batteries

Peter

yep....agreed woth you there mate.he just has to put a clean empty plastic bucket to catch the water.

rain water still contains too many minerals

snapper49
mate,i have been using rain water in all my batteries since i can remember.

never ever had a problem with any of them.

My Dad use to collect rain water from a tile roof then have it sit in glass flagons for near 6 months to settle. He then transferred the water over to another clean flagon with a big syringe, making sure not to disturb the contents and leave a good inch in the bottom. And this he used to top up his batteries.
He owned Taxis for twenty odd years or more and Never had a problem with batteries.
I'd hate to guess how many times in a 24 hour period a cab got started, and sometimes the trip was lest then a five minute journey back to the rank, switch off, wait for the next fare, start up again.
Hmmm

rain water comes from the oldest and most respected distillary ever

not quite sure how you imagine it would have significant amounts of minerals

Dunno where the rest of this post went but Rain water is water which has been evaporated by nature and is as pure as distilled water provided you collect it from a clean non metallic source, discarding the first run to ensure that no dust etc is collected.

¨ a Ph level of 0¨??

That would be pure acid, wouldn´t it? Surely you mean a Ph level of 7, which is neutral.

Well, a pH of 0 would have a hydrogen ion concentration of 1 mol/L which would be quite concentrated. This corresponds to a sulphuric acid concentration of 500 mmol/L. What's the concentration of sulphuric acid in a lead-acid battery, Peter?

:-)

Chemistry is complicated...

Charles

Sure. But the OP is talking about topping up his battery, not filling it from empty. Distilled water is hardly likely to have a Ph of 0, eh??


cheers
John

Of course not... Sorry, I wasn't referring to the pH of the water... Moreso how concentrated your H+ ion concentration has to be to cause a pH of 0.

I remember being taught in lower school chemistry that the pH scale went from 1 to 14... That was turned on its head when I studied thermodynamics at university.

The pH of rain water will be slightly lower than 7 - possibly in the range of 6.8 to 6.9 due to the dissolved carbon dioxide and other acids from the atmosphere.

Distilled water, following our previous line of reasoning, will have a pH of -log(1x10^(-7)) which of course is 7. The concentration of H+ in pure water is 1x10^(-7) mol/L due to the dissociation constant of water: [H+].[OH-]=1x10^(-14) for pure distilled water.

Fully agree with you, Happychap! pH is 7, which is much greater than 0! :-)

Charles

Just went and looked at the water container that I still have and checked the label again. It says Ph Neutral, what ever that means. I’m no chemist, and don’t want to be either. So didn’t pick up the error.

Going to the super market is still the best way for the average person to get clean water for radiators, washer bottles and batteries.

Cheers Clive.

your talking about drinking water which still should have moderate amounts of minerals

better way is to go to the cleaning section and around the area which has irong needs will be the proper distilled water

Rain water is not “distilled” water, the only definitions of "distilled water" from various sources are in the theme of:

•Distilled water is water that has virtually all of its impurities removed through distillation.
Distillation involves *boiling the water* and then *condensing* the steam into a clean container.
en.wikipedia

•Water *heated to the boiling* point, vaporized, cooled, condensed, and collected so that no impurities are reintroduced.
www.cdc.gov

•Water that has been *purified* so it contains no mineral deposits.
www.pbs.org

Rain water has never been *purified* or *boiled* etc in it's natural state, I could not find any source that stated rain water is *distilled* in any way.
However if it can be shown rainwater in its natural state is boiled etc, I will accept the information as correct.

Maîneÿ . . .

I cant believe i just read that

of course distilled water is boiled. it is the quickest way to turn water into water vapour

when producing distilled water your not going to wait for natural evaporation are you?

has the same effect though as in water turns into vapour

this is the important part

by your reckoning rain made by sea water would be salty because it hasnt been boiled ROFL


condensing is commonly called clouds - you know the white fluffy things that turn grey and drop

- rain

sure not distilled water by definition myabe but exactly the same thing

Just Mainey having another Brain Snap??

It's not the boiling that makes water distilled, it's the evaporation. Evaporation can happen at minus 200 degrees or 100 degrees. It just happens faster at warmer temperatures and when boiling.

Evaporation is the process of hotter molecules leaving the surface of the water ( steam)

Otherwise you would never get clouds unless the temperature was 100 degrees at the surface.

When they condense it is pure water.

Then if it is rain, it gets dirty on the way down.

The problem with rain water for the battery is what it picks up as it falls or hangs around in clouds. Depending on what is in the air, rain water, no matter how it is collected can contain acids CO, CO2 and assorted other chemicals that are suspended in the air that we breath.

