Sandspit Holiday Park, Warkworth - with its own little beach

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Tuesday, 20 Feb 2007

Give your holiday caravan extra grunt with a second battery to cope with modern demands

Out there on the road an extra  battery pays  off
Out there on the road an
extra battery pays off

We fitted an extra battery to a Jayco Heritage 23.72-1 (June 2005 Model) to see if it would cope with the workload we put on our equipment. We decided to fit a battery to the battery holder that came standard with the caravan.

GoSeeNewZealand does not see the caravan as being away from power for an extended time away but we think the arrangement works well for a caravan which is constantly on the move. Charging from the vehicle was not installed at this time as it was not considered necessary for our projected usage patterns, but the installation of an "Anderson Plug" will be covered for those that would like information on charging from a vehicle.
Items ready for installation
Items ready for installation

Battery Installation

The Jayco caravan already came fitted as standard with the battery holder and wiring to the Jayco’s 12 Volt Power converter. Battery holders come standard in all Jayco Sterling Caravans and Pop Tops models plus the Destiny outback models. Where a battery holder comes standard there is generally a power point in close proximity.
ST35A power converter
ST35A power converter

The power converter is the hub of the Jayco’s power system. Its prime purpose is to convert 240V to 12V when the caravan is plugged into mains power. It also processes the 12 V from any battery supply (car or internal installed battery) with low voltage shut off protection.

This power converter also has the ability to charge a battery at a rate of 5 Amp or 10 Amps at 13.8 V +/- 0.1v depending on the model of power converter fitted (ST20A or ST35A). Our Jayco had the larger unit (ST35A) fitted as standard. It depends on the model and what the potential total current draw adds up to be to determine whether it’s a ST20A or ST35A is fitted but generally toilet/ shower units are fitted with the ST35A. 
Packer at each end
Packer at each end

The battery we finally selected as recommended to us by Battery World local was a Sealed Gel Tech Part number 8G31DTM which can provide 98 AH @ 20Hr. It is suitable for all "Deep Cycle" continuous discharging and recharging plus marine applications. This battery also has the ability to handle a float type service when not in demand.

The battery weight is notable, and there are two packers fitted at each end to stop sliding movement during travel. The two packers we used (one at each end) were 10mm thick and they made a nice tight fit. The battery holder is located just over the caravan’s rear axle under the bed so there was no real effect on the centre of gravity in the caravan.
Charger xantrex true Charge
Charger Xantrex True Charge

Battery Charger

Although the Jayco power supply is capable of charging at 13.8v up to 10amp. We decided to ensure our battery was always at optimum readiness and installed a separate dedicated charger. The one selected for the job was the Xantrex True Charge 10.

This charger is multi-stage, fully automatic and adjustable in respect of battery type and charge rates. Some other chargers have too higher float or maintenance voltage for Gel batteries.

The Xantrex True Charge 10 is also ideal for deep-cycle, marine, RV and industrial uses. This was fitted to the bed box wall by 4 wing nuts and bolts adjacent to the battery holder and plugged into the 240V power plug provided as standard fit by Jayco.

The location allowed a nice air flow for the cooling fins to do there work. The charger had its battery clips removed and terminals were fitted to allow it to be permanently connected to the battery.
Inverter 350W
Inverter 350W

240V Inverter

We also decided to install an inverter to power the few items we have that require 240V. The inverter selected was a 350 W which is the maximum we would suggest be used on a single battery and not for protracted periods on full load.

This allows use of small current draw appliances such as medical equipment like CPAP machines Televisions, DVD players, Notebook Computers, Most Ink jet style printers (NOT laser) etc. Before attaching an appliance to an inverter make sure that the power requirements are under the rated inverter capability.
Jayco Pre-Wired to Battery Holder
Jayco Pre-Wired to Battery Holder

The inverter we selected also has a Battery low alarm, Battery low shutdown and overload protection. It was also installed with in line fuse protection.

This Inverter was also fitted adjacent to the battery as the leads to the battery should be as short as possible to prevent voltage drop to the inverter. When the inverter is working at full capacity of 350W it will be drawing in the vicinity of 30 Amps. The location of this fit also allowed for air around the inverter for cooling.

Car charging

We didn’t install car charging at this time as we feel it will not be required for our usage pattern. However, here is some information should it be required. Due to the potential of higher current a separate system needs to be installed from the car to the battery with connection between the car and caravan via "Anderson Plug".
Mark completes the installation by replacing the battery Holder cover
Mark completes installation by replacing the battery Holder cover

Most 4WDs can charge up to three batteries simultaneously, and most cars (capable of Towing) can easily charge two batteries. However it is recommended that a Smart charging system be used where the car batteries are charged first then the extra batteries later with the excess alternator capacity.

The towing vehicle should have an isolator between the main battery/ies and the caravan or trailer battery. This should be wired in such a way as to prevent current flow from the van battery during vehicle crank at start up.

Solar Cell Charging

Should you decide to install solar charging as another alternative then you need to do some serious calculations of your requirements.

Material Used:
  • Battery: Sealed Gel Tech Part number 8G31DTM Approximate cost $429
  • Charger: Xantrex True Charge 10 Approximate cost $349
  • Inverter: 350W inverter (not true sine wave) Approximate cost $150


Labour Charges:
Complete Installation
Complete Installation
Inverter to back left and
Xantrex True Charge right

Labour charges will depend on the installation car and caravan and what components are being installed. GoSeeNewZealand strongly recommends that you have a competent qualified installer carry out the work such as Battery World.

Note: GoSeeNewZealand purchased our own equipment for this project

For more information
contact: Garth Morrison
Editor GoSeeNewZealand Directory
Jayco holder already Fitted
Jayco holder already Fitted
Battery Isolating Switch
Battery Isolating Switch
Mark fits terminals to inverter
Mark fits terminals
to inverter
All Wired Up And In Line Fuses visible
All Wired Up And
In Line Fuses visible

Battery World
Battery World

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