tankless hot water heaters?

Bogo

Adventurer
West Marine also handles the IsoTherm water heaters units. They are a high temperature tank water heater. they use waste engine heat form the engine coolant system to heat the water, or use 120VAC. When heating from the engine they will easily heat the water over 160F. They then mix hot and cold water to cool the water into the 110F to 120F range for use. The main drawback is they require a pressurized water system with fresh water supply tank.
 

Nullifier

Expedition Leader
The propane omega unit Chris Cole uses on his campa trialers is really nice. Looks good and works very well.
 

AxeAngel

Expedition Leader
I use this, two sources for heat. Either place near campfire(rubber feet can be removed) or plug the heater element into your 12v cig plug.

No power wires, or any complicated things to break. Runs off CO2 or on board air. 20psi works nicely and holds 5 gallons. Since its food grade aluminum with a stainless steel liner, it can also serve double duty to carry drinking water.

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-Sam
 

AxeAngel

Expedition Leader
Hmmm, a fizzy bath in soda water. Wouldn't even need soap! :victory:

Hahaha, the water doesn't get any signs of carbonation until you go much much higher in the psi range. I run the shower at 20psi. Add some syrup and crank it to 75 or so psi and you can get your favorite soda pop or adult beverage

-Sam
 

greentruck

Adventurer
We just bought a Triton tankless water heater to replace a circa 1978 model heater that died on our last trek. It's made by Camp Chef. It's not designed for installed mounting, so may not work for what the OP asked about. However, it does put out plenty of hot water.

I modded it so that it hangs from the rim of the tub on our trailer. The gas hose hooks up to the LPG tank on the trailer tongue. The cold water feed is provided by a Reliance On Tap water shower pump. You just drop it into the water jug sitting in the trailer bed to feed the heater. There is a handheld shower that attaches to the heater for output.

The thing heats so much water so fast and hot that we'll stick to our old practice of filling a bucket just so full to take a shower with. We can carry plenty of fuel, but carrying enough water for long hot showers is harder. We have a second On Tap shower that we use just for taking a shower, so we have a backup if one goes on the fritz.

The whole kit, heater, two On Taps, and gas lines, fits in a box that is 14" wide, 9.5" tall and 34" long. Takes about two minutes to set up and have hot water going.
 

TomH

Adventurer
This is how I am going to have a nice hot shower.The water tank is going to be mounted in my truck under my sleeping platform. The tankless part will be mounted to a frame with the propane setup also. Coleman makes a propane setup that allows you to have 2 1lb propane cannister together to give you better volume. I will run my shower head into the shower stall and when you press the trigger the pump will turn on which in turn will ingnite tha tankless heater in which my wife will have many :):):):):):):):):):):):) on her face.
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Those little non-refillable/disposable Coleman propane cylinders are so expensive. Manchester makes a small refillable model with 1.2 gal./4.25 lb. capacity that is only a bit over a foot tall. It's available at Cabellas, Camping World, Amazon, and all over the web. It costs more than a std. 5 gal. refillable cylinder, however the propane itself is so much less expensive than those disposable Coleman cylinders that it will pay for itself quickly. The necessary adapters are available at the same places already mentioned.
 

bat

Explorer
The problem I have is the sleeping platform I am going to build is 11 inches inside and my stove, heater, lamp all use the smaller container. I have talked to others who do the refill thing and all say they never had a problem, just keep the refill with each container to 3. I do have the big tank for my BBQ now so it is not a big deal to refill. I had the luxury of a 4x4 CC Diesel before and I am in a Tacoma now so trying to fit 10lbs in a 2lb box.
 

Bogo

Adventurer
Another link for small Marine/RV electric on demand:

http://www.eemax.com/EX2412M

Let's see... Running some numbers.

