Dual (Back-up) Battery
Installation (All Range Rovers)
Introduction
Classsic Range Rover Installations
4.0/4.6 Installations
Mk III Range Rover Installations
Photo: Ray
Lindner's back-up battery installation on his Mk III Range Rover.
Introduction
A second battery is useful not only for emergency starting if the
main
battery goes bad out in the backwoods, but also for winching operations
so as to avoid draining the starting battery. Various owners have
reported methods of installing a second battery in each of the various
Range Rover models, and their experiences are reprted below.
Classic Range Rover
The Classic models have a
spare battery space on the left front corner under the air intake horn,
making installation relatively easy. For details, see Ron
Beckett's installation on his Classic, and the well-illustrated
installation done by John Purnell.
4.0/4.6 Models
When changing the battery on my 4.0/4.6 model, I have
noticed the battery tray in the 4.0/4.6 is very wide. I have always
replaced my battery with the OEM Interstate model which perfectly fits
the space, but when investigating various other brands of pattery that
would be suitable I have found they are considerably smaller.
Therefore, I think it might be
possible to fit two modern smaller batteries in side by side.
Wayne
Hubbell reports that on his 1999 4.6, there is room for a second
battery
right behind the main battery. The space is small, but the new "Black
Panther"
batteries will easily fit. These are true deep cycle cells, of dry
electrolyte
design, that are extremely small for their capacity and current
density.
They are moderately expensive (around $200), but have a long life. He
plans
to fabricate a simple tray for it. He previously had a second battery
with
an isolator in his Jeep, but for this installation decided to go with a
simpler high current solenoid system from Northwest Power Products.
Jim Haver did a very neat
second
battery installation in the spare tire compartment in the rear of his
P38 Range Rover (photo at right), and posted a detailed illustrated
description at this
link. Note that in this case the intention was merely to power
accessories when the engine is off, not to provide enough amps for
starting. Jim was therefore able to tap into the wiring harness at the
rear instead of running heavy cables as would be required in the latter
case.
Mk III Range Rover
The Range Rover III comes with a convenient
storage compartment under the loadspace floor behind the right hand
rear wheel well. If you lift up the hinged floor pane and lift out the
black plastic compartment liner/tray, you will see a fairly large empty
space including threaded mounting holes for securing a small sealed battery, which can be dropped straight
in.
Wiring is also made easy as there is a thick battery cable running to
the air suspension control computer, mounted just above the storage
compartment.
Ray Lindner of Australia reports: "I installed a GELL Battery in
the rear of the vehicle (see photos below). I use it to run a 12 volt
fridge. A battery management system cuts out the main battery at a
pre-set voltage when the vehicle is not running, thus ensuring the main
battery will always start the car. I can camp for a couple of days and
leave the fridge running all the time. The main battery fully
charges before the system re-charges the 2nd battery.
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"The Mk III Range Rover has a convenient storage bin at the Right Hand
Rear of the luggage area. We fitted the battery into that
space. At the top of the two photos above, you will see a double
12 volt outlet. The left hand photo shows the battery with the
floor cover open and the other with it closed. Apart from the
dual
outlet, one would not know the second battery existed!
Tim
Sanderson in Australia has some more hints to add after doing a
similar
but more elaborate installation on his 2003 DSE. He designs and sells
dual battery charge controllers and associated equipment for a living,
so his approach ensures that the
two batteries will work together optimally. "When you open and remove
the floor cover, there is a plastic storage
bin. Just pull the long sides of the plastic bin in towards the centre
of the bin and it will lift out. In the walls of the recess where the
bin fits, there are battery mounting points already installed.
If you are going to run nothing more than a small fridge then the
wiring is also made easy as there is a thick battery cable running to
the air suspension control computer, mounted just above the storage
compartment.
In the middle of the picture below, you can see a thick red cable
winds down around to a bolt connection. You can pick up your positive
for the auxiliary battery at this point and just find a solid earth to
bolt your auxiliary battery’s negative to.
As I am also powering a camper trailer, I had to run separate twin
sheathed 10mm battery cable from the main battery, down the left side
of the RR and then across the rear to the dual battery controller
(actually a triple battery controller) mounted in the rear battery
compartment.
From the dual battery controller, one cable goes to the auxiliary
battery in the rear of the RR and another cable goes to an Anderson
Plug to supply power to the trailer.
Running new cable is a big job. It took 7 hours and required removing
27 panels and covers and the front seat!"