4 June 2011
There have been many comments on how badly Recreational Vehicle dual battery systems perform. Regular complaints are that the fridge in the back does not run for long enough off the second battery. In fact nearly all the problems relate to Voltage drop in cable.
We changed over 4WD cabling only last week that had .9volt drop between front and back because an installer wired with not only cable too small but used negative chassis connection to the second battery withour proper chassis bonding. We changed the cable to 13.5mm cross sectional area and ran positive and negative from the front to the back. The customer now gets an extra 15hrs from his fridge. When charging a deep cycle battery your Vehicle Alternator will only take it to 75% of fully charged unless using the new AGM battery. If voltage drop is added as well then the battery may only get to 60% charged. This continued under charging rate will eventually sulphate the battery.
With only 14.2Volts from your alternator you need the maximum voltage to your second battery. Under sized cable and bad chassis negative connection does not help. Minimum size under the bonnet should be 13.5 cross sectional area and run in positive and negative NO CHASSIS EARTH.
‘Springers’ have been installing in Caravans, boats, mobile homes and 4WD now for 3 years. Their installers are fully trained professionals in cable sizing and Battery technology. Should you want a hassle free installation then call ‘Springers’
Photo attached is a work vehicle with Solar charging to a dual battery system and inverter for running tradesmans tools.