How to tell when water heater is at max?

I turn my water pressure down too. Just enough to make it come out.

Does anyone have a rough guess of how much propane is used to heat up the tank? There are times, like this morning, where i forgot to turn my electric element on. Wanted to flip the propane on too to hurry up the process but also hate having to go refill propane.

1200W electric heating element can only put out about 4,100 BTU per hr.

Comparing that to the gas burner of the water heater which has a 40,000 BTU input gas burner and at say if the efficiency rate was only 60% conversion the water would get 24,000 BTU of heat..

4,100 electric vs 24,000 gas, you do not have to be a math genus to figure out that using gas is going to heat the water much faster, maintain the hot water temp for much longer even with extremely cold incoming water.

At a min it is going to take 6 times longer to heat the water with the electric heating element that it does with the gas burner.. Typically for my RV water heater it only takes 10 minutes or less to get scalding hot water using gas.. Mine doesn't have electric heating element but I can guess it would easily take 60 minutes or more with electric heating element only..

If you are looking for a long, long, long super hot shower on electric only, you are going to be disappointed.. Since RV electrical systems have considerable electrical capacity limitations like limiting the water heater electric element to about 1200W it is slow to heat, slow to recover and extremely fast to lose temperature when water is being drawn out..

A couple of things you can do to make the hot water in your shower last longer..

#1.. Take a "Navy" shower.. Turn on water to get wet, turn off water to lather up and turn on water to rinse off..

#2.. Do what I do, turn on water JUST ENOUGH TO GET A LIGHT SPRAY from the shower head.. Lets face it, you are not in a sticks and bricks with an unlimited supply of water and you are not going to get a shower that pins you to the shower wall if you want a long, long hot bath.. The faster you use your supply, the shorter amount of time you have to use it and the faster it goes down the drain.

Using this method, I can get a 20 minute shower with no noticeable drop in temp and 5 minutes later the next person can get a shower..

Correct cold water is replacing the hot water. But it does not seem to mix. Someone has posted a picture of the water heater insides. It has baffles that i believe are designed to keep the cold water from mixing with the hot.

Which goes alone with how the shower feels. Temp is normal. I feel it get colder and i turn the water handle to full hot. That lasts about 5 seconds and everything that comes out from there is cold water.

It's not perfect but I usually have a good idea based on our voltmeter. If you are paying attention, it will jump by a couple volts typically when the heater goes off. It's not perfect because each campground will have a different voltage and other things can move the voltage depending on what else is running but I can usually tell when a large draw is applied.

Better would be to install an amp meter on the main power inlet but it's a lot easier and cheaper to plug a volt meter into an outlet that's within easy visual range.

I would be very surprised if the temp of the water in the tank is inconsistent by more than a degree or two. The heating element is towards the bottom and hot water will tend to rise resulting in a nice mixing. What you are likely seeing is as you draw hot water out of the tank, it is replaced with cold water at a rate faster than the heating element can compensate. With only 6gal (typical hot water heater), by the time you use 3 gal, the temp can be significantly cooler.

I would guess that it would take at least 45 minutes to heat up from cold. I never heat up the water entirely. Instead for showers I have a timer set for about 20 minutes. That is just right for a hot shower without using any cold water. That way I do no waste any water on adjusting the temperature. When I am boondocking and do not have access to water, I want to take a hot shower with no more than a total of 1 gallon of water.

I believe the light to ours, when in electric mode, turns off when it reaches max temp. Ours takes longer to heat then when in propane mode, so we rarely use the electric mode.

I turn my pump off and open a hw faucet. When it starts dripping (for the 2nd time), water is hot. Of course this is using my tank.