hot water heater

[elcoyote]

They need a continious flow of water or they melt down, according to a friend who ruined one.

That is if you are referring to the Zodi Hot Tap Series, not the Hot Man Extreme.

 

[articulate]

Those are just regular water heater elements though. you can buy those at any hardware store.

Might not be a bad idea though....small tank, switch up front and turn it on before you plan on stopping.

I'm reviving this to come back to your comment here. You opened my eyes! Having never dealt with replacing/fixing/working on a hot water heater in my home or elsewhere, I had no idea. Beautiful point you make, bro! Beautiful.

Now I assume, though, that these hardware store heater elements use 120v power. And they all seem to be upwards of 1440 frickin' watts.

Some how, the 12v elements for 300 watts are more practical.

I'm thinking about Scott's comment:

Very interesting. That 600 watt one at 12v would consume what 50 amps? 300 watt one is a little more interesting at 25 amps, but that's some serious current requirements for a rig.

Like Cap'n said, we're not looking to make boiling water here. We just want to warm it up. What, run the heater for 20 minutes maybe as we pull into camp . . . Is it too unsafe or impractical to do?


Input?






Edit: A little searching found a "tankless on-demand" (AKA in-line) water heater for Marine/RV use at this page about 1/3rd down. Note that they require 120v and are nearly $300. Cap'n, this might be the sort of thing you wanted in the beginning. Got a power inverter? If so, for $300 you're back in the expedition business with Linda.

 

[blupaddler]

So without me filling up a 1 gallon container of water and pouring out over a minute...What is 1gpm? Or any idea of something I can compare this too?

 

[Tucson T4R]

This is a little over kill unless you are just using it in a base camp. Last week I tried out the Zodie X-40 Hot water heater. What I found was I had to replace the weak hose clamps with real screw down hose clamps on the bottom of the heater and on the output of the pump. After that it worked reliably.

One drawback was the burner adjustment is only a 90 degree valve so it was over sensitive and would be dificult to get set right for the shower. What we ended doing was using the carry case with a garbage bag in it to hold the supply water. Then we recirculated the water while heating until the entire supply of about 5 gallons was up to our desired temp. Then you just turn off the burner and pump the pre-heated water for you shower...no worries.:victory:

 

[njtaco]

Just some thoughts here...


Homeowner water heater elements are 240V usually, about 1500 watts, 38 ohms.
This is too much resistance for 12V, not enough heat made. (3.78 watts)

There are 120V models available, but IMO, they will not work well.

A 300 watt 12V element needs 25 amps to push through .48 ohms...manageable, but not ideal.

Using the 600 watt, .96 ohm, 24V element (sold above) in a 12V system will halve the needed amps (to 12A), and produce half the heat (150 watts). Driving all day will produce plenty of hot water with little effect on the truck. A thermostat on the tank will prevent overheating, and avoid overuse of the available power.

As noted earlier, a 70+/- amp hour battery dedicated to this project would keep a small tank warm for quite a while. Also, the warmer the water is going into the tank (start with a solar bag) the less draw for hot water later.

Wiring to the element plays a big part, too. Less line loss=more volts (and watts) at the tank=more hot water.

So... is my math right? What are your collective thoughts on this idea?

Regarding the GPM question: Run your home shower at the lowest acceptable flow into a 5 gal bucket, and time it. Keep dropping pressure till it takes 5 minutes to fill. This will seem like forever, of course. This will also be 1GPM. A typical RV water supply (demand) pump provides from 2 to 3 GPM in the best of circumstances, at about 40 PSI. My supply at home is about 60-70 PSI. Yours is probably close to that.

I hope this helped, more than hurt. :smilies27

 

[OutbacKamper]

IMO 12volt water heaters are about as practical as 12volt air conditioners. What I mean is that they are theorectically possible, but not the most efficient choice. If you have to run your engine most of the time because of the heavy amp draw, then wouldn't it be more practical to use coolant from the running engine in a heat exchanger (such as the Glind and Helton systems mentioned earlier)?

A friend in Australia has what I consider to be the ultimate, expedition style,hot water shower. It is also the lightest, simplest and cheapest system I have seen. It consists of a canvas bag (about 2 1/2 gallon capacity) a short hose, valve & shower head attached to the bottom of the bag. He hangs the bag from a tree branch, roof rack etc. and fills it 3/4 full of ambient temperature water. Then add one billy can of boiling water, mix and shower (gravity feed). With a little experimentation to determine the ideal amount of cold and boiling water to mix, the water temperature is actually more consistant than my heat exchanger sytem on the 4wheel camper.

Cheers
Mark

 

[njtaco]

Thinking out loud again...

If my 240V, two element (2x1500Watt) 40 gallon water heater takes an hour to heat up to 120 degrees, wouldn't a 12V, 150 watt, single element in a 2 gallon tank take an hour, too? Maybe less? This would provide two showers (mixed with cold water.)

This is dirty math at best, but you get the idea...

 

[fisher205]

I haven't seen the Zodie's and have actually used a weed sprayer. Paint it partly black and it heats up almost as well as my old solar shower. We sometimes supplament with warm water on the stove. The problem I see is that these electric pump systems all will use more water. This water is in the potable tanks and you are hauling a lot of water (weight) just to have the convenice of a hot shower. We only shower if there is a water source nearby. I use only a hand pump with my system to help conserve water and power. I know it's a Luddite thing, but is reliable and you don't seem to waste as much if you have to hand pump it.

 

[cruiseroutfit]

I'm very happy with my engine mounted heat exchanger...

Its a great setup for me... it only takes a couple of minutes to warm up after the engines been sitting overnight, and I like to warm up my motor before I head out... so no loss there.

 

[spressomon]

I'm very happy with my engine mounted heat exchanger...

Its a great setup for me... it only takes a couple of minutes to warm up after the engines been sitting overnight, and I like to warm up my motor before I head out... so no loss there.

Ditto. I added a hand throttle to my 100 for winching...and it serves second duty as a temp regulator for the HH!

 

[cruiseroutfit]

Ditto. I added a hand throttle to my 100 for winching...and it serves second duty as a temp regulator for the HH!

I use the hand throttle on my FJ40 too

I've done a couple installs for folks where we plumb it after the heater control valve (which essentially controls the amount of coolant entering the heat exchanger)... That way you use the heater contol selector on your dash to control your shower

 

[Desertdude]

something like this one...

2 years and still going...

full Tacoma install photos

 

[CAPTAIN COORS]

I'am going with a submersible electric hot water heater elements, plan on installing parts this weekend, if all goes well, i'll post some pics of the installation and some info as to how well it heats the water

 

[CAPTAIN COORS]

finished the instillation of the submersible water heater element, seems to work ok, cheap at around $60, will field test it and let all know how it worked

 

[njtaco]

Which element did you use? (Voltage?)