Comments for Green Products and Alternative Energy Review Ratings » Green Products and Alternative Energy Review Ratings

Comment on What is the power rating on Solar panels mean? by Rudydoo

Rudydoo — Wed, 15 Dec 2010 16:48:31 +0000

Hey JT, J3 is correct on the math, except that 12 volts is the, "nominal," voltage of the system. The problem here is that to charge a 12 volt battery usually requires at least a 15 volt power source. To accommodate this, panels are generally wired for 18 volts, allowing the charger controller or other wiring to use up a small amount, and still leave enough for the battery to charge on. A 7 watt panel that is wired for a 12 volt nominal system will likely have an open circuit voltage of 18 volts. To get to the amperage, take the watts and divide by the panel voltage (7 / 18 = .4 amps) When a manufacturer states rated watts, they are taking the panels open circuit voltage and multiplying it by its short circuit current. A panel that has an open circuit voltage of 18 and a short circuit current of 1 amp will be advertised as an 18 watt panel. Hence, a 9 watt panel will put out 1/2 amp.

In actual practice, you will never be able to reach the rated watts, because the panel voltage always degrades to match the battery’s charge curve voltage at the time. So even if you get an 18 watt panel, with an amp rating of 1 amp, it will put 1 amp into the battery, but if the battery voltage happens to be 14.5 while it’s charging, then the wattage from that 18 watt panel is 14.5 X 1 = 14.5 watts.

Charging a 5AH battery is no problem for a panel that only puts out 10 or 15 watts, it will take a few days. If it’s just one 5 AH battery, I would go with one of the battery maintainers at the auto parts store for $30 or so, they don’t usually put out more than 1/2 amp or so anyway. At 1/2 amp, it would take 10 solid hours of sunlight to put 5 AH into your battery. If you’re looking at panels online and don’t know what to get, just look for the specific ratings, not the wattage. Make sure the VOC, or open circuit voltage is at least a few volts higher than your battery voltage, and the short circuit current is about how many amps you want to charge your battery at. The watt rating doesn’t matter much for battery charging, only the amps. Good luck, Rudydoo

Comment on What are some of the best places to find quality "tabbed solar cells" online? by Dave S.

Dave S. — Mon, 13 Sep 2010 07:12:24 +0000

You can look on eBay for sellers. that way you can check there rating. Most of your DIY solar ebooks suggest eBay.

Comment on What type of solar panel is this? by sd3r

sd3r — Sat, 07 Aug 2010 09:17:51 +0000

these are older panels, but should be equivalent to current productions with a slight degrading for their age. a solar panel, after all, is only an unregulated battery (when the sun is out). the 110 probably refers to the panel wattage rating. most panels of this sort put out slightly more than 12-14 vdc which makes them ideally suited to charge standard 12 volt batteries. you need some sort of regulator, but again, you should be able to adapt something.

Comment on What do you think of creating your own wind and solar energy? by Lester

Lester — Wed, 14 Jul 2010 21:54:55 +0000

Wind Power wouldn’t really benefit you unless you have a lot of wind near your house. Also Wind Turbines cause a lot of noise pollution (annoying noise) and kill birds (I’m not kidding, migratory birds get killed when they get near the turbine because they get stuck). I wouldn’t invest in wing power unless I live near the beach where there is a lot of wind or a place with a lot of wind.

It will take you about 10 years to get back the money you have invested in a solar panel. Keep in mind that the days get shorter during winter until the winter solstice and there is less sunlight. Solar Panels absorb very little of the energy of the sun.

Keep in mind what I said before investing in solar and wind power. I suggest waiting till the solar panel cost gets cheaper till you buy.

