Advanced Marine Electrics and Electronics Troubleshooting A Manual for Boatowners and Marine Technicians

range from –20°F to 200°F) so it can compen-
sate for the temperature.
In this same vein, many battery chargers
have potentiometers that allow for temperature
compensation adjustments based on the aver-
age temperature of the battery compartment.

temperature monitoring 65

The temperature display on the inTELLECT EXP-1000.

These adjustments, which maximize battery

charging voltage output potentials, are often

overlooked, but they can make a real difference

in battery performance and longevity. The

infrared heat-sensing gun can help here as well.

Galvanic Isolators

Temperature can also be a critical issue with

diode-type galvanic isolators in several ways.

First, a high case temperature may indicate a

serious AC fault on the boat and a safety issue.

There could be enough AC fault current flow-

ing through the isolator to heat the case but

not high enough current to trip a breaker, cre-

ating a shock hazard.

Second, galvanic isolators have been

known to fail due to excessive ambient tem-

peratures in their mounting locations. It is not

at all uncommon for low-level currents to be

running through an isolator for indefinite

periods of time, resulting in a buildup of heat.

This heat must be dissipated; otherwise, the

diodes that are the key components within the

isolator can be damaged from the thermal

overload. ABYC Standard A-28 for manufac-

turers of galvanic isolators defines the ambient

temperature for isolators that are either

ignition-protected or intended for installation

in machinery spaces at 122°F (50°C). For

non-ignition-protected isolators and those

that are not intended for installation in machine

spaces, ABYC pegs the ambient temperature

at 86°F (30°C).

Value and Utility

Before installing a galvanic isolator, battery

charger, or other similar device on your boat,

it makes sense to check temperatures to deter-

mine the suitability of a specific location

and/or the need for supplemental ventilation.

(In fact, this should bepart of a professional-

grade installation.) A normal thermometer

Temperature compensation adjustment on a battery
charger.