Filtered vs distilled water in lead acid battery

[Circlotron]

Not that you have to top up car batteries very much nowadays, but if you do then distilled water is recommended rather that straight tap water with all its impurities. What about tap water that has been through a domestic 2-stage filter? Might that be nearly as good as distilled water?

[T3sl4co1l]

What's the filter going to catch?

It better be a goddamned good filter, to do anything at all (aka reverse osmosis)!

Tim

[helius]

I have a filter that is advertised to remove particulates, cysts, and VOCs.
It does not remove dissolved salts (ions), which are what cause problems for batteries.

[Mr. Scram]

Some filters put out what's effectively the same as distilled water, but it really depends on the equipment.

[beanflying]

Water Science is a black art but some basics.

Domestic Filtration will take out some nasties including some tastes and taints but not generally minerals or TDS. So DON'T use it on batteries, the minerals and remaining chemicals will react with the acids and plate chemistry.

R/O or reverse osmosis will remove a lot more of the TDS, minerals and tiny particulates and these are generally preceeded by filtration similar to domestic filtration. Depending on the source water R/O can be to pure to drink and is actually re mineralised and ph corrected for human consumption in some cases. R/O will get you between 10-100 ppm on even the worst water. Potentially usable in batteries but a little more post treatment would be in order generally.

De Min or De Ionised waters are nearly pure to under a couple of PPM maximum and a lot lower for lab water supplies. It can corrode stainless steel and destroys copper and some brasses very quickly as well. This is the stuff that goes in batteries and not into humans 

50PPM for making Espresso Coffee
100-200 for making Brewed Coffee, Beer or Tea (if you really must).

[james_s]

I strongly suspect that the biggest difference between a car battery that lasts 2 years and one that lasts 10+ years is the purity of the materials and electrolyte. Seems prudent to just use distilled water if you have to top one up, it's not like it's expensive or has to be done particularly often.

[nanofrog]

Seems prudent to just use distilled water if you have to top one up, it's not like it's expensive or has to be done particularly often.

Winner, winner, chicken dinner (IMHO of course).

[Red Squirrel]

Domestic filters arn't designed to take away all the minerals as some of them are beneficial for you to drink.  So the water that comes out will still have some minerals in it.    You want the purest water within possible means.  I just buy distilled water at the grocery store.  I assume it's good enough. 

[Doctorandus_P]

"Distilled" water is not what it used to be.
If you go to a grocery store / super market and buy "distilled" water ( sold for ironing clothes and such) and you read the fine print, you will very likely see it is "de-mineralized".
This very likely means it's pushed through a reverse-osmosis filter or similar.
Distilling the water is too expensive with no extra benefits.

So what do you mean by "filtered" water?
What kind of filter?

[tautech]

Put a bucket outside on a wet night and decant it into some storage bottles marked, you guessed it; battery water !

[beanflying]

"Distilled" water is not what it used to be.
If you go to a grocery store / super market and buy "distilled" water ( sold for ironing clothes and such) and you read the fine print, you will very likely see it is "de-mineralized".
This very likely means it's pushed through a reverse-osmosis filter or similar.
Distilling the water is too expensive with no extra benefits.

So what do you mean by "filtered" water?
What kind of filter?

De Mineralised isn't R/O in the Scientific meaning it is only Mineral Reduced. For it to be regarded as DeMin normally a secondary process is then carried out on it to remove more of the minerals.

Distilled water and Demin Water are 'generally' closer in chemistry so your bottle is maybe just distilled as it is a simple one step process.

The biggest issue here is the snake oil filter and water supply companies out there with their 'far infrared' and 'magnetic' filtration technologies taking water filtration back to pseudo science. 

Unless there is data on process, ppm, tds, ph and proper chemical analysis you are still most likely being fed BS.

Put a bucket outside on a wet night and decant it into some storage bottles marked, you guessed it; battery water !

In Gods country removed from most of the pollutants you could do worse I used to live about 100m off the Southern Ocean so a little more mineral in the form of Salt than good for batteries

[Red Squirrel]

"Distilled" water is not what it used to be.
If you go to a grocery store / super market and buy "distilled" water ( sold for ironing clothes and such) and you read the fine print, you will very likely see it is "de-mineralized".
This very likely means it's pushed through a reverse-osmosis filter or similar.
Distilling the water is too expensive with no extra benefits.

