Watts To Amps Converter Calculator (With 1 Amp = Watts Examples)

Example: A 1500 watt heater is running on a standard 120V. How many amops does it draw? Exactly 12.5 amps.

How to find amperage or amps from watts?

To convert electrical power to electrical current (Watts to Amps), we need to use the electrical power equation:

P = I × V or Watts = Amps × Volts


  • P is electrical power, measured in Watts (W).
  • I is electrical current or amperage, measured in Amps (A).
  • V is electrical potential or voltage, measured in Volts (V). The standard voltage for most electrical devices is 110-120V, and upgraded voltage powerful electric devices use 220V or 240V. Batteries run at 12V or 24V.

Using this equation, we can convert watts directly to amps, if we know the voltage. The higher the wattage, the lower the amps will be for the same amount of watts.


  • 1 amp is equal to 220 watts at 220V voltage.
  • 1 amp is equal to 110 watts at 110V voltage.
  • 1 amp is equal to 120 watts at 120V voltage.

To help you out, we have prepared an easy-to-use Watts To Amps calculator. Below the calculator, you will find examples of how to make the conversion and 5 calculated tables of watts to amps as 12V, 24V, 120V, 220V, and 240V.

watts to amps conversion
In this article.

Watts To Amps Calculator (W to A)

Here you can easily convert watts to amps using this calculator. You can play around with numbers a bit as well:


To demonstrate how watts can be converted to amps, we solved a few examples of how many amps is 500 watts, 1000 watts, and 3000 watts. In the end, you will also find a watts-to-amps table at 120V electric potential.

You can check our detailed post about 1500 watts to amps here as well.

Here’s a quick useful piece of info:

How many watts make an amp?

At 120V, 120 watts make 1 amp. That means that 1 amp = 120 watts.

How many watts in 1 amp at 220 volts?

At 220V, you get 220W per 1 amp.

With that in mind, let’s look at the 3 examples:

Example 1: How Many Amps Is 500 Watts?

Let’s say we have a 500W air conditioner plug into 120 V voltage.

Here is how we can calculate how many amps is 500W:

I = P/V

If we input the P = 500 Watts and V = 120 Volts, we get:

I = 500 Watts/120 Volt = 4.17 Amps

In short, 500 Watts equals 4.17 Amps.

What if the voltage would be 220V?

Let’s calculate how many amps is 500W at 220V:

I = 500 Watts/220 Volt = 2.27 Amps

At 220V, 500W draws 2.27 amps.

Example 2: How Many Amps Is 1000 Watts?

If we repeat the exercise and ask ourselves how many Amps equals 1000 Watts, we get:

I = 1000 Watts/120 Volt = 8.33 Amps

We see that a 1000 W device draws twice as many Amps as a 500 W device.

For 220V, we get this watts to amps calculation:

I = 1000 Watts/220 Volt = 4.55 Amps

In short, 1000W draws 8.33 amps at 120V, and 4.55 amps at 220V.

Example 3: 3000 Watts Equals How Many Amps?

3000 Watt devices can be plugin into 120V or into 220V. In cases with higher wattage, it’s not unusual to use a higher 220 voltage. This is designed to reduce the amperage.

For example, 3000 Watt equals to:

  • 25 Amps, if you use 120 V.
  • 13.64 Amps, if you use 220 V.

For 25 Amps, for example, you would already need an amp breaker. But if you plug such a device into 220 V, the current generated is only 13.64 Amps (there is no need for amp breakers).

Example: Bigger multi-zone mini-split units usually need amp breakers. You can check 2-zone, 3-zone, 4-zone, and 5-zone mini-split systems to see how many amps they run on.

Watts To Amps At 12V (For Batteries)

Watts: Amps (at 12V):
1 Watt to amps at 12V: 83 mA (milliamps)
10 Watts to amps at 12V: 830 mA
50 Watts to amps at 12V: 4.17 Amps
100 Watts to amps at 12V: 8.33 Amps
200 Watts to amps at 12V: 16.67 Amps
300 Watts to amps at 12V: 25.00 Amps
400 Watts to amps at 12V: 33.3 Amps
500 Watts to amps at 12V: 41.7 Amps
600 Watts to amps at 12V: 50.0 Amps
700 Watts to amps at 12V: 58.3 Amps
800 Watts to amps at 12V: 66.7 Amps
900 Watts to amps at 12V: 75.0 Amps
1000 Watts to amps at 12V: 83.3 Amps
1100 Watts to amps at 12V: 91.7 Amps
1200 Watts to amps at 12V: 100.0 Amps
1300 Watts to amps at 12V: 108.3 Amps
1400 Watts to amps at 12V: 116.7 Amps
1500 Watts to amps at 12V: 121.7 Amps
1800 Watts to amps at 12V: 150.0 Amps
2000 Watts to amps at 12V: 166.7 Amps
2500 Watts to amps at 12V: 208.3 Amps
3000 Watts to amps at 12V: 250.0 Amps

