The AERL "Micro-Cathodic Converter" is a general purpose CP control designed for use with solar electric and/or TEG power units. It is intended primarily for applications where the impressed current is relatively small, such as small pipelines and wellheads. Units range from 4 Amp to 8 Amp, and are available for either 12 or 24 volt battery systems. The units can also be operated from a DC power supply running on AC.
All AERL controls feature excellent efficiency (97%+), and is the only CP control specifically designed for use with solar electric power systems. Because all AERL CP controls use a high frequency DC to DC switching converter there is almost no wasted power, unlike almost all other CP controls and rectifiers. This reduces costs for solar and TEG powered CP power systems by 20 to 50% in most cases.
All AERL CP controls and Maximizers come with a 2 year warranty.
With the exception that the Micro-CP units are not available with digital metering and does not come in an enclosure, the specifications and instructions are the same as the standard full-size Cathodic Converters.
1. Controller Type
High efficiency, non-isolated, common positive (+), DC-DC step-down MOSFET switching power converter. All AERL CP controls are constant current or constant voltage (user selected). Reference cell control is available as an option. Physical size is approximately 2-1/4" x 2-1/4".
2. DC Voltage and Current Ranges
Input voltage is either 12 or 24 volts DC (specify). Output current units are available for 4A, 5A, 6A, 7A, and 8A maximum output. Output current accuracy is 2% or better over a 30 degree C temperature range.
3. Operating Range
All AERL CP controls are designed for -20 degrees C to +50 degrees C. Input voltage ranges are 11 to 16 volts for the 12 volts unit, and 22 to 32 volts for the 24 volt unit. Input current will be equal to or less than the output current in all units.
4. Usage
The Micro-CP units are designed primarily for use on gas wellheads, bridges, underground tanks and other applications that require 4 to 8 Amps constant current. They may also be used with pipelines and/or reference cell input with the addition of a "Surge Buster" option for lightning protection. Although these can be used in constant voltage or reference cell input, they are normally operated in constant current mode. The output current is adjustable over the full range down to zero.
5. Power Savings
Because all AERL CP controllers use "smart" DC to DC switching rather than resistance to obtain the correct output voltage, they are much more efficient that any other CP control currently available. Typical savings of 20% to 50% are typical for solar powered systems. Power is converted on a "Watts to Watts" basis, so you don’t waste money on oversized solar or TEG systems.
The entire unit is only about 2.25" square, making it very easy to fit into existing control boxes or panels.
AERL CP controls are typically 98%+ efficient. This can save you 15% to 40% on the cost of panels for solar powered CP systems.
Because the AERL controls are microprocessor controlled constant current, there is no problem in matching to your groundbed. The controls automatically adjust to whatever voltage is needed to provide the required current. You can use industry standard 24 volt PV array and battery systems. For example, if your groundbed requires 6 amps and is 2 ohms, the Micro-CP control will take 24 volts at 3 amps and convert it down with 99% efficiency to 12 volts to supply 6 amps.
To avoid damage and excessive cycling of your batteries, AERL controls will disconnect from the load at 11.5 volts and reconnect when the batteries are recharged automatically. Batteries that have been discharged too low are also very susceptable to freezing.
To prevent excessive power draw from undersized PV arrays and systems, AERL controls can be set to automatically switch to voltage mode rather than constant current mode.
Note!! The most common setup problem for the Micro-CP is that the unit will not turn on. This gives the appearance of no output
This is almost always due to the low voltage disconnect circuit in the unit. This circuit is designed to cut the output load off at 10.5 (or 21 volts for a 24 volt system) volts, and not turn back on until the batteries are back up to near full charge, which is about 12.5 to 12.6 volts (25 volts for a 24 volt system).
To temporarily defeat the low voltage disconnect; note that at the top edge of the board, (to the right of the toggle switch) there is a white "T" printed on the circuit board. The bottom part of the "T" encloses two small terminals. After all input and output connections are made, and the unit is powered up, briefly short out these terminals - this will force the unit to turn on even though the input voltage is less than 12.5 volts (25 for 24 volt system). Note that if the voltage is less than 10.5 (21 volts for 24 volt system) volts, it will turn off again! This will allow you to setup the unit and do the current and voltage adjustments that might be needed.
All of our current production solar systems with the Micro-CP unit are wired so that the CP control runs off of the LOAD terminals of the Morningstar charge control. This control will go into Low-voltage disconnect at 11.5 volts. This results in longer battery life and protects batteries against freezing in very cold temperatures. If you prefer to run directly off of the battery, please contact us. All Micro-CP controls manufactured since Oct 1996 are set to cut off at 11.5 to 11.8 VDC.
Note: if you are running the unit from an AC operated DC power supply, the power supply MUST be adjusted to put out 13.8 to 15 (27.6 to 30 for 24 volt systems) volts DC. If the supply is set too low, the Micro-CP may never turn on. It is a common misconception that a battery is fully charged at 12.6 volts, but this is only partly true. For more information on batteries and battery charging, see our battery FAQ's.
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