De-ionised water

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Plan_B

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Topping up the batteries on Sunday I ran out of D-i water. Wife had just emptied the De-Hum tank into bottles to take home and use in the iron (stops it scaling).

I have heard that air-conditioner condensate is similar to distilled and de-ionised water but does anyone use this or X de-hum water in their batteries?

As we have 5 big batteries I'd hate to risk using water that might cause damage.

DD
 
5litres of deionised water from my local pharmacy costs £3.25.Is it worth risking an expensive battery for such a small outlay. You also get left with a plastic container for which a use can always be found.
 
Condensation water from your Aircon unit is all but de-ionised. The water drips from a metal evaporator and also pick up all the air pollution that comes from the airflow though the evaporator.

So, it might contain less 'pollution' then tap-water, in the long run it will still affect your batteries.

Cheers,

Arno
 
I bought a 5l can of "De-ionised" water from Halfords last week. The ion generator analysed it and said, sorry guv, too much mineralisation.

What I need is steam distilled water; another reason to start home brewing.
 
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I bought a 5l can of "De-ionised" water from Halfords last week. The ion generator analysed it and said, sorry guv, too much mineralisation. What I need is steam distilled water;

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Properly deionised (demineralised) water should be purer than distilled water.
 
Not the cost Franky - shops were miles away and probably shut. I could of been somewhere miles from anywhere up a river.

Had about 2 lts on board but used it all.
 
That's what I thought when I bought it, but a rather sensitive gadget in the lab said it wouldn't play as the mineral content was too high.

(Jar was washed out with distilled, prior to use, by the way !)

I am going to have a word with Half Lords.
 
Have you tried tasting the water from your dehumidifier? Nothing pure about that at all.

The water that you get from defrosting the freezer is probably much purer
 
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but a rather sensitive gadget in the lab

[/ QUOTE ] And what was that? I would have simply gone on conductance. What did you want the water for.
 
[/ QUOTE ] Properly deionised (demineralised) water should be purer than distilled water.

[/ QUOTE ] eh? You can't be serious? De-ionised water may contain any amount of minerals albeit in a non-ionic form. Distilled water is simply H2O with no minerals whatsoever, maybe dissolved N2 and O2, but nothing else. Dehumidifier water at best is as good as distilled water but will normally be contaminated a little by the atmosphere.

If you go into a garage workshop you will find that they make their own de-ionised water - basically just a zeolite ion exchange cartridge just like a domestic water softener.
 
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If you go into a garage workshop you will find that they make their own de-ionised water - basically just a zeolite ion exchange cartridge just like a domestic water softener

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Something like a domestic water softener would be no good at all. That is just a cation exchanger in the sodium form that replaces the calcium and magnesiun ions with sodium ions. Probably what you have seen is a mixed bed cartridge

By proper demineralisation I would mean a cation exchanger in the hydrogen form that removes most of the cations (sodium, potassium, calcium and magnesium) followed by degassing to remove the carbon dioxide resulting from the bicarbonate content, then an anion exchanger in the OH form to remove the bulk of the remaining anions, mostly sulphate and chloride. A final polishing though a mixed bed (cation exchanger in the H form and anion exchanger in the OH form mixed together) will then remove virtually all the remaining anions and cations. (The whole lot would probably be preceded by a some form of pretreatment system and if intended to treat water with a high hardness separate units might be used to remove that ahead of the main cation exchanger. In cases where the water supply was expected to be high in organics an additional unit would be included to remove them (basically an anion exchanger in the chloride form).

A typical spec for water from such a plant to be used for high pressure (150 bar) boiler feedwater makeup would, in the days when I was invoved in this sort of thing, have been a conductivity of not greater than 0.1 microsiemens/cm and a reactive silica concentration below 0.02 µg/ml. You'd be lucky to get much below 10 ms/cm for distilled water

The trouble with distilled water from any ordinary still is that is is liable to contain some dissolved solids as as "carry over" (mist and spray from the boiling water)and of course high concentrations of carbon dioxide, from decomposition of bicarbonates in the raw water feed or dissolution from the atmosphere. Where critical for laboratory use the distilled water can be treated by passing through a mixed bed deioniser.

