What is Temperature Compensation?

It is common knowledge that the specific gravity of electrolyte in a battery is not only affected by charge level, but also by temperature.  As the temperature of the battery decreases, the specific gravity of the electrolyte will increase.  Conversely, as the temperature of the battery increases, the specific gravity of the electrolyte will decrease.  These changes in specific gravity does not mean that the battery charge level is increasing or decreasing, it simply means that the temperature of the battery is changing.

These changes can be observed on the chart below. To summarize, for each 10° F change in temperature, the electrolyte changes by .004 specific gravity points. (For each 10° C change in temperature, the electrolyte changes by .007 specific gravity points.) If this condition was not addressed, these types of fluctuations could lead to false indications by the Magic Eye. To compensate for this phenomena, ITW Delpro has formulated the ball floats to have the same thermal coefficient as the electrolyte. This means that as the specific gravity of the electrolyte changes due to temperature fluctuations, the specific gravity of the ball floats also changes to compensate.

This unique feature assures that the Magic Eye will provide an accurate indication of the state of charge regardless of the batteries temperature.

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