Solar powered inverters

Escott

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Ok ladies and gentlemen, if you have any knowledge about Solar Powered Inverters such as efficiency on the North Coast and specifically Sosua please share your knowledge.

Personally I think this isn't an option but to satisfy others on a board for a condo project I sit on I am asking if you wouldn't mind sharing info about this.

Size:

Costs:

Lifespan:

Savings if any to run:

Upkeep:

Problems:

Knowledge of other items that I haven't put on the table:



If you know nothing about the subject please don't respond.

Thanks,
Scott
 

MrMike

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My early analysis into the situation shows that it would take over 10 years to pay off the investment of a 2.5 kilowatt system as opposed to buying the same amount of electriciy at the current rate of 12-17 cents per kilowatt hour.

(this is wholesale solar panels alone, does not include inverters, batteries etc.)

This is based on the idea that there are approximately 5.5 hours of useable solar hours per day in the DR.

Currently I am pricing some panels and wind turbines in order to mount an experiment on the roof of my shop and have real-life experience with this equipment, what REALLY can be expected from it, etc. I am planning to spend around US 15k on panels (not including inverters and batteries which I already stock) so I should have a mid to high range system to blab about in 6 months or so.
 

leromero

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MrMike said:
My early analysis into the situation shows that it would take over 10 years to pay off the investment of a 2.5 kilowatt system as opposed to buying the same amount of electriciy at the current rate of 12-17 cents per kilowatt hour.


This is based on the idea that there are approximately 5.5 hours of useable solar hours per day in the DR.

5.5 hours of useable solar hours? I think you can get 10+ hours if you use a solar tracker. Maybe as much as 12 hours depending on the time of the year.

Of course you can always compare the the price of using a solar cell to that of purchasing the electrical power, but are you basing this on the current 2 to 4 hours of useable electrical power per day? I would be interested in the figures that you came up with. I just recently purchased a battery/inverter combo with a solar cell to recharge it to send to my father in the DR. He should have it by the weekend if Fedex delivers the package to me tomorrow. :)
 

rdost

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purchased a battery/inverter combo with a solar cell

What is the make and model of it and where can we see information for it on the internet? What did it cost to ship?
 

andy_089

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Mar 23, 2003
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solar panels

Here is an articel about a solar panel seller in Charamicos


Link

Maybe they can give you some information?
 
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Ken

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MrMike, please help me get this straight in my mind. From your post and the others, I have the impression that the only real difference between a solar powered and electric powered inverter is that one uses the sun on solar panels to keep the batteries charged and the other uses power from the grid or from a generator to charge the batteries. Is this correct?

If it is, it seems to me it would be hard to justify the additional cost of the solar panels and related costs if you are using the inverter for backup power during the hours when there was nothing from the grid and the generator was off to reduce fuel and maintenance costs.
 

Hillbilly

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Jan 1, 2002
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We run the beach house off of solar/inverter power

BUT, we are not there much. Weekends, and then the main use is to pump water up to the tanks,and a couple of fans at night.

I agree with MrMike, the time period is fairly long to recoup investments.

In Santiago there is a small, very modern company that is doing wind and sun powered installations and have take their own house off the grid.

They are giving 7 year guarantees on batteries and 12 year guarantees on the solar cells. Cost per kw is still very high, and you are looking at 7 years, at least to recoup your investment.

However, in the current environment, with the national grid on the edge of collapse and no possible solution in the short term, it might make sense, but you have to change your way of life to accomodate the limitations of solar power.

HB
 

MrMike

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Ken, all an inverter does is convert DC to AC, usually raising the voltage from say 12, 24 or 48 to 110 or 220 depending on the design and application.

The "inversores" popular in the DR are actually "Inverter/chargers" to everyone outside the country.

Since the sun doesn't shine at night, or very brightly when it is cloudy or raining batteries are used to store the electricity for these times, really the role of the solar cells in this case is to charge the batteries, and of course to pass the current straight to the inverter during those hours when it is possible.

