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©Denis Lenardic
2001-2010
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Friday
12th Mar, 2010
05:12
This page was last time updated on
25th Nov, 2007
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Charge regulators
"Why do the people who know the least, know it the loudest?"
(Geoff Metcalf, KSFO San Francisco)
Different charge regulators produced by STECA GmbH
(courtesy:
Steca GmbH)
The solar charge regulator main task is to charge the battery and to protect it from deep discharging. Due to overcharging electrolyte boiling could occur causing damage to the battery or even its destruction. Deep discharging could also damage the battery. Charge regulator electronics is most sensitive and crucial to assuring stable photovoltaic system operation. Charge regulator malfunctioning result in high maintenance cost including battery replacement. An important parameter to consider is charge regulator efficiency percentage. For small photovoltaic systems charge regulators from 5 A to 30 A are available. Some of them could be used in both 12 V and 24 V DC systems.
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Charge Regulators |
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There are many different
types of charge regulators available on the market, the simplest
switch on/off regulators, PWM charge regulators which charge the
battery with constant voltage or constant current (they are the most
often used regulators in PV systems) to the most complex MPPT
(Maximum Power Point Tracking) charge regulators. MPPT charge
regulators are more expensive and suit large systems better, where
the investment in an expensive MPPT regulator returns quickly. In
most cases, including inexpensive charge regulators for small
systems, regulator set includes all necessary electronics for battery
protection, such as protection against deep discharging and against
overcharging. Charge regulator functioning is characterised by two
different voltage thresholds, battery and module voltage, upon which
the battery is charged. At higher voltage, usually 12.4 V for 12 V
batteries, charge regulator switches the load to the battery, at
lower voltage, typically 11.5 V, regulator switches the load off. On
the market you can find charge regulators which allow manual settings
of these thresholds, or you could merely adjust the battery type to
Pb acid or Gel type, and the regulator will adjust the two voltage
thresholds automatically according to the battery type without losing
the performance. If excessive ambient temperature swings of more than 5°C
are expected, temperature compensated charge regulator electronics
should be used.
The energy produced during the day, which wasn’t consumed by loads, is
saved in batteries. Saved energy can be used at night or during the
days with bad weather conditions. Batteries in photovoltaic systems
are often charged/discharged; therefore, they must meet stronger
requirements than car batteries. Due to the fact car batteries are
not suitable for PV systems use! There are many solar battery types
available in the market. Most often used classic Pb acid batteries
are produced especially for PV systems, where deep discharge is
required. Other battery types, such as NiCd or NiMH are rarely used,
unless in portable devices. Hermetical batteries often consist of
electrolyte in gel form. Such batteries do not require maintenance.
Typical solar system batteries lifetime spans from 3 to 5 years,
depending heavily on charging/discharging cycles, temperature and
other parameters. The more often the battery is charged/discharged
the shorter the lifetime.
Lifetime depends on charge/discharge cycle
rates numbers. The deeper the battery is discharged the shorter the
lifetime. The most important battery parameter is battery capacity,
which is measured in Ah. Battery capacity depends on discharging
current; the higher the discharging current the lower the capacity,
and vice versa. Batteries can be charged in many different ways, for
example with constant current, with constant voltage etc., which
depends on the battery type used. The charging characteristics are
recommended and prescribed by different standards. The solar
batteries prices are higher than the prices of classic car batteries,
yet their advantages are longer lifetime and lower discharging rates.
Consequently, the maintenance costs of the photovoltaic system are
lower.
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Charge regulators, interesting web sites |
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Steca Solarelektronik - The Steca Company was founded in 1976. Today this is a medium-sized company. The business area solar electronics covers photovoltaics and solar thermal technology. Languages:
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Morningstar Corporation - Morningstar Corporation, a privately-owned corporation, is a supplier of photovoltaic controllers using advanced technology. Languages:
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Phocos - Phocos is a leading player in the world of renewable energy in grid-independent power supplies. Company manufactures a wide range of system components for energy conversion, energy management and energy utilization. Languages:
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ETA Engineering - Manufacturing and worldwide distribution of a patented line of solar charge controllers and battery capacity meters. ETA has manufactured and sold charge controls and meters since 1992. A real workhorse, these units were designed to deliver many years of service on sustainable development projects in developing countries and in remote areas. Languages:
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Blue Sky Energy, Inc. - Blue Sky Energy, Inc. is a privately owned company located in Vista, CA. Their product range are MPPT solar charge controllers used in various, even extreme, conditions. Languages:
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Helios Technology SRL - Established in 1981, Helios Technology is currently the oldest manufacturer of solar cells, modules and photovoltaic systems in Europe. Its product portofolio includes also charge controllers and accessories. Languages:
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Battery related web sites |
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Any Batteries - Interesting battery related link collection. Languages:
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Solar Street Lighting |
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AirTherm Solartechnik - With more than 30 years of experience in photovoltaics AIR THERM is your best contact for R&D, distribution and all services in photovoltaic systems. We support you with all components for your solar energy system in German quality. Languages:
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Literature and more information |
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Dankoff, W.: What is a charge controller? Home Power, September
1999.
