Many battery manufacturers claim; sealed, no-maintenance batteries. However, on the majority of those you will find 2 vent manifolds beneath the label/sticker... which can be removed to allow the battery to be serviced ...

... why would a battery manufacturer want you to add water to a battery ?

 

Lead-acid batteries must be vented. The batteries produce hydrogen gas when they are being charged. If not allowed to vent, they become very dangerous items.
The battery manufacturers advertise sealed batteries. But they all have a hole in them somewhere. Flip a "sealed" battery upside down and see what dribbles out.

Creek

 

Gel cells and AGMs are truly sealed... they have a diaghragm and a pressure relief valve in case something goes awry.

 

I agree, but note, I stated "lead-acid".

 

I did my research--before I placed extra batteries under by bunk---

new technology Bob: Silver-cadmium batteries were developed FIRST for use by Nasa--- they had a problem--Satallites in orbit were for some reason--getting slighly out of position.. It was discovered:::

As Creek Jackson pointed out above----lead/acid batteries give off--hydrogen gas---this gas was acting as a propellent in space.
Silver-Cadmium batteries use no lead in them--and produce NO HCL gas--
thus require no venting-

Do some research yourself.

also Google "adding tap water to batteries" will result in finding
that this practice ---shortens the life span of a battery--
you either use "distilled water" or you add New electrolite---they sell it at AutoZone.

@creek Jackson---I can turn my Sealed Wet Silver-Cadmium Heavy Duty Truck Battery purchased from Peterbuilt $89.00 several year ago----upside
down or any end---nothing comes out--and the label wore off years ago...no holes now how is this possible?

You have to take University Chemistry -----
lead-acid battery:
contains sulfric acid & water--- which is what makes up the electrolite
they are vented because they gas which is correct.
the flaw in What Happens to the "water level" is the problem.
It doesn't evaporate-----the O atoms ionize to the lead plate--
which then leaves the H2-free as a gas atom= hyrogen gas!
________________________________________________
silver cadmium battery doesn't have lead plates-
the O atoms don't ionize to them---no gas discharge-- hence no venting needed.
__________________________________________________ ____
back to the lead-acid battery:

tap water???
contains????

usually--clorine
now when you add tap water to a battery:
you introduce a new gas discharge along with the explosive Hydrogen gas
you also discharge clorine gas
SEE: WWI( clorine gas is also called Mustard Gas and killed many soldiers during WWI
__________________________________________________ ________
Submarines Use Batteries
Submarines carry people that don't want to be gassed with mustard gas.
The Navy never used Tap water in it's batteries-wonder why?
___________________________________________
During WWI & WWII--subs had to surface to vent the hydrogen gas.
When the Navy head about Nasa's little problem with Orbital wobble--caused by gas discharged from the batteries---and that the Brains
at Nasa were now going to try to Engineer a solution----
they said---Hey, we sure could use whatever you come up with too

Now Subs can stay down longer.

 

Sorry for my hasty assumption that silver-cadmiums were just standard low- or no-maintenance batteries like most of us use.

I had no idea you had acquired your truck batteries from NASA… my bad.

 

Well, I tried to do some research.

I googled;

Sealed Wet Silver-Cadmium Heavy Duty Truck Battery

Nothing. Not one single application of a silver-cadium battery in an automotive type use.

I don't know what to tell you except that you must have some pretty special batteries.

Creek

 

bob,--I got my silver-cadmium batteries at Peterbuilt

NASA and the space program has been responsible for many technological advancements....

yeah, I even get my TANG from NASA as well..

google---- Nasa spinoffs & space benefits it's not a complete list


Imagine what kinds of technology we could develop, with a goal & the will to dream about doing the impossible--

 

I've found that adding electrolyte to an old battery is a good and fast way to have to replace it.

 

yeah, I found that one too...problem is .....you can find another site --which
states correctly- that adding straight sulfuric acid--does that instead.

they you can find a site that tells how to "test" the PH? of the electrolyte/acid- and level//go to this table- and figure how much surfuric acid to mix with distilled water---to properly replace the electrolyte to manufacture spec.

then there's the quick trip to the parts store and find the 60/40 preblended--the 60 being the water--- to refill real quick.----

or hell, just use tap-water.
did you find where they recommend distilled water?

I just checked batteries at Bozzleman's-
they have all the "low maintance" batteries--with vents & caps on top....
man has the price tag gone up. $120.99 for a battery.
there are:

Nickle-Cadmium
Silver-Zinc
batteries too---both produce different chemical reactions.