I thougt I'd share my Dual Battery Installation since this appears to be a common thread lately and perhaps it will be useful for other Forum Members looking to do the same.
My need for a second battery was driven by a few factors:
1) An Alpine 800W 5-Channel Amplifier (mainly driving a 400W-10" sub that draws the most power),
2) A VisionX Lightbar with ten-10W LEDs,
3) A Safeglo 200-LED whip,
4) Two old-style Polaris 35W PIAA halogen lamps,
5) Never needing a jump start after listening to the sound system for extended periods of time.
I considered a single, larger battery (such as an Optima), but chose not to go that route because a), I did not want to cut or modify the battery tray, B) I did not want to chance my (main) starter battery going dead after running accessories for too long.
Deep cycle AGM (absorbed glass mat) batteries are a great second battery as they have low internal resistance, are small in size, and are designed for continuous, lower amperage duties such as running a sound system amplifier.
A couple batteries I considered were the:
1) Odyssey 925
(925 cranking amps / 28 Amp-hour),
2) The Kinetik HC800
(950 cranking amps / 36 Amp-hour),
3) And the Shuriken SK-BT35
(950 cranking amps / 35 Amp-hour)
Ultimately, I chose the Shuriken battery due to its affordable cost, size (7-3/4"W x 5-1/4"D x 6-3/4"H), and availability (the Kinetik was my first choice with higher Amp-hours, however, it was not available when I started my project).
Here is a picture of the Shuriken battery mounted in the storage compartment under the driver's seat:
This close-up picture shows the 1/4"-20 threaded rod I used to hold the battery in place. The rod is covered with PET Expandable sleeving
that is available at Fry's or similar electronics outlets (I use this stuff to cover all my wiring along with short pieces of heat shrink at either end). The battery is also held in place (fore/aft, side-side) using heavy duty velcro on the under-side (available in 2" wide strips at Lowe's). The threaded rod is installed between the seat-frame rails.
To obtain the highest reliability of a two battery system, some type of battery isolator must be used. There are several types of isolators that can be used, from a simple relay / contactor (example, Stinger SGP32
) that closes when the ignition key is on, to electronic units that keep the batteries electrically separate via a set of diodes or MOSFET design
A hybrid version of these two types of battery isolators is one that electronically monitors the battery and charging system voltages, and closes only when the charging system voltage is above a pre-set level (say, 13.3V on your main battery) and opens whenever the charging system drops below a pre-set level (say, 12.7V when you're idling or running at low RPMs).
AOPEC makes just such a device for UTV's ATV/UTV Dual Battery Kit | Smart Battery Isolator
. Here is a picture of where I mounted my AOPEC isolator (in the tray just below the ECU):
Another close-up picture:
The final aspect of my dual battery installation was to add a 65 Amp six-position fuse block
. All of my new accessories were wired through this new fuse block, leaving all the original Polaris wiring intact on the main battery. A wiring diagram of my accessories is shown below:
As for where I picked-up the input for the AOPEC Battery Isolator, I came off the input side of the starter solenoid with #6 wire. This provided a larger termination for the #6 lug and is closest to output of the Voltage Regulator without having to install a wire all the way to the regulator. It's the the BRIGHT RED wire in the photo below.
I added two blocks of wood (painted black) cut to match the shape of the support steel between the inner and outer frame rails. The blocks rest on the aluminum skid plate and are screwed to the bottom of the storage bin. The Shuiken battery weighs about 24Lbs, so I wanted to make sure the plastic storage bin wouldn't crack under the additional weight.
Aluminum skid plate lowered for better view (yes, tacky wood - but at least it's painted):
Finally, I have a pigtail for my trickle charger while at camp. Though it looks like the wires are touching the underside of the driver's seat frame in this picture, they are not (I believe this clearance is known as an RCH).
So far, my new battery has provided 2+ hours of listening to music at a moderate volume before the battery voltage dipped below 12.0V. The stock (starter) battery typically maintains adequate charge with normal riding, and the auxilliary battery only charges when the main battery and charging system is operating above 13.3V. This has been very reliable for our duning night rides and daytime music listening.
For information on my sound system installation, check out this link: