Introduction:
Looking for a cheap dual battery setup for your Ranger or Bronco II?
Note: This will not work on the 2019 and newer Ford Ranger because they use a smart alternator.
There are a few things you’ll need:
- (2) batteries
- Battery cables (some have found it’s cheaper to buy a set of jumper cables and cut the clamps off) – Battery Cables
- Battery lugs for your cables (You’ll need these for your cable ends) – Battery Lugs
- Battery terminals to connect to the batteries – Battery Terminals
- 12 gauge wire – 12 Gauge Wire
- ANL Fuses & Fuse Holder (1 For Each Battery) – ANL Fuse & Holder
- Battery Isolator Relay (Choose One):
Diagram & Instructions:
Follow the picture above
Find a location to mount the second battery..
Make a short battery wire (4GA-6GA) from your main starting battery (+) positive to a fuse block.
Make another battery wire (4GA-6GA) from your fuse block to the isolator.
Make another battery wire (4GA-6GA) from the other side of your isolator to the other fuse block.
Make a short battery wire (4GA-6GA) from the other fuse block to your other battery (+) positive.
Make a single battery wire (4GA-6GA) from the (-) negative on your starting battery to the (-) negative on your other battery.
Connect a 12GA wire from pin on the isolator to a fuse in your fuse box that is only ‘hot’ when the key is in the ‘ON’ position.
Jim Oaks is the founder of TheRangerStation.com, the longest-running Ford Ranger resource online since 1999. With over 25 years of hands-on experience building and modifying Ford Rangers — including magazine-featured builds like Project Transformer — Jim has become one of the most trusted authorities in the Ford Ranger off-road and enthusiast space. In 2019, he was loaned a Ranger FX4 by Ford Motor Company to test and document across the TransAmerica Trail. Jim continues to inspire and guide Ranger owners around the world.