One good example where you need to calculate the amps from watts is 12V wire sizing. If you want to pick the correct size wire for the 12V circuit, you have to know the minimum ampacity you need from your wire. You can check how to correctly calculate a 12V wire size here.

Watts To Amps At 24V (For Batteries)

Watts: Amps (at 24V):
1 Watt to amps at 24V: 42 mA (milliamps)
10 Watts to amps at 24V: 420 mA
50 Watts to amps at 24V: 2.08 Amps
100 Watts to amps at 24V: 4.17 Amps
200 Watts to amps at 24V: 8.33 Amps
300 Watts to amps at 24V: 12.50 Amps
400 Watts to amps at 24V: 16.67 Amps
500 Watts to amps at 24V: 20.83 Amps
600 Watts to amps at 24V: 25.00 Amps
700 Watts to amps at 24V: 29.17 Amps
800 Watts to amps at 24V: 33.33 Amps
900 Watts to amps at 24V: 37.50 Amps
1000 Watts to amps at 24V: 41.67 Amps
1100 Watts to amps at 24V: 45.83 Amps
1200 Watts to amps at 24V: 50.00 Amps
1300 Watts to amps at 24V: 54.17 Amps
1400 Watts to amps at 24V: 58.33 Amps
1500 Watts to amps at 24V: 62.50 Amps
1800 Watts to amps at 24V: 75.00 Amps
2000 Watts to amps at 24V: 83.33 Amps
2500 Watts to amps at 24V: 104.17 Amps
3000 Watts to amps at 24V: 125.00 Amps

Watts To Amps At 120V (Standard Outlet)

Watts: Amps (at 120V):
100 Watts to amps at 120V: 0.83 Amps
200 Watts to amps at 120V: 1.67 Amps
300 Watts to amps at 120V: 2.50 Amps
400 Watts to amps at 120V: 3.33 Amps
500 Watts to amps at 120V: 4.17 Amps
600 Watts to amps at 120V: 5.00 Amps
700 Watts to amps at 120V: 5.83 Amps
800 Watts to amps at 120V: 6.67 Amps
900 Watts to amps at 120V: 7.50 Amps
1000 Watts to amps at 120V: 8.33 Amps
1100 Watts to amps at 120V: 9.17 Amps
1200 Watts to amps at 120V: 10.00 Amps
1300 Watts to amps at 120V: 10.83 Amps
1400 Watts to amps at 120V: 11.67 Amps
1500 Watts to amps at 120V: 12.50 Amps
1800 Watts to amps at 120V: 15.00 Amps
2000 Watts to amps at 120V: 16.67 Amps
2500 Watts to amps at 120V: 20.83 Amps
3000 Watts to amps at 120V: 25.00 Amps

Example: How many amps is 1500 watts at 120V? Simply consult the chart: There are 12.5 amps in 1500 watts (at 120V voltage).

Watts To Amps At 220V (220V Outlet)

Watts: Amps (at 220V):
100 Watts to amps at 220 volts: 0.45 Amps
200 Watts to amps at 220 volts: 0.91 Amps
300 Watts to amps at 220 volts: 1.36 Amps
400 Watts to amps at 220 volts: 1.82 Amps
500 Watts to amps at 220 volts: 2.27 Amps
600 Watts to amps at 220 volts: 2.73 Amps
700 Watts to amps at 220 volts: 3.18 Amps
800 Watts to amps at 220 volts: 3.64 Amps
900 Watts to amps at 220 volts: 4.09 Amps
1000 Watts to amps at 220 volts: 4.55 Amps
1100 Watts to amps at 220 volts: 5.00 Amps
1200 Watts to amps at 220 volts: 5.45 Amps
1300 Watts to amps at 220 volts: 5.91 Amps
1400 Watts to amps at 220 volts: 6.36 Amps
1500 Watts to amps at 220 volts: 6.82 Amps
1800 Watts to amps at 220 volts: 8.18 Amps
2000 Watts to amps at 220 volts: 9.09 Amps
2500 Watts to amps at 220 volts: 11.36 Amps
3000 Watts to amps at 220 volts: 13.64 Amps

Example: In many cases, you need to convert watts to amps if you are looking to find an adequate size wire for AC. You can look at examples of how this is done by checking the air conditioner wire size calculator here and the AC breaker size chart here.

