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Aug 26, 2021


  • Technology

A liftgate that continually cycles is crucial for the function of a business when it comes to pick-up and deliveries of goods. Non-operational or slow cycling liftgates cause delays, leading to downtime and a loss of revenue. Pallets may have to be broken down and unloaded by hand, causing a ripple effect that could back up other drivers waiting to unload. So what’s the solution? Liftgate batteries are the immediate source of power to operate and cycle a trailer liftgate. These batteries rely on a charging system that pulls from the tractor batteries to replenish power levels. Proper spec’ing and maintenance of this system will support keeping the liftgate operational and cycling for on-time deliveries.    


Liftgate batteries lose their charge with frequent cycling and operation of the liftgate system. The heavier the load, the greater the draw on the auxiliary batteries that power a liftgate’s electric motor. Frequent liftgate usage and heavy loads require a reliable and strong charge for full batteries. It is common for a liftgate to get stuck on the ground because the batteries don’t have enough charge to raise it. A best practice is to always leave the yard for the day’s route with fully charged liftgate batteries. When the liftgate batteries run low and the liftgate is struggling, it will pull power through the charging system direct from the tractor batteries and it can overheat the charging system. If using a single pole set up, it might be time for an upgrade. And if using a dual pole set up, there are alternative over-the-road charging options available.

When selecting a system, there are two options, dual or single pole systems. Some trucks and fleets are still using single pole sockets and charge cords. The single pole relies on the 5th wheel and the kingpin for a ground connection. However, the grease that coats the 5th wheel acts as an insulator that creates a poor ground connection in-between the 5th wheel and the kingpin plate. Direct current requires a solid ground connection. Without it, it can result in a weak or intermittent charge. Spec’ing a dual pole system has many key attributes that make it a superior system over single pole. Using dual pole sockets and charging cords will help improve the connection giving the battery a full charge. The dual pole system has its own built-in ground, reducing charge time substantially, which means less downtime for the truck. A dual pole system also has a stronger ground connection directly from the battery to the socket, making the charging connection much more dependable.  

Additional products that can be spec’ed are trailer power management systems that manage the charge to auxiliary batteries by maintaining a consistent trickle charge from an on-board charger. Battery status indicators can also keep a driver informed of the batteries’ state of charge.

While spec’ing dual pole products and trailer management systems ensure a solid and reliable way to charge liftgate batteries, spec’ing products that protect against cable damage and corrosion are also important. Proper back-of-cab cable support will keep cables from rubbing, dragging, and sagging between the tractor and trailer. 

Installation, Support, and Maintenance

The leading cause of corrosion in the liftgate connection is a lack of proper maintenance but improper installation can also lead to corrosion. It is challenging to prevent corrosion completely; however, routine maintenance and properly installed products will help prevent or slow the process of corrosion and ensure that charge cables are in good working order.  

Installation and Support

Proper installation and use of liftgate system products are important to benefit from their full potential. Sockets installed at an angle facing up catch and trap moisture like a cup filling up with water. Sockets should be installed flush to a 90-degree surface to avoid trapping moisture and contaminants, which create corrosion. When coupling, the socket lid should latch to the plug for a tight connection. Liftgate charging systems require the same care as 7-way electrical systems. Cables need proper support to avoid damage to the jacketing that can expose the internal copper to the outside elements. When not in use, keep the liftgate assembly stored in a safe place, such as a stowage system on the back of the tractor.

Electrical Maintenance

Connections require maintenance to ensure a solid connection and keep corrosion at bay. Liftgate electrical systems are no stranger to the effects of corrosion. Moisture can enter the electrical system, causing corrosion, restricting the direct current, and interrupting the charging process. The liftgate system carries a much larger current/amperage, which creates heat. When heat and corrosion mix, there is the potential for a thermal event. During routine PMs, liftgate sockets and plugs should be inspected for moisture, contaminants, and debris. Phillips recommends using a plug and socket brush designed for auxiliary connectors, or a mini wire brush, with electrical cleaner to clean the socket and plug union. Use dielectric grease on the back of the socket to keep corrosion out. Check the charging cable for any damage and replace it when necessary.

Note: Before cleaning sockets and plugs, if a tractor socket has a manual circuit breaker or master disconnect, turn it off. If not, disconnect the positive cable from the battery before cleaning. 

Phillips Charging System Product Solutions

Phillips provides multiple product solutions to keep liftgates cycling for on-time deliveries. From premium corrosion-resistant back-of-cab charging cable systems to trailer power management systems that offer a faster and reliable way to charge auxiliary batteries or keep track of battery state of charge. Coming soon, Phillips will also offer a cleaning kit for auxiliary sockets and plugs.

Products like the Dual Pole QCS2™ (Quick-Change Socket) and WEATHER-TITE™ M2 assemblies will help alleviate moisture and contaminant intrusion reducing the chances of corrosion at the coupled connections. Cable support for charging cables, only available through Phillips and the first of its kind, is available with QWIK-CLAMP™ technology. The STA-CHARGE™/PERMALOGIC™ Smart-Charge system charges the batteries from multiple sources, increasing the number of liftgate cycles. The V-CHECK™ II battery status indicator measures the state of charge with a digital display and LED color-coded light so that a driver knows if the liftgate is ready for the ride.

With the right products, proper installation, and routine preventative maintenance, liftgate charging systems will keep liftgates cycling for on-time deliveries.