RO Water for Batteries???

[WStayton]

Hi, Guys!

  It's me again - with another dumb (or maybe "not so") question!

  Is reverse osmosis water acceptable for use in deep discharge convention flooded cell batteries?

  The reason I ask, is that I already have an RO unit (for a CPAP machine, but that's another story!) and it is capable of something like a gallon of water an hour, though I use more like two gallons a week, right now.

  The specs for this unit say that it removes 99.9% of all disolved materials/salts in the feed water - and it certainly leaves the tank of the CPAP machine spotless - nothing in the present CPAP machine after five years of use, so that would be something like 500 gallons of water through it.

  It's the 0.01% that I am worried about - is that too much, long term, for a deep cycle battery?

  Opinions please!

Regardz,

Wayne Stayton

[Tom Reed]

That sounds adequate for bats. Mine will rain water in a pinch. Mine use 2-3 gal per month.

[WStayton]

Tom:

  I've heard that, despite being free of large molecules (unless you have a lot of pigeons sitting on the roof that is your collector! <grin>) rainwate does have lots of dissolved small molecule in it due to it washing all of the air pollution out of the air - think oxides of nitrogen, etc., etc. and, that because of this dissolved "junk" rain water isn't a great choice for battery watering - though it is vastly superior to what comes out of your tap - unless you have and use a cistern!  <smile>

  Because of that, I THINK that my RO water is better than rain water - but that is just a guess, not known fact.

  Your opinion is appreciated - its always better to talk to somebody who actually waters batteries than to just read the manufacturers directions! <grin>

  FWIW, you mileage may vary . . .

Regardz,

Wayne Stayton

[LowGear]

I've wondered the same thing about RO systems and batteries.  I was raised in the Distilled water or nothing world.  I do know ROs will not remove fluoride but RO water has to be a serous step towards salvation when compared to county water.  My RO system has a particulate and charcoal pre-filter and then a "polishing" post filter to the RO membrane cavity.

Rain water is out here on the Big Island.  Many fish can't even live in it.  Too acid from the volcano venting.

Casey

[WStayton]

LowGear:

  Flouride is pretty low on my list of concerns, since my water will/does come out of a spring on the other end of the property which is about 30-35 ft above the house.  Their isn't much flouride in groundwater in NY, but I am worried about the dissolved salts of calcium . . . If you place a tea kettle in service here for six month, it will look like the inside of the Howe Caverns and the deposits will be a quarter of an inch, at least.

I am not sure how the 0.1% of "stuff" gets by the RO filter and into the water - maybe a very few of the "holes" are bigger than standard?  Their are RO units that gaurantee to remove 99.999 of the stuff in the water, but the price of such units puts them way beyond me!

  My RO unit was a very reasonable solution to the CPAP supply problem, in that is uses water pressure for the driving force so the power consumption is exactly zero and the first cost of the unit was about $125, including the "faucet" to install it at the sink - I figure that I payed for it in a year of use, easy.  So far, it has not required replacement of the RO membrane, which the manufacturer's propaganda says is good for a thousand gallons with appropriate pre-filters to get the undissolved "junk" out of the water - IF it will work for batteries, and it would seem that, so far, everybody thinks that it will, it will be a VERY good investment!  <grin>

  Thanx for the input, guys - it is good to hear that I did something right, for a change!  <smile>

Regardz,

Wayne Stayton

[Thob]

I was looking on the web concerning filters to remove salt, and what I found indicated that RO would remove salt at first, but later in it's life it would no longer remove the salt.  I didn't find any explanation as why; but they suggested that distillation is the only way to reliably remove salts.

I would think that a solar still would be cheap and easy to build and would supply enough water for batteries.  You take a wash tub, or similar, fill it part way with raw water and set it outside.  A smaller collection pot sits in the middle of wash tub, and clear plastic covers the whole thing.  Put a small weight (rock) on the plastic centered over the collection pot.  Water evaporates due to heating, then condenses on the plastic (because the plastic is cooler).  The condensed water will trickle over to the low spot and then drop off into the collection pot.

If you live up north you may have to make enough water in the summer to last all year.

[WStayton]

Thob:

  I had thought about a solar still if RO water doesn't work for batteries, but I was concerned that:

1)  Here in the frozen north, "solar distiled" isn't possible, without pretty sophisticated equipment (read: expensive) for a large part of the year due to water being frozen solid.

2)  Since I will probably need 1 to 2 gallons a week, I would have to have a pretty big solar still to get that production in six month, due to weather/freezing, for the other six (ok, maybe only five!) months.

  I suppose I could use commercial distilled water at $1.20 a gallon for six months and solar distilled for six months and save SOME of the cost . . .

About the degradation with time: 

   This is the first time I've heard that the quality of the water degrades over time, good to know!

  I have heard that the quantity of output degrades over time as some of the pores get clogged by "junk", and that lots of pre-filtering helps that, so I have a "whole house" filter and an iron/metals filter in front of mine, and it has a three stage filter in front of the membrane,  . . . so far (five'ish years) I see no degradation in either quality (as in deposits in the CPAP machine) or quantity (as in how long it take to do five gallons). 

  Also, the estimates for how much water I use are low, since I use five gallons about every six weeks to brew a batch of beer - I use the RO water so I can start with a blank slate and add what I want in it without worrying about what I carred over from the source.

  Maybe I will have to have my RO water tested to see just how much "stuff" is getting through the filter, but I THINK that a new membrane and set of filters is less than the cost of a test, unless I can convince the county to test it as my drinking water, which is something they have been doing for free, since all the bru-ha-ha about gas in the water in PA, six miles away and feeding into the Chemung river whcih runs through the middle of Elmira.

  Thanx for the input guys, it is appreciated!

Regardz,

Wayne Stayton

Regarfdz,

Wayne Stayton