Comment on 12V Solar panel directly to 12V inverter…and restult.? by pvdirect81

pvdirect81 — Tue, 13 Jul 2010 19:20:12 +0000

12v (12v nominal) is a descriptive term, not an actual voltage figure given. it serves to identify components that will work together in a system. your 300w inverter needs to see a constant voltage supply likely between 10.5 and 14.5 volts in order to function. a 12v battery (hopefully a deep cycle one) will remain at these voltages in day or night. your pv module (aka solar panel) is designed to work at 15-17 volts. why? because you have to be at a higher voltage to charge the battery which may not be full until 13 or 14 volts.

your pv module is not intended to be wired to the inverter,and the inverter manual will only describe wiring to a battery for this reason. not only will unregulated pv be too high a voltage, but it is also variable based on sunlight so it wont work at nigh, and is also only 5% of your inverters capability. the other answerer is correct, solar module to charge controller, charge controller to battery(s), battery to inverter, inverter to appropriately sized load. if your installation is permanent rather than mobile, you would be subject to national electric code, and also have to include appropriate grounding, overcurrent protection and disconnects.

very few loads can "run" directly from solar (aka pv direct). these are often things like fans or pumps that can handle variable voltage and power outputs.

james
altestore.com staff

Comment on earth4energy.com – Have you used it? by LeftWingGuy

LeftWingGuy — Sat, 10 Jul 2010 21:51:32 +0000

Never heard of it.

Comment on Is Earth4Energy A Scam? by shadowbot

shadowbot — Thu, 08 Jul 2010 21:54:14 +0000

I was wondering the exact same thing and my searchings led me here. I would advise you to be very careful for a few reasons.
1.) Any system that PROMISES you can cut down your electricity by a certain percent is a lie. Some people have electric bills that are 100 dollars a month and others may pay 500. How do the creators of this system know? They dont.

2.) This is an e-book. Its not a kit of any type. All you get is a file on your computer with text and pictures telling you how to build things.

3.) The internet already has TONS of completely free info about making your own wind turbines and solar systems, just check youtube or http://www.instructables.com

4.) Even if you do build the stuff earth4energy tells you about there is no guarantee your area has the same amount of sun/wind needed to provide 80% of your electrical needs

5.) It is not very easy to build your own electrical systems and have them connected to your house and appliances. Electricity on that level can kill you, fry your appliances, start a fire, or all 3.

6.) Be very wary of "review" sites that offer you a discount for buying it by clicking their links. They are almost always just fake good reviews that get money every time they send a buyer to the company’s website.

One homemade wind turbine will definitely not produce even 20% of the power you use, unless maybe you are living in a bachelor apartment by yourself and are very conservative with your power.

However if you do decide to buy this please let me know. Myself and others would like to know how legit it is. Good luck, and seriously, be careful with the electrical stuff.

Comment on From which website can I get a solar panel rated at 12V or above? by greg x

greg x — Wed, 07 Jul 2010 12:03:39 +0000

harbor freight.com will not ship to india.
your best bet is going to ebay.com
being in india the places you get to pick from are going to be very limited because of shipping.

Comment on www.earth4energy.info??? by Tim Ninyet

Tim Ninyet — Tue, 06 Jul 2010 17:04:25 +0000

its good to learn how to make windmills and solar power.
like if you want to power a few things from your home. I bought it a few days ago and am just about done on my windmill,. I will finish it this weekend

Comment on What time it would take for a 1.8 W (12v) solar panel to charge a 300w (12 v) battery? by sd_ducksoup

sd_ducksoup — Sun, 04 Jul 2010 19:21:20 +0000

If the battery wouldn’t self-discharge, it would be:

300W/1.8W = 166 h 40 m

With 12 hours of sunlight per day, it will take about 14 days.

However, since all rechargeable batteries self-discharge over time, it would take much longer, if it could be done at all. Many batteries give a figure of 1% per day loss, so that would be 3 W per day, or 1 h 40 m per day required just to recover to the level of the previous day. So, if there were only a 1% loss per day, you’d only get a net gain of 10 h 20 m per day. That would take a total of 16 days of 12 hours of sunlight.

If you lost 8% per day, you could never fully charge the battery…