Batteries

Difficult. The manufacturers of car batteries have become extremely coy about the performance parameters of their products, probably because they don't want to be forced to meet them by a court.

However, I would suspect that it would be in the vicinity of 30-40 ampere hours. That means that it can deliver 30-40 amps for one hour, so at a voltage of 13.2 volts, that means 396 - 528 watt-hours, ignoring the fact that the voltage decreases as it discharges.

The "Cold cranking" current is a red herring...that is just the current it can supply for a short time, limited by the internal resistance of the battery.

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Battery manufactures have gone to a Reserve Capacity rating which is more realistic than using the Amp-Hour rating. Reserve capacity is the number of minutes that a battery can maintain a useful voltage under a 25 ampere discharge at a temperature of 25 degrees C. To maintain a high RC number a battery requires higher quality cell materials. The RC rating of a BXT-65-650 is 130.

To convert RCR (Reserve Capacity Rating) to Ampere-Hours at the 25 amp rate, multiply RCR by .4167.

In order to determine what size of resistor is required to operate an LED from a 9V battery, first start by knowing the current and voltage required for the LED. That information is available in the LED's specifications.

For discussion purposes, lets assume a typical LED at 2.5V and 50mW. The translates to a forward current of 20mA.

Build a simple series circuit containing a 9V battery, a resistor of an as yet unknown value, and the LED.

By Kirchoff's current law, the current in the LED is the same as the current in the resistor, which is also the same as the current in the battery. This is 20ma.

By Kirchoff's voltage law, the voltage across the LED plus the voltage across the resistor equals the voltage across the battery. This is 6.5V. (9 - 2.5)

By Ohm's law, resistance is voltage divided by current, so the resistor is 6.5 / 0.02, or 325 Ohms. The nearest standard value to that is 330 Ohms.

Cross check the power through the resistor. Power is voltage times current, or 6.5V times 0.02A, or 0.13W. A half watt resistor is more than adequate for this job.

It is an oxidation/reduction reaction. Electrons flow from anode to cathode.

yes Batteries only produce direct currents

There is internal resistance in a battery because a battery is not an ideal voltage source. It may be close, but it is not ideal. As a result, analytically, there will be some series resistance, resistance which places a limit on the maximum current that the battery can provide.

While no battery is ideal, most are sufficiently ideal to not require any consideration of the internal resistance. If your circuit is dependent on the internal resistance of a battery, then it is probably not well suited for that application.

Quite a few differences. Nickel-metal-hydride (ni-mh) batteries:

Charge Faster;

Hold a charge longer;

Have far less 'memory effect';

Last longer;

But are generally more expensive.

Ni-mh batteries are by far the better choice.

Depends on the battery but they are current sources as opposed to voltage sources

Standard AA, AAA, C and D batteries all give 1.5 volts each, but rechargeable NiMH batteries are often 1.2 or 1.25 volts.

you would have to put some type of resistor in the circuit with the motor...the resistor would have to be in series with the motor and would have to be of a high enough value to lower the voltage by 9 volts....There is a formula for working this out but you would need the amperage of the motor to figure this....

http://books.google.co.in/books?id=Y-ruqUWv5UIC&pg=PA157&lpg=PA157&dq=ballistic+galvanometer+leakage+method&source=bl&ots=ZNigwuasnM&sig=KPDIj8E3asAS2xuNjSurDIB3fAA&hl=en&sa=X&ei=6oc8UZ_qIMfPrQf6ooCIDQ&ved=0CD0Q6AEwAw#v=onepage&q=ballistic%20galvanometer%20leakage%20method&f=false

This depends on the actual battery and what it is made of.

A 1.2 volt rechargable NiMh battery typically gives off a voltage of 1.3 to start with, then it rapidly goes down to 1.2 volt where it stays stable until almost empty, then it quickly drops below and down to .5 volt or even further down..

The same applies to Lead Acid or NickelCadmium batteries.

Different types of batteries have different properties.

NickelCadmium normally are able to give a lot of current until empty.

where as the current you get from a NiMh battery is rather limited.

Lead Acid are capable of a very high current but still dependant on the internal design of the battery.

Unfortunately one can not give a correct (for all) answer to a general question.

Regards.

Well firstly, is the capacitor connected to a DC or AC supply.

On a DC supply the capacitor would draw current until it had fully charged, at which point the current falls to the leakage current. Electrolytic capacitor will always leak a little.