So what do you mean by "filtered" water?
What kind of filter?

Wait are you saying there could still be stuff left in it?  Is there a way to test this?  How would I go about making my own distilled water, is it safe to just boil water and collect the steam or will there still be other particles in that like dust?   I didn't realize I was slowly killing my batteries by using distilled water from the grocery store.

[GerryBags]

"Distilled" water is not what it used to be.
If you go to a grocery store / super market and buy "distilled" water ( sold for ironing clothes and such) and you read the fine print, you will very likely see it is "de-mineralized".
This very likely means it's pushed through a reverse-osmosis filter or similar.
Distilling the water is too expensive with no extra benefits.

So what do you mean by "filtered" water?
What kind of filter?

You can test the purity of water with an EC meter, it measures electrical conductivity and gives results in ppm that indicate how much stuff that's not water is there. As I'm sure you know, pure water isn't conductive. They (the meters) are commonly used by hydroponic growers to monitor how much nutrient they are adding and are fairly cheap <$50 I think.

Wait are you saying there could still be stuff left in it?  Is there a way to test this?  How would I go about making my own distilled water, is it safe to just boil water and collect the steam or will there still be other particles in that like dust?   I didn't realize I was slowly killing my batteries by using distilled water from the grocery store.

[IanB]

Wait are you saying there could still be stuff left in it?  Is there a way to test this?  How would I go about making my own distilled water, is it safe to just boil water and collect the steam or will there still be other particles in that like dust?   I didn't realize I was slowly killing my batteries by using distilled water from the grocery store.

Probably not very much.

One way to test is to evaporate some of it to dryness on a glass plate or dish. If you do this with tap water you will probably see a significant white residue left behind. If you do it with distilled water you should see no residue and no murky film left behind on the glass.

De-ionized water is industrially made by passing the water through ion exchange beds, but I doubt they can do this and have a potable, food grade product for sale on a supermarket shelf. So I suspect the supermarket product is really made by distillation as it says on the label, or perhaps by RO.

[IanMacdonald]

It's the minerals (salts) that matter. Water that's been through a proper ion exchange column is acceptable. Domestic filters, no. 

[nctnico]

Some filters put out what's effectively the same as distilled water, but it really depends on the equipment.

Unless these are industrial filters I strongly doubt that. Drinking water needs to contain a certain amount of salts and other 'contaminants' otherwise too much salt will dissolve in it causing cell membrane damage. Drinking distilled water isn't healthy and the lethal dose is much smaller compared to regular 'drinking water'.

[beanflying]

Probably not very much.

One way to test is to evaporate some of it to dryness on a glass plate or dish. If you do this with tap water you will probably see a significant white residue left behind. If you do it with distilled water you should see no residue and no murky film left behind on the glass.

De-ionized water is industrially made by passing the water through ion exchange beds, but I doubt they can do this and have a potable, food grade product for sale on a supermarket shelf. So I suspect the supermarket product is really made by distillation as it says on the label, or perhaps by RO.

R/O is NOT De Mineralised! This is a BS internet MYTH

De Ionised water as you state is the sort of 'secondary' step I was talking about post an R/O process this typically gets water under 1-2ppm (effectively demineralised) and is acidic and not fit for human consumption (large doses will kill you).

However a resin bed (ion exchange) after rough filtering will yield much higher ppm counts if not fed R/O as a pre filter.

Ion exchange filtration is done post basic/carbon filtration in the coffee industry in particular to obtain water stripped of most minerals but leaving the ph balance and ppm levels safe for human consumption generally levels around 50ppm are the point aimed for. ** No Good for Batteries but fine for humans.

[JohnnyMalaria]

Drinking distilled water isn't healthy and the lethal dose is much smaller compared to regular 'drinking water'.

That's utter nonsense. There's so much FUD about distilled water on the web with nearly all of it from people who know NOTHING about the science but are out to make money on thoroughly debunked BS.  All this crap about corroding your arteries and organs. I mean, think about it.

