[SOLVED] 2000W Car Power Inverter powered from 120W car's power outlet

Hi,

Would a 2000W Car Power Inverter work from 120W car's power outlet ?


https://www.aliexpress.com/snapshot/0.html?orderId=8014030968455373

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The answer is no though. The current to produce 120W from a 12V source is 10A (W = V * I).
To produce 2000W would need about 167A, enough to melt the cables and probably the car battery too.

Brian.

I'm sorry ! Here's another link:

https://www.aliexpress.com/snapshot/0.html?spm=a2g0s.9042647.0.0.2fc74c4doyTN8P&orderId=8014030968455373&productId=4000163490128

wow that what I thought.

But I thought that there would be like a boost converter with 2000W/220V = 9A

So the car's outlet can deliver 120W/12V = 10 A


I'm sorry didn't mention the main specs of the adapter:

Brand Name: BEJIXIONG
Output Voltage: AC 220V±10%
Output Frequency: 50Hz
Conversion Efficiency: 0.9
Rated Power: Other
Input Voltage: DC 12V

eagle1109 said:

But I thought that there would be like a boost converter with 2000W/220V = 9A

Click to expand...

That power multiplication is magic. If we use this large scale, we can supply energy to the entire world from a single battery. Just add enough stages of magic power multiplication.

Hi,

eagle1109 said:

I'm sorry ! Here's another link:

https://www.aliexpress.com/snapshot/0.html?spm=a2g0s.9042647.0.0.2fc74c4doyTN8P&orderId=8014030968455373&productId=4000163490128

wow that what I thought.

But I thought that there would be like a boost converter with 2000W/220V = 9A

So the car's outlet can deliver 120W/12V = 10 A


I'm sorry didn't mention the main specs of the adapter:

Brand Name: BEJIXIONG
Output Voltage: AC 220V±10%
Output Frequency: 50Hz
Conversion Efficiency: 0.9?
Rated Power: Other
Input Voltage: DC 12V

Click to expand...

If this is all the information provided, then where did you get your current values from?

Your choice of power values here give an efficiency of (2000W/120W)*100% = 1667%. The specified efficiency for the inverter is 0.9 = 90%.
Boost converter boosts the output voltage and produce an output current that is below the input current such that Vout*Iout < Vin*Iin. That less-than sign cannot even be replaced with a less-than-or-equal-to sign.

volker@muehlhaus said:

That power multiplication is magic. If we use this large scale, we can supply energy to the entire world from a single battery. Just add enough stages of magic power multiplication.

Click to expand...

oh well .. so I made a mistake of buying this adapter ! I wanted it for my 180W laptop adapter. They already shipped it.

I think I just have to resell it when it arrives, or try it and measure output current.

Also my car is hyprid, I don't know how the power management of a normal or hyprid car works.

So, for example, a normal car battery that is 12V, if we shorted the battery out, then what we get ? 12V/1ohm = 12A

And with car's power management, there's 120W on the power outlet with 12V so the max current wouuld be 10A

Anyway I'm not planning of loading that adapter to its max power, I want it to run my 180W laptop adapter, so I think it would work, do you agree with me ?

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Akanimo said:

Hi,


If this is all the information provided, then where did you get your current values from?

Your choice of power values here give an efficiency of (2000W/120W)*100% = 1667%. The specified efficiency for the inverter is 0.9 = 90%.
Boost converter boosts the output voltage and produce an output current that is below the input current such that Vout*Iout < Vin*Iin. That less-than sign cannot even be replaced with a less-than-or-equal-to sign.

Click to expand...

Yep, it's actually an inverter that can be powered from car's power outlet.

How about this review ?

https://www.carguideinfo.com/2000w-power-inverter-review

So, for example, a normal car battery that is 12V, if we shorted the battery out, then what we get ? 12V/1ohm = 12A

Click to expand...

That is true if you connected a 1 Ohm resistance across the battery, a short circuit would typically be 100 or more times smaller than 1 Ohm so the current would be hundreds of times higher. Usually, if you short out a car battery it boils the acid and if you are lucky it doesn't explode.

It would be unusual for a laptop to need 180W of power, it would get extremely hot! Power adapters are rated by the maximum load you can place on them, not the actual load of the laptop. There will be some safety margin and the rating would be for using it and charging a completely empty battery and with full brightness and volume and with all USB sockets at full capacity. The chances are you will never face that scenario so the 120W rating may be adequate.

Brian.

[edit] Take a close look at that article - the picture says 2000W, the headline says "1000W continuous" and the text below says "900W continuous". Always treat adverts like that with great suspicion!

betwixt said:

That is true if you connected a 1 Ohm resistance across the battery, a short circuit would typically be 100 or more times smaller than 1 Ohm so the current would be hundreds of times higher.
Usually, if you short out a car battery it boils the acid and if you are lucky it doesn't explode.

Click to expand...

oh yeah !! right, shorting with cables that could have like 0.1 - 0.2 ohms resistance, so yeah current would be x10 times the battery max current !

It would be unusual for a laptop to need 180W of power, it would get extremely hot!

Power adapters are rated by the maximum load you can place on them, not the actual load of the laptop. There will be some safety margin and the rating would be for using it and charging a completely empty battery and with full brightness and volume and with all USB sockets at full capacity. The chances are you will never face that scenario so the 120W rating may be adequate.

Click to expand...

Alright ! Seriously thank you for alerting me to these important points ! So the 180W means the power this laptop would need with maxing everything on that laptop. OK really good point to understand.

So here another important point I have, which is I have a power adapter I used to power my dell's laptop that has a power adapter rated for 130W and I have bought a 300W inverted for my laptop when I go out with the car and it worked ok, sometimes the inverted doesn't work so I have to switch it ON/OFF until it works.

Then I bought this msi laptop that has 180W, but the 300W inverted didn't work with it at all, so there's something missing here that I don't understand.

It's either the inverted isn't a true 300W, or it doesn't have the initial current to run the laptop charger.



This is the Dell laptop 130W charger with the 300W inverted.



This is my new msi laptop 180W charger.

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So I thought that 2000W inverted would at least run my laptop charger, so according to the charger max current 9.23A, then I won't reach this ampere I guess.

[edit] Take a close look at that article - the picture says 2000W, the headline says "1000W continuous" and the text below says "900W continuous". Always treat adverts like that with great suspicion!

Click to expand...

Yeah I was got this suspicious feeling in this page, I said what is the page talking about exactly ! title about 2000W inverted, the secondary title about 1000W then lowers it to 600W for continuous power ! There is a lot of power loss in this page to the point that it can't happen in this world

It also says max 150W when run from an accessory socket (cigarette lighter socket). Do not believe adverts, particularly ones from a certain country!

It is important to understand that the ratings on the power supply are not what it produces but what it is capable of producing. Think of it like the speedometer dial on your car, it may go up to 160KPH but that doesn't mean it is traveling that fast, it is just the limit you can push it to. I can't read the label in the top picture but the rating of 19.5V and 9.23A equates to 19.5 * 9.23 = 179.98W so you can see where the 180W rating comes from. However if you draw less than 9.23A, the power it is called to produce will be less.

What matters more than the rating of the inverter is where the power going in to it comes from, normally that is the limiting factor. The current is the most important thing and you can calculate it by dividing the number of Watts by the input voltage, that is where the figure I quoted earlier comes from. So 2000W/12V = 166.66 Amps. The calculation makes an assumption that all the power is converted with 100% efficiency, in the real World that doesn't happen and even the 90% efficiency claimed is 'stretching' credibility somewhat. You probably have to factor at least an additional 20% input current to be sure so that 2000W output probably really needs 166.66 + 20% = 200A!

