Fuses and fuse holders – LED circuit protection

To determine the fuse rating, divide the power of your LED lighting (in watts) by the circuit voltage (12V or 24V) to obtain the current in amps. Then add a 20 to 30% margin. For example, for a 120W at 12V LED light bar: 120/12 = 10A, so a 15A fuse is suitable. For a 50W headlight: 50/12 = 4.2A, a 5A or 7.5A fuse is suitable. A fuse that is too small will trip for no reason, while an oversized fuse will not effectively protect the circuit.

These names refer to the physical format of the blade fuse, not its rating. The micro is the smallest format, used on recent vehicles with limited space. The mini is the most common format currently, compatible with most modern fuse boxes. The standard (or ATO) is the classic format, still common on older and utility vehicles. The maxi is reserved for high-current circuits (40A and above). Check the format used in your vehicle’s fuse box before ordering. All four formats exist in the same ranges of ratings.

A fuse tap makes it possible to add a new electrical circuit by plugging directly into an existing slot in the vehicle’s fuse box. It replaces the original fuse and adds an additional output, protected by its own fuse. This is the cleanest and reversible method to power an LED accessory without cutting or soldering any cable. Simply remove the original fuse, insert the tap in its place, and connect the output wire to your equipment. AGM Vision offers adapters in micro, mini and standard formats

A waterproof fuse holder protects the fuse against water, dust and humidity when the installation is carried out outside the passenger compartment. For roof LED bars, auxiliary lights or bumper lighting, the cable runs outside, where it is exposed to bad weather and splashes. Without waterproof protection, humidity can cause corrosion on the fuse blades and create poor contacts or short circuits. AGM Vision waterproof fuse holders are designed to withstand the most severe off-road conditions.

Two methods can be used to check a fuse. The simplest is visual inspection: remove the fuse and look at the metal filament through the transparent housing. If the filament is cut or blackened, the fuse is blown. The most reliable method uses a fuse tester or a multimeter in continuity mode: place the probes on the two blades of the fuse. If the circuit is open (no beep), the fuse is faulty. AGM Vision offers fuse packs with an integrated tester screwdriver to quickly check the condition of your fuses.

Each independent circuit must have its own fuse. For a typical installation including a roof LED light bar, two auxiliary lights and a control panel, plan for at least 3 to 4 fuses: one per lighting circuit, plus a main fuse on the battery power supply cable. If you use a multifunction control panel, it often includes its own fuses per channel. For complex installations with 6 circuits or more, a fuse pack with an assortment of ratings is recommended. Always keep spare fuses in the glove box.