Sorry to point out the obvious, just wanted to make sure we're on the same page before I continue.

My supposition that there are 5.5 hours of useable solar power per day in the DR is based on a comment from an engineer friend of mine who installs transmitter towers in remote areas powered by solar cells, inverters and batteries. He told me also that a tracker would only extend this by maybe 1.5 hours a day, though admittedly I have never researched this independently and should get a second opinion.

Now, back to the obvious, when you use an inverter/charger system to give you the illusion of constant electricity in the DR, you are using the same amount or more of grid power as if the lights were on all the time, (though most if us are using less since we are no doubt trying to conserve battery life)

A household that consumes around 6 amps of AC power to run it's appliances may be drawing as much as 50 amps when charging batteries with a powerful inverter/charger so it's electricity bill will never really go down during blackout periods like this one.

So my math works like this:

On average, 2.4 killowatts of solar panelling will run around 10k US. Warrantees vary between 10 and 25 years on the equipment, so I assume the lifespan is considerable.

2.4 Killowatts is an easy number to work with since this is the size of my inverter at home and 5-6 hours of street power per day is just enough to charge my 8 batteries keep my house running with minimal economy fulltime.

2.4 killowatts at 24 volts (as per Ohm's law) gives me 100 amps of charging power which theoretically will fill my 450 amp/hr battery bank in 4.5 hours, in other words, I should be able to recharge pretty much daily with a little breathing room.

I use 360 Kilowatt hours per month charging these batteries, which at current rates is running around 0.0925 US per kilowatt hour (wow, thought it was higher) so that's 33.3 bucks a month, 400 bucks a year, well OK scratch the 10 year thing, it would take around 25 years to pay for itself at my home consumption level, during which time I would probably have to replace my batteries nearly 7 times, and the inveter possibly once or twice if I was nearer to the sea. (the salt air tends to eat the boards over 10 years or so)

I supposed the benefits of being completely independant of the power grid should be taken into account, the damaged equipment from power spikes AND low voltage over 25 years would have to be factored in, and the convenience of not caring whether or not there was grid power EVER must be worth something, but that's the math.

In conclusion, my earlier 10 year statement would only apply to people who consume more electricity than I do and are billed at 20 cents per Killowatt hour, my humble abode does not exemplify the economy of scale necessary to justify a solar power investment at this time.

Now, you're all welcome to poke holes in my math and figures which were hastily put together with very little coffee.
 

Ken

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Good explanation, MrMike..

But I'm still wondering if I have the two straight in my mind.

1. The inverter/charger that uses electricity to charge the batteries seems pretty straightforward. You have your inverter/charger and batteries and when there is no power the inverter takes over and when there is power you get it from the grid or planta at the same time as your batteries are charging.

2. The inverter/charger that uses solar panels seems more complicated since you must have a solar panel located somewhere where there is good sunlight for much of the day and you must have some means of getting the energy from the solar panel into the batteries. I would think this would mean a significant increase over cost of the inverter/charger that uses electricity.

If I'm right about the increased cost, then as long as the inverter/charger is used primarily as a backup, supplying power when the grid and planta are shut down, what is the benefit of buying a solar powered inverter/charger if it takes so long to make up the additional cost from the savings from not having to charge your batteries when their is electricty?

One other question. Can the batteries used with a solar inverter/charger also be charged by the generator/grid power?
 

Ken

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An addition to my previous post.

I'm in the same condo complex as Scott and there is discussion here about ways of dealing with the power situation. Inverters as backup is one of the options being discussed, and there has been some interest expressed in solar powered inverter.

For about 15 years my wife and I lived on a cruising sailboat and we saw boats that used solar panels to help keep batteries charged. They were always located where they could catch the sun for much of the day. The distance from the solar panel to the battery bank was very short.

But now I live in a 3-story condo building. I have a balcony that gets sun, but only for a short part of the day. It seems to me if I had a solar panel it would have to be mounted on the roof. If I were in a ground floor apartment, for example, how would I get the energy from the solar panel on the roof to the battery bank in my apartment and how much loss is there likely to be enroute?
 

Criss Colon

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Think Like a Dominican!.....Steal your Electricity!

The day that EVERYONE pays for their electricity,at a verifiable rate,is the day that I will pay for my electricity! Until then,I will not! ( I pay about 1 to 2 thousand a month,"My Fair Share!")Costs me about 10,000 pesos a month now,for "Gasoil" to run my "Planta" when there is no power from the street,and to charge my 8 batteries when there is not enough power from the street to charge them! :bandit: :bandit: :bandit: :classic:
Same goes for "Cable TV",and WATER!
"What A Country!"
CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
 

MrMike

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Ken said:
Good explanation, MrMike..

But I'm still wondering if I have the two straight in my mind.

1. The inverter/charger that uses electricity to charge the batteries seems pretty straightforward. You have your inverter/charger and batteries and when there is no power the inverter takes over and when there is power you get it from the grid or planta at the same time as your batteries are charging.

2. The inverter/charger that uses solar panels seems more complicated since you must have a solar panel located somewhere where there is good sunlight for much of the day and you must have some means of getting the energy from the solar panel into the batteries. I would think this would mean a significant increase over cost of the inverter/charger that uses electricity.

If I'm right about the increased cost, then as long as the inverter/charger is used primarily as a backup, supplying power when the grid and planta are shut down, what is the benefit of buying a solar powered inverter/charger if it takes so long to make up the additional cost from the savings from not having to charge your batteries when their is electricty?

One other question. Can the batteries used with a solar inverter/charger also be charged by the generator/grid power?

Actually an inverter for solar applications can be much simpler and cheaper since it doesn't need to include a charger at all, or an automatic transfer.

The solar panels themselves are the chargers and come in voltage configurations that don't require any additional equipment, though charge controllers should be used to prevent overfilling, most of us will have the oposite problem.

There are also some extremely expensive ones that allow for options like connecting to a generator and automatically turning it on and off based on battery levels, selling excess power back to the grid, (not useful in the DR) and other fancy but expensive options.

The answer to your other question is yes, though I still don't have the details, you definitely can configure your setup so that the solar panels and grid power "assist" one another rather than leaving you completely dependant on one or the other to charge.
 

Robert

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What happens when you have no power to steal?

Back on topic....

We have looked into this and like MrMike has expalined, it's not cheap and you have to be in it for the long term, 7-10 years.

It's not only the cost of the panels, it's the mounting frames, the installation and all the other little bits and pieces that add up real quick.
 

Thebes

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The correct figure for insolation in the DR will be around 5.2 in the worst month and 6.5 in the best month. You can find simular data by googling insolation chart (will probably not have non US data) or look at the worst month insolation map at http://www.sunwize.com/info_center/insolmap.htm

A tracker will help some, but they generally do not pay for themselves and are prone to mechanical troubles and serious wind load troubles. They help most in Northern climates. In no case will you get 8-12 average good hours of sun, the atmosphere prevents that from ever happening, anyplace on the planet.

You get the number of amp/hours per day produced by multiplying the rated amperage by the insolation number. The insolation number is the theoretical number of good sun hours per day, on average. Most systems should be sized for the worst month, but in the DR, with A/C you may wish to size based upon your summer load.

Typical economic paybacks are generally 15-25 years. This number can be reduced by going through your condos and replacing high load items to be run off of solar with more efficient models; ultimately this will make the needed solar system much cheaper and will more than pay for high efficiency appliances. Refridgerators are a great place to start. Replace electric hot water with solar or gas.

Once you have a good figure for the amount of energy you need per day (in kw/hrs), divide that by the insolation value. Then divide by .85 (figure an 85% efficiency) and you know how many watts of panels you will need. Your installed cost will probably be around $6-7 per watt for the system, figuring US prices, low labor costs and a wholesale cost. This would be for the batteries, inverters, charge controllers, panels and locally fabricated mounts, etc. To size your battery bank, figure the number of amp/hrs per day and the number of days you will be without sun then multiply by 2.

