Cheap CNG Tanks

[BRodri]

If you are looking for a cheap way to extend your range. Check the auto salvage. i just got A CNG tank with 1175 SCF capacity for $217.00 and that's it now i've just got to put it on which by the way i'm going to do myself. all the fittings i have already changed over to mine that exist on my truck and and i've got the same kind of line that it uses on my truck. i don't need it purged because it already has fuel in it and it would pass any visual inspection that anyone wants to put it through. got the tank out of f250 that was in a front end crash. truck was finished but tank was fine. type 3 tank

just thought this might be some helpful info for you guys wanting to expand your horizons.

[Idarusskie]

Re: Cheap CNG Tanks

Do you have to re-certify it? Maybe a hydro test???

[cngmike]

Re: Cheap CNG Tanks

DOT requires a visual inspection after a vehicle is involved in an accident.

[BRodri]

Re: Cheap CNG Tanks

truth be told if they saw my truck they would probably say that it is illegal anyway it has no filter between the tanks and the pressure regulator it has three tanks in the back 2 of which are from different years and the newest tank that is on my truck is rated for 3000 psi while the rest of them are for 3600. so truth be told it doesn't really matter what i do to this truck as long as i know that the paint on this tank was on it before the accident and there aren't even any scratches on the tank.

[rodneydiller]

Re: Cheap CNG Tanks

Interesting thoughts on locating a tank. My conversion kit should be getting to me next week, but I haven't lined up a tank, yet. I didn't realize getting your hands on a tank was going to be the hard part.

I've googled looking for a formula to convert cylinder dimensions and pressure to GGE, with no luck. Some of these sellers don't know what the tanks hold. I can estimate within a couple of gallons, but a formula would be great. Anyone?

[Adrian]

Re: Cheap CNG Tanks

Interesting thoughts on locating a tank. My conversion kit should be getting to me next week, but I haven't lined up a tank, yet. I didn't realize getting your hands on a tank was going to be the hard part.

I've googled looking for a formula to convert cylinder dimensions and pressure to GGE, with no luck. Some of these sellers don't know what the tanks hold. I can estimate within a couple of gallons, but a formula would be great. Anyone?

100 L volume at 3600 psi equals 8 GGE (that's the size of my Civic tank). Calculate the volume in cubic feet, convert to L (cubic ft*28.3168), then divide the result by 100 and multiply by 8 to get your GGE at 3600 psi.

[CNG MOTORS]

Re: Cheap CNG Tanks

With the recent explosion. I hate to see the word "CHEAP" next to the word "TANK"

[Steve]

Re: Cheap CNG Tanks

There is a Wikipedia article that does the volume conversions as well:

http://en.wikipedia.org/wiki/GGE

[afvman]

Re: Cheap CNG Tanks

I'd like to add that not only should the tank/cylinder be inspected after an accident but also any time a cylinder is moved from one vehicle to another.

While it's OK to mix cyl. mfg's, years and pressures, BE SURE you only fill to the lowest rated cylinder pressure. Duh.

Good luck and I'm gonna check the junk yards!

B/R,

afvman/Bill

[tsta5780]

Re: Cheap CNG Tanks

Know thisis an old thread - but need to mention this for safety.

May I suggest that you consider the impact of air in the tank? It will create a combustible mixture.

If that tank was not filled with nitrogen, it should go in the garbage. Because as natural gas is added to the tank, if there is oxygen in there, at a certain point you will reach a ratio of natural gas and air that will be explosive.

If that certain point happens to be at a high enough pressure. it will ignite (think diesel engine, ignition by comprssion).

We do this all the time in the oilfields to get heavy oil out. By just pumping air underground, the oil actually burns (under serious pressure underground).

So do yourself a favor and just buy the proper tank. Anyone reading this old thread (its high on google ratings), I would strongly suggest against using a tank not filled with nitrogen.

Quick representation of how an explosive mixture forms when N2 not used - see image below:

Untitled drawing.jpg

[karl]

Re: Cheap CNG Tanks

Good point on safety.
If you have a link describing the proper procedure to purge a tank of air using nitrogen, it would be helpful for you to post it
Is this a theoretical warning or have cng tanks actually exploded. It seems like the tank wouldn't have enough air in it to support a combustible mixture by the time the gas added under pressure reached enough pressure to ignite.

Karl

[300mileclub]

After getting several calls from used car buyers who had not heard that the tank in their vehicle had an expiration date (or was expired), I throw out a simple request that someone add the following paragraph to the Wikipedia writeup about CNG so that the word gets out (Link given to cite source):

There are two other things to consider when weighing the purchase of a CNG-powered vehicle: The tank must be inspected by a certified technician every three years, and tanks have a shelf life of 15 to 20 years. I spoke with a technician at Fowler Honda in Norman who said an inspection costs $115 and takes about 90 minutes to perform. He could not quote me on the tank replacement, citing that they have not had to replace one yet. Googling about, it seems the cost of a tank replacement in 2013 dollars is between $2,000 and $4,000. But by the time my 2010 Civic will need a new tank (in 2025), I imagine the cost to replace it will have dropped a considerable amount due to the advancement in technology.

http://newsok.com/article/3867155

I would do it myself but do not have any experience adding something to Wikipedia. Routine searches I did on the internet did not reveal the tank expiration aspect of CNG vehicles. And many buyers of used vehicles genuinely do not know the vehicle they are buying may be unusable (or, in some cases, that fueling hoses do not fit the 3000 psi receptacle.)