On an AC connection, current will pass continuously, and the capacitor may rupture if connected across an AC supply.

The current that would flow on an AC connection is given by the impedance, which is calculated from the reciprocal of 2 x Pi x F x C

Because it is the reciprocal, the impedance reduces as the capacitance in Farads (F) increases. So, the bigger the capacitance, the higher the current.

Therefore, for AC, only low values of capacitor are found connected across the supply (usually with a resistor in series) for interference snubbing across a contact or switch. Larger values are placed in series with the current, to act as current limiters or high pass filters.

read the boring science book

mAh is a measure of the amount of charge stored in a cell or battery (set of cells). One (1) Ah is the equivalent of 1000mAh, and so the statement can be made that a cell with 2000mAh of stored charge can supply a device drawing one (1) mA for 2000 hours -- before needing replacement or recharge.

It also means 1/1000*C/s*3600s.(1 milli= 1/1000, C=Unit for charge, s=seconds) which finally means that a battery rated 1mAh can hold a charge equal to 3.6 coulombs of charge.

yes it does i have done a experiment and energizer last longer that duracell

No. There are losses involved with each stage of the conversion, from DC to AC, and from AC back to DC. The battery running this would gradually discharge. Any other result would constitute a perpetual motion machine which, in this imperfect world, is impossible.

Rather trying to explain all the technology that goes into battery construction, go to Related Links. All your questions will be answered there. AH means Amps Hour every battery has that term stated What it means is so many amps can be supplied for so many hours. Means amps Vs time

Use a multimeter that has both scales on it . All you need to do is change the scale from AC to DC

Yup......But only if u connect them in PARALLEL! Connecting them in parallel (e.g. the positive cap from Battery 1 is connected with the positive cap from battery 2.....the negative cap from battery 1 goes with negative cap from battery 2) adds the amperage (voltage remains the same).......Connecting them in SERIES (as in any flashlight the positive cap of battery 1 goes with the negative cap of battery 2 making a "bigger battery" that has the positive cap from battery 2 and negative cap from battery 1...) adds the voltage (the amperage is the same). Note: Use same batteries either parallel or series connection.

No current flows through the battery.

There is a current through the external circuit. I = E/R = 9/10 = 0.9 amperes.

Transformers rated 1 KVA and larger single phase,3 KVA and larger three phase can be reverse connected without any adverse effects or loss in KVA capacity. The reason for this limitation in KVA size is, the turns ratio is the same as the voltage ratio. On transformers rated below 1 KVA single phase, there is a turns ratio compensation on the low voltage winding. This means the low voltage winding has a greater voltage than the name plate voltage indicates at no load. Terminals on a single wound transformer, primary side are labeled H1,and H2 and on the secondary side X1 and X2. Just reverse the input voltage to the X1 and X2 terminals and the take the load off of the H1 and H2 side.

That would depend on the actual battery's specifications. I've seen some D cells rated as low as ~2000 mAh. However a full true D cell should have a rating between 10,000 mAh and 15,000 mAh.

Unless it's an old vw bug, cars usually run on a 12 volt dc system nowadays.

Motorcycles often run on a 6 volt dc system.

Different systems require different charging voltages so you won't ever be able to charge a 12 volt car battery from a 6 volt motorcycle battery charger as the output voltage would be way too low.

However, if you can set the battery charger's output to give either a 6 or a 12 volt output, then you must always remember to set it to 12 volts if you want to use it to charge a 12 volt car battery.

No, Terminal voltage of a battery can't be zero. For example, if my mobile's battery is at low charge. It is showing only one point of charge on screen, but there will be no fluctuation on its screen, all the other features like audio, video, display will remain same unless it will become fully out of charge. Charge could be zero but the voltage can't be zero.

Well, actually the terminal voltage of a battery can be zero, but only when the battery is totally dead and unable to take a charge (if it was a rechargeable type battery). At this point it must be disposed of.

One exception is wet cell batteries (like lead acid), if the liquid electrolyte is removed the terminal voltage goes to zero but the battery is still good and can be restored to normal operation by refilling it with electrolyte. In fact wet cell batteries are often sold fully charged but with no electrolyte and their terminal voltage is thus zero on the store shelf until the salesman fills them with electrolyte.

That will depend on the internal resistance of the battery.

I = E / R

Where I is the current, E is the open circuit battery voltage, and R is the internal resistance of the battery.