Regular AA batteries are always 1.5V for voltage, but rechargeable AA batteries that I have seen are either 1.2V or 1.25V. Why is that? Also what (harm) does the slightly lower voltage do to my devices such as digital cameras, remote controls, wall clocks etc?
So they produce different voltages based on the characteristics of the chemical reaction that produces electricity. Zinc-carbon battery – Also known as a standard carbon battery, zinc-carbon chemistry is used in all inexpensive AA, C and D dry-cell batteries. The electrodes are zinc and carbon, with an acidic paste between them that serves as the electrolyte. Alkaline battery – Alkaline chemistry is used in common Duracell and Energizer batteries, the electrodes are zinc and manganese-oxide, with an alkaline electrolyte. Lithium-iodide battery – Lithium-iodide chemistry is used in pacemakers and hearing aides because of their long life. Lead-acid battery – Lead-acid chemistry is used in automobiles, the electrodes are made of lead and lead-oxide with a strong acidic electrolyte (rechargeable). Nickel-cadmium battery – The electrodes are nickel-hydroxide and cadmium, with potassium-hydroxide as the electrolyte (rechargeable). Nickel-metal hydride battery – This battery is rapidly replacing nickel-cadmium because it does not suffer from the memory effect that nickel-cadmiums do (rechargeable). Lithium-ion battery – With a very good power-to-weight ratio, this is often found in high-end laptop computers and cell phones (rechargeable). Zinc-air battery – This battery is lightweight and rechargeable. Zinc-mercury oxide battery – This is often used in hearing-aids. Silver-zinc battery – This is used in aeronautical applications because the power-to-weight ratio is good.
why are regular AA batteries 1.5V while rechargeable AA batteries are usually 1.2V or 1.25V?
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"Regular" AA batteries use a carbon-Zinc chemistry that generates about 1.5 volts.
"Alkaline" and Ni-cad cells use different chemistry which generates about 1.2 volts.
Lithium-ion cells are again different,t hey generate about 3 volts per cell.
The voltage is no indication of how long the battery lasts or how much power it can deliver. For instance, alkaline cells have a lower voltage than carbon-zinc, but many times the energy.
An old flashlight will be a bit dimmer with 1.2 volt cells. Most newer electronic equipment can compensate.
References :
Comment by Lisha Barta — August 12, 2010 @ 5:34 am
The voltage is determined by the elements that make up the battery. Did you ever see the experiment of sticking a copper wire into one side of a lemon, and a steel wire in the other side? You can measure the voltage between the two just because they are different elements.
http://www.energyquest.ca.gov/projects/lemon.html
Different elements have different natural electrical potentials between them. One common type of non-rechargeable battery is called Alkaline batteries. These are your Duracell and Energizer batteries. They use the natural electrical potential between Zinc and Manganese. There are other combination whose electrical potential is very close to 1.5 volts, like Zinc and Carbon.
Rechargeable batteries are made of elements like Nickel and Cadmium, which has a similar, but slightly lower natural electrical potential. Lithium batteries use the electrical potential between Lithium and a host of other elements like Manganese, Cobalt, and Carbon, and their voltages vary widely.
It is safe to undervolt an electrical device by a little, but it is never safe to overvolt a device. Use the correct batteries for your device.
I hope this helps.
References :
http://www.pc-control.co.uk/battery_types.htm
Comment by Elisabeth — August 12, 2010 @ 5:43 am
The voltage a battery produces is determined by the chemistry. A carbon-zinc battery produces 1.5 volts per cell. An alkaline battery produces 1.5 volts per cell. A NiCd or NiMH battery produces 1.2 volts per cell. A lead acid battery (like in your car) produces 2.0 volts per cell. A lithium battery has several voltages depending on the exact chemicals used. Lithium-copper oxide produces 1.5 volts per cell. Most lithium cells produce from 3.5 to 3.7 volts. A lithium-ion battery can produce from 3.3 to 4.2 volts depending on it’s chemical mix. The size of the cell doesn’t matter, it will produce the voltage due to it’s chemistry not it’s size.
References :
Comment by wires — August 12, 2010 @ 6:30 am
So they produce different voltages based on the characteristics of the chemical reaction that produces electricity. Zinc-carbon battery – Also known as a standard carbon battery, zinc-carbon chemistry is used in all inexpensive AA, C and D dry-cell batteries. The electrodes are zinc and carbon, with an acidic paste between them that serves as the electrolyte. Alkaline battery – Alkaline chemistry is used in common Duracell and Energizer batteries, the electrodes are zinc and manganese-oxide, with an alkaline electrolyte. Lithium-iodide battery – Lithium-iodide chemistry is used in pacemakers and hearing aides because of their long life. Lead-acid battery – Lead-acid chemistry is used in automobiles, the electrodes are made of lead and lead-oxide with a strong acidic electrolyte (rechargeable). Nickel-cadmium battery – The electrodes are nickel-hydroxide and cadmium, with potassium-hydroxide as the electrolyte (rechargeable). Nickel-metal hydride battery – This battery is rapidly replacing nickel-cadmium because it does not suffer from the memory effect that nickel-cadmiums do (rechargeable). Lithium-ion battery – With a very good power-to-weight ratio, this is often found in high-end laptop computers and cell phones (rechargeable). Zinc-air battery – This battery is lightweight and rechargeable. Zinc-mercury oxide battery – This is often used in hearing-aids. Silver-zinc battery – This is used in aeronautical applications because the power-to-weight ratio is good.
References :
http://electronics.howstuffworks.com/battery3.htm
Comment by boss — August 12, 2010 @ 7:03 am