This is something that till now don't exist in the world, i wanna know why humans why haven't you made something similar for yourselves.

this one of my simplest and easiest projects even it qualifies for my most useful project list also. for an in-depth view of the making process please checkout FULL VIDEO TUTORIAL

Step 1: Why You Need One

In winters i prefer warm water as its good for my health and even helps in maintaining overall immunity.

also warm water help loose some of your extra fat.

now we get that warm water for drinking purposes is very beneficial but warming it up still remains a hassle.

a risk of overheating is always their,even pouring it here and there makes the task inconvenient.

the water heating kettles are not portable and need a high power outlet which is not always handy.

also you can't warm your water while travelling or when out in the wild.

thermos flask may pose a solution but they can't keep your water warm more than 12 hours.

Step 2: THIS IS WHAT ALL YOU NEED...

30 swg copper wire

usb to 2.1mm power plug cable

2.1mm power plug jack

insulated water bottle

hot glue gun

heat shrink tubing

soldering iron

hot glue gun

some more basic tools and measurement devices

Step 3: Prepare the Bottle

choose a well insulation padded water bottle. don't go for vacuum based thermos flask.

hammer off the bottom or try to open up the outer plastic casing of the bottle in order to make the insulation accessible.

with the help of a utility knife scrape off the insulation material.and peel it off (preferably intact).

Step 4: HEATING ELEMENT

cut a piece of 30 swg copper wire in 5 metre length as 30 swg copper wire has a resistance of 1 ohm per 2 metre.

and we need a resistance of approx (2.5-4 ohm) that will be revealed later in calculations.

now cover it with the help of hot glue gun and put back the insulation on

Step 5: CONNECTING IT ALL TOGETHER

AFTER HEATING the copper wire ends just rub off all the insulation with a fine grit sandpaper,

connect it to the powerplug wires (polarity does not matter) solder them together and seal it with some heat shrink tubing.

Step 6: MAKING SPACE

with the help of a hot knife simply cut through the outer plastic body of the bottle making room for the jack.

slide the body back into place.seal out any remaining air gaps. and fix the jack with hot glue.

Step 7: FILL and POWER UP

USING SOME KIND OF PORTABLE 5 VOLT POWER SUPPLY(power bank) OR SOME PHONE CHARGER(USB) PLUG IT IN

AND YOUR DRINK STARTS TO WARM UP.

Step 8: POWER OUTPUT

I did all the calculations before hand so you don't have to

if your needs are different then go for different wire or different length of wire even increasing the battery in series will increase the power then prefer calculating before using the device.

in my case

voltage=5.14 V

current=1.40 A

resistance=3.5 ohm

power output = voltage X current=7.19 watts