Watts To Amps At 240V (240V Outlet)

Watts: Amps (at 240V):
100 Watts to amps at 240V: 0.42 Amps
200 Watts to amps at 240V: 0.83 Amps
300 Watts to amps at 240V: 1.25 Amps
400 Watts to amps at 240V: 1.67 Amps
500 Watts to amps at 240V: 2.08 Amps
600 Watts to amps at 240V: 2.50 Amps
700 Watts to amps at 240V: 2.92 Amps
800 Watts to amps at 240V: 3.33 Amps
900 Watts to amps at 240V: 3.75 Amps
1000 Watts to amps at 240V: 4.17 Amps
1100 Watts to amps at 240V: 4.58 Amps
1200 Watts to amps at 240V: 5.00 Amps
1300 Watts to amps at 240V: 5.42 Amps
1400 Watts to amps at 240V: 5.83 Amps
1500 Watts to amps at 240V: 6.25 Amps
1800 Watts to amps at 240V: 7.50 Amps
2000 Watts to amps at 240V: 8.33 Amps
2500 Watts to amps at 240V: 10.42 Amps
3000 Watts to amps at 240V: 12.50 Amps

If you have a specific question about how to convert Watts to Amps, you can use the comment section below, and we’ll try to help you out.

Note: Figuring out watts to amps can help you, for example, to calculate how long does it take to charge a Tesla car.

When you figure out amps, you will probably need adequate wiring for your amp size. You can consult the ampacity AWG chart with wire sizes in mm, mm2, and amps here.

You can also check what wire sizes you need to conduct certain amps:

82 thoughts on “Watts To Amps Converter Calculator (With 1 Amp = Watts Examples)”

  1. I have a product that plugs into a 120v outlet that draws up to 3000w. Is that safe, or should I consider rewiring the product for 240v? (It’s 120/240 compatible

        • Hello Jemievir, you use the basic electric power equation: P (power) = I (current) × V (voltage). In terms of units, this means Watts = Amps × Volts. Here’s how you express amps: Amps = Watts / Volts = 6500W / 220V = 29.5A. So, your 6.5kW generator puts out 29.5A at 220V. Hope this helps.

          If you need some additional help, you can check out this ‘Generator Amps Calculator’ here that will help you calculate how many amps your generator draws.

    • It is illegal to make a device that pulls anything over 15 A on 120v because most receptacles can only handle 15 A At 120v and most breakers On receptacles is a 15 A . You can only pull close to 1500w witch is 75% of the breakers capability as if you pull 1800W your at 100% of the breakers capacity and it will trip …

    • Depends on the circuit, it’s purpose and the breaker used in line. Chances are good that if the circuit it’s hooked to isn’t rated for that much draw on a consistent basis. Switching to a 220v or 240v dedicated line would save money in the long term because 220/240 v power uses less juice than 110/120v does.

    • Hello there, the amperage remains constant. 250-watt heater on 220V will draw a bit more than 1 A. 1 amp is, by definition, 1 C (Coulomb) per second. In short, a 250-watt heater draws about 1 A, if you run it 1h, 6h, 12h, 24h, and so on.

  2. Watts divided by volts =amp
    2300 w ÷120 v=19.16 amp
    Amp multiply by volt =watts
    19.16×120 =2299.999
    2300w ÷220v =10.45 amp
    10. 45 amp×220 v=2299.99w

    • Hello Louis, 240V * 40 A = 9,600 watts. Be careful about the start wattage; that could be higher than 10,000 W. Otherwise, 10,000 W would be enough, yes.

  3. Question, I am buying a plasma cutter one plugs into 120 outlet and the other into a 220 outlet.other wise they are the same, they both draw 45 amps no more no less. Would the output be the same or would the 45 amps in the 220 be more. Thanks ruben

    • Hello Ruben, with the input, we can calculate the total wattage. 120V * 45A = 5,400W; and 220V * 45A = 9,900W. So, the input of the 220V unit is almost twice as high as the 120V unit. How does that affect the output? Depends upon efficiency, but usually, if you have a 9,900W unit is has a higher output than a 5,400W unit.

