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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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).
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.
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).