Battery juice

System

Here's a new one.. A good friend has an interstate car battery 12v Ah unknown at this time, (something very common), but with the date to rely on it is now on its 14th year in working operation transferred from vehicle to vehicle. The catch is he has added distilled white vinegar as needed. An old timer thing. Anyone heard of this. It must keep the plates clean??

westbranch

Re: Battery juice

HMMM....Vinegar = acetic acid at 5- 7%, pH of about 2.4...

"" from Wikidepdia

'So-called "white vinegar" (actually transparent in appearance), or sometimes referred to as spirit vinegar,[3] can be made by oxidizing a distilled alcohol."

"Acetic adids structural formula is represented as CH3COOH. Pure, water-free acetic acid (glacial acetic acid) is a colourless liquid that attracts water from the environment (hygroscopy), and freezes below 16.7°C (62°F) to a colourless crystalline solid. ....

It is considered a weak acid due to the fact that at standard temperature and pressure the dissociated acid exists in equilibrium with the undissociated form in aqueous solutions, in contrast to strong acids, which are fully dissociated.

Sulfuric (or sulphuric) acid, H2SO4, is a strong mineral acid. It is soluble in water at all concentrations. "

Although nearly 100% sulfuric acid can be made, this loses SO3 at the boiling point to produce 98.3% acid. The 98% grade is more stable in storage, and is the usual form of what is described as concentrated sulfuric acid. Other concentrations are used for different purposes. Some common concentrations are

10%, dilute sulfuric acid for laboratory use,
33.5%, battery acid (used in lead-acid batteries), ...."

From the Lead acid battery section... Electrochemistry
Each cell contains (in the charged state) electrodes of lead metal (Pb) and lead (IV) oxide (PbO2) in an electrolyte of about 37% w/w (5.99 Molar) sulfuric acid (H2SO4). In the discharged state both electrodes turn into lead(II) sulfate (PbSO4) and the electrolyte loses its dissolved sulfuric acid and becomes primarily water. Due to the freezing-point depression of water, as the battery discharges and the concentration of sulfuric acid decreases, the electrolyte is more likely to freeze.

The chemical reactions are (charged to discharged):

Anode (oxidation): ' this picture would not copy, sorry... ej'

Cathode (reduction): 'as above comment'
"

Acetic acid has 1 hydroxyl group -OH and suphuric has two hydroxyl groups 2x -OH thus the re;ative 'strength of each acid.

Any chemists out there that can identify a possible chemical interaction between these 2 in a battery?

PS I had a Ford factory issue battery that went 16 years in my F250, entire life in the same vehicle then it went 5 more years as a camper battery on the other side of the engine compartment...??

Cheers,
Eric

GreenerPower

Re: Battery juice

Vinegar, un-usual but it might work. I think this was to mainly reduce the internal resistance for the cranking amp needed to start the engine. People usually use epson salt for this but it has long term effect on the battery life.

With vinegar (acetate acid), the electrolysis process would produce irreversible lead-acetate that doesn't dissolved in the electrolyte (sulfuric acid). The plates are probably "eaten". The amount of lead left probably provides little capacity. You can use a small 150W inverter to run a 100W bulb to decide from full to 50% discharge to see how much capacity left.

If it has been 14 years, use it for something not power demanding as it lasts.

GP

westbranch

Re: Battery juice

had another thought about using vinegar... It would have been a source of 'pure water' if it had been sourced from the distillation method, ie no impurities. probably the most readily available source in the 'old days' for distilled water. Just had a bit of weak acid included.

Eric