PRODUCT FAQ's
INTERNAL VS. EXTERNAL TEMPERATURE COMPENSATION RELAY VS. SOLID-STATE CONTROLLERS OVER CURRENTS / CURRENT DERATING
Some of our customers absolutely require internal temperature compensation. Although we counsel against this, we will install internal compensation at no additional charge over the cost of standard temperature compensation.
Basically, we recommend solid-state (transistor) units for currents less then 30 amps, and relay or hybrid relay/transistor units for currents above 30 amps.
Although Specialty Concepts no longer manufactures relay-based controllers, the information above is still useful. In recent years, more efficient FET transistors have allowed ever-higher currents to be controlled more efficiently.
All products can handle a 30% current overload for at least 1 minute when the unit is operating at its MAXIMUM ambient operating temperature (usually 50 C). At lower temperatures, products can carry the overload current for significantly longer periods of time.
See "WHAT IS LFCS PULSE-CHARGING" below for a further explaination.
Specialty Concept's solid-state regulators use a modified PWM charging technique, known as LFCS (Low-Frequency, Controlled-Slope). Instead of operating at a fixed frequency, these regulators switch at a frequency determined by the batteries state-of-charge (SOC). The higher the SOC, the lower the frequency. Usually, many seconds occur between each cycle when the battery is not fully charged. Near full charge, each cycle can take many minutes.
Additionally, the rise and fall times of the switching element (the shunt transistor) are controlled so that they do not generate harmonics that can cause additional radio interference.
In fact, these regulators can work reliably when COMPLETELY IMMERSED in salt water. (The only caveat here: the electrical connections to the terminal block must be protected with an appropriate gel-type protectant).
Last update: Nov. 3, 2012
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