Maximum voltage of batteries

[Segilla]

It was always said that even if you could build a battery as large as Everest, no more than 1.8 volts could be had from it.

The digital camera I bought came with two batteries each marked showing a higher voltage.

Please explain how this can be.

[fo3nix]

"even if you could build a battery as large as Everest, no more than 1.8 volts could be had from it."

when was this said? I don't see how it can be at all true.

[Postdog]

so how do you explain a 12volt car battery?

[scotstone]

A typical dry cell battery is limited to about 1.5volts irrespective of size. A lead-acid cell has an emf of about 2 volts so a car battery of 12V is six of these cells connected in series to give the required voltage output.

[john91]

a 12v car battery is actually 6 single 2v cells in series, a single cell battery whatever the size will only supply about 1.5v - 2 v depending on type, what a battery the size of Everest will do is supply its 2v for a much longer period.

[Toureman]

I wonder how Submarines of several hundred tons worked on only 1.8 volts

[tomtech]

the batteries that you use for ,say, a smoke alarm, they are about the size of a packet of chewing gum and have the male and female connectors both on top, are nine volts. also the wafer thin batteries used in watches or car locking remotes are three volts.

[lightoftruth]

i would assume that submarines would have a generator on board

[heathfield]

Submarines? If they're not nuclear powered, they run submerged on batteries providing 110 volts to the electric motors.

[baileys]

british telecom run their phone lines on a 50 volt supply provided by battery power,not mains

[BillyBB]

Batteries with a higher voltage than 1.5v are just a stack of separate cells in one case. Even tiny camera batteries, partly why they are expensive.

[kempie]

It depends on the chemistry of the battery.

Lithium-ion batteries have a nominal voltage of 3.6 V and a typical charging voltage of 4.2 V

[Catso]

Segilla, when you say battery, you aren't being very specific.

As kempie says, a battery (meaning a single cell) has a nominal voltage, depending upon the technology. Lead-acid would be around 2v, nickel-cadnium 1.2v, lithium 2v etc etc, there's loads of different combinations. The voltage produced depends upon the chemical's characteristics.

Battery is more often taken to mean 'collection of cells' and this is how you get higher voltages. The cells are connected in series and the voltages of each are summed. 12v car battery = 6 x 2v cells in series. Submarines had (have?) hundreds of cells connected together, to make a battery with hundreds of volts. Incidentally, so do many telephone exchanges, even today.

So, Segilla, you're more or less right, in that no matter how physically large a cell was constructed the voltage would never be any different to that determined by the chemistry involved. Lead-acid 2v, etc etc. But a bigger battery would have a bigger storage capability (IE run for longer).

[Space]

I remember reading that the reason why batteries are called "batteries" is that they are usually made of a stack of several cells, to increase the voltage.

[Jay70]

I think people are getting confused between batteries and cells. Cells are combined to create a battery.

[Jay70]

If you combined enough cells to equal the size of Everest and each cell had a potential difference of 1.8 volts between each terminal and they were connected in parallel then the total emf would still be 1.8v but they would be able to supply a total current equal to the sum of I max for each cell multiplied by the total number of cells. If you were drawing the same current for a given load from this BATTERY as was required from the single CELL of same pd then the battery would last much longer as it's capacity has now increased. This is referred to as the Amp Hour (ah) rating.

If the cells were connected in series to form a battery then the total emf would equal the sum of pd's of each cell but the I max would be restricted to the I max for the individual cell.

[aidantraffor]

There is a clue in the word "Battery"
You have one gun, any more becomes a "Battery" yea?
Same with cells!