Saturday, September 23, 2017
Mixing solar panels of various voltage or wattage, or produced by different manufacturers, is a frequently asked question by most DIYers.
Though mixing different solar panels (for example: RENOGY 100 WATT SOLAR PANEL KIT ) is not recommended, it’s not forbidden and things would be ok as long as each panel’s electrical parameters (voltage, wattage, amps) are carefully considered.
When you intend to wire two panels produced by different vendors, the vendors actually are not the problem. The problem is in different electrical characteristics of the panels, together with different performance degradation.
Solar modules are connected in series to obtain higher output voltage. The maximum system voltage however must not be exceeded.
For modules connected in series total power is calculated as follows:
Total connected power = 150W + 150W + 150W + 150W = 600W
However if among modules connected in series a module has rated power lower than the other modules, due to lower rated current of this panel compared to the other modules belonging to this string, that module might drag the overall system output down:
Mixing different solar panels in series
Solar modules are connected in parallel to obtain higher output current.
For PV modules connected in parallel total power is calculated as follows:Mixing solar panels in parallel
Total connected power = 150W + 150W + 150W + 150W = 600W
Unlike connection in series, if among modules connected in parallel there is a module of power output lower than the output of the other modules, this might not affect seriously the total power output of the array,provided that this module has equal to the other modules rated voltage:Mixing different solar panels in parallel
Maximum voltage on a string of modules must always be lower than maximum input DC voltage of the inverter.
When connecting different solar modules, it’s not the different wattage, it’s actually the current (for series connection) and voltage (for parallel connection) that could drag down the performance of the solar array composed of those modules.
Only solar panels of exact or similar current should be wired together in series. When you connect a 3A panel to a 3.5A panel, the overall current will be dragged down to 3A. Such a reduction in current will by all means lead to a reduction in power output and therefore loss in system performance.
Similarly only solar panels of exact or similar voltage should be wired together in parallel. When you connect a 15V panel to a 24 V panel, the overall voltage will be dragged down to 15 Volts. Such a reduction in voltage will lead to a reduction in power output and therefore loss in system performance.
Compared to voltage and current, wattage is not a significant concern. When you wire together a 60W panel to a 100W panel in series, the total connected power would be 160W, provided that the two panels are of equal current.
Here any difference in voltages is not important, voltages with just sum up and all you’ve got to consider is that the total voltage should fall within the inverter voltage window.
If their current ratings are different however, you should be prepared to expected unpleasant surprises, since the overall current would be the lower of the two, which will means that you’re not going to obtain a total of 160W but always less. How much less – depends on difference in rated currents.
Furthermore when you wire together a 60W panel to a 100W panel in parallel, the total connected power would be 160W, provided that the two panels are of equal voltage. Here any difference in currents is not important, currents with just sum up and all you’ve got to consider is that the total current should not exceed the maximum inverter input current.
If their voltage ratings are different however, you should be prepared to expected unpleasant surprises, since the overall voltage would be the lower of the two, which will means that you’re not going to obtain a total of 160W but always less.
How much less – depends on difference in rated voltages.
Why it is not recommended to connect different solar panels?
Apart from rated power, each panel has a power degrade percentage.
This means solar panels’ output degrade in a different way over time.
Moreover the stated degradation not always coincides with what is written on a panel’s nameplate. Therefore it’s not easy to find an exact panel match of different solar vendors. ‘Exact match’ means both almost similar ratings and ratings degradation.
For panels connected in series, voltage is additive while current is the same, provided however that all the panels have equal current rating.
If among the panels connected in series there is a panel with rated current lower than the others, it will drag down the current passing through all the remaining panels.
Therefore each of the remaining panels (with higher current rating) will underperform which means that will produce lower current (and power) than stated on its nameplate.
In other words if two dissimilar modules are wired in series, the voltage is still additive, but the current will be equal to the current produced by the panel with the lowest current output in the series string.
For panels connected in parallel, current is additive while voltage is the same. If among the panels connected in parallel there is a panel with rated voltage lower than the others, it will drag down the voltage on all the remaining panels.
