Jeep Commander Forum banner

1 - 11 of 11 Posts

·
Registered
Joined
·
28 Posts
Discussion Starter #1 (Edited)
Some thoughts on upgrading your headlights. Why upgrade? OEM wiring and headlight switches are engineered to balance low cost with minimum standards of safety and reliability. The moment you want to give yourself better lighting you have to take into consideration the capabilities of the current OEM wiring and headlight switch. Before you upgrade your lighting you should have knowledge of electrical properties and nomenclature. Basic electricity lessons can be found all over the internet and I recommend you learn before you upgrade. Knowing how is only half the battle. It is in your best interest to know why.

Before you begin you'll want to source all your wiring and components. Look for high quality in the components you buy. It will save you time and frustration in the long run. Things to look out for are relay amperage rating, wire size and capacity, terminal construction and durability. Simple things like soldering, shrink wrapping and wire loom wiring and terminal ends not only give a neat appearance but also add strength to the connections. Ground wires should be the same size or larger than your power wires.

As you select the components, pay special attention to the wire gauge. Looking at Ohm's law, we see that current (amps) = watts / electromotive force (volts). In my case I have 400 total watts of high beams, so 400w / 12 volts = 33.33 amps. That's more than enough to damage and burn you and/or your vehicle!
From Injection molding, Batteries, Battery Chargers, Custom UPS, and power supplies for OEMs in a hurry from PowerStream

As you might guess, the rated ampacities are just a rule of thumb. In careful engineering the voltage drop, insulation temperature limit, thickness, thermal conductivity, and air convection and temperature should all be taken into account...
...The Maximum Amps for Chassis Wiring is also a conservative rating, but is meant for wiring in air, and not in a bundle. For short lengths of wire, such as is used in battery packs you should trade off the resistance and load with size, weight, and flexibility.
From the Handbook of Electronic Tables and Formulas:

18 ga 16 amps
16 ga 22 amps
14 ga 32 amps
12 ga 41 amps
10 ga 55 amps

As quoted, the values are for open air wiring. Loomed wire in a hot engine compartment needs to be considered when choosing wire and relay carrying capacities. For my upgrade (85 Lincoln Towncar) I chose 40 amp 5 pin relays (two 87 outputs), 10 ga wire and ceramic H4 plugs. I also split the high beams into two circuits. My two high beam circuits are carrying about 17 amps and my low beam circuit is carrying about 18 amps. All circuits are protected using 25 amp ATO fuses. I gave myself a good margin to protect against overheating and wire temperatures that will occur in the summer time.

About me:
I am a journeyman HVAC/R tech with over 25 years experience. I troubleshoot, service and repair AC and DC electrical components and various types of refrigerant systems in commercial, supermarket and industrial applications. I enjoy working on virtually anything mechanical and electrical.

Sent from my SM-G920V using Tapatalk
 

·
Super Moderator
Joined
·
5,882 Posts
That's all very useful information, thanks for posting.

One thing you need to think about in this day and age of technology, most lighting upgrades involve light emitting diodes (LED) lighting which are far more efficient then standard filament & halogen light bulbs.

You can upgrade to LED Headlights, interior lights and tail lights which draw about half the voltage and provide brighter, crisper lighting and they actually put less of a demand on the factory OEM wiring harness than the stock OEM lights do.

All of the lights in my Commander have been upgraded to LED's with the exception of my front & rear turn signals and my fog lights, I love them.
 

·
Registered
Joined
·
148 Posts
That's a very good read Kodiak, thank you for sharing. With LED's cutting the voltage consumption of the interior lights, can it let a higher wattage headlight?
 

·
Super Moderator
Joined
·
5,882 Posts
Headlight bulbs Big Blue, if so up to what extent?
That's kind of a half-baked question sporty because LED lights are not rated by wattage like conventional light bulbs - they're rated in Lumens.

The Pucto Silver-Lux LED headlights I have are 4000 Lumens a piece which is far brighter than standard halogen headlights.

You can see the specs here: Silver-Lux by PUTCO
 

·
Registered
Joined
·
309 Posts
That's a very good read Kodiak, thank you for sharing. With LED's cutting the voltage consumption of the interior lights, can it let a higher wattage headlight?
Not exactly. The headlight is directly limited to the wiring that services the lights only. So I imagine from the the fuzes to the switch and out to the relays for the lights. When I upgraded my XJ (for reference only) I had to replace all of the total wiring harness for the front end to support the newer lights I wanted to use. It did not matter how little I was using on the other circuits.

Also, LEDs have a different feedback on the system for the CAN bus, sometimes you need to add resistance in the form of a resistor inline with the lights to give the computer an idea that an object it is expecting is still hooked up. If you do not, then sometimes you will get flickering. Most of the newer systems come built with this into the newer wire packs you get with the new light kits.

Dave
 

·
Super Moderator
Joined
·
5,882 Posts
Not exactly. The headlight is directly limited to the wiring that services the lights only. So I imagine from the the fuzes to the switch and out to the relays for the lights. When I upgraded my XJ (for reference only) I had to replace all of the total wiring harness for the front end to support the newer lights I wanted to use. It did not matter how little I was using on the other circuits.

Also, LEDs have a different feedback on the system for the CAN bus, sometimes you need to add resistance in the form of a resistor inline with the lights to give the computer an idea that an object it is expecting is still hooked up. If you do not, then sometimes you will get flickering. Most of the newer systems come built with this into the newer wire packs you get with the new light kits.

Dave
The quality LED Headlights today come with anti-flicker harnesses to install if needed, however they are not always needed.

Most manufacturers recommend trying them without the anti-flicker harness first and only adding them if you experience flickering after running the lights without them.

The days of having to add in-line resistance to LED headlights are gone - and so are the days of having swap out wiring harnesses - as long as you buy a quality LED headlight. Now if you have a vehicle that is say pre-2005, than you may run into issues with having to upgrade the wiring harness - but with Commanders, it's a non-issue

What you're saying has merit Dave - but not really with the technology that is on the market today unless you are dealing with a vehicle that is older (pre-2005).
 

·
Registered
Joined
·
309 Posts
True dat!

I tinker way too much and still have yet to buy a completely built kit :) Well... Lets see what came with the new lights from HID, maybe those are one stop shop.


Dave
 

·
Super Moderator
Joined
·
5,882 Posts
True dat!

I tinker way too much and still have yet to buy a completely built kit :) Well... Lets see what came with the new lights from HID, maybe those are one stop shop.


Dave
I remember you posting pics of those fancy multi-colored HID lights, I'm looking forward to seeing what they can do when you install them.
 
1 - 11 of 11 Posts
Top