Emergency Battery in the Wilderness

Imagine this situation:
You're camping in the wilderness. In the area where you have your tent, there live carnivorous man-eating scorpions which are active at night because they are afraid of light. So in the evening you are testing if your flashlight is still working, because you need it to scare off the scorpions. You see that the battery is empty.
Is this a reason to panic?
NO!
Because you have read this instructable!
You don't have a working battery anymore, but you probably do have: some coins containing copper, aluminum(from a can or a lightweight cooking set), sour body liquids(urine, or even better, puke), something that can absorb(like toilet paper but just some earth will also work), some leaves from a tree(the bigger the better), and some tape or rope.
In the last step I will tell how you can use the battery in the wild, first I'll demonstrate how to make the battery with kitchen products. Try that at home as a practice! You'll need it in the wilderness, it works the same there. For example, we'll use vinegar or lemon juice, instead of urine or puke, but it will all work(So if you find a lemon tree in the wilderness I recommend to make use of that instead of your body liquids, so your battery won't be so disgusting.)
Let's go on to the next step!

Step 1 What You Need

For this experiment, we need:
- vinegar OR lemon juice
- tape
- aluminum foil
- strong paper
- paper towel
- a bowl
- coins(you won't lose them!) containing copper, or copper-plated(these often look red-brown, and are mostly the coins with the smallest values, like 1,2 and 5 eurocent coins. I believe the USA one penny coin is copper plated, and maybe the 5- and 10 cent coins aswell. You can look it up)

you also need something to test the battery, like a bycicle light, or a multimeter.

Comments

[Electroinnovation]

Using pennies from before about 1970 work a lot better because they are 95% copper instead of just a thin coating of copper, also I used dish soap and got about 3v from only 7 pennies. Of course after an hour the voltage dropped down to around 1v but it was enough to power an led for a long time.

[Shiftlock]

I don't think urine would be acidic enough for this to work, nor would vomit after a meal, but if you could vomit on an empty stomach and produce some gastric acid, that would surely work, since it's primarily hydrochloric acid. That would work even better than the vinegar or lemon juice.

[sharp8874]

 so you want to carry alot of old penny's while camping

[VLOEIBEER]

I tested it, it worked!

[acedolcholine]

It may be useful to know that pre-1982 pennys are a mixture of 95% copper and 5% zinc, while post-1982 pennys have a 97.5% zinc core with a 2.5% copper plating. That may not make a difference, but it's a fun fact regardless.