PRODUCT FAQ's

INTERNAL VS. EXTERNAL TEMPERATURE COMPENSATION

RELAY VS. SOLID-STATE CONTROLLERS

OVER CURRENTS / CURRENT DERATING

PULSE-WIDTH-CHARGING

WHAT IS LFCS PULSE-CHARGING™

ENCAPSULATED CONTROLLERS


INTERNAL VS. EXTERNAL TEMPERATURE COMPENSATION

We FIRMLY believe in EXTERNAL TEMPERATURE COMPENSATION. We have NEVER doubted this. Even though it is a hassle for us to build and for you to install, it is the ONLY acceptable way to ACCURATELY measure battery temperature and charge the batteries accordingly. Regulators with INTERNAL compensation measure the temperature of the heat-generating regulator and its environment, not that of the battery.

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.

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RELAY VS. SOLID-STATE CONTROLLERS

Both relays and transistors have their pros and cons. Basically, relays are MUCH MORE efficient at higher currents. They also are better at handling high surge currents and are more forgiving of hookup "mistakes".

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.

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OVER CURRENTS / CURRENT DERATING

The published current rating for all of Specialty Concept's products are the maximum continuous rating. However, this is a VERY conservative number and therefore there is some leeway in actual values.

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.

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PULSE-WIDTH-CHARGING

All of Specialty Concept's solid-state regulators use a modified form of pulse-width-modulation (PWM). Instead of a fixed-frequency, variable pulse-width scenario, SCI products use a low-frequency, variable-frequency, variable-pulse-width technology.

See "WHAT IS LFCS PULSE-CHARGING™" below for a further explaination.

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WHAT IS LFCS PULSE-CHARGING™

One major problem with PWM charging schemes is that they opperate at high frequencies. This can cause interference in various nearby radio devices. It is very difficult to eradicate such interference.

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.

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ENCAPSULATED CONTROLLERS

All of Specialty Concept's ASC™ series of solid-state regulators are fully encapsulated in waterproof epoxy. NONE of the control electronics are exposed to any adverse environmental conditions.

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).

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Last update: Nov. 3, 2012
This document copyright © 2000-2012 Specialty Concepts, Inc.
All product descriptive names within this document are copyright © 1981-2012 Specialty Concepts, Inc.