A tow vehicle or motorhome is a rolling 12V electrical system: an engine computer, body modules, one or two batteries and the cables that tie them together. Faraday Defense builds its vehicle protection around one idea. The damage an electromagnetic pulse (EMP) or a nearby lightning strike does to that system arrives as very brief, very high-voltage transients on the cables, and small, fast devices placed at the right points can shunt that energy away. This guide covers what each part does, what is in the 4-piece and 7-piece diesel kits, and where the pieces go on a truck, van or RV.
What a transient does to a 12V vehicle
Faraday Defense describes the threat to a vehicle this way: the E1 and E2 components of an EMP, like the radiated energy from a close lightning strike, induce high voltages on the vehicle's wiring. Those transients last from nanoseconds to microseconds. They are far too fast for a fuse to react to, but because they are so brief they carry limited energy, which is why a device that fits in your palm can suppress them. A house faces a different problem, since the power grid also delivers a large E1 current surge through the service lines; a vehicle that is not plugged into the grid has no such path, so the job is to catch what the cables pick up.
The same parts guard against the everyday transients Faraday Defense lists alongside EMP: load changes such as an air conditioner compressor cycling, conducted transients from a charging port, and lightning.
The three parts of a vehicle kit
T.R.A.P. 12V: the accessory-socket plug
The T.R.A.P. 12V (Transient Reducing Auxiliary Plug) is a 5,000 W transient voltage suppression device in a plug that goes into the 12V auxiliary (cigarette-style) socket. Faraday Defense rates the suppressor's turn-on time at under one picosecond and the plug itself at 25 A continuous, with bronze nickel-plated contacts, a gold-plated center contact and a Bakelite body. It is 3" long, so check there is room in front of the socket. The back is enclosed, so it does not pass power through. Faraday Defense says a T.R.A.P. draws essentially no current unless there is a significant overvoltage, so it will not run the battery down, and it keeps working with the ignition off because the cable assemblies are still connected.
T.R.A.P.-B: the battery version
The T.R.A.P.-B holds the same 5,000 W suppressor in a form that connects across the battery terminals with ring terminals. The battery is where every circuit in the vehicle meets, so a suppressor there sees transients from any direction. Faraday Defense's own advice is a T.R.A.P. in every auxiliary outlet and a T.R.A.P.-B across the battery, with each extra "trap" doing a better job of shunting energy away.
Auto high-saturation ferrites
Ferrites clamp around a cable and damp high-frequency current. The catch, as Faraday Defense explains, is that most clip-on ferrites saturate and stop working once more than a couple of amps flow through the wire, which rules them out on a battery lead. The auto high-saturation ferrite is a custom part modified to carry far more current before it saturates, so it can sit on the main battery leads. Faraday Defense says it withstands normal vehicle transients and an EMP without damage. The kits include two per battery.
Two more T.R.A.P.s worth knowing
The T.R.A.P.-OBD2 plugs into the OBD2 diagnostic port, which puts a suppressor close to the engine computer and leaves the accessory socket free for the standard T.R.A.P. or a phone charger. It is about 3" long, so check the clearance under the dash. The T.R.A.P.-AC plugs into a three-prong 120 V receptacle (NEMA 5-15) on an inverter or portable generator; like the other plugs it is enclosed at the back, so it occupies the outlet rather than passing power through. Faraday Defense suggests T.R.A.P.s at more than one point on a generator or inverter, and an EMP bag for the unit when it is stored.
DEFCON Vehicle: the heavy-duty layer
The DEFCON Vehicle is a different kind of part. Where a T.R.A.P. is a small, fast suppressor, the DEFCON Vehicle is a metal oxide varistor module that mounts across the battery terminals and is rated by Faraday Defense to shunt 270,000 A of surge current, with an energy rating of over 2,000 J and a turn-on under one nanosecond. It runs on 12 to 15 V DC, draws about 9 mA on standby, and comes potted and weatherproof with 36" automotive-grade leads (battery positive, battery negative and chassis), ring terminals that fit most battery clamp bolts, marine-grade heat shrink and mounting holes for tight spots under the hood. It measures 4.5" x 3.375" x 1.875" and is made in the USA. Faraday Defense marks it not for home use: do not apply AC voltage.