I agree that the natural process of evaporation and condensation is the same as distillation but it is not in a controlled or clean environment (sadly). Therefore the water can not be guaranteed as clean or mineral free, which is what distilled water claims to be.

So as far as I can see the answer to the original question is; yes you can use rain water but it will shorten the life of your battery.

I have used rainwater in batteries, but only in an emergency., If I can possibly get distilled or demineralised water I would.

Duncs

Yep, I agree, hence the need to let the first falls run to waste, that will minimise any dust that comes down with the first bit of rain. The rest of the gaseous contaminants come out of solution very quickly.

The problem is that rain generally has a spec of dust inside it - a nidus for condensation to form around. In most models involving condensation/precipitation, you require a saturated solution and a nidus to form around. This is true of rain as well. It then dissolves gases from the atmosphere in the same manner that evaporation occurs in the first place - a process of equilibrium in a non-closed state system.

I could now write a long follow-up involving thermodynamics and probabilities/statistical analysis, but we have moved so far away from the original topic debating whether rain water can be used in batteries.

Rain water is not pure water - it is filled with dust, and dissolved gases (the most abundant being carbon dioxide due to its great solubility, followed by nitrogen, followed by oxygen in much smaller amounts)

Evaporation is a similar process to boiling, but not the same. When water evaporates, it is because a proportion of the water molecules posses enough kinetic energy to break free of the hydrogen bonds holding the water together as a liquid. They leave in the gaseous state via the surface of the liquid. Boiling is slightly different - it occurs when the AVERAGE kinetic energy of the molecules is greater than the boiling point of water (100 degrees celsius, or 373.15 degrees kelvin at one atmosphere/101.3 kPa/760 mmHg/whichever units you prefer) when molecules throughout the ENTIRETY of the liquid enter the gaseous state - hence the bubbles observed when boiling a billy on a fire. The end result is the same - water in a gaseous state.

Distillation then commonly involves a process whereby the gas is recondensed by a countercurrent heat exchanger in clean laboratory/industrial equipment (where the nidus for recondensation is often a glass surface) and is collected in a container.

I disagree that gaseous contaminants come out of solution quickly. They will come out of solution compared to the concentration at altitude, but only due to the temperature of the water. Liquids lose their ability to dissolve gas as their temperature increases - hence why raising the temperature of a pond by even a degree is a threat to marine life - oxygen loses its solubility in the water. At a given temperature and partial pressure of gas solute, the concentration of dissolved gas is in equilibrium - the gas leaving solution does so at a rate of new gas entering solution. Water sitting on your sink will have carbon dioxide and other gases dissolved at a concentration depending on atmospheric pressure and temperature.

Theoretically, (please if anyone can correct me with thermodynamics, equilibrium, or other principles of applied chemistry, I welcome it) the distilled water added to a battery would contain as much carbon dioxide dissolved (as carbonic acid) as rainwater after it were hypothetically added, and equilibrium allowed to ensue. Although the equilibrium constant would be altered by the presence of the hydrogen ions from the sulfuric acid...

From a semantic point of view, I guess you could argue (once again from a semantic point of view) that rain water has been distilled - distillation is a process by which a solvent is removed from a solute, by conversion to the gaseous state (usually where different boiling points exist). You could, in theory, distill water by evaporation, though as get outmore argued, it would take a long time. In fact, there are well documented and practiced survival techniques involving moist ground and plastic sheets that rely on this technique! (I can fairly easily argue that collecting water in this fashion does not rely on increasing the local temperature to >100 degrees celsius). This could be considered a method of distillation. However, we are dancing around an important point - rain water is not PURE water. It is contaminated, and much more so than "distilled water" as purchased for batteries/ironing/cleaning etc in containers in a grocery shop.

Okay, I'm rabbiting on, and starting to sound like a know-it-all. (Hey, at least I admit it!)

As I mentioned before...

Chemistry is complicated :-)

With respect,
Charles

A couple of things

There is no evidence that rain requires dust to form nuclei to make it rain.

CO2 and Oxygen will both dissolve more readily in cold water. As soon as the water warms up they will bot come out of solution untill as you say equilibrium is reached, of course once put into a battery they will very quickly come out of solution due to the warmth and bubbly of Hydrogen through the solution.

There is no evidence that dissolved gasses in water are detrimental to batteries, it is the dissolved minerals that matter.

Notso, I must respectfully disagree - while I concede that the condensation of water occuring around a nidus may be theory, to my knowledge there have not been any other accepted theories proposed by physicists. In fact, I found a reference from Balkovsky et al. (2001) with the title 'Intermittent Distribution of Inertial Particles in Turbulent Flows' from Physical Review Letters (American Physical Society) where the theoretical effects of dust and wind (the novel part of their theory) is explained. Unfortunately I do not have access to the full text, not having access to my alumni university's library any more.