Anyway - OP, just go to the grocery store, buy a gallon of distilled water (which is usually listed as ozonated, too, but it doesn't matter). It will not have any detectable minerals. Put it in your battery and use the rest to make a decent cup of tea or other drink. If you are worried, take a multivitamin first. Not that it's necessary. Even mineral water provides only a minor contribution to the daily requirement of minerals (here). The majority comes from food.

[T3sl4co1l]

De Ionised water as you state is the sort of 'secondary' step I was talking about post an R/O process this typically gets water under 1-2ppm (effectively demineralised) and is acidic and not fit for human consumption (large doses will kill you).

Yeah, it's deadly stuff.  Reacts violently with n-butyl lithium!  Even so, people are so careless around the stuff!  DHMO kills so many thousands each year.  (Millions?)

Tim

[JohnnyMalaria]

De Ionised water as you state is the sort of 'secondary' step I was talking about post an R/O process this typically gets water under 1-2ppm (effectively demineralised) and is acidic and not fit for human consumption (large doses will kill you).

That's because all water exposed to the atmosphere will quickly dissolve CO₂ eventually giving a pH of ~5.6. The acid in your gut (HCl) is at pH 1. That's a factor of approx. a million greater than the water with the CO₂. Yet we survive for decades with all that high acid sloshing around.

[beanflying]

Except that several liters a day of de ionised water will increase the stripping of useful minerals from the body and may in some cases cause health issues. This is not pseudo science but is a fact!

[IanB]

Except that several liters a day of de ionised water will increase the stripping of useful minerals from the body and may in some cases cause health issues. This is not pseudo science but is a fact!

Absolutely it is a fact! Drinking several liters of water a day is bad for your health. Drinking several gallons of water a day might even kill you. I think most health professionals will agree upon that 

[T3sl4co1l]

I forget how much dietary mineral comes from hard water, though I recall it's a not insignificant amount in areas with hard water (which includes plenty of calcium and magnesium in my area, incidentally).

If you're not getting enough minerals in your diet, because of what water you drink, that's your problem; easily solved with a multivitamin if nothing else, but a more varied diet should do just as well.

Tim

[JohnnyMalaria]

Except that several liters a day of de ionised water will increase the stripping of useful minerals from the body and may in some cases cause health issues. This is not pseudo science but is a fact!

Absolutely it is a fact! Drinking several liters of water a day is bad for your health. Drinking several gallons of water a day might even kill you. I think most health professionals will agree upon that 

Yes, that is a fact. Drinking several gallons of water a day WILL kill you - distilled or not.

A proper diet contains enough minerals such that drinking distilled water will have no ill effects. If you eat a poor diet then, yes, it could lead to problems. Look at that paper I linked to - drinking tap water provides only a fraction of minerals your body gets everyday.

I'm sorry but all this "distilled water will kill you" shit is exactly that. Unless you have a dreadful diet and that's what will kill you.

And don't get me going on that high pH water fad    I can't believe people waste their money on it. They are literally pissing it away.

[IanB]

Some people live in areas with soft water, with barely any dissolved minerals at all. I always notice this when vacationing in such places as the soap becomes so slippery it won't rinse off at all no matter how hard you try. Basically what comes out of the taps (faucets) is rainwater (aka distilled water)...

[gildasd]

On the ship i’m on, we have a water plant.
It produces fresh water from sea water with waste heat and vaccum.
It is effectively distilled water that must go through a couple of processes to be human drinkable.
The raw untreated water is called “technical water” and is used for many critical ends such as engine cooling or oily water detector flushing.
But that is not sufficient for battery top up, we have a 25L container of distilled water for that.

[tautech]

Some people live in areas with soft water, with barely any dissolved minerals at all. I always notice this when vacationing in such places as the soap becomes so slippery it won't rinse off at all no matter how hard you try. Basically what comes out of the taps (faucets) is rainwater (aka distilled water)...

It is, but mostly stored on concrete tanks, passed through metal housing pumps, through various metal fittings in the plumbing network, maybe through a hot water cylinder and then finally through a metal tap after which it's gained a good selection of metal ions and salts, not to mention some organic matters from the guttering along with a possible splattering of guano.
All mainly harmless. 

