Kick off the summer season with the SteadyCharge

The SteadyCharge was developed originally for a company that needed their heater batteries to be charged during the summer. Heaters are used in trailers during the cold seasons when products that can’t be frozen—such as produce or drinks—need to be transported. However, during the summer, those heater batteries are not in use and lose their charge.

In addition to the cost of the actual battery when the dead batteries must be replaced at the end of the summer, there are also a few other problems that come with replacing these batteries. They are usually mounted quite high up on the trailer, which means the technician faces some safety risks when changing the batteries in a precarious location—especially since batteries are quite heavy.

The SteadyCharge utilizes the 7-way to charge and protect any auxiliary battery (even though it was originally built to meet the needs of heated trailers, it will charge and protect any auxiliary battery).


  • Simple installation
  • Guaranteed power source, since drivers must plug in 7-way cord
  • Aux circuit protections
  • Temperature compensated charging
  • LEDs for easy diagnostics
  • Weatherproof

Simple installation

The SteadyCharge is designed to save time and money; its installation process was also designed with that in mind. It includes a simple, 4-bolt pattern, as well as four simple connections (positive and negative to 7-way nosebox, positive and negative to the battery).

Guaranteed power source

Since the SteadyCharge uses the 7-way to charge, and drivers always have to make sure the 7-way is plugged in to make the lights on the trailer work, it always has power.

Aux circuit protections

In addition to keeping your auxiliary batteries charged, the SteadyCharge comes with built-in safety features to protect your truck and vital systems such as ABS and Roll Stability. In order to turn on, there must be key switch voltage—meaning the truck has to be turned on—so that it doesn’t drain the truck batteries. The ABS and Roll Stability need approximately 9 volts to function, so the SteadyCharge will turn off if the 7-way voltage drops to 10 volts. It will check the voltage again approximately two minutes later to see if the voltage is high enough to turn back on.

Temperature compensated charging

This means that if it is cold outside, the SteadyCharge will automatically increase the voltage going to the batteries to keep them properly charged. Likewise, if it is warm outside, it will decrease the voltage to make sure the batteries don’t get damaged.

LEDs for easy diagnostics

There are two LEDs on the front of the SteadyCharge—one labeled Source and one labeled Battery. The Source is the charging source (7-way), and Battery is the auxiliary battery being charged. The lights indicate the following voltages:


The SteadyCharge is intended to be mounted on the outside of the trailer. We know that means it could be hit with a lot of things, including salt spray, rain, or any other weather-related moisture. As such, it has been designed to withstand any of the weather conditions you would expect to find while on the road.

Visit the SteadyCharge product page for additional information (specifications sheets, guides, videos, etc.). For more information about Purkeys products, tech tips, educational webinars, and more, sign up for our newsletter.

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