Therefore each of the remaining panels (with higher current rating) will underperform which means that will produce lower voltage (and power) than stated on its nameplate.
Mixing solar panels with different electrical characteristics is not recommended if you use an MPPT charge controller. Different wattages make impossible for the controller to find the optimal operating voltage and current, since they are different for each panel type.
The solution is simple: utilize panels that have similar electrical characteristics to the original panels.
Therefore, when connecting different solar panels, to minimize the losses:
Connect only in series panels of the same brand and of the same current
Connect only in series panels of the different brands and of the same current-this is your second option if for whatever reason you cannot find the same brand panels
Connect in parallel panels of the same brand and of the same voltage
Connect in parallel panels of different brands and of the same voltage-this is your second option if for whatever reason you cannot find the same brand panels
Connecting different solar panels with the same array is not recommended since either the voltage or the current might get reduced. Therefore if you are planning to use dissimilar panels, try to pick the ones with similar voltage and current.
If you liked this article you may also like our new kindle books:
1. ‘The Ultimate Solar Power Design Guide: Less Theory More Practice’ [Paperback and Kindle Edition] This is the Missing Guide For Proven, Simple & Fast Design Of Solar Electricity Systems For Your Home, Business, Boat, Vehicle Or Other Outdoor Activities. Written by Experts For Beginners And Professionals Alike.
Wednesday, July 12, 2017
It’s devilish hard to write something thoughtful about video glasses! It appears as if these devices are quite familiar to us, and the manufacture of such video gadgets is going swimmingly thanks to hi-tech industry giants… But we still lack something!
First, millions of users can hardly distinguish between video glasses ( for example: MOULTRIE HD VIDEO GLASSES ), stereo helmets and visors of augmented reality. This terminology confusion turns the discussions in forums into something incomprehensible.
Second, we can’t say that the video glasses are now the part of our routine life. Though many geeks are really keen on such devices, all these technologies are still regarded as something exotic, that is why we lack the information from buyers and users.
To put it shortly: this review is devoted to video glasses only, i.e., a compact gadget intended to watch films at home, in plane or car as well as play modest experimental games. Together we will examine the main parameters of up-to-date holographic lenses, their cons and pros.
WHAT FOR ARE THEY NEEDED?
Before getting acquainted with new technologies in video sphere, you should first determine how you will use the unusual glasses and how much you are ready to spend on them.
To buy ordinary video glasses is not the reason to overpay. In case you are looking for a road-gadget to watch films and look through photos in any private area in plain or train, you may save money and pay minimally. In case you are in search of high quality and 100% video immersing, you have to pay much more.
WHAT DOES THE PRICE OF 3D VIEWERS DEPEND ON?
Let’s examine the price range. Drop in any large on-line market and you will see: today the price of video glasses varies from 75$ to … 3000-4000$ (as a rule, the latter models really possess the home cinema functionality). There are even more expensive models, but their price can’t be regarded as reasonable.
For 75 – 400$ the buyer will get an ordinary variant: spectacles with internal memory, SD card slot and minimal complete set. Light and compact models (Karlton2 50inch model, TBS 3170 and others are among them) can’t be customized at will and you are certain not to get a high quality picture. Nevertheless, they may be an optimal road gadget for many users. We advise to buy models with AV interface, e.g. Av-in and WGA.
From 400$ the range burst begins. Here are flat glasses which direct the ready image to the eye retina, more classic small screen glasses, adjustable diopter glasses, and real mini-helmets. Their functionality exceeds greatly that of “road models”. Among them the following models are especially worth of mentioning:
Home cinema glasses, a real alternative to TV set;
glasses for gamers with the total in-game effect;
«remote displays» for different devices which can be useful for IT-specialists, designers, programmers, …and film fans again;
universal products covering the functions of video glasses, augmented reality visors, etc., and claiming to compete with Google Glasses.
KEY PARAMETERS OF UP-TO-DATE VIDEO GLASSES
Some key parameters are common for all models including the cheapest ones, so every potential purchaser should be aware of them. Let’s look closer at them.
