I regularly refill my disposable bottles so I know the signs.  For this test
I actually used a stethescope though.  You can hear the end of flow very
clearly at the donor tank.

With the valve open on the overfill you change litte except to add propane
to the air. You can actually do some expansion vs flow math but it is not
worth the time.  Propane has a volume expansion approx 270x.
jimt

On 5/22/05 11:19 AM, "Edward Maglott" <emaglott@BUNCOMBE.MAIN.NC.US> wrote:

> thinking out loud:  So 2# gets you less than 1/2 gallon.  Tank capacity is
> about 3-3.5 gallons.  1/2 gallon is not really enough to make this
> fill-at-home set up very valuable...  Thinking about the 80% valve being
> open on Westy tank, hose going from Westy tank fill port to external
> tank.  Propane in Westy tank is vaporizing, absorbing heat, cooling down,
> making it harder to vaporize.  How did you measure flow through the
> hose?   Are you sure there was no flow?  It might have been slow...
> Edward
>
> At 12:55 PM 5/22/2005, you wrote:
>> As noted on the tests opening the overflow port on the small tank made no
>> difference to flow rate.
>>
>> Propane weighs  4.2 pounds to the gallon and about 21,500 btu per pound.
>>
>> http://tactical-bus.info/propane/
>>
>> jimt
>
>