An alternative to distillation or demineralisation is of course reverse osmosis. I have no practical experience of that but my understanding is that it would have to be followed by demineralisation, mixed bed treatment anyway, to acheive the sorts of purity levels I am talking of. For battery top-up purposes that may not be necessary nor would the mixed bed stage of the complete demineralisation I have described, and a simple mixed bed cartridge on its own, that I suspect you have seen in garages, would also produce water of adequate purity. I would not trust any garage that I have come across to replace the cartridge as soon as required though.

Dissolved oxygen or nitrogen wold not be of any significance in the applications I am considering (or for battery top up purposes) indeed the degassing stage would lead to air saturated water. I'm not sure that I understand what you mean by minerals in a non ionic form.
 
I was just trying to make about 500 ml of "silver water" at 5 ppm, for an experiment.


I just love the forum when everyone starts talking technical; it reminds me that there is life after the daily office grind.

I have been running the dehumidifier on board today, so will try the condensate in the ion generator. Watch this space.
 
You said that "Properly deionised (demineralised) water should be purer than distilled water" That is untue; deionised water may contain any amount of (nonionic) impurities e.g. organic impurities. Properly distilled water (double distilled water) is as pure as H2O gets though crude school chemy-lab home made distilled water isn't so good, for sure and it is true that dissolved CO2 is hard to avoid - but then you can't avoid dissolved CO2 in deionised water either.
 
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So would water from a brita water filter be good enuf for a battery? It shaw do make a much better cup of tea than tap water!

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No Brita filters are essentially a water softening cartridge, but contaning an ion exchange resin in the hydrogen form which only removes the scale forming temporary hardness, and an activated carbon filter which removes such things as chlorine, pesticides and other organic compounds.
It is removal of chlorine which is probably what makes your tea taste much better. The removal of the temporary hardness prevents scaling and is particularly useful if your use certain types of coffee making machines, at least if you live in a hard water area. If you don't then really all you need is the carbon filter.
Our water is fairly hard so the Brita stops the Teasmade and the Russell Hobbs filter coffee maker scaling up but we do not seem to suffer from high chlorine levels so we notice no difference in the flavour of the tea. As our water has come from wells in to the chalk it is relatively free of most other artificially introduced nasties and has not already been drunk two or three times and laced with female hormones, antibiotics and heaven knows what else. We actually prefer the taste of it straight from the tap to being Brita filtered but that is presumably because the calcium and magnesium concentrations have not been reduced.

We actually only bought it on the recommendation of the Vet when they thought the cat was suffering from a form of FLUTD caused by struvite (magnesium ammonium phosphate) crystals. In fact she has some abnormality of the bladder wall.


There is good reading on the Brita website especially here
 
In my job(steelplant) we had to determine the oxygen potential of the waste water and found that we could not use the de-ionised water. We had to buy a distiller just for these analyses. Evidently there is a difference between the two types, but I don't know what. De de-ionised water was OK for all the other analyses. Using de-ionised water to top up a battery is no problem what so ever.
 
Hi Jim,

For our watermaker we have a special probe to measure conductivity - I think that it is an ion specific probe of some sort. The output from the watermaker is around a Total Dissolved Solids of 300ppm, ISTR. Isn't that a better way than conductivity?

ps your charts were great coming down to the Med and your pilot books are still in regular use! The land masses are remarkably stable round here, it seems.
 
I would expect anything giving a reading of TDS to be simply a conductivity measurement. A conductivity probe would be much more reliable and robust than a specific ion electrode. Ok the conversion factor from cond'y to TDS would depend on the solutes present but if the insrument is intended for use with a watermaker running on seawater then it would be pretty well constant and known by the makers.
I really cannot think of any reason why it would be a specific ion electrode. What ion would you monitor, sodium perhaps, but the conversion to TDS would depend even more on a knowledge of the analysis of the water. In theory, if not in practice, you could have zero sodium but very high Ca and Mg concentrations. That would give a zero TDS figure which would clearly be wrong. A conductivity measurement may well give an inaccurate figure perhaps but never that misleading!

A chloride (silver/silver choride) electrode would be robust enough I suppose but again it would only give meaningfull figures if the ratio of chloride ions to total ions remained constant.
 
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