1. Virtual screen size
The size of virtual screen is very important as it is the screen which you will have before your curious eyes. By the way, do you know that in the majority of models the “picture” is transmitted to each eye separately?
Commonly, the video glasses work with 52, 72, 84 and 98 inch format. However, there are models that make you believe that you watch many meter plasma or even movie screen. It’s true that you appear to see it from the distance of some meters. It is normal, otherwise you would cast your eye over the whole screen “body”.
Wednesday, March 29, 2017
In today’s globalized world, it’s all too easy to imagine disaster striking at the heart of your business. Take a moment to mull over some of the scares we’ve had recently that could derail your business. Last year, Computer Weekly reported on the distinct chance that we could see a new flu pandemic. Global terrorism in the summer of 2016 targeted two-dozen different countries, including the US. Flooding destroyed thousands of homes and businesses in Louisiana. And wildfires are still ravaging parts of California.
With all these disasters or potential disaster hitting businesses in the US, what can they do to ensure continuity?
David Van Allen is the VP of operations at INetU. He’s an expert in disaster recovery and planning. But he has some rather unusual advice for businesses contemplating disaster. This is what he says:
Don’t Just Focus On the Technological Side of The Business
When we think about business continuity, we typically think about keeping IT systems up and running. But unless your business is entirely on the blockchain, it’s likely it still has some physical component. Van Allen reminds businesses that they need to think about what would happen if there was a non-technological problem. Sure, their businesses might operate over the cloud. But they still need office space for people to be able to do their work. If there was a fire, does the business have a fire damage restoration plan? What if workers all got ill, thanks to a pandemic? How would the business cope with only a skeleton crew? Van Allen recommends that businesses spend a few days thinking through disasters that could hit things other than their IT. He suggests starting simple and going from there.
Monday, March 6, 2017
Small businesses contribute greatly to a country’s economy. In the U.S., for instance, data from the U.S. Census Bureau showed that the number of small businesses has risen by 49 percent since 1982. Today, many individuals and groups continue to set up businesses targeting the local and international market.
Starting a business of any type requires the proper legal documents and insurance to ensure that everything is legitimate and your business is protected from various risks.
Being knowledgeable about the different types of insurance is a must. Here are 10 of them you need to consider regardless of the size of your business.
A general liability insurance will protect your business whether you are operating a physical store or one based at home. This policy will provide coverage in the event your employees, products or services cause physical harm to a third party. It can also be applied to any property damage to a third party.
Sunday, February 26, 2017
It’s no big secret that Amazon is the world’s largest online retailer. The e-commerce giant started out life as a small website that just sold a few books. Today, you can go on the Amazon website and buy just about anything! Yes, they still sell books. But, you can also get electronics, homewares, even food!
Jeff Bezos, the guy behind Amazon, is worth around $66.9 billion. And all that from a small e-commerce website founded back in 1994. Now, I know what some of you are thinking. Amazon got established during the Web’s infancy. There’s no way anyone could start an e-commerce store and topple Amazon today! Or, is there?
Amazon does have some stiff competition from the likes of eBay and AliBaba.com. Plus, many promising new e-commerce sites look set to grow at a rapid pace! Are you thinking of setting up an online store? And have you ever wondered if you could be as big as Amazon?
In short, the answer to the latter question is yes. You just need to have a combination of excellent business skills and timing. Let me give you a few examples of what has made Amazon the success that it is today. I’ll also give you some pointers that can help you speed up growth for your e-commerce site:
Cheap pricesOne of the many reasons for Amazon’s success in the e-commerce world is their prices. For the majority of products, Amazon is significantly cheaper than other online sellers. Part of their business model involves buying lots of stock at the lowest prices possible.
Mixing solar panels of various voltage or wattage, or produced by different manufacturers, is a frequently asked question by most DIYers...
It’s devilish hard to write something thoughtful about video glasses ! It appears as if these devices are quite familiar to us, and the ...
Small businesses contribute greatly to a country’s economy. In the U.S., for instance, data from the U.S. Census Bureau showed that the nu...
In today’s globalized world, it’s all too easy to imagine disaster striking at the heart of your business. Take a moment to mull over some...