good morning sirs
i need to be able to fill a 2.5 gallon (~9.5L) reservoir with hot water, and have it maintain a temperate of at least 100F (~38C) for 6 hours fir a handwashing station. Ambient temperatures will generally be 90F+, so this can probably easily be accomplished by insulating the the reservoir and lines well, and filling with very hot water (it's for a handwashing station on a cargo bike, so i'd probably have to run small cool water reservoir and use a mixer valve so i don't scald myself) but I need to be able to show some sort of heating system to satisfy the bastards at the city. Could I rig up an immersion boiler that's powered by rechargeable batteries?
Immersion boilers draw a lot of power all at once, batteries hate that.
I would look into mucj more gentle ways of heating the water.
Pet rock for cold blooded animals, they make heat tape too to wrap animal dishes in so they dont freeze.
Dipstick probe heater for diesels in the cold would also be an idea.
Heating water off batteries though is just kinda not ideal. Solar hot water setup a possibilit? They kick ass.
not all of them tho, i have a few of varying power ratings, from 25w to 19kW and a lot inbetween, then there's dimmers which lower the power they use as well.
a cheap 300w immersion heater on 12v and a PWM based dimmer would do the trick. a sensor (and a microco- or PID-)controller to control the temp is available off the shelf. a friend made a yeast growing/fermenting chamber from an old fridge to keep his beer at just the right temperature. i lightbulb instead of an immersion heater, but the rest was all off the shelf shit from Chinkia
was cheap too, less than 100 euro total
Theres on demand hot water heaters for horse people and people who cant camp without a shower.
20 lb propane tank, ignition is done by 2 c batteries when water flow is asked for.
Probably a better setup
There are battery powered heating bottles on amazon, maybe take one of those apart
What am I missing. You need a hot water station on your cargo bike? In the summer when it’s over 90F outside? Who is the hand washing station for? Are you selling food?
How big is a cargo bike? Do you have photos of what other people do in this situation?
The municipality doesn't want mobile vendors competing with the shops, so they've imposed a bunch of shitty regulations. I sell ice cream on a cargo bike. I'm going to rig up a hand washing station to satisfy their requests. It doesn't have to work good, it just needs to be there.
I may just insulate it and fill it with boiling water every morning and run some wires and a fake temp gauge because I don't think the zoomer black chick who does inspections can tell the difference.
It's a bakefiet I made out of a tricycle. I put a 1x7 drivetrain and diff on it, with a ln electric motor assist on the front hub. The cooler is bolted into the bike, but it's less than 100lb when filled with product. I just need to rig up a small gravity-fed hand washing sink with a collection reservoir. Weight isn't a big deal, I can haul 300+lbs on this thing.
>The municipality doesn't want mobile vendors competing with the shops, so they
Allow mobile food vendors to operate if they meet the most vasic health related requirements for food vendors.
FIFY
Do Americans really call them bakefiet? That’s pretty funny
> wires and a fake temp gauge
You could put a real thermostat if you’re going to mix hot and cold. But if there’s an inspection I’m not sure if it would pass that way, doesn’t hot water have to be >120f to prevent legionella where you are?
Anyway have you considered a fish tank heater? They are very often 12V
>bakefiet
never heard of it before, must be a bordertown thing
rig the top of your freezer/basket with a solar panel, battery and cheap charge controller for power
Can you link the regulations?
thermal siphoning, but it may exceed your required temperature so you'll need to add a mix for cold with an anti-scald at the use spigot.
2.5 gallons, starting with the correct temp, a couple Sterno can should be able to maintain it
Insulated water heater. Run it on AC power for a few hours at the highest temperature (~70ºC) then unplug and move to location. Use a thermostatic faucet to avoid wasting hot water and mix it with cold water to make it usable.
Stumbled upon this
How about a portable propane tankless water heater?
https://www.eccotemp.com/portable-tankless/
Plenty of odd advice in here...
Heating elements are just big resistors. They don't care what they're being powered with, and you can easily adjust how much heat they're putting out by changing voltage.
You could just straight-up use a heating element for a small water heater, like:
https://www.ebay.com/itm/314608245015
2000W at 120V implies approximately 7.5Ω of resistance. The same element would put out just ~20W on a 12V battery. With adequate insulation, that's probably just about right. A typical 20Ah lead acid battery would power the thing all day, and have enough reserve capacity that it should last many cycles.
Attach a thermal switch directly to the element to ensure things don't get too hot and start melting and that's pretty much all you need.
https://www.ebay.com/itm/186102301044
Waterproof it if it isn't already. Bacteria growth comes to mind as a concern if you keep the water at much less than about 60°C/140°F, but I don't know how much of a problem that would really be if the tank only ever has water in it. You also need to mix with cold at the spout if you do that, so I'm not sure it's worth it. Something to keep in mind, though.
I expect free paletas for this advice.
Solar panels used on golf carts do 35v. There's a company making a boost mppt that can charge a 48v with a 35v panel. And I've seen 70v panels, now, that would work with off the shelf equipment.
The residential panel is 40" wide and varies in length, but generally makes a good topper by itself for a golf cart.
Using your math, figure out how much power a 70v panel would dump into a small electric hot water heater, like what you find on a trailer or motorhome. That's at peak sun though. So some thermal switch is needed so doesn't overheat in the middle of the day. 70v is high so drive an electronic switch that can handle 70v, like a solid state relay.
If there was only a piss cheap solution for the problem.