    • Hello Zo, there is a way, yes. You can use the electrical power equation: P (watts ) = I (amps) * V (volts). You already know you have 20 amps. Just include the voltage; either 120V or 220V. Let’s say that you have 220V; that would yield P = 20 amps * 220 volts = 4.400 watts. Per hour, that’s 4,4 kWh. Hope this helps.

  4. On a site I am a member of we have a lot of people putting in multiple amplifiers into boats. Often these amps are 15 feet away from the battery so the questions always come up….what size wire do I need to run? This is 12V DC.

    So if I install 3 amps rated at 1000 watts each, 15-20 feet from a battery, what size cable should I run to them?

    • Hello Julian, an interesting question. 1000W amplified on 12V DC will produce 1000W/12V = 83.3A. So, you would need wires that can handle up to about 100 amperes of current. For 100A, you would need #4 AWG copper wires or #2 AWG aluminum conductors; both of them have a minimum conduit size of 1 ¼ inch. Hope this helps.

  5. I am trying to power a 760 watt 2 channel audio amplifier 12 v 125 rms per channel. How many amps would I need the converter to put out?

    • Hello Chris, for 760 W and 12 V you can use the P = I * V equation. Basically, 760 W / 12 V = 63.3 A. You would need your converter to put out 65 amps minimum.

  6. I have 4 ea. 120 volt heaters that are rated @ 1500 watts each and they are 20 ft from my breaker panel what size wire should I use.

    • Hello Jim, that’s an interesting question. Each of these units draws a bit less than 15 amps. For 15 amps, you can use 14-gauge wires. Hope you find this useful.

  7. Greetings
    I have an electrical panel with 150 Amps
    So that means I need 16500 Watts??

    Trying to move to a solar panel

    I calculate 7 solar panels for a 200 Amp service with four 300 amp/hour batteries
    Need your advice

    • Hello Willy. 150 Amps is a huge current; at 110V, that is 16,500 Watts, yes. Be aware that solar panels produce electricity at a lower voltage (12V or 24V). To get 16,500 Watts at 24V, you would need 687.5 Amps. Hope this helps.

    • Hello Darica, 6500 watts at 220V is a little below 30 amps. 30 amp breaker would be enough in theory. In practice, however, it’s better to get 2 30 amp breakers because the amps are uncomfortably high for only 1 30 amp breaker.

    • Hello Chris, 182 kW is a huge wattage. You can use the electric power equation to easily see how many amps would be sufficient. Here’s the calculation:

      182,000W / 220V = 827.3 amps

      You’ll need 827.3 amps; that’s quite an enormous amount.

  8. Hi … trying to learn about all this because my kitchen (actually my whole house) is electrically challenged. My fridge is 11.6 Amps & big toaster oven pulls 15 Amps (1800W); they are on the same 20 Amp circuit. I would think this would be too much to run both at the same time, but they have never thrown the circuit. Am I doing the math right? Together I’m coming up with 3192W (26.6 Amps) … shouldn’t that be too much for a 20Amp circuit? Thanks

    • Hello Sandra, do both run on 120V? If they run on 220-240V, the amps are halved. Additionally, the fridge might draw 11.6 amps when running at 100%. Most fridges run on much a lower percentage and hence draw much fewer amps. If your 10 amp circuit can handle that, you’re fine.

  9. Hello,

    I have an inverter AC (1750 watts, 220v). With the equation you provided, it consumes 7.95amps. I am planning to run two of these units through a 5kVA 24Volt Victron inverter/charger with two 200Ah lithium batteries. Is this a feasible setup? Am I correct in saying I can run the AC even 24hrs? Thanks

    • Hello Franz, two 200 Ah batteries have a 400 Ah capacity. However, the batteries run on 24V while AC runs on 220V. At 220V, it does consume 7.95 amps, your calculation is correct. However, at 24V, it consumes 1750W/24V = 73 amps. That’s about 10x as many amps due to roughly 10x lower voltage. So, if you have 400Ah capacity, that will be enough for 400 Ah / 73 amps = 5.5 hours. You can prolong that time if you don’t run the AC on 100% output but not to 24h. Hope this helps.

