Venting Portable Fuel Tank?

[kaivorth]

I'm moving my batteries to the compartment my fuel tank is in. They'll have some space between them.

The fuel tank currently has a ventless design? I want to somehow directly connect a tube from the cap to a vent so I won't have gas vapors building up where the batteries are.

What's the easiest way to accomplish this? Haven't really found a solution or maybe I'm not searching correctly.

 

[GA_Boater]

An EPA tank doesn't vent to the atmosphere. Do nothing, just move stuff around the way you want. Remember EPA tanks swell up like a watermelon when the gas warms up and you need to leave room for the expansion if it's crowded with the batteries.

 

[SkaterRace]

Most new tanks I have seen don't vent, you might have one of those 6-gallon tanks that did have a vent cap on them. I would just replace the cap or close the vent on it. As GA said, make sure there is room for it to expand. If you've never seen one expand you are in for a surprise how big they get.

 

[kaivorth]

Yeah I've seen them swell. I just don't feel comfortable with my batteries in the same compartment as my swelling gas tank. Wanted a way to either let it vent out to the atmosphere with a tube or something.
Do most people just run them together anyway? Or keep the fuel tank deck side?

 

[GA_Boater]

You're being a worry-wort. So many boats have tanks and batteries close together with no problems, even tanks with vented caps. If you try adding some kind of vent, you may be making a problem to worry about.

You know the batteries are venting hydrogen?

I take it that this an outboard boat.

 

[matt167]

The non permeable tanks do have a safety vent which opens at around 5 PSI IIRC. It does not discharge all of the vapor, just keeps the pressure at a safe level.

If you don't have one, you should have a fuel demand valve in line with your engine, so that the pressure does not over prime your carburetors while the motor is shut down

 

[roscoe]

Instead of venting the tank somehow, why not add venting to the compartment.

 

[Chris1956]

Gee, the way I understand it (per CG regs) is that portable fuel tanks must be in a vented compartment, at lease since 1940. If the compartment is in any way non-vented, you are both breaking the law and inviting an explosion.

 

[kaivorth]

The compartment does have a passive vent. When the boats moving, air goes in one side and out the other side.

Although upon further inspection, the vent itself was broken.

Think I'm going to keep batteries under center console instead