Renewable Energies Solar Cells Product Number : SB122Solar Regulator
Good Solar cells are very expensive and people who buy and use them want the maximum power they can possibly get from their investment. In order to make an informed decision as to which type of solar regulator you need then you must understand how a solar cell performs and the difference between the 3 main groups of solar regs. As with most things in life, you get what you pay for, a typical 20A / 12V solar regulator can vary in price from £20 - £200+, why? Is the £20 as good as the £160 or at least nearly as good or is it a total waste of money. Its extremely important to know which technology you purchase.How does a solar cell work and what are the important operational features? (please note all Sterling regs are waterproof).As a solar cell is a current making device at a given voltage, the important thing to remember is the basic formula: Power (watts) = amps x volts. Therefore, to get the maximum power out of a device you must have as many volts and amps as possible. If the voltage was allowed to reduce, then the performance and hence the power manufactured by the cells drops off, and same for the amps. Maintaining maximum volts and amps is absolutely critical to achieve maximum harvesting potential of a solar cell.In order to achieve maximum power form a solar sell we must find its Maximum Power Point (MPP) on the solar cells power curve. This is the ideal point where one can best obtain the most power from that solar cell.Other key things to think about with solar regs. Remember a solar cell only works for about ½ a day (if even). However, the solar regulator works for 24 hours regardless of whether the solar cell is producing power or not (night or cloud cover). So, the key question is, what power does the regulator use to exist (we call this the quiescent current)? With most solar regulators this averages from 25-50 mA (on a 12V system). That means, for example, a 50 mA drain over 1 years is about 430Ah. However, at Sterling, we try to keep the quiescent current below 1 mA, this means the loss in current over the year would be more in the region of 8A not 430A. Therefore, 422Ah, which would otherwise have been wasted running the regulator can effectively be harvested and passed into the battery system. Low quiescent power consumption is achieved by the use of a more expensive micro processing chip set, some manufactures are reluctant to spend the money on this type of device. Obviously other features which are of vital important are 4 step battery charging and the ability to select the different battery types being charged. This ensures the best charging curves for the battery and also prevents damage to battery bank.
These are simple switching devices which switch between 2 voltages, typically they come on at about 12.9V at the battery and switch off at about 14V ( x 2 for 24V), this is effective at covering power loss from the battery but will not charge well or effectively use the maximum power potential from the solar cell, which for a lot of applications is absolutely fine. Ideal for low cost 10-100 watt low quality solar cells.The ideal use for this type of reg is, for example, if you had a motor home or a small boat on a swinging mooring and a small solar cell who’s only job was to keep the starter battery topped up when vehicle / boat is not in use, then this product is perfect, a low cost cell and low cost switching regulator will do the job. However, if you have a good quality, expensive solar cell, who’s job is to effectively and efficiently contribute useful power into a system then this type of regulator would be a very poor choice indeed, as such we limit the range of this product as to use this technology on larger cells simply makes no sense. Advantage: very low cost. Suitable for: Low cost cells where the objective is simply keeping a relatively inactive battery topped up (such as a starter battery) as opposed to contributing useful power into a system. Disadvantages, very ineffective at maximising the harvest from a solar cell.