  10. We live in our 5th wheel. My wife needs a CPAP with O2 at night. The CPAP transformer uses 140 watts and the O2 concentrator 240 watts, both 120 volt. I’m trying to figure a way to provide power for her needs at night. Generators run out of gas. I was thinking about deep cycle rv batteries and solar panels to charge the batteries during the day. There are many 12v deep cycle batteries that put out 105 AH for their 20 hour capacity. I just don’t know how many batteries or solar panels I will need to facilitate my wife’s needs. She only uses her CPAP and O2 in bed at night. Thanks.

    • Hello Jim, that’s a difficult case. To simplify it: You would require 140W + 240W = 380W for lets say 12 hours. Can 12V batteries provide that amount of power? To produce 380W, you would need 380W/12V = 32 amps output. If a battery you have in mind can output 105 amps at 12V for 20 hours, that’s a viable option. We simply don’t have the full knowledge to help you out adequately with this one, sorry.

  11. I am considering hard wiring ( with switch boxes) a 250 amp welding mach./ generator to my house. Generator is rated at 10500 watts peak / 9500 watts continuous, is this going to be sufficient to supply power to my 200 amp service

    • Hello Roy, it depends on the voltage. If you use a 120V generator, you will get 10,500W/120V = 87.5 amps. If you use a 240V generator, you will get 10,500W/240V = 43.75 amps. In both cases, the generator is too weak; it doesn’t provide 200 amps. You would need a much stronger generator for 200 amps.

  12. Hello,
    I have a wall baseboards heaters in my basement for a total of 4000Watts. My breaker is 25 Amps. Can I add another 1000 Watts?

    • Hello Serge, the voltage is 220V? If so, the current baseboard heaters draw 4000W/220V = 18.2 amps. Additional 1000W would add the total to 5000W and 22.7 amps. You can add another 1000W; the net amps draw won’t surpass 25 amps.

  13. Hello’
    I’m considering running 3 crypto miners at my house, they are listed at 3500w each at 220v. My understanding is that I would need to run 3-20amp circuits to carry this load is that correct? Also, can you calculate the cost of electricity used in a 24hr time period @ .10Kwh, Thanks!

    • Hello Max, nice rig. Each miner runs on 3,500W/220V = 15.9 amps. It’s recommended that you connect an electric device that uses a maximum of 80% of the amp breaker. In a 20 amp circuit, that’s 16 amps. You have 15.9 amps, so that is perfect. Your understanding is correct; you will need 3 20 amp circuits.

      Alright, let’s calculate the cost of electricity. You can use our power consumption calculator here for all these calculations. Basically, you have a combined power of 3×3,500W = 10,500W. Each hour, you consume 10.5 kWh. In 24 hours, that’s 252 kWh per day. If the price per kWh is $0.10, you’ll spend $25.20 on electricity running the rig. Hope this helps.

  14. Hello,

    I’m confused with a labeling in an AC/DC power adapter. Hope you can help me understand it.

    I have a wall plug 230V/13A, so this can handle total 2990W I assume.

    And now I have a device which needs 180W DC power. An AC-DC power adapter has been provided and it has the following.

    AC Input : 110-240V / 2A
    DC Output : 12V 15A

    My question does the amperage in DC Output needs to match the amperage of the wall socket (13A)?

    Second question is, if it doesn’t have to do anything with the wall socket amperage can I plug multiple of these devices to the same wall plug as long as it doesn’t exceed the 2990W?

    Thanks for your help in advance

    • Hello Alex, the DC output amperage doesn’t need to match the AC amperage. Do keep in mind that the total wattage of the 12V 15A DC output is 12V*15A = 180W. In theory, you can set up multiple of these devices as long as the net wattage doesn’t exceed the 2990W, yes. But that’s in theory; in practice, it can get quite tricky getting all 2990W DC output.

  15. Hello,

    If I have a 24 V 700 Ah battery and I use a converter to change the 24 V (DC) into 220 V (AC) to run an airco of 1200 W (5.5 A), will I still have 700 Ah available or is it less because of the higher Voltage ?

