What is the best way to check propane amount?

I have always just run my hand down the side of the tank. Where the propane level is is cooler. Its not perfect but I only have 1 tank so I can tell when it gets close. I go have it filled and its always 10% or less.

Get transparent tanks so you can see the propane level.

It looks like the very best way would be to get a scale and weigh the tanks. Use the tare weigh subtracted from total weight of the tank. Just like at the fill stations. Thank you all that responded.

Ok, now I have another point to check of for getting a FLIR camera...especially now that I know the cheap one can be modded for 320x240 resolution.

I bet you could see the exact level on the tank with one of those.

During the winter in the garage, we just looked at the tank for the frost line. On humid days, the frost was so think we couldn't see the tank. That 100k btu salamander would put a hurting on a 100 pounder.

The frost line (sometimes dew line) is how I watch the level my 2 pounders on my grill.

But most accurate is the scale. Like the IR gun, but since my tank sits in a plstic cubby hole without bottom drain, too much chance on the water going to the wrong location.

The only ACCURATE method I know of is to run the tank dry, let the auto changeover do it's job, and go fill the empty one.
What difference does it makes untill the tank is empty?

(The above assumes a 2 tank system)
B

JumboJet wrote:

powderman426 wrote:
If you don't want to remove a bottle, a I R temperature gun like found at HF works well as the temp changes when going from air to liquid.

I have one of those IR temperature guns and will try that this afternoon. I do have a couple tanks that have gauges on them, but I have found them to be less than accurate.

This method works best if you are using propane at the time.otherwise the pressure in the tank is equalized and the temp difference is small. Even a small discharge like a fridge pilot light is enough.

An IR thermometer is a good thing to have. I use it to monitor tire air pressure and axle hub temps while on the road.

Here's a way to tell how much propane is in your portable tanks. Boil a kettle full of water and then pour it over the tank and wait a couple of secs. there will be frost where there is propane. The top of the frost is where your level is. This would be a good time to weigh your tank and then you would know where your propane is at that weight...

My two tanks are probably too big or I use too little, but I generally just take them to get filled every year or so.

I do find all of the methods interesting though. I might have to start doing one to have a more exact method. BTW, I've really only ran out one time.

powderman426 wrote:
If you don't want to remove a bottle, a I R temperature gun like found at HF works well as the temp changes when going from air to liquid.

I have been using this method since 2009 and it has served me well.