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very diy water heating

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OhYou_

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Joined
Apr 13, 2023
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174
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I'm tired of taking cold showers outside (at night) at my shop/weekend hideout with a crap camping shower kit.
Has anyone messed around with immersion heaters? I have a 100gal plastic tank i got used I am thinking about cleaning out and putting on the roof of the shop and mounting the immersion heating coil just hanging in the middle of it.
Might even put in a temperature probe but my plan was big knife switch, the coil I have is 12v 600w.

my primary concern is that I am not sure how to seal the wires leading down the coil since they would be submerged. my initial plan is to use copper water pipe to both support the coil and send the power, and insulate it with something just in the rare possibility something goes wrong, but really they should never touch without help.

My inspiration is the little camping water heater kits which are a collapsing bucket, a battery operated pump with a shower hose on it, and a 120vac immersion heater. they are used by filling the bucket, then heating the water, then yeeting the pump in the water and showering.
 
OhYou_ said:
I'm tired of taking cold showers outside (at night) at my shop/weekend hideout with a crap camping shower kit.
Has anyone messed around with immersion heaters? I have a 100gal plastic tank i got used I am thinking about cleaning out and putting on the roof of the shop and mounting the immersion heating coil just hanging in the middle of it.
Might even put in a temperature probe but my plan was big knife switch, the coil I have is 12v 600w.

my primary concern is that I am not sure how to seal the wires leading down the coil since they would be submerged. my initial plan is to use copper water pipe to both support the coil and send the power, and insulate it with something just in the rare possibility something goes wrong, but really they should never touch without help.

My inspiration is the little camping water heater kits which are a collapsing bucket, a battery operated pump with a shower hose on it, and a 120vac immersion heater. they are used by filling the bucket, then heating the water, then yeeting the pump in the water and showering.
Click to expand...
Cut out the middle man (electricity) and go straight to solar thermal -50-70% efficiency vs solar PV's 20% - to heat water. Watch Youtube videos for simple solar thermal water heaters.
 
sunworshipper said:
Cut out the middle man (electricity) and go straight to solar thermal -50-70% efficiency vs solar PV's 20% - to heat water. Watch Youtube videos for simple solar thermal water heaters.
Click to expand...
I would but the cost of all the tubing and space for it greatly exceeds the $20 immersion heater I already own.
I kinda mathed it out and realized that 100gal is too much to heat so I am now looking at maybe 35-55gal barrels.
 
OhYou_ said:
I would but the cost of all the tubing and space for it greatly exceeds the $20 immersion heater I already own.
I kinda mathed it out and realized that 100gal is too much to heat so I am now looking at maybe 35-55gal barrels.
Click to expand...
Most RV's and travel trailers only have a 6/10 gallon water heaters - If you set a reasonable flow, you should be able to get away with much less. Unless you're looking to take 30 minute showers.
 
I suggest that you heat no more than 10 gallons and use a shower with a valve on the handle. We have been showering for a long time with a 6 gallon water heater in the RV. It is damn hot. 10 gallons heated just right will be fast.
 
Sounds destined for failure. 100 gallons is quite a lot of water to heat especially at 12V. I heat with PV and for small systems these point of use tanks work quite well, I have two in series for about 12 gallons which suits our needs including a dishwasher. 120V elements are good if you have a 60V or higher array. Just need to control switching to prevent arcing.
 
I had 3x 10amp 12v immersion heaters joined together wired to an Anderson plug.

I'd connect to my car battery with engine running and heat a 9L bucket of water hot enough for a nice camping shower within 10mins.
 
efficientPV said:
Sounds destined for failure. 100 gallons is quite a lot of water to heat especially at 12V. I heat with PV and for small systems these point of use tanks work quite well, I have two in series for about 12 gallons which suits our needs including a dishwasher. 120V elements are good if you have a 60V or higher array. Just need to control switching to prevent arcing.
Click to expand...
yeah I'm looking at those too but its like $400. I realized the 100gal early on was nfg, kinda looking at 35gal barrels now.
I hadn't really thought about just direct panel to element. I have a small army of 75w 12v panels doing nothing I can put together and just let it heat all the time. Instead of switching off the power, I can probably just regulate the water itself, letting some cold water in to maintain temp.
 
skyking1 said:
Smaller yet. only heat what you can immediately use. The advantage of a 10 vs a 35 Is the 10 will recover fairly quickly.
Click to expand...
I was planning on not doing a more traditional water heater setup and instead just you fill the tank, you heat the tank up to temp, and then you drain the tank as you shower. I suppose in the direct PV powered setup I could include a knife switch to shut down the power if I shower during the day so that it doesnt risk overheating the coil.
If that's the case, I have a few old 10gal propane tanks even, pressure rated. I could weld a bung in one for the element properly and just let it heat. I'll have to math out the limits on that though, obviously with a pressure relief as a backup.
 