    • Hello Dave, it’s less due to higher voltage. The true measure of capacity is Wh or Watt-hours. You can use this Ah to Wh calculator to figure out how many Wh you have. Here’s how the basic equation looks like: Wh = Ah × V. In your situation, you have a 24V 700Ah battery; that’s 700Ah × 24V = 16,800Wh.
      Alright, so you have a 16,800Wh battery. Want to hook it up to 220V to run an AC? You can calculate Ah; 16,800Wh / 220V = 76.4 Ah. Want to know how long will this battery run an air conditioner? The AC you have has a 5.5 amp draw. Here’s how you can calculate that: 76.4 Ah / 5.5h = 13.89 h. Basically, this battery can run your AC unit at 100% output for almost 14 hours. Hope this makes sense.

    • Hello Victor, the Panasonic AC draws (when running at 100% capacity) 2,650W/220V = 12 amps. 30 amps AVS/surge will be more than enough.

    • Hello Ron, depends on the voltage. If you have a 110V generator, that’s 110V×50A = 5,500W. If you have a 220V generator, that’s 220V×50A = 11,000W. If you have any other voltage, you can use this simple formula to calculate the wattage.

  16. The peak kWh for my home daily usage is 61.4. I want to install a backup generator. What size generator (in Watts) do I need to purchase?

    • Hello Dick, in theory, you would need a backup generator that matches your peak wattage. That would be a 61,400W generator in your case; which is pretty absurd. The way you go about calculating the wattage of a backup generator is explained in our article about how to size a generator for your house. It’s a simple 3-step method that takes into account running wattage and, more importantly, the peak wattage. Peak kWh of your home is usually not the metric that we can adequately base the size of the backup generator on.

  17. Hello

    I have a device that consumes 10W.
    I found a small sollar kit with a 40W solar pannel, PWM 10A, 12V 18Ah AGM battery and 12V – 220V inverter. How much this configuration last? Or can I use max 20 W for 10h?

    Thank you very much!

    • Hello Iancu, the key here is that you know the device runs on 10W. That means that you have to have a 10 Wh battery capacity to run the device for 10W. Now, a 40W solar panel with 5 peak sun hours will produce 200 Wh per day. Your 12V 18Ah has a battery capacity of 216 Wh; that’s perfect. With such a setup, you have a well-optimized solar system to power a 10W device almost 24h per day. Hope this helps.

    • Hello Wayne, how many watts does the stick welder run on? If it’s a 225 amp welder, it probably runs on 220V. That means it requires 49,500W to run. The 225 amps is absolutely massive.

    • Hello Terry, for this calculation, you will need amps as well. 120V at 10A current is 1,200 watts and 120V at 8.3A is 1,000 watts.

  18. I have a automobile alternator output project. I am hoping to take a 220 v motor and tie it in with my alternator to produce upto 10K watts. But I really am starting to feed stupid tring to understanding the conversion from 12v system to my idea. What the hell am I missing? If I can get upto 80a out of my 12v system in my auto, what would I have to do to get my needed result. Thank you for your time!

    • Hello Jerald, you only need to operate with the basic electric power equation: P = I*V (or Watts = Amps*Volts). Let’s say you have a 220V voltage and want to get 10,000 Watts. Here how you calculate this: 10,000W / 220V = 45.5 A. Basically, you need a current of 45.5A on 220V voltage to be able to generate 10,000W. 12V voltage and 80A current will only generate 960W; this is less than 10% of what you are hoping to get. Hope this helps.

  19. Hello.
    I want to install in the house four radiant panels of 600W / 220V each. I am thinking of powering them from a converter that is powered by storage batteries from four photovoltaic panels.
    What power should the converter have?
    About how many batteries would I need?
    12V or 24V?
    Thank you.

    • Hello there, you have 4 600W radiant panels; the total wattage is 2,400W. You would need a converter that can handle at least 2,400W. If you run them for 24h per day at 100% output, they will require 57.6 kWh of electricity. Hopefully, you can use this data to set up a system with 12V or 24V batteries.

  20. Hello,
    How do I calculate a solar irradiance meter reading into amps ?
    Example:- irradiance meter reading of 1000 watts per meter squared ?
    Solar pv system has solar panels with a Voc of 47volts and Isc of 9.8amps .

    Can’t find the formula anywhere !

    • Hello Adam, here is how you can think about this: You have 1000 watts per m2 and an open-circuit voltage of 47V. You can divide the watts by volts to get the amps: 1000W / 47V = 21.3A. So, you would have a 21.3 amps current. I know this is not exactly what you have in mind but this is kind of how these calculations are made, hope it helps a bit.

    • Of course, Nikola, you can put 8 amps on 10A circuit (NEC 80% rule). At 240V, a 10A circuit can handle 1920 watts. So 9 watts is nothing for such a circuit.

