HOW TO UPGRADE YOUR ELECTRICAL SYSTEM
Article by: Matt Adams
Photos by: Matt Adams and Jeff Bakke
The heart of any truck is not necessarily the engine, but rather what allows the engine to run - the electrical system. The addition of any electrical parts may make it necessary to accommodate your upgrades. The electrical equipment that comes stock is designed to support the base equipment on the vehicle – the engine, the starter, the stereo, your headlights and windshield wipers, etc.
Depending on what your vehicle will be used for and what you are running for accessories, you may be able to get by with simply upgrading your batteries or you may also find it beneficial to upgrade your alternator. Stock F-150’s and Expeditions come with a 95 amp alternator, and if you have a lightning or a truck equipped with towing package you have a 130-amp alternator to compensate for additional electrical accessories and additional charge. The alternator is what keeps the battery charged and produces electricity based on the cycling of the engine. If your alternator is not producing sufficient electricity, the vehicle will have to draw extra power from the battery, possibly draining the battery prematurely or even reducing the life of the battery.
To find out how much electricity your accessories are drawing, there is an easy electrical formula to keep in mind when upgrading your electrical system, and that is how many watts equal how many amps. For example, most modern vehicles are 12-volt systems (some older vehicles are 6-volt, many military vehicles are 24-volt). At full charge your vehicle should be charging approximately 14.5 volts. To find out how many amps your accessories are using, divide the wattage by the volts. For example, on the roof of our project F-150, there are 5 PIAA 80 Pro XT lights, running 120 watts per lamp. 120 x 5 = 600 watts.600 watts divided by 14 volts equals approximately 45 amps. A 1200-watt stereo amplifier will draw approximately 80 amps, over half of what the stock alternator is designed to handle!Failure to upgrade the alternator will result in excessive battery draw, in which case both may need to be upgraded. One of the accessories that draws the most current is a self-recovery winch, which can draws as much as 450 amps (nearly 6500 watts)!Regardless of what electrical systems you upgrade, heavy consistent use of these high-drain applications is going to hurt your electrical system over time.
Upgrading the battery is one of the easiest and most standard upgrades for vehicles. A stock F-150 battery has an amp rating of
540 amps, and lightnings/trailer towing equipped vehicles will have higher capacities, up to around 650. Optima batteries red top battery produces 800 Cold-cranking amps and a maximum amperage of 980 Amps. The red-top battery is designed as a starting battery, and are typically used in single form as an Original Equipment replacement. The Optima yellow-top, while it actually has a lower amperage rating, is actually designed for higher-load applications (massive wattage amplifiers, winches, etc.). Running two batteries in parallel allows you to run higher draw applications, as well as allow your batteries to last longer.
For our installation, we used a dual-battery tray from Wrangler NW Products. Wrangler NW specifically designs their battery tray for the F-150’s/Expeditions so the tray can be fit with only minor modifications made to the engine compartment. Wrangler NW also produces dual battery kits for F-250’s and F-350’s/Excursions. The kit includes everything you need for the setup (except the batteries, which can be purchased separately or along with your dual battery kit). It includes the tray itself, isolating relay, an in-cab switch to switch between the batteries, all necessary cabling, all battery clamping material, and additional military-grade battery terminals for the second battery. The only item not included in the kit that we used that was not included was extra battery terminals to replace the factory terminals. The optima batteries we used are red-tops, but the tray will also accommodate yellow-top optima batteries, as long as they are top-post only style. Because space is so extremely tight, the Optimas with side-posts will not fit. While the installation may seem overwhelming because of the amount of steps required, an average installer should be able to complete the task in just a few hours.
1) Before doing any electrical work, it is always recommended to remove your ground terminal from the battery. Removing the ground will prevent anything from becoming shorted or sparking, and will prevent the possibility of wiring damage or even fire. Once the ground is disconnected, you can safely remove the positive battery cable and place both safely away from battery terminals.
Removing battery terminals from factory battery. Ground comes off first!
2)Remove the battery cover and set aside. Remove the battery hold down and set aside. Remove battery and set aside. These may be saved for later use or discarded. Keep in mind that batteries must always be recycled properly, your local auto shop should be able to inform you of local regulations.
3) Attached to the stock battery tray is a wiring harness that can now be pried apart from the battery tray. This can be done with a flat head screwdriver or a trim removing tool.
