When I tried to purify my gallon jug of water (10) with the charcoal water purifier with only 2 charcoals loaded in, I got the error message “You don’t have enough battery power to purify all the water.”, which made me scratch my head for a moment.
I don’t currently have enough resources to test other charcoal-powered items how they handle this situation.
Version: Windows SDL 0.8-257-g529a989
I’m not sure if it’s bugged, but I tried this earlier in my playthrough and the purifier needed 1 “charge” of charcoal for every unit of water, I think.
If this isn’t a bug, charcoal for this purpose is really inefficient currently. For 10 units of water you’d need 10 two-by-fours just for the charcoal! Considering that a single two-by-four in a rock fireplace will burn long enough to boil those 10 units (and then some!) I think the numbers need tweaking a wee bit!
There’s a fix in-progress for the error message.
As for balance, yea that might be a little excessive, it looks like the process you’re using in game would have about 50% yield by volume, so we might want to bump that up a bit, also I’m not really sure what the exchange rate for a carbon filter SHOULD be…
Also after reading about it, carbon shouldn’t be remotely sufficient to purify even regular groundwater to a safe state, much less goo-infested danger water 
Water purification needs a total rework ><
Also word of warning, if you search for “carbon filters”, or “DIY activated charcoal”, it will return a ton of weed growing resources, I’m fine because I’m on every watchlist known to mankind already, but others beware <<
Does the ultraviolet light kill it?
… wait a second, since I can only assume from how long the water cleaning takes that we are only boiling the water, not distilling it…
Then in what temperature (in Celcius) does the goo die?
As best as I know the goo isn’t actually contributing that much to bad water poisoning (though it might help just a bit). The major problems come from the radioactive and other toxic stuff that have been dropped into the water along with a bunch of other junk (which means that boiling water to clean it really wouldn’t do much at all).
boiling away radiation
Yeah no. It works from a game-y perspective though.
I have a more involved proposal outlined at https://github.com/CleverRaven/Cataclysm-DDA/issues/72
but it hasn’t trickled to the top of anyone’s task list, so we still have a crappy model of water safety.
Like I said it makes sense from a game-y perspective though. You want people to be able to get it without too much trouble since you need so much of it so regularly.
[quote=“Hex, post:2, topic:3165”]I’m not sure if it’s bugged, but I tried this earlier in my playthrough and the purifier needed 1 “charge” of charcoal for every unit of water, I think.
If this isn’t a bug, charcoal for this purpose is really inefficient currently. For 10 units of water you’d need 10 two-by-fours just for the charcoal! Considering that a single two-by-four in a rock fireplace will burn long enough to boil those 10 units (and then some!) I think the numbers need tweaking a wee bit![/quote]
Yeah it’s meant to be inefficient. The charcoal you produce in-game is a pretty far stretch from the fancy activated charcoal such filters normally use. Add that to the fact that the purifier unit is a cobbled together collection of bottles and hoses, and you’ve got a leaky, inefficient system.
The charcoal purifier’s benefit is that it’s a portable water purifier that doesn’t use any of your precious batteries, instead running off of cheap and easy to produce charcoal.
That being said, I think I might boost charcoal’s production efficiency a bit, to make the inequality slightly less over the top.
Edit: Charcoal production efficiency has been doubled.