I think your 10 gallon as a gravity tank would be fine. Just learn to "RV shower" .
get wet. shut off water. Soap up, rinse off with water to spare.
you could even put a float valve on it so it fills automatically. If you ran that inlet water through some black HDPE pipe on the roof it will get pre-heated on a sunny day.
You can also put an RV 12v pump after the gravity tank to give it more power spray action.
 
During the fires here in NorCal, we were without power for 5 days. We made do with a very hacked setup that worked out well: EGO Powerstation, supply of EGO batteries swappable, a number of EGO battery chargers, A Honda eu2200 generator to daily charge the batteries, charged away from home (noise) in the trunk of the car at a park. Naturally, we only ran critical loads, which were fridge, a few lights, and charged laptops, phones, and pocket cell hotspots, and occasionally used a portable inverter cooktop, and my electric kettle for pour over coffee, and....showering. Dumped water to fill about a third of a standard Depot 5 gallon bucket, heated up 2 liters (1L kettle) over a few minutes, used a drop-in pump shower kit, and enjoyed reasonably hot showers for those 5 days. Takeaway points, don't overuse energy, only enough to get the singular task done, then optimize for heat timing efficiency (mere minutes in this kettle) when the need presents.

Decided the only upgrade tweak I wanted was an insulated bucket, and found one at Wally's that doubles as a solid seat:
 
Last edited:
fuzzmunky415 said:
During the fires here in NorCal, we were without power for 5 days. We made do with a very hacked setup that worked out well: EGO Powerstation, supply of EGO batteries swappable, a number of EGO battery chargers, A Honda eu2200 generator to daily charge the batteries, charged away from home (noise) in the trunk of the car at a park. Naturally, we only ran critical loads, which were fridge, a few lights, and charged laptops, phones, and pocket cell hotspots, and occasionally used a portable inverter cooktop, and my electric kettle for pour over coffee, and....showering. Dumped water to fill about a third of a standard Depot 5 gallon bucket, heated up 2 liters (1L kettle) over a few minutes, used a drop-in pump shower kit, and enjoyed reasonably hot showers for those 5 days. Takeaway points, don't overuse energy, only enough to get the singular task done, then optimize for heat timing efficiency (mere minutes in this kettle) when the need presents.

Decided the only upgrade tweak I wanted was an insulated bucket, and found one at Wally's that doubles as a solid seat:
Click to expand...
yep, that's what I was thinking, only scaled up a bit. however, the cost of all of it was quickly adding up to just buying a tankless heater.
I like the more simple approach like you did but unfortunately after scanning through the listings on amazon for the pump type shower things, they all seem to fail after a few months or even uses.
I think I'll just keep things trivially simple and grab a bucket, put a bulkhead fitting in the bottom of it, and attach a diy shower head to that with a valve. just dunk the heater in to heat it up then hang it up high on a hook and stand under it. Only problem is it's not as simple to use so I dont know how much ill actually use it.

some point I'll build a bathroom/shower out there but ehh septic is more cost prohibitive than driving 1/2 mile to the house.
 
I have a Sure-flo 12V pump I bought for a camper resto I abandoned, but haven't adapted it to the bucket system yet. That Imation still works a few years later, and simplicity is best/ain't broke-dont fix it. It would be a better pressure upgrade, but use more water. Wife has long hair, washes daily, so I need to get the system up and primed just before we're ready to shower, and heat loss to bucket/environment is real, so heating speed helps a lot. Just made a round of coffee, that Oxo heated 1L of water from 76 to 200 in 3:34...so about 7 minutes for two liter batches, makes a comfy shower, using cold to final adjust temp. Want more water to fill bucket? add a 3rd liter of hot, solved. Cheers!
 
Almost forgot, because they got stored in the garage out of site...
I bought a couple of these on clearance:
slickdeals.net

HART 20-Volt 50 PSI Rinser Kit, (1) 20-Volt 2Ah Lithium-Ion Battery - $49.00 at Walmart

Built-in 5-gallon water tank • 70/30 PSI https://www.walmart.com/ip/HART-2.../536777869
slickdeals.net slickdeals.net
My plan was to use them for emergency shower, take to the beach, or water container plants without hose dragging. Could work, but not insulated.
 