Prying fuseable link connection from factory battery terminal
4) Remove the four bolts holding down the battery tray, and remove from engine compartment. Save the bolts, as these will be reused later. Keep in mind there is a vacuum canister and several vacuum lines behind the battery tray, use care to not disconnect or pinch any lines.
5) You will notice a plastic body bolt protruding through the fender, underneath the battery tray. Using a dremel cut-off wheel or razor, trim this flush with the fender. This trim bolt will still hold connection, but will allow the Wrangler tray to be installed.
6)Relocate your battery cables as much as possible towards the firewall. It may be necessary to disconnect vacuum lines and reconnect them after rerouting your battery cables, but use care to not pinch or damage any vacuum lines.
7)Remove the three bolts holding the windshield wiper fluid reservoir down and remove the reservoir from the engine compartment, leaving the fluid lines attached. Notching the mounting holes is required, but can typically be done with all fluid lines still attached to prevent spilling. The best method for notching is to use a Dremel rotary tool to expand the hole approximately ½” longer, in the direction facing towards the rear of the vehicle. On one or two of the holes, the braces may also have to be notched to allow the bolt to be tightened. Reinstall the fluid reservoir and tighten bolts, with washer fluid now ½” closer to the front of the vehicle.
Notching windshield wiper fluid reservoir for relocation
8)Install the Wrangler battery tray. Ensure windshield wiper fluid line underneath the tray and vacuum lines behind the tray are not pinched or touching the edges of the tray. Make sure the stock battery cables are located between the firewall and the battery tray as routing them later will be impossible.
9)Reinstall the four mounting bolts from the stock battery tray and tighten.
Install the Wrangler battery tray and tighten bolts
10) If your vehicle is equipped with a metal distribution center, one corner may need to be grinded away so as to allow access for the optima batteries. You will know if this needs to be modified if the rear battery will not slide all the way back. Once again this can be done with a grinder or a Dremel rotary tool.
Removing lip from metal distribution center to allow battery clearance (99-03 only)
11) If you plan on reusing your factory battery terminals, the terminal will need to be modified to allow for a longer bolt (included with kit). To modify, drill out the center threaded fixed nut with a ¼” drill bit. Replace the factory stud with the provided bolt. If you plan on using new terminals the factory terminals should be removed and ring connectors added to cable ends. Installing new terminals is the recommended method, as additional accessories can overburden the factory terminal. For our installation, we used additional military grade terminals, which can be purchased from Wrangler NW.
12) Install the included relay to the wrangler battery tray using the supplied bolts and corresponding holes in the tray. Nothing needs to be wired at this point.
Attaching Wrangler relay to battery tray (shown with batteries installed)
13) Because space is so extremely tight in the Wrangler battery tray, the hold-down lips will have to be removed from the long sides of the batteries. These are the protrusions approximately 1/8”-1/4” wide along the bottom side the length of the battery that are designed so you can clamp the battery down in factory locations. It is easiest to use a dremel cut-off wheel or a very sharp razor to remove this lip. When removing, use caution and wear proper eye protection to prevent hot plastic from causing personal injury.
Removing hold-down lip from the length of Optima battery
14) Install optima batteries into the tray facing towards each other, and clamp the battery to the tray using the provided j-bolts, hold down bar, and wing nuts. Depending on available space, it may be necessary to place j-bolts loosely in place before installing the batteries and then tighten. Make sure the “J” faces away from the batteries!
15) You can now wire up the batteries. It’s best to save the final connections to the live battery until everything else is complete, to prevent accidental sparking, arc welding, or worse, physical damage. Use the included 2-gauge black wire to connect the grounds of the two batteries together. You can also use the two included red (positive) power cables to connect the positive terminals of the battery to the relay, using the positive posts of the relay that correspond to each battery. All connections are wclearly labeled for ease of installation. The purpose of the relay is to direct electricity to and from which battery you have specified with the switch.
Wiring the batteries positive cables to the relay
16) The switch can now be mounted in the cab. Wrangler provides enough wiring to mount the switch anywhere in the cab you choose. For our installation, we chose to mount the switch near the 4-wheel drive floor shifter, easily within sight and reach of the driver at all times.