You should have a planta for backup use, sizing your batteries for a worst case situation will cost more than a modest planta. Or plan on street power as an occasional backup. Most solar electric systems are designed to provide all electric needs 85+% of the time, very few are designed for 100% of the time.

They array size should fit on the roof of the condos without trouble. The panels would all need to be in good sun, not a single tree branch etc.

Panels come with 10-25 year warrentees. I have never heard of someone claiming on one. There are many panels older than 25 years which still output most of their original power. The only normal failures are due to weather damage.

Inverters are not particularly reliable. In your case you would want an array of inverters such as exceltechs, which have multiple redundant components; the mean time between failures is around 15-20 years on these compontents and it can lose one or more while maintaining continuing to function. They are more expensive than Trace, but also more reliable.

Batteries will vary with brand and use. Figure 3-20 years. Rolls and Shurette (?spelling) make very durable batteries, but from a cost point the best are probably Trojan L-16 HC's. If treated well (EDTA will help) these can and do last 15 years at the high end. Untreated Trojan T-105s (what I saw in the DR for some peoples inverters) may last only 3.

Charge controllers are pretty reliable. You would probably want MPPT controllers which will nurse every last watt from the panels. You will be able to have high voltage (96, or whatever) arrays and still use a sane battery pack like 48v or 24v (these are nominal voltages, working voltage is higher)

If you actually do this, you will want to fly someone with a lot of experience in large installs down from the US. You are talking about a very large system, if its for a whole condo complex, even most professionals in the US have not done an install this large.

Also, many people fail to consider the likely $/kwh of electricity over a systems lifespan, as opposed to what it is today. No one can say what electricity will cost in ten years, but it is fairly safe to assume it will be quite a bit higher than today (based upon fossil fuel demand vs supply prediction models).

Hope this helps.
 

AZB

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If solar power was so efficient and cheaper than the grid, everyone would have a system in their house by now.
Let get some things straight:
If a solar panel is rated at 80 watts then it doesn't mean you are getting 80 watts constantly. This is the maximum rating under ideal conditions. You may actually get alot less wattage in normal conditions.
Now if you are charging and using electric at the same time then you are actually diverting the charging current towards usage ex: fans, tv, stereo, computer etc etc. If you are using the power to light up your appliances, electronic equipment then you have very little power to go towards charging your batteries. If you must charge your batteries efficiently then you must disconnect everything from the circuit and let the batteries charge. You need heavy current to charge up the batteries quick (which I don't see it happening).
So may assisment of the solar power system is this: its only good for places like hillbilly's beach house where they only need it to run fans and low wattage bulbs. What you can't run is heavy motors ex: a/c compressors (no a/c) no heavy duty washing machines, no blow dryers, can't run fridge for a long time etc etc. You would need a sinewave inverter (expensive) to run some sensitive motorized equipment. The regular inverter only puts out crude a/c (modified sinewave) so you can damage some sensitive equipment which rely on pure sinewave AC voltage.
So folks if you think you can spend 15-20 k dollars on some solar panel / inverter equipment and expect to run a/c, washing machines (american brand heavy duty) and fridge, you are mistaken.
AZB
 

Escott

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Thanks for all the imput and please if you have anything to add keep it coming.

I thought that this thought was a waste of time and impractical. When ever you have 16 different owners you have things that you must spend time on that makes no sense. I just wanted to get some info to end this discussion and so far it doesn't fly.

This cost is to be borne by the individual owners and didn't understand why we had to look into this as a board in the first place but now that it has been discussed and unless I am making a mistake impractical I think we can be finished with it.

Thanks for your imput and time helping to research this matter for Ken and I.
Scott
 

Island Treats

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Escott said:
This cost is to be borne by the individual owners and didn't understand why we had to look into this as a board in the first place but now that it has been discussed and unless I am making a mistake impractical I think we can be finished with it.
AMEN :rolleyes: