Batteries -- the old kind.

[flying dog]

And ok, not so much FLYING, but for my car.

 

I'm an old fart and have an OLD battery in my car. The type where you can add water.

 

Recently I was looking and there was a bit of white powder around the top where the clamp is. Corrosion. :(

 

Ok, cleaned it and got rid of the muck.

 

While there, I looked in the 6 cells. The FIRST and LAST were low in water.

 

It has been too long since I did battery physics. Why the end two only?

 

 

[Robbo]

Water Loss, Acid Stratification and Surface Charge - Battery University

[flying dog]

Yeah, but why the end two and not others?

 

 

[nomadpete]

Not all cells age equally. If the end cells have a slightly higher internal resistance than the others, the end cells are receiving more charge than the others, therefore greater water loss. Another factor might be if the end cells are exposed to more heat than the others.

 

 

[Downunder]

More exposed to engine heat and therefore evaporation?

 

 

[flying dog]

Yeah, ok. Got the first part. Nothing is perfect, etc.

 

Kinda remember stuff about internal resistance.

 

But how do you get the end ones getting more heat? If the chemical reactions create heat, wouldn't the middle ones get hotter as they have less external surface area?

 

The end ones have a whole side exposed.

 

Ah, "Downunder" posted while I was typing.

 

Yeah, ok. Fair enough.

 

For a 10 year old battery, I guess it has to die at some stage.

 

 

[Robbo]

There are many reasons why this could be happening, could be as simple as heat evaporation or it could be the current draw the battery is getting, it could even be a dodgy battery.

 

 

[Downunder]

5 years from a factory battery is about normal.

 

A quality replacement might see double that. Depending on operating conditions ( usage/charge/temperatures).

 

 

[flying dog]

Wow, that's news for me.

 

I got 24 out of my first one....... Hang on..... 107-84= close enough.

 

 

[Robbo]

They don't make things like they used to :)

 

 

[flying dog]

Kinda shame - huh?

 

 

[cooperplace]

depends on where you live. We lived in Chicago a long time ago. Despite our Corolla having what looked like a truck battery (standard there), you were lucky to get 3 winters out of a battery. When it's 20 below it's a real strain, starting an engine. And you don't want to break down in a bad part of town, so putting in a new battery just before that 3rd winter was cheap insurance.

 

 

[spacesailor]

I have used a lot of Absorbed-Glass-Mat batteries & find they don't last very long at all, before the Mat has had the electrolyte dried out,

 

used to say it was gravity pulling the water down the cell. The Flooded cell batteries cannot survive being over discharged many times.

 

spacesailor