De-humidifier water

[vyv_cox]

My father as a marine engineer dealt a great deal with battery banks (certainly in those days!) all wet cells, and used cooled previously boiled water! (actually condensed steam!) In his private life he had a caravan (poor soul), but maintained wet cell batteries (car and caravan) for some 45 years or more.
I followed suit as an Engineer (and with the water, not the caravan!) and like him I have never had a wet cell battery last less than 15 years.
The only ones that fail, are "maintenance free" sealed batteries, and people seem lucky if they get 5 years out of them!

All the wet cell manufacturers used to suggest cooled boiled water in the event of nothing else, and Rolls Royce used to recommend topping up with tap water! Good enough for them, certainly good enough for me!

Try this little experiment. Add a little salt to your kettle, then fill with water. Make sure you can taste the salt. Now boil it, let it cool and taste it again. It will still taste of salt. Boiling has achieved nothing, or, as LML has rightly said, it is actually rather more concentrated.

Chlorides are particularly bad for batteries and much tap water contains various varieties of them.

 

[neale]

Having carried out some basic tests on dehumidifier water I would say it would be safe to use in batteries. It is very low in both general and carbonate hardness, is on the very slightly acidic side of the PH scale, contains no nitrates or chlorines as found in tapwater and provided it is collected in a clean environment with a clean container should contain few impurities.

All IMHO of course.

 

[late-night-lochin]

No you've pretty much got it in one!

The battery wasn't made and isn't kept in "sterile" conditions so there's always bound to be some contamination from day one.

There are several proceesses for purifing water including filtration (including reverse osmosis), de-ionisation and distillation. The combination used depends on client's requirements and specific requlatory authority requirements and these can vary from country to country.

One of the purest forms is called WFI (Water for Injection) that is basically formed by firstly purifying by RO and DI then feeding the purified water into a still which firstly boils the water turning into what is known as "pure steam" )which is used in many processes its self and when the pure steam is condensed; it becomes WFI.

Now, water out of the tap is pretty impure but (at least in this country) it should be drinkable.

If you boil the tap water and condense the steam you will have distilled water. It won't be totally pure but it will be good enough for some purposes. The trouble is that you would only be doing it inside a normal room (which is actually very far from clean) and not within an enclosed controlled environment.

Most of the impurities will not be turned into steam and will remain in the water which is left over in the vessel.

So, boil tap water an collect the steam by all means but the water that remains in the kettle will be worse than when it came out of the tap.

When you can easily buy distilled water which is likely to contain less impurities than condensed steam from a kettle or condensate from cooling coil in a de-hum unit; why bother?

 

[vyv_cox]

Halfords sell 5 litre bottles of de-ionised water for £3.99. That will probably last most users in UK a couple of years. At that price and convenience is it worth the risk to use anything else?

 

[nigelmercier]

Try this little experiment. Add a little salt to your kettle, then fill with water. Make sure you can taste the salt. Now boil it, let it cool and taste it again. It will still taste of salt. Boiling has achieved nothing...

With common salt (sodium chloride), no. But boiling causes calcium salts to form a precipitate, which is why kettles get furred up. Left to stand, boiled water has less calcium salts than before.