

The best research I've done involved an email trade with a college professor. Greatly condensed, he wrote the real world energy payback for the best PV is about 15 years. Further, PVs almost never last 30 years as the link implies within its graph.


As an economist I am always willing to learn. If the payback is really 3-5 years instead of the 15 or more I think-I may put some pvs on my house in Dallas and my farm in West Texas.

[budbrew]

I don't buy the argument that solar power is useless. Every house that uses it is one more house that does not require a coal-fired/nuclear/natural gas/etc power plant to produce its energy. And when you reach a critical mass PV cells could power PV cell production facilities. As was said by one poster, no power source is 100% efficient. But once the PV cell is created at least it does not add any additional gunk to the atmosphere. I imagine that solar technology will become cheaper to produce and more effective.

The Real Goods web site describes that adding solar to an extisting house may not be cost effective in the short run. In this case a better investment would be to improve the overall efficiency of the house. But building a new house that requires new power lines but instead using solar power would be cost effective. Not to mention any new house can be made to be highly efficient in the first place. 

If what EDS_ claims is in fact true using new PV technology it is similar to what some argue about the Toyota Prius, that the energy needed to produce it is more than for a similar traditional gas-powered car.

I also don't believe that solar can be taken on purely economic terms. For some of us it goes beyond that. It's a philosophical/lifestyle choice. It was just reported that the number 1 reason people buy Prius's is to make a statement.

Back to RWA battery chargers... this looks like a good option:

http://www.vdcelectronics.com/batteryminder_solar_15W.htm

They also have a smaller 5W version. It will not overcharge the batteries.

[EDS_]

No system is 100% efficient either.  Just because the panels do not give out as much energy as was put into making them does mean that they are not competitive with other means of producing energy.  If you burned the 5,000,000 BTUs to create energy you would not get 5,000,000 BTUs of energy for use.
I have no clue what is best, but a comparison to something else is required here.

Sure no system is 100% efficient. I think you might want to reconsider your second line above.
If the net energy return is as poor as I think...society would be better off using electricity straight from the power company instead of investing it in pv solar. We could use that 5 million BTU today instead of 5 million BTU that MIGHT be returned over the next many years.

[samplesj]

Funny how that link reads like an advertisement.

Advertisment?  Did you not notice that the domain ended in .GOV?  

[EDS_]

I don't buy the argument that solar power is useless. Every house that uses it is one more house that does not require a coal-fired/nuclear/natural gas/etc power plant to produce its energy. And when you reach a critical mass PV cells could power PV cell production facilities. As was said by one poster, no power source is 100% efficient. But once the PV cell is created at least it does not add any additional gunk to the atmosphere. I imagine that solar technology will become cheaper to produce and more effective.

The Real Goods web site describes that adding solar to an extisting house may not be cost effective in the short run. In this case a better investment would be to improve the overall efficiency of the house. But building a new house that requires new power lines but instead using solar power would be cost effective. Not to mention any new house can be made to be highly efficient in the first place. 

If what EDS_ claims is in fact true using new PV technology it is similar to what some argue about the Toyota Prius, that the energy needed to produce it is more than for a similar traditional gas-powered car.

I also don't believe that solar can be taken on purely economic terms. For some of us it goes beyond that. It's a philosophical/lifestyle choice. It was just reported that the number 1 reason people buy Prius's is to make a statement.

Back to RWA battery chargers... this looks like a good option:

http://www.vdcelectronics.com/batteryminder_solar_15W.htm

They also have a smaller 5W version. It will not overcharge the batteries.

1. I did not say solar is useless-I am all for research and development as it may well be our long term salvation-energywise. The sun has 4-6 billion years to go.
2. In a world where energy is scarce, in the economic sense, using more now to make less in the future is really stupid.
3. Economics does not allow for feelings and statements. Frankly, the best micro-economic theory forbids emotion. I could make a statement by burning an eternal flame outside my front door and feel good about it-that would still be silly.

[EDS_]

Funny how that link reads like an advertisement.

Advertisment?  Did you not notice that the domain ended in .GOV?  

Yes I did.

[samplesj]

If the net energy return is as poor as I think...society would be better off using electricity straight from the power company instead of investing it in pv solar.

Several people has questioned you statements of net loss.  You have even been provided with a governmental agency's writeup that cited several research papers denying that and still have provided NO concrete support of you position or rebuttal of those documents, yet you continue to make statements like this.

Are you perhaps confusing economic payback vs energy payback?  No one is arguing that economic payback won't take many many years.

Again I ask what is your agenda?

[EDS_]

Okay,  I understand where you are coming from.  Does this mean all the solar panels that are used to augment power in the so called "Eco friendly" houses are not really green?  What about wind or water turbines?  Geothermal?  What resources are "green" in this sense?  If we don't use them for the reasons you give, how do we improve the manufacturing process to eventually make the equation "green?"

Knowing just enough about these topics to be dangerous.......
1. PV solar is a loser now....but may be a huge winner soon.
2. Wind is a massive net loser that we will likely abandon pretty soon. Energywise turbines are grossly expensive to make, install and maintain.
3. Geothermal is a huge net winner and has been for a long time.
4. Water is the best of all now.

My theory is we should do anything reasonable to break our need for mid-east oil. For example if we could harvest methane-hydrate safely our energy worries would end.

[mfsoa]

Couldn't help but notice that someone with two homes is so concerned with the future of our natural recources.

EDS - I'm just joking with you - I have no idea whether or not you are more energy-piggy than the rest of us!

[EDS_]

If the net energy return is as poor as I think...society would be better off using electricity straight from the power company instead of investing it in pv solar.

Several people has questioned you statements of net loss.  You have even been provided with a governmental agency's writeup that cited several research papers denying that and still have provided NO concrete support of you position or rebuttal of those documents, yet you continue to make statements like this.

Are you perhaps confusing economic payback vs energy payback?  No one is arguing that economic payback won't take many many years.

Again I ask what is your agenda?

1. No agenda
2. I'm an economist. I get energy payback vs. money payback then profit, opportunity costs, marginal costs etc.
3. I said I would read some of the work on the gov. site you provided and report back.
4. Actually, you are the only one who has directly questioned my net energy loss claim.