Going with a 5 minute shower. That is 5 minutes at 2.4KW from the inverter. Assuming an 80% efficient inverter that is 250Amps @ 12V at the battery for 5 minutes. 21Amp Hours use from the battery bank. That is 1/2 to 1/3 the usable charge from a single 100 Amp Hour deep cycle battery at that discharge rate. The faster you discharge a battery, the smaller it's usable capacity. It is mainly due to internal resistance in the battery. A battery with a lower internal resistance is able to utilize more of its charge at high output current rates.

Now if the incoming water is real cold, then you may wish to heat it up twice, or if you want two showers. That would be 42 Amp Hours use. A bit harder on the battery bank. That is well over half and possibly all of the max usable capacity from a single 12V 100AHour deep cycle battery at that discharge rate. At that point, I'd say two + 100AHr batteries is an absolute minimum with 3 or 4 being much better, or plug the RV in, or use a generator.

Note, the water heater unit draws 20 Amps @ 120VAC. That is at or above the current many older campsites allow. If the circuit breaker has been tripped a number of times it may not allow you to draw a full 20 Amps even if it is rated for that, circuit breakers do wear out and are usually only rated for 50 to 100 overload trips. A 30 Amp hookup would be required. Also it's current draw could easily overload smaller generators if something like a microwave or air conditioner was also running at the same time.

Because the load is resistive, it should only need a 2.4kW inverter to power it. Bigger would be better so you aren't pushing the inverter at maximum capacity.

Given the current draw at the battery. I'd have at least 2 batteries if not 3 or 4. Also I'd seriously look into a 24VDC house battery bank. That would halve the current in the wires between the inverter and battery bank, but it has other issues. Adding a 24VDC alternator to the engine is one of them. On the flip side 24VDC input inverters are usually 5 to 10% more efficient than ones designed for 12VDC battery banks. Same goes for refrigerators designed to run on 24VDC.

Yeah, the numbers don't look good.
 

Engineer Guy

New member
Solar Water Heating

Here's a novel water heating idea:

http://offgridrving.com/solar-water-heater/solar-water-heating/

This coil behind a small piece of used Tempered Glass in a wood 'picture frame' mount would be a small profile, rugged Solar Panel w/o the reflector 'wings'. Alternately, this profile of Solar Collector could be sized to drop-fit the front of a Solar Cooker, thus serving double duty. Quick disconnects and 'small' Radiator Tubing would permit Collector placement/storage flexibility. Black Engine exhaust paint, etc., would work well. Translucent Fiberglass, as used at Greenhouses, lets solar through and can't break. A special type I used decades ago resists UV delamination.

I spray painted black a clean Garden Sprayer for a Shower. Montero Boondocking around Lake Powell in late October, it hit 110 F after 4 hours in the Sun; more quickly with reflective Astrofoil backing that unfolded to reflect Body IR under the bottom Bed sheet. The Indoor/Outdoor Thermometer is not in place in this pic. If the desired water temp is not met, Stove-heated water can be added. A coil, as shown above, was commercialized years ago to sit down in Campfire coals, or on a Gas Stove, to heat circulated water. A Home Water Heater Overpressure Valve provides cheap overpressure/over-temp safety.

The insulated Water Coolers seen on most Construction Trucks would seem to be a good shape and size to store heated water, however achieved. I've hoisted a dark Bucket of hot water ~3' above my head on a pulley and used a RV Hose and close-able, 'trigger' Hand Sprayer for showering. Siphons need no power.

Combining 2 Copper coils in an insulated Cooler full of fluid would be one way to Engine-heat [1 coil] potable water [the 2nd coil] safely on the cheap.
 

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I use one of these as an outfitter 12 months on the road

[ame="http://www.youtube.com/watch?v=VsSd2iFqxAc"]YouTube - Coleman Hot Water on Demand[/ame]

primus also make one but my clients like the hot cold tap idea

i've also got the shower nozzle and mains water adaptor and propane bottle adaptor for it cost me $400 AUD which is about the same US at the moment.

DOES NOT LIKE THE COLD, didnt like high altitudes or the snow much....
 

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