  21. Good morning,

    I want to install 6 solar panels 550 watt each that mean if i am right should be give 3300 watts ,Please advice how many Amps should i get on 220 volt , and its enough for normal house to use ( fridge , wash machine , Ac…Etc . additional if i add 4 batteries 200 amps each how many amps will give at night and it`s enough ?
    the engineer advised me to be use inventor 5 kw , Please advice

    Thank you

    • Hello Rabih, basically the 550W units can produce more than 550W of electricity per hour if it’s a very sunny day. That’s a fellow engineer advised the use of a 5 kW inverter, instead of a 3.3 kW inverter. If you would be producing 3,300W, that would be exactly 15 amps on a 220V circuit. Now, if it is very sunny and you actually are getting 5,000W, the amps increase to almost 23 amps.
      If you presume that you have 5 peak hours per day, that would produce 3,300W × 5h = 16,500Wh or 16.5 kWh per day. Fridges can use anywhere from 1 to 6 kWh per day; so you have more than 10 kWh per day for washing machine and so on. All in all, it seems feasible that you would be able to run your house on solar power alone.
      4 200Ah 12V batteries can store up to 9.6 kWh of electricity; that’s almost 10 kWh. You could use additional battery or two to get closer to 16.5 kWh per day. All in all, this is quite a good setup. Hope some of this helps a bit 🙂

    • Hi William, we are talking 200 amp 110V service, presumably? That’s a total wattage of 200A*110V = 22,000 Watts. A 1,000W solar panel will produce 1,000W of electricity when the sun is shinning (peak sun hour). The rough answer would that you need a 22kW solar system for continuous 200A 110V service. Hope this helps a bit.

  22. Hi, I’m moving my bandsaw to Europe. Saw has 110 Volt and 1500 watt the motor is 2 HP. The shop in Europe is 220 Volt. What type of converter will I need?
    PS: I forgot the manufacturer said I can’t use it because of the difference in 50HZ vs 60HZ in the US.

    • Hi Rolf, that 50 Hz vs 60 Hz difference makes this quite unusable, yes. Otherwise, you would need a 220V to 110V converter; the wattage will remain the same (1500 watts) but, because now you are using half the voltage, the amp draw will double. The 1500W 220V draws 6.8 amps and the 1500W 110V draws 13.6 amps. Hope you find an adequate substitute here.

  23. I love your presentations. If I want to charge a Level 3 stations with 150A at 400 VDC, how mayy solar panels would I need or how many batteries would I need to charge to handle this. Since the outputu of panels is DC, same for batteries, can I skip the double inversioo from DC to AC and just go straightt DC to through the charger to the car?

    • Hi John, thank you. Solar panels can charge an electric car via a battery. Namely, here you look at your car battery capacity. Tesla Model 3 has a 75kW, for example. If you charge it from 10% to 90%, your solar panels will have to generate 60kWh of electricity. Alright, let’s say that you have a 5kW solar system and live in an area with 5 peak sun hours per day. This system will produce 25 kWh per day. It will generate 60 kWh in about 2.5 days. This is how you go about thinking how many solar panels and what size solar system you need for an electric car.

      For number of batteries, well, this depends on many factors but you can use 10 kWh batteries or 11.5 kWh Tesla Powerwall to store the electricity generated by the solar panels.

      Now, here is an interesting thing you suggested; for solar panels to charge the car directly. In theory, that makes sense, right? An electric car is basically a big battery. Why would you need an additional battery as a kind of middle-man to charge your car? I have to admit that I don’t really know if you can charge an EV directly from the solar panels.
      What you would normally do is install solar panels, use charge controller to charge the batteries, and then charge an EV from those batteries.
      John, I know we haven’t exactly came to 100% direct answers but I hope the logic about how to think about all of this helps a bit.

  24. If a 13amp 220V type G power source is the input into a power transformer and it converts it to 110V, how many total amps are available on the 110V output side? If the transformer has (2) 110V outlets to plug into, how many amps are supplied to those (2) 110V outlets?

    • Hi Scott, the key here is that the wattage stays the same. If you reduce the voltage by 2 (220V to 110V), the amps will increase by 2 (13A to 26A). If you have one 110V plug, it will have 26 amps. If you separate the voltage into two 110V plugs, you should see 13 amps in each plug. Hope this helps.


Leave a Comment