Demineralized vs distilled water for battery

[WaterEnthusiast]

Hi,

As I removed my battery for the winter, I noticed that some of the cells are missing a bit of water (although they are all within the acceptable range).

I read that I need to add distilled water, but could only find demineralized water at the local grocery store/pharmacy. Those are usually used for CPAP machines.

Is demineralized water acceptable to add to my battery?

I know they are *almost* the same, but the difference is not only the method to obtain it... the end result can be (slightly) different. I just don't know if that small difference matters or not for the battery?

Thanks

 

[mikidymac]

No clue honestly as every store here in the States carries distilled water.

It should be fine though if it is all you can find.

 

[Arkie Bob]

ANY water you'd put in your mouth isn't going to hurt your battery.

 

[mikidymac]

ANY water you'd put in your mouth isn't going to hurt your battery.

That isn't true. The minerals in regular tap water is not good for the plates.
Will it kill it, probably not but it will lower the efficiency and life of the battery.

 

[sktn77a]

Demineralized water is fine. Most people just use tap water - not great for the battery but what can you say?!

 

[Sportster-2001-951C-Stock]

What kid/size battery is yours? If the plate tops are covered in the case of a small battery I'd leave it alone. I've noticed watering many large batteries it's easy to overfill them which seems to cause crosscurrents between cells, so be careful and keep it to a minimum (IMO).

Otherwise for the larger wet cells, Trojan makes the best bateries out there IMO, here's a link to their suggestions:
https://www.trojanbattery.com/pdf/WP_EffectOfImpurities_0612.pdf

 

[mikidymac]

What kid/size battery is yours? If the plate tops are covered in the case of a small battery I'd leave it alone. I've noticed watering many large batteries it's easy to overfill them which seems to cause crosscurrents between cells, so be careful and keep it to a minimum (IMO).

Otherwise for the larger wet cells, Trojan makes the best bateries out there IMO, here's a link to their suggestions:
https://www.trojanbattery.com/pdf/WP_EffectOfImpurities_0612.pdf

Be careful of the Trojans as they are not as good as they once were. I have been to quite a few dealers for Trojan that have told me that they were bought out by a larger company and they are not at the same quality as they were years ago and the same for Optima. I have a couple Optima's and Trojans from 2006 that are still working and all the dealers have told me don't expect that kind of life on any of the new ones.

 

[skiasylum]

Deminerlized water is what our northern neighbors call distilled water, they are the same.

 

[WaterEnthusiast]

Actually, no, distilled and demineralized are not the same: The former is made by boiling water and then consending the vapor, so that you are left with only H20. The demineralizing process uses a different technology/process (that is cheaper) to remove mineral from water, but I don't know if the water is "as pure" as distilled (which is 100% pure).

Thanks for the suggestions.

 

[Sportster-2001-951C-Stock]

If it really does need water, I suspect it's toast. At least from my experience.

 

[skiasylum]

Demineralised water is water completely free (or almost) of dissolved minerals as a result of one of the following processes: distillation. deionization. membrane filtration (reverse osmosis or nanofiltration)

Demineralised water is essentially water with its minerals removed. The most common way of achieving this is to pass water through and ion exchange resin which strips the incoming water of its ions (minerals) to produce demineralised water. However modern processes also involve passing the water through activated charcoal filters to strip any organic chemicals from the liquid and also to irradiate the water as it passes through the purification process with ultra-violet light to remove bacteria from the water. The product, Demineralised Water, is suitable for premixing coolant concentrate, use in steam irons and batteries.

 

[Sportster-2001-951C-Stock]

One more thing I want to try to explain based on my experience is if there's enough electrolyte above the plates to draw up and fill a specific gravity test bulb without having to jam the tube into the plates, then I'd be happy with the present level. I typically use the small tester available for a few $ from Wal-Mart but if you are to the point you need to test specific gravity due to lack of performance the battery is usually beyond it's useful life (2~5 years old, depending on capacity).

 

[mkov608]

Enough with the water already. Get a Big Crank AGM battery.

 

[jonniex5]

When filling your battery, regular tap water isn’t going to cut it. Tap water contains minerals that are harmful to batteries, even if added in small amounts. This is particularly true for water softened by water softeners which contain chlorides. To be safe, distilled water is your best bet and is a much smaller investment than a new battery.

Remember, that water will sit on top of the acid solution in your battery until it is mixed by the bubbling produced by charging. If you are taking hydrometer readings of the electrolyte, it’s best to take them after charging is complete.

 

[skiasylum]

Enough with the water already. Get a Big Crank AGM battery.

I thought it was very enlightening to learn that I now can use both distilled and demineralized water in my steam iron.