Mounting dual battery switch to dash
17) Run the wiring from the switch through the firewall. Most F-150’s have a large grommet available near where the steering goes through the firewall, if you cannot find one you will need to drill a hole approximately ½” wide and grommet the hole to avoid damage to the wiring. Route the cable through the engine bay and connect to the appropriate terminals on the isolating relay. To hide away from sight in the engine compartment, most f-150’s have a wire channel near where the hood connects to the engine compartment, designed to hide wiring for the computer as well as running the windshield wiper fluid to the drivers side. This can be loosened with a few screws and pried away from the firewall, and the wires can be run through this channel. If this channel is unavailable, Wrangler provides some wire loom to avoid damage to the wire from heat inside the engine compartment. The connections to the relay are clearly labeled for ease of installation.
Running switch wire through the firewall
18) The last component of the switch to hook up is the ignition source switch. This allows the switch to be activated only when the ignition is on and not when the vehicle is off. The easiest source to hook this up to is your radio fuse or some other fuse that is only on when the vehicle is on. For our installation, we had previously mounted a separate fuse block run off of the radio fuse to power multiple “switched” items such as light switches, CB radio, GPS, etc. and we simply tapped an available fuse from this block. Wrangler provides fuse taps to use for standard installations. An example is shown in the following image. For instructions on which fuse controls what device, consult your manual, or use a voltmeter to determine which fuses are hot when the vehicle is on, and off.
Example of a fuse tap that Wrangler includes for you to “tap” into an existing fuse
19) Because Optima batteries are typically shipped with ½-2/3 charge, it is a good idea to charge the batteries before starting the vehicle. It is recommended you use a slower trickle-type battery charger, but a standard battery charger should work just fine.
20) Once batteries are charged sufficiently, start vehicle and using a voltmeter ensure batteries are being charged correctly.
When your installation is complete, you will have a switch mounted in your cab that will be activated only when the vehicle is turned on (except emergency mode, which is constantly available). This switch allows you to choose from one of three modes: dual off (single battery mode), dual on (both batteries being charged and used equally) and emergency on (using your secondary battery to charge the first). It may be a good idea to “double-check” your work, by flipping the switch to each mode and testing the voltage of each specific battery. When in dual battery mode, both batteries should be reading a voltage of approximately 14 volts. When in single battery mode, only the primary battery should be receiving 14 volts.
A higher output alternator will allow the truck to charge the battery more efficiently and to allow for more power to be utilized from the constant alternator source rather then draining power from the battery. Assuming you were driving along with a fully charged battery and your alternator died, you would have approximately 5-15 minutes to find a place to stop before the battery completely died. Not using devices like the stereo and headlights would help, but not much.
The alternator we used for this project is manufactured by the same company that made our dual battery tray, Wrangler NW. Wrangler NW makes alternators in 150 and 200-amp varieties, more then sufficient for even your highest-wattage needs. The alternator is designed to fit in the stock location, although separate cables are run to the battery to accommodate the additional electricity.
1) Before upgrading the alternator, it is recommended that you ensure your batteries are properly charged. Failure to do so could result in your new alternator working too hard to charge the batteries when first installed. In circumstances where your alternator is not charging the battery sufficiently, it is recommended you charge your battery before using your new alternator to avoid an initial power drain on the alternator.
2)As with any electrical work you do on your vehicle, you should first disconnect the negative terminal of your battery. This will prevent unnecessary sparking, shorting, and possibility of damage to components. In the event you have a dual-battery setup, just disconnect the primary batteries ground connection.
3)You may find it more convenient to remove your air intake system at this time. This is done by removing the belt hoses connecting it to the throttle body, disconnecting valves and electrical connectors, and prying out of the engine compartment. While it may be possible to do the alternator project without removing this, it will make it more convenient for accessing bolts, pulleys, etc. It will also allow more room for removal of the alternator as well.
4) Remove the serpentine belt from the stock alternator pulley, loose enough so it is not tight around any pulleys, but tight enough that the belt will not need to be re-routed after alternator installation. To remove the tension on the belt, consult your manual or your radiator cover for a diagram of where the tensioner is located. On the f-150’s and most other current trucks the tensioner is a ½” wrench hole in the tensioner itself. To loosen use a ½” socket wrench or breaker bar in the hole and rotate. If you use too short of a bar you may find it difficult to loosen the tension enough to slip the belt over the pulley.