I would be interested if you could cite an article, research, or theory where this is refuted?

Another article I found, written by Asman et al. all the way back in 1981, determined the concentration of H, NH4, Ca, Mg, K, Na, SO4, NO3, Cl, F, Pb, Fe, Br, Mn, V, and Al in rainwater in the Netherlands in their work, 'Meteorological interpretation of the chemical composition of rain-water at one measuring site'. The concentrations were non-zero.

Furthermore, Root et al. (2004) from Carleton University in Minnesota performed a study on the geographical differences between anion concentrations in rainwater across the United States. There is no reason to suspect that this study would totally lack external validity. They found variable concentrations of chloride, nitrate, and sulphate in practically all samples, with less prevalent concentrations of nitrite and phosphate. Interestingly enough, chloride concentrations were largest in rain forming over bodies of salt water, and lowest over bodies of fresh water in their analysis.

They cite Ayers et al. (2001) in 'Chemical composition of rainwater and anthropogenic influences in the Piracicaba River Basin, Southeast Brazil' from Atmospheric Environment, claiming that during evaporation of water bodies, small quantities of anions and cations (ie: sodium and chloride) travel with the vapour.

I agree with one point - I doubt the dissolved gases would have an effect on batteries. I also agree that they would become less soluable. However, the cells in a serviceable lead acid battery are on tight - forming a closed system. Although your equilibrium constant will change, favouring the gaseous state of the CO2, O2, and N2 (amongst others), in this closed state system the effect will not be nearly as pronounced as in an open state system - a new equilibrium will form.

Now, whether the small concentrations of minerals in rainwater is of any practical application to wet cell chemistry, I'm not certain. Perhaps the concentrations are low enough to be of no detriment. Perhaps they are. It would be difficult to show with any confidence that temporary use of rainwater has any effect on battery life.

The difference between "distilled water" as purchased, and rain water (which as above I agree goes through a process of distillation, is purity. Rain water is not as pure as commercially produced "distilled water".

I'm interested - what is your background? You put together a logical and convincing argument which you form around evidence. A combination of rarity in this forum. :-)

With respect,
Charles

Yes, as I have always stated there will be gasses etc in the water, and as we are talking about "Topping Up" a wet cell battery then obviously the gasses would escape along with the generated gasses from the battery charging.

Re the work from Holland on non 0 findings in rainwater, have you ever seen the effects of "Acid rain" in Europe, not a pretty sight. I haven't seen anything about these effects in Aus yet, but I'm sure if one collected rainwater from over Sydney forinstance, and over Forbes out here in the Central West, there would be minor differences..

Surely if anions and cations travel across with evaporation then the same would occur in the more violent environment of boiling water? I wonder if anyone has ever done this research.

My background is varied, Left home at 14, Water Treatment and laboratory technician for 20 years, then about 33 years doing other more interesting stuff.

Just interested in logical discussion.

An interesting investigation would be the concentration of dissolved gases in wet cell electrolyte. Hydrogen gas would escape the cells/closed state system much more readily than the others, due to its very low density, and small molecular size. Carbon dioxide would be much harder to rid, in theory. I would have thought that no matter how much the battery is heated up, and no matter how much it is used, you will still retain of all of these gases in the electrolyte. This doesn't matter whether "distilled water" or rain water is used. I don't have any experimental evidence to show this though.

Yes, I don't like the idea of acid rain over in Europe. Neither does the paint of my car! :-) The composition will be different, for sure. But our rainwater will still contain anions and cations, and like in the American research, I'd imagine that the concentration of sodium and chloride in our rainwater varies with distance from the coast.

Not sure about the content of "distilled water" - perhaps several distillations are used? Each time the water is distilled, it would decrease the concentration of solutes. I would have imagined an exponential decrease in concentration with serial distillations.

Just performed a wikipedia check - apparently double distillation is the defacto standard for purification of water for laboratory techniques. Also, deionised water is produced differently - through the use of charged membranes to trap ionised particles. Doesn't capture organic non-charged molecules, viruses, or bactaria. So the concentration of ions in the water we usually use for filling batteries should be very low. Should be easy to determine the ionic concentrations with simple analysers or titration, but that would have to be left for someone with access to such equipment.

We can have the "Wikipedia debate" another day, perhaps? :-)

Charles

No room for a bit of common sense eh?


there is potential for rainwater to pick up very small amounts of contaminants depending on atmospheric conditions

but tap water is what contains minerals. This is due to many reasons but mostly due to runoff water collecting minerals and concentrating them at collection points

as i said - use your head theres a good reason rain created from evaporation from sea water isnt salty...........