[anupmathur]

Originally Posted by Sudipto-S-Team

Water - once it gets inside the battery doesn't remain water any more. It becomes acid and that acid can indeed harm the balance and first cause damages to the plates inside before causing collateral damages outside.

Sudipto, a battery is initially filled with dilute sulphuric acid and it's specific gravity is maintained within certain specified limits. Adding water only helps to maintain the correct dilution of the acid, which is the electrolyte in the battery!
To say that acid will damage the plates is ludicrous, LOL! The very principle on which a battery functions requires the acid to be present!

[Sudipto-S-Team]

I didn't say acid damages batteries. I said excess acid does.

[R2D2]

Originally Posted by Sudipto-S-Team

I didn't say acid damages batteries. I said excess acid does.

What you call as acid in the battery is actually a mix of water + dilute sulphuric acid. Adding water to the already present electrolyte does not increase the sp. gr. in fact may wind up diluting it a bit by a point or two. A fully charged battery at 27 deg C should read 1.250-1.270 and open circuit voltage @ 12.66v.

Therefore adding water is not like adding acid which is a strict no-no. Adding acid will damage the plates. Adding water does not.

Rgds,

[ascertain]

Originally Posted by rkavthekar

Tata Green is actually manufactured in collaboration with Yuasa, which is pretty known brand.

Let's see how much this one goes for me.

take care and drive safely

hey- hope you have a much better experience with the tata green battery . Mine was not that great an experience- went bust after 1 year.

[Sudipto-S-Team]

Here is a wonderful explanation of the subject
Lead-acid battery - Wikipedia, the free encyclopedia

if you look at the chemical equation given there you will understand how excess h2o can crate a disbalance in the whole thing. Of course this will require some basic understanding of chemical equations.
In the battery industry the acid water mix is loosely called acid and it indeed is acid. I mean it's not water.
Please understand that a manufacturer would love to save even the ten paisa that would be spent on making the top up level mark. They don't spend that money for nothing. So if they are doing it and saying it there has to be a good reason for it.

[anupmathur]

Originally Posted by Sudipto-S-Team

Please understand that a manufacturer would love to save even the ten paisa that would be spent on making the top up level mark. They don't spend that money for nothing. So if they are doing it and saying it there has to be a good reason for it.

IMHO, the good reason is to let conscientious users know where to stop adding make up water.
Nowhere is it said that overfilling with pure water will harm the battery. It will cause spillage which will cause needless secondary damage perhaps, but it will not damage the battery!
Kindly find some other article to prove the point. The wiki article says nothing about it. The equations tell nothing about it.
There is a RANGE of specific gravity that is permitted. Adding excess water might take the acid to the lower end of the range. So what?

[Raccoon]

Now its obvious that what leaks out (when the batt is overfilled) is no longer just water. Acid leaks out and that changes the specific gravity within the cell.

There could be other factors too. Basically, if the upper mark is there, its there for a reason! So it has to be heeded!! And it is very much mentioned in the instructions in manuals/batt cards that the electrolyte is to be maintained between the upper and the lower mark only!

[R2D2]

Originally Posted by anupmathur

IMHO, the good reason is to let conscientious users know where to stop adding make up water.
Nowhere is it said that overfilling with pure water will harm the battery. It will cause spillage which will cause needless secondary damage perhaps, but it will not damage the battery!
Kindly find some other article to prove the point. The wiki article says nothing about it. The equations tell nothing about it.
There is a RANGE of specific gravity that is permitted. Adding excess water might take the acid to the lower end of the range. So what?

Absolutely! The max mark is there to tell us when to stop filling water. Why? So that there is sufficient space between the vent caps and the water level for expansion of the electrolyte and for the hydrogen gas that is produced during use. Adding water doesnt damage the battery only changes the sp.gr by a point or two. But excess water will result in electroyte 'boiling' out of the battery and causing corrosion of the holders/clamps, terminals and any other object that it touches.

Some old enough may recall those hard rubber batteries used in cars back in the 70s and 80s. They had no min and max indicators and were not lo maintenance. All were filled to the brim by default by the trusty neighbourhood mechanic.

The best reading on LA batteries is at Car and Deep Cycle Battery FAQ, Battery Manufacturers and Brand Names List, and. I would urge interested TBHP members to read it.

Rgds,

[mithun]

So, what's the use of the overflow vent in battery ?

[anupmathur]

Originally Posted by mithun

So, what's the use of the overflow vent in battery ?

Mithun, it is not so much an overflow vent as just a vent. The normal batteies in use are the vented ones. The Hydrogen & Oxygen formed in the cells is allowed to escape from the vents.
The maintenance free 'sealed' batteries use a pressure release valve. These are Valve Regulated Lead Acid batteries.

[mithun]

Originally Posted by anupmathur

Mithun, it is not so much an overflow vent as just a vent. The normal batteies in use are the vented ones. The Hydrogen & Oxygen formed in the cells is allowed to escape from the vents.
The maintenance free 'sealed' batteries use a pressure release valve. These are Valve Regulated Lead Acid batteries.

Oops...I thought the vent was meant for water to flow out when the battery was overfilled !

[Narencar]

i think Amaron is the best brand in sealed maintenance free batteries and will last till 4 years.

[ankan]

can anyone please tell if tata battery is any good?? it was installed in our m800 today. this will be the third battery in our car. the first was OEM battery lasted about 3 years then next was an exide battery with 3 years warranty lasted 6+ years( finally died today).

had no option so purchased a tata battery. is it any good?

[SS-Traveller]

Originally Posted by ankan

can anyone please tell if tata battery is any good??

Of course Tata Green batteries are very good. Tata are one of perhaps 3 manufacturers in India who make their own batteries from scratch (the others are Chloride & Amara Raja). Tata batteries are definitely good.

[janitha]

Originally Posted by SS-Traveller

Of course Tata Green batteries are very good. Tata are one of perhaps 3 manufacturers in India who make their own batteries from scratch (the others are Chloride & Amara Raja). Tata batteries are definitely good.

Then, I am wondering why my Tata Vista came equipped with Exide Freedom battery!