Faraday Defense positions the DEFCON Vehicle as part of one vehicle system with the T.R.A.P.s and ferrites, which is why the DEFCON Vehicle + EMP Vehicle Protection Kit bundles the module with the four parts of the gas-vehicle kit.
4-piece gas kit vs 7-piece diesel kit
| Kit | Contents | Built for |
|---|---|---|
| EMP Vehicle Protection Kit, 4-piece | 1 T.R.A.P. 12V, 1 T.R.A.P.-B, 2 auto high-saturation ferrites | One-battery gas vehicles: tow trucks, SUVs, vans and gas motorhomes |
| EMP Diesel Vehicle Protection Kit, 7-piece | 1 T.R.A.P. 12V, 2 T.R.A.P.-B, 4 auto high-saturation ferrites | Two-battery diesel trucks and diesel motorhomes |
| DEFCON Vehicle + EMP Vehicle Protection Kit | 1 DEFCON Vehicle, 1 T.R.A.P. 12V, 1 T.R.A.P.-B, 2 auto high-saturation ferrites | One-battery vehicles where you want the 270,000 A module as well |
The difference between the two T.R.A.P. kits is simply the second battery. The kits follow a pattern of one T.R.A.P.-B and two ferrites per starting battery, so a diesel with two batteries gets two T.R.A.P.-Bs and four ferrites. If your diesel has a single battery, the 4-piece kit covers it; if your gas motorhome carries two chassis batteries, the 7-piece kit is the better match. Every part is also sold on its own.
Where each part goes
- T.R.A.P. 12V: into a 12V accessory socket. Faraday Defense recommends one in every socket for the most protection; each kit supplies one, and single plugs are sold separately.
- T.R.A.P.-B: across the terminals of each starting battery, using its ring terminals.
- Auto ferrites: clamped on the battery leads, two per battery.
- T.R.A.P.-OBD2: into the OBD2 port under the dash, if you want a second point near the engine computer.
- T.R.A.P.-AC: into a spare 120 V receptacle on the generator or inverter.
- DEFCON Vehicle: across the battery terminals, screwed down in the engine bay; the 36" leads let it sit away from the battery if space is tight.
On a motorhome the kits address the chassis (starting) batteries. The house bank, the inverter and the solar charge controller are a separate system; a T.R.A.P.-B and ferrites can be added at the house battery and a T.R.A.P.-AC at the inverter, but plan those as extra parts rather than expecting a vehicle kit to reach them. Tell us what the rig carries and we will list what fits.
Spares belong in a bag
Suppressors protect what is wired in. For the electronics you would want afterward, a spare engine module, a handheld radio, a backup charge controller, Faraday Defense's answer is storage in a Faraday bag. The 7-mil NEST-Z kits are the storage bags for that job; which line does what is in Faraday bag types compared, and a packing list for an RV is in what to keep in a Faraday bag. If you want to know when an event has happened, the DEFCON detectors are the companion pieces.
FAQ
Will a T.R.A.P. or T.R.A.P.-B drain my battery?
Faraday Defense says no. T.R.A.P. products draw essentially zero current except during a significant overvoltage. The DEFCON Vehicle is the one part with a standby draw, about 9 mA, which Faraday Defense gives as typical standby consumption.
Does the kit protect the vehicle when it is parked and switched off?
Yes, per Faraday Defense. The cable assemblies stay interconnected with the ignition off, so a T.R.A.P. keeps acting as a high-frequency energy sink whether or not the vehicle is running.
Is the 7-piece kit only for diesels?
It is for any vehicle with two starting batteries. Diesel trucks and diesel motorhomes usually have two, which is why Faraday Defense names it that way, but a two-battery gas chassis needs the same count of parts.
Where do Faraday Defense kits ship from?
Every Faraday Defense product here is genuine, covered by Faraday Defense's limited lifetime warranty to the original retail purchaser, and ships free to the lower 48 states, with tracking by email. Browse the full Faraday Defense range, or ask us which kit fits your rig before you order.