How to Make an HHO Generator for a Car

by Nathaniel Miller

Hydrogen-hydroxide (also known as HHO) generators have been around for decades and can still be a viable option for many vehicles on the road today. HHO generators harness the powers of hydrogen as an alternative fuel and the safety of a self-contained generation device to increase the gas mileage of your vehicle. The HHO generator passes an electric current through an ionized water solution, producing hydrogen-hydroxide or "Brown's gas," which is then passed on to the vehicle's air intake system. The vehicle burns the HHO gas in addition to the air/fuel mixture, thereby cutting down on the fuel needed to power the engine. Though it sounds complicated, building an HHO generator is actually quite simple.

Attach the two screw caps to either end of a 12-inch-long piece of 3-inch diameter PVC tubing. Unscrew one cap and use this as the "top" of the HHO generator.

Use the drill to make a 1/2-inch diameter hole, 2 inches down from the lip of the top of the generator. Press one end of the plastic tubing through this hole, and use the silicone to cement it in place.

Use the hacksaw to cut the steel plate into a dozen or so strips that are 3 inches long and 1/2 inch wide. Drill a hole in the top of each strip and then string together along the bolt.

Drill two holes 6 inches from the top of the HHO generator so that you can secure the steel plates inside the generator body. Use the silicone to waterproof the ends of the boltholes.

Connect the battery cable to either end of the bolt, and then mount the HHO generator inside the engine compartment with the conduit bracket and included bolts. Make sure you mount the generator close enough to the battery so that the battery cables will reach the terminals.

Fill the HHO generator with 3 tbsp. of baking soda and fill the water up to a level above the steel plates. Screw the cap into the top of the HHO generator, and connect the plastic tubing to the air intake hose via the blow-off nozzle on the lower portion of the hose.

Connect the battery cables to the terminals, and start the car up. The current that passes through the steel plates will create a reaction in the water, forcing HHO through the tubing into the air intake hose.


  • check If you want the HHO generator to only run when the car is on, you can install a switch on the interior of the car that will interrupt or complete the circuit.


  • close HHO generators are for the most part harmless and pose no threat of explosion; however, pressure can build up in the HHO canister if the car is not running enough to use the built-up HHO. Be careful when uncapping the canister to avoid getting sprayed.

Items you will need

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