Remote Sense Alternators – Improved heavy duty charging technology that really makes sense
The battery is the source of a vehicle’s electrical power but the alternator is its true lifeline – the heart that keeps the power available at a constant rate. The alternator voltage regulator needs a connection or reference point to monitor system voltage; this allows the regulator to “see” or “sense” voltage and either increase or decrease the field current to the alternator rotor in an attempt to maintain appropriate system voltage and keep battery charge maintained at the optimal level.
Conventional alternators use a connection inside the alternator as a “sense” point for the battery voltage. Unlike conventional alternators, remote sense alternators utilize a special terminal that allows for a wire connection directly to the vehicle’s batteries. This design moves the regulator’s reference (or “sense”) point from inside the alternator to the batteries.
Non-remote sense alternators – which utilize an internal sensor – attempt to keep alternator voltage at the required level. Appropriate for vehicles with little or no load, non-remote sense alternators use cables that have inherent voltage “loss” or “drop,” thereby reducing the amount of voltage seen at the battery terminal. Therefore, an alternator set at 14.0 volts and charging the batteries through cables may, if exhibiting a loss of .5 volts, deliver only 13.5 volts at the battery terminals under full output.
When a remote sense alternator is used in the same example, the regulator automatically adjusts output voltage to compensate for voltage “drop.” In the Remote Sense example, you would see 14.0
volts at the battery and 14.5 volts at the alternator output terminals, a significantly improved operating condition. That half a volt may not seem like much but it can improve battery charge time by 50% and can decrease battery warranty claims by 30%. Remote Sense provides highly accurate voltage readings and optimizes battery state-of-charge resulting in improved efficiency and overall battery life. In turn this can extend starter life which can be diminished by poorly charged batteries.
Remote Sense is ideal for any heavy duty vehicle that makes frequent stops including school buses, trucks with lift gates and delivery trucks. It is also a valuable investment for vehicles with high load like emergency services vehicles. Remote sense alternators are fitted into many applications as original equipment (OE) and it is very important in these instances that the replacement unit features the same remote sense functionality.
Remote Sense is a feature available on many Delco Remy and Prestolite alternators. Careful consideration of alternator type and wiring configuration should be made when retrofitting a vehicle with a non-remote sense alternator to this new technology to ensure optimum performance and eliminate any chances of overcharging batteries. For further information contact your local Baxters branch.
The Delco Remy remote sense alternator on the left and the Prestolite with remote sense on the right.