Belt removal. (A) Belt tensioner (B) Alternator pulley
5)This is a good time to inspect your belt for any wear or damage. Grooves, cracks, etc. may lead to more trouble down the road, and this is the perfect time to replace your belt while you have things apart anyways. This job can be a much bigger pain when you are in the desert or a snowstorm without proper tools, so make it convenient for yourself and if it is damaged, replace it now! Be sure when replacing your belt to use a good quality brand such as Gates or Goodyear. You get what you pay for!
Inspecting belt for damage. Cracks, uneven wear, and minor tears should be given attention and belt replaced if necessary.
6)Disconnect all connectors from the alternator. These consist of two plug-type computer connectors that can be pulled apart and two ring terminal electrical connectors that are held on with nuts.
7)Once all electricity and computer connections have been removed from the alternator, you can remove the mounting bolts that hold it into place. There are two bolts on the top and two on the front, near the bottom, that hold the alternator in place.
Removing stock alternator bolts prior to alternator removal
8)Remove the alternator from the engine compartment and compare it to the new alternator. Pulley sizes, mounting holes, etc. should be similar. Keep in mind that for the Wrangler alternator, the top-post mounting holes will not be identical as the mounting uses a different bracket to attach. The front two holes should be the same.
Side-by-side comparison of alternators. Wrangler NW (left) and stock alternator (right)
9) The Wrangler NW uses grooved mounting holes for the front posts. This allows you to leave the mounting bolts partially installed and place the alternator on top of the bolts, allowing for less muscle strain and more alternator control. Once the alternator is set in place on to the positioning brackets, these bolts can be tightened to snug the alternator into place.
10) The top posts for the alternator are modified with the Wrangler alternator, and require a bracket (provided) be used. Place bracket into place so one bolt goes into one of the holes on the alternator, and the other hole lines up with the mounting hole.
Connecting top mount alternator bracket (shown with wires attached and loomed)
11) Because the higher powered alternator is able to produce more electricity, it requires better wires be run. For the Wrangler 150 amp alternator, 2 gauge wires are included, and for the 200 amp alternator, 1 gauge wires are included. Depending on how you want your wiring to look when completed will depend on how difficult you want this job to be. The easiest method is to simply tape off the electrical connectors that go to the starter solenoid and run the new wires, however this leaves a lot of excess wire in the engine compartment and definitely is not “show quality”. This doesn’t really require any instructions, you can simply tape off the connectors and zip-tie your wires out of the way. If however you choose to remove all unnecessary wiring more efficiently, you will need to remove the wire loom from the alternator to the starter. The computer connector wires and the power wires are run in the same bundle, and the computer connector must remain while the power wires can be removed. You will have to remove the nut from the starter solenoid connector to remove the power wire.
12) Run the provided cables directly the positive and negative posts of the battery. If you have a dual battery, make sure it is hooked up to the primary battery and not the secondary battery. Typically you can follow the same wiring route as your computer connector and connect directly to the battery. The reason for running the power cables directly to the battery is this is a more efficient means of charging the battery then being diverted through the starter solenoid.
13) Once you have a good idea of how the battery cables are going to be run, you should also choose a location for the terminal Wrangler provides. This terminal is a fused location so in the event of a catastrophic electrical problem, the system will sustain minimal damage. For our installation, we chose to install the terminal near the starter solenoid, on the distribution block.
Attaching the alternator terminal to the distribution block
14) The larger of the two computer connectors can be plugged into the port on the alternator. The smaller plug is the stator lead, and is not used with the new alternator. This can be taped off in case of future need.
15) This is a good time to put the belt back on the alternator and ensure the tension is set properly. It is recommended you have a friend release the tension, while you hook the belt over the pulley. Verify the belt is tight and completely over all pulleys, and release the tension on the belt.
16) Connect the alternator cables to the corresponding terminal on the battery, and reconnect the battery.
17) For an additional added look to your engine compartment, it is advised to use wire loom to wrap the alternator cables, not only keeping it bundled but having the appearance of stock wires.
18) Start the vehicle and ensure battery is receiving proper voltage by testing with a voltmeter. Allow the vehicle to idle for 15-20 minutes after installing.
SOURCES:
Optima Batteries
888-8OPTIMA (888-867-8462)