CommandoJoe said:
Most RV's and travel trailers only have a 6/10 gallon water heaters - If you set a reasonable flow, you should be able to get away with much less. Unless you're looking to take 30 minute showers.
Click to expand...
During a very austere time in my youth, washing with cold water on cold mornings was worse than reeking at school. We did have an electric stove. A very tolerable solution was to put about 3 gallons to boil on the stove. That was dumped into a tub filled about near half with cold water.

I'm not sure how well those little bucket immersion heaters can get five gallons to near scalding temp, but if you had the luxury of five gallons of water that hot, a rather warm bath can be conjured.

I could see rigging a solar-electric shower for an individual at night time. Gravity fed from an insulated tank. Excess solar production would be heating water in the afternoon. Insulation keeps it warm until bed time after dark. Ten gallons of 104°f water would give enough for a wetting/off/lather/off/rinse. After dry off, make sure the tank is refilled the next day's showering.
 
Flunkyboi said:
During a very austere time in my youth, washing with cold water on cold mornings was worse than reeking at school. We did have an electric stove. A very tolerable solution was to put about 3 gallons to boil on the stove. That was dumped into a tub filled about near half with cold water.

I'm not sure how well those little bucket immersion heaters can get five gallons to near scalding temp, but if you had the luxury of five gallons of water that hot, a rather warm bath can be conjured.

I could see rigging a solar-electric shower for an individual at night time. Gravity fed from an insulated tank. Excess solar production would be heating water in the afternoon. Insulation keeps it warm until bed time after dark. Ten gallons of 104°f water would give enough for a wetting/off/lather/off/rinse. After dry off, make sure the tank is refilled the next day's showering.
Click to expand...
When the 6 gallon water heater in my trailer failed and I was waiting for an on demand propane heater to arrive, I had a 100' hose laid out in the sun that fed into my city water connection. It was plenty hot for a quick shower by mid afternoon. Luckily it was summertime...
 
I use one of those "outdoor only" tankless water heaters inside my hidey hole. It uses D batteries for ignition (which I have had to change once in the past 10 or 12 years) and I gas it with 20# bbq propane tanks, which last far longer than you'd expect and are fairly cheap to exchange at about any gas station. I get 2 or 3 months out of one, but I shower quick and sometimes not every day. <_< I only have one sink and one shower, right next to each other, such that I can reach out of the shower to adjust the flame on the water heater, because the heat of the water is a function of the flow rate through it (ie, open the tap wider and the water gets cooler, close it down some and the water gets hotter).

I know this is a solar forum, but this has been working very well for me for many years now. I think the water heater was like $100 on scammazone. Probably more now of course, but I still think it's extremely reasonable compared to other options. I have a deep well pump here, but when I finish moving everything up on the mountain I plan to use the same setup with a cistern and a 12v RV water pump.
 
Flunkyboi said:
During a very austere time in my youth, washing with cold water on cold mornings was worse than reeking at school. We did have an electric stove. A very tolerable solution was to put about 3 gallons to boil on the stove. That was dumped into a tub filled about near half with cold water.

I'm not sure how well those little bucket immersion heaters can get five gallons to near scalding temp, but if you had the luxury of five gallons of water that hot, a rather warm bath can be conjured.

I could see rigging a solar-electric shower for an individual at night time. Gravity fed from an insulated tank. Excess solar production would be heating water in the afternoon. Insulation keeps it warm until bed time after dark. Ten gallons of 104°f water would give enough for a wetting/off/lather/off/rinse. After dry off, make sure the tank is refilled the next day's showering.
Click to expand...
I use this one as it has built in thermostat:


Will take 5 gallons from 68 degrees to 175F in about 50 minutes, using 1800W of ac power.
 
Brucey said:
I use this one as it has built in thermostat:


Will take 5 gallons from 68 degrees to 175F in about 50 minutes, using 1800W of ac power.
Click to expand...
Thanky, kindly. If things got really rough, i could catch rain off the roof of my house or solar shack, then stick one of those in a bucket and get a warm SHTF fumunda wash. :)
 
Flunkyboi said:
Thanky, kindly. If things got really rough, i could catch rain off the roof of my house or solar shack, then stick one of those in a bucket and get a warm SHTF fumunda wash. :)
Click to expand...
I don't get fancy just a red solo cup serves as the ladle 5 gallons is plenty.
 
Last edited:
sunworshipper said:
Cut out the middle man (electricity) and go straight to solar thermal -50-70% efficiency vs solar PV's 20% - to heat water. Watch Youtube videos for simple solar thermal water heaters.
Click to expand...
I like the idea. My only concern is space. I assume the solar hot water panels need a storage tank to empty hot water into, if so how big of a tank is needed?
 
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