Must be why visitors say the tea and coffee tastes different here. 

[gildasd]

Some people live in areas with soft water, with barely any dissolved minerals at all. I always notice this when vacationing in such places as the soap becomes so slippery it won't rinse off at all no matter how hard you try. Basically what comes out of the taps (faucets) is rainwater (aka distilled water)...

It is, but mostly stored on concrete tanks, passed through metal housing pumps, through various metal fittings in the plumbing network, maybe through a hot water cylinder and then finally through a metal tap after which it's gained a good selection of metal ions and salts, not to mention some organic matters from the guttering along with a possible splattering of guano.
All mainly harmless. 

Must be why visitors say the tea and coffee tastes different here. 

Nonono, the taste is due to it being upside down.

[Red Squirrel]

Actually without using a special meter suppose you can just do an ohm test to check too.  I'll have to check the distilled water I buy and see how good it really is.

We actually have a distiller system here at work they use for the batteries in the battery room, so I can always take some water from there too.

[SeanB]

I have a ion exchange bed at home, removed from service, and it is capable of producing really low dissolved ion water at low flow rates, abut does not remove any particulates ( the 0.3micrometer filter before it does that) or chlorine or other dissolved gases, which is done with activated charcoal filters after it. Good enough to use in batteries, I use it for the fish instead as it solves the needing to decholrinate the water. It gets down to around 0.1uS on the conductivity meter or better.

Soft water area, though with the kilometers of old asbestos cement pipe, old Victorian era cast iron, half century old concrete and steel tankage at the water treatment plants, along with the copper pipe and then the HDPE and polypropylene pipe in the ground and leading to the tap, along with the obligatory soldered connections and brass and cast fittings used, means there is a pretty high amount of ferric chloride added in plant to keep corrosion down.

The sediment filters go brown after around a day of regular water use, so just putting them in your water would be a good idea, especially if you live in NY, with the water treatment being essentially a big screen to remove pebbles, and there being a viable ecosystem living in the whole system, including small cocepod shrimp.  Resin is expensive, but the filters are cheap. Buy industrial housings and filters instead of the overpriced ones sold for home use. The filters and housings, while unbranded, are the same ones sold in the big box store, and a lot cheaper, plus the store ones are 10micron only, while off the shelf industrial ones go down to 0.3 micron

[rdl]

Two years ago when I was experimenting in hydroponics I tested a lot of the different brands and types of water from the grocery store. As I recall there was a fairly large range in TDS, basically between nearly zero and close to 100ppm. The distilled water I use says steam distilled on the label. It even identifies the source. I'd definitely use actual distilled in a battery. It's not that expensive. I keep a gallon or so around at all times mostly for cleaning purposes.

[JohnnyMalaria]

I have this:

https://mypurewater.com/shop/mini-classic-ct-distiller/

I've probably generated about 500 gallons so far. I use deionized water as the input which I get for 39 cents a gallon. It's used for drinking and for my lab.

I started with one of those cheap POS off eBay that look like coffee jugs. I used it twice. The output water stank of toluene.

[Fungus]

Put a bucket outside on a wet night and decant it into some storage bottles marked, you guessed it; battery water !

So what was all that acid rain worry about then?

I'm sure acid won't affect a battery but I also heard that water might contain dissolved CO2? I might even I have a can of some high-CO2 water somewhere in the fridge.

[Electro Detective]

The first downpour of rain will have loads of local airborne crap coming down with it

If you want the real deal distilled water from Heaven Breweries, start catching it later, preferably with no wind

Drink and be merry, and your car battery won't complain,

unless you fill it to the top 

[T3sl4co1l]

Acid rain is sulfuric actually, not a problem. CO2 dissolved is at saturation, same as any other water exposed to air for a while.  Even if it bubbles up later, batteries are vented for obvious(?) reasons.

As mentioned, the salts, dirt, minerals and organics floating around fresh rainwater make it not the most pure resource, but the middles (a proper distillation term!) will be better, yes.

Tim