# Water Miser Battery Caps



## K.B. (Sep 7, 2012)

Has anyone here used these battery caps?
http://www.ebay.com/itm/Water-Miser-Battery-Caps-/320858054353?_trksid=p2141725.m3641.l6368

While I was checking my battery bank this weekend, I was looking at the gaskets/o-rings on the battery caps and remembered that these water miser caps were designed as a kind of 2-part cap. I like the idea of not having to remove the whole cap each time I check the level. 

The description also claims that the amount of acid fumes are reduced during charging, which I think would also be helpful in avoiding potential corrosion in the battery box connections. 

I have not had to add very much distilled water to my batteries to keep them topped off, but my daily cycle doesn't go below 80%, so I am not charging them very long or intensely to bring them back to full charge. 

I am curious if the water miser caps make it more difficult to see the level of electrolyte in the cell.


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## JeepHammer (May 12, 2015)

The caps you are looking at are simple condensation recovery caps.
Expansion room for the gasses, extended up above the battery top to hopefully be in cooler air to help with condensation.

Some of these caps have a water container the 'Burp' from the battery has to go through that will further remove your electrolyte/moisture before waste gasses are released.

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I'm sure you already know this,
So this is sort of education for people learning...

There is a plastic collar that extends down into the cell,
There is a slot in the side of that collar to vent gasses,
That slot also helps you see the electrolyte level in the battery.

As long as the electrolyte level completely covers the plates you are usually good,
But keeping the electrolyte level up to, or even into the collar gives you 'Reserve' electrolyte in the event you have to deeply discharge/charge the battery.

Most battery 'Watering' systems use a float of some sort in the cap,
Mostly because the float will 'See' mostly water instead of full strength acid mixture.
This is so the acid doesn't attack your watering system as much.

*IF* your battery watering valve reaches DOWN INTO the cell,
Then you can usually rely on the indicator built into the watering system.

I've tried a half dozen watering systems, each one has a weakness.
I've mixed & matched until I got a RELIABLE watering system.

The claims of reduced losses/diluted electrolyte are usually true,
Some 'Burp' the battery gasses through a water bath that recovers the electrolyte,
Then returns the electrolyte to the cell when the cell needs water again.

There are also caps that catch the 'Burp', condense the recoverable electrolyte,
And allow it to drain directly back into the cell.

Both work at varying efficiencies, the water bath seems to work a little better.

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There are a few types of simple floating check 'Ball' valves that I don't care for much...
When the cell is full, the ball floats, blocking incoming water.
This does two things I don't care for,
The first is, the valve leaks allowing the cell to fill completely up.
If you don't have a VERY good seal, it will leak all over the place.

With the ball firmly seated, the cell can't 'Burp', the pressure builds up and the caps blow off the cells and leak all over the place.

If you have the screw in type caps, you can split the cell container/battery case!
Which I don't have to tell you is a real mess and costly!

I would track the fill levels MANUALLY until I built confidence in the watering system.
I have found that keeping the reserve tank on automatic watering systems LOW,
Just above the battery tops, reduces the gravity pressure on the valving and reduces issues.

And like with any flooded battery,
ONLY use distiller water!
You don't need the lime/solids/chlorine contamination in your watering system/cells.


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