Your battery energy capacity is

**12**volts x 40 amp-hours, for a total of**480 watt**-hours. Divide this by**50 watts**, and you get 9.6 hours. BUT. This is a car battery, not a deep-discharge marine battery.Similarly one may ask, how many amp hours is a car battery?

A standard small car battery is about

**45**amp/hours. That means that it will supply over two amps for**20**hours. A battery should not be discharged at a higher current draw, or asked to deliver more amps than its amp/hour rating divided by 10 in order to get maximum capacity out of it.1

## How long will a 12 volt battery run a refrigerator?

A very small user of power is a 1.2 watt LED light running on a 12 volt power source will use 1.2W / 12V = 0.1 amps. Therefore a 100ah (amp hour) battery will last for

**1000 hours**. A slightly different example is a 60 watt fridge running on a 12 volt power source uses 60 /12 = 5 amps, but only while the motor runs.2

## Can you get a shock from a car battery?

Your body is just not conductive enough to be fried by 12 volts. Ray: The danger from

**car batteries**is not so much**electrocution**as it is explosion. If**you**touch both terminals with a metal wrench, for instance,**you can**create a spark that**can**ignite hydrogen gas in the**battery**.3

## How long can you run an inverter off a car battery?

If you do not have a deep cycle battery, we recommend that you run the engine of your vehicle when operating the power inverter. When operating the inverter with a deep cycle battery, start the engine every

**30 to 60 minutes**and let it run for**10 minutes**to recharge the battery.4

## How long is a car battery supposed to last?

While a battery that allows a car start at the first turn of the key is a joyful thing, it doesn't last forever. In fact, depending on where you live and how you drive, the condition of your charging system, and a number of other factors, a battery lasts

**about four years**on average.5

## How many amps are in a car battery?

Cca ratings are how many amps the battery can deliver to starter motor if an average car has a capacity of around

**48 amp**hours which means that, fully charged, it delivers 1 for hours, 2**24**8 6 and so on best answer most batteries called 12 volt, although when running, go as high 14 volts.6

## How long does it take to charge a 12 volt car battery?

A car battery usually holds 48 amps so if you take that it charges at approximately 1 amp per hour you can work out how long it will take to charge your battery with various amperage chargers. Charging your battery with a four amp charger will take

**about 12 hours**to get a full charge out of this low amperage.7

## How long does a 200ah battery lasts?

This means that a battery has a 100 A.H. capacity if it is discharged over

**20 hours**, or at about 5 Amps-per-hour (100 A.H. /**20 hours**= 5 Amps DC). However, this same battery would last only**one hour**if the discharge rate was 50 Amps-per-hour (50 Amps DC x**1 hour**= 50 A.H.) because of the high rate of discharge.8

## How many watts does it take to charge a 12 volt battery?

To Calculate how much time You'll need to charge the battery with a

**15 Watt**solar charger You'll need: Calculate the Ampere per hour of the charger:**15 Watts**/12 Volts = 1,25 Amperes. Calculate the division: 50 amp hours / 1,25 ampers = 40 Hours of direct sunlight. Add 10%: 4 hours.9

## How do you calculate battery watt hours?

Multiply these two numbers to get the

**watt**-**hour**rating (Ah × V = Wh). Note: If the capacity of your**battery**is expressed in milliampere**hours**(mAh)—like in the image above— you will need to divide by 1,000 to**calculate**the ampere-**hours**(Ah) before multiplying.10

## How long is a laptop battery supposed to last?

This varies depending on your usage, of course, but

**the**average**laptop battery**is good for around 400 recharges (a.k.a. cycles). After that, it starts to lose its capacity to hold**a**charge. That's why**the battery**that once gave you, say, 3-4 hours' worth of runtime now peters out after just 1-2 hours.11

## How much power does a car use?

If electricity is 12 cents per kWh — the national average — it would cost $3.48 to go 100 miles. Another way to calculate cost is to use the number of kilowatt-hours it takes to recharge the EV's battery. If an EV requires

**20 kWh**to fully recharge and the rate is 12 cents per kWh, that's $2.40 to fill up the car.12

## Do inverters use power?

This is the DC current the

**inverter**will**use**to operate the 1500 watt load. Note – if this 150 amps is drawn from the battery for one hour, 150 amp hours (AH) of battery**power**will be used. Formula: 24 volt**inverters**require approximately one (1) amp of DC input for each 20 watts of AC output.13

## How do you calculate amp hours for a battery?

The key is to use the watts you know to

**calculate**the**amps**at the**battery**voltage . For example, say you want to run a 250 watt 110VAC light bulb from an inverter for 5**hours**.**Amp**-**hours**(at 12 volts) = watt-**hours**/ 12 volts = 1470 / 12 = 122.5**amp**-**hours**.14

## How many volts can be in a taser?

A standard stun gun or cattle prod can only be used at close range; Tasers can shoot someone from 20 feet away. Once the electrodes hit their target, the Taser sends a pulse with about

**50,000 volts**and a few milliamps.15

## How many milliamps is in a car battery?

It is the same concept, they just use milliamps instead of amps for these lighter duty batteries. A typical rating might be 1200 ma/Hr which is the same as 1.2 amp/hour. A standard small car battery is about

**45**amp/hours. That means that it will supply over**two**amps for**20**hours.16

## How many volts does a car alternator put out?

A car alternator needs to be putting out at least 13-

**14 volts**(ideally between**13.8**and**14.2 volts**) to effectively charge a**12 volt**car battery. If the alternator is putting out too much voltage (**15**+ volts), it is likely your battery acid will boil over out of the battery.17

## How many joules are in a car battery?

A Manganese/Alkaline AA cell it rated at about 2.4 amp-hours. If we assume 1.5 volts average this gives approximately

**3.6**watt-hours (slightly optimistic). Since there are**3,600**seconds in an hour this is equivalent to**12,960 Joules**.18

## How many watts are in a Volt?

Using Ohms law, you would multiply amperage times volts to get watts. For instance a 12 volt circuit drawing 2 amps would consume

**24 watts**of power (12*2=**24**). A**60 watt**light bulb powered by 120 volts in a house would draw .5 amp of current (60/120= .5).19

## Are car batteries AC or DC?

A

**car battery**is**DC**. However it is charged by an alternator, which is usually a three-phase**AC**generator. Of course the output of the alternator windings is immediately rectified to**DC**inside the alternator.20

## How many watts is a car alternator?

at a charging voltage of around 14 Volts that yields in

**560**to**770 Watts**. In modern cars alternators have outputs between 70 and 180 Amps! especially when catalytic converter systems with heating elements etc are used. Sometimes alternators are water cooled as well (BMW 150 Amps).