RV FEATURE
In a previous issue , we looked at the advancement of RV electrical systems , showing you a method of calculating your battery ’ s performance while camping offgrid using watts as the basis . As good as this is , it will only estimate what you can expect from your electrical system under a variety of conditions .
When it comes to actually camping off the grid and running all those appliances in your RV without flattening your batteries , you need to have an accurate system for monitoring your battery ’ s state of charge ( SOC ) as it charges and discharges over the course of your camp .
This is where you need a battery management system ( BMS ) but , as we will discover , these systems can take many forms and they have evolved into something with capabilities we would never have considered 20 years ago .
BASIC BATTERY MANAGEMENT
Before the introduction of lithium battery technology to the RV scene , lead-acid batteries were all that was available for most caravans , campers and motorhomes .
Most 4WD owners also installed dual battery systems in their vehicles with at least one deepcycle battery . Sure , there were options of wet cell , gel or AGM batteries , but these all functioned in much the same way . They were no more than a container with six sections filled with an acid and a couple of electrodes .
They charged at a certain voltage and , as they discharged , their resting voltage dropped . This meant we could estimate their SOC based on this resting voltage . The chart on page 25 explains how we did this and all we needed was a simple voltmeter connected to the battery .
This Enerdrive battery management system is fitted to our Roadstar caravan . It features a Simarine monitor at its heart and also includes temperature monitoring , low voltage cutout and circuit breakers on critical components .
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