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Truck Camper Application Notes


The Basic Auxiliary Battery isolation setup is ideal for Truck Campers.  When the Truck Camper is loaded Camper sunsetonto the truck, the camper electrical is typically plugged into a connector in the bed or to the trailer harness.  The Truck Camper is typically left connected to the vehicle for long periods of time.  Therefore, it is important to use isolation from the main vehicle battery.  With our BIC-95150B wired in the Auxiliary Battery setup, you can connect your Truck Camper and leave it connected without worry about it draining your main battery(ies).

With this setup, installation is very simple! However, there are several important considerations. Often, a Factory trrailer harness uses a relatively small wire for the charge line or power line. This Dodge Ram, for example, uses only a 14 AWG wire in its factory harness for the 12V power line. This limits your average and peak charge rates to levels that may be considered too low for good performance. We recommend using 8 AWG wire as the optimum size for a minimum of 20 feet and up to 35 feet and then fused at each battery end with 50A or 60A circuit protection. If your application needs more than 35 feet of wire length, then increased size to 6 AWG may be appropriate. Although the BIC can be mounted in the camper itself, Best performance is achieved when you mount the BIC-95150B camper installBIC under the hood of the truck rather than in the camper.

Best protection is achieved by locating the circuit protection closest to the battery ends. Note that in the picture of this install, the wire between the Battery (+) terminal and the circuit breaker is about twice the recommended 1 foot or less and that length of wire is not protected by fuse or CB. That is a small risk that we chose to accept due to the more convenient mounting location of the circuit breaker.

By installing another plug, dedicated for the camper, in the bed of the pickup, you Camper plugwill still have the factory trailer connection available for towing a trailer, for example if you want to trailer your 4x4 off road rig with you or take your boat to your favorite lake campsite. For the camper turn signals, brake lights, etc., those wires can be run from the new plug in the bed and splice the appropriate wires to the trailer harness. And, obviously, a slide-in camper does not need brakes, so the pin for a brake controller is not needed for the camper plug.


Truck Camper Auxiliary Battery Isolation Diagram

Basic Auxiliary diagram


If you have considered a diode isolator, battery separator, or other combiner, and want the best option, then look no further than a Hellroaring BIC!

A diode isolator has voltage loss regardless of how low your load demand is. Our BIC's have no diode voltage drop.

A typical Battery separator or other combiner is based on a Mechanical solenoid relay device which have contacts that tend to arc and wear out over time as well as develop inconsistent contact resistance when there is battery voltage on both sides. Our BIC's have no mechanical moving parts to arc or wear out. So, the very low ON resistance is consistent over time.

Low Voltage Disconnect Module

Another thing to consider in your camper is average daily power consumption. A camper such as the one in the picture above comes with a power switch for the camper. This switch controlled a relay to switch battery power on or off to the whole camper (except high power stuff such as an inverter). This switch needs to be ON all the time to keep the water heater, heater, and referigerator operating as needed. This switch controlled a relay that consumed a minimum of 0.5A of power. So, just by keeping that switch ON, at least 12 AH of capacity per day was being consumed. For a 1 week dry camping excursion, this meant a consumption of 84 AH.  That is quite a reduction available from two 105AH batteries. That is 40% of the total battery capacity gone just for keeping the camper power switch ON!

So, what we did is replace that factory relay with one of our SSR's and in conjunction with a LVM-xxV control module, the combination of which, consumes only about 0.01A to keep the power ON when the switch is ON. SSR-LVM imageThis translates to only consuming about 1.7 AH of capacity over a 1 week period of being ON continuously. That is a savings of 82 AH of battery capacity that could be used for other camper use, or better yet, at the end of that 1 week dry camp, you would have discharged your battery bank significantly less, which typically translates into longer battery life!!

We have many SSR models and ratings to choose from and the LVM-xxV module to control them are avaible now.

We also have a Low LVDM small Voltage Disconnect module and SSR integrated into one complete unit (LVDM-22.0V-2.5H-25A-70S) designed for a 24V battery system for up to a 25A maximum continuous loads. We will soon release a 12V version without a timer which is rated to 50A or 60A continuous.



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Last modified: 10-31-2023