The next consideration is how long the car battery would last under that load. My car is also a hybrid but it has two batteries, a 150V lithium battery for the traction motor and a standard 12V battery for everything else. I would guess you have a similar battery arrangement in your car and only the 12V would be available for use. Most hybrid 12V batteries have a rating of 45AH, that means they are rated to supply 45A for 1 hour or at half that current for two hours and so on. So doing the calculation for a 2000W inverter under load I would anticipate your fully charged car battery lasting about 13 minutes! Of course after that you wouldn't be able to start the car again.

Brian.

First of all I'm sorry I think I didn't clarify the main specs of the inverters I'm talking about:

1. The one I have right now: DC 12V - AC 110V inverter @300W, which means the max output current is 300W/110V = 2.7A.
2. The one I just purchased: DC 12V - AC 220V inverter @2000W, which means the max output current is 2000W/220V = 9A.

betwixt said:

It also says max 150W when run from an accessory socket (cigarette lighter socket). Do not believe adverts, particularly ones from a certain country!

Click to expand...

My car is a Camry 2019 that has a similar label to this one:

It is important to understand that the ratings on the power supply are not what it produces but what it is capable of producing. Think of it like the speedometer dial on your car, it may go up to 160KPH but that doesn't mean it is traveling that fast, it is just the limit you can push it to. I can't read the label in the top picture but the rating of 19.5V and 9.23A equates to 19.5 * 9.23 = 179.98W so you can see where the 180W rating comes from. However if you draw less than 9.23A, the power it is called to produce will be less.

Click to expand...

Wait a minute !! I got it, so the fact that the 300W inverter didn't run my new laptop charger is because there's not enough current to kick the laptop's charger, am I right ? So the inverter max current is 2.7A and the laptop charger max current is 9.23A.

But I know the laptop's charger doesn't need 9.23A right away to start working, but I think there's a threshold current that has to be achieved to start running the charger.

Where the inverter didn't run the charger, then 2.7A isn't even enough to run the charger, so the laptop's charger should need more than 2.7A to work. That's my conclusion based on the points you mentioned.

What matters more than the rating of the inverter is where the power going in to it comes from, normally that is the limiting factor. The current is the most important thing and you can calculate it by dividing the number of Watts by the input voltage, that is where the figure I quoted earlier comes from. So 2000W/12V = 166.66 Amps. The calculation makes an assumption that all the power is converted with 100% efficiency, in the real World that doesn't happen and even the 90% efficiency claimed is 'stretching' credibility somewhat. You probably have to factor at least an additional 20% input current to be sure so that 2000W output probably really needs 166.66 + 20% = 200A!

Click to expand...

Yep, as I mentioned above, I'm sorry I didn't post the main specs of the inverters.

That means the current should be 2000W/220V = 9 Amps

The next consideration is how long the car battery would last under that load. My car is also a hybrid but it has two batteries, a 150V lithium battery for the traction motor and a standard 12V battery for everything else. I would guess you have a similar battery arrangement in your car and only the 12V would be available for use. Most hybrid 12V batteries have a rating of 45AH, that means they are rated to supply 45A for 1 hour or at half that current for two hours and so on. So doing the calculation for a 2000W inverter under load I would anticipate your fully charged car battery lasting about 13 minutes! Of course after that you wouldn't be able to start the car again.

Click to expand...

Interesting information ! Thanks

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Well, my last conclusion is that the 2000W inverter I purchased might work just to run the laptop's charger because:

1. The charger is 180W, and needs 9.23A at max situations which maybe even if I played games on the laptop in the car which is a heavy load to the processor and the GPU, I even might not reach 9.23A current consumption.
2. So, the inverter would provide me 220V with max power of 2000W and current of only 9A, so it might barely run the laptop's charger, and there's a small assumption that it might not run the charger, but I have a big hope that it would work.

You are confusing the power, voltage and current.

If you assume it is 100% efficient, and it certainly isn't, the input power from the car battery would be the same as the output power at 220V.

Power = Volts multiplied by Amps (W=V*I)

So the input voltage multiplied by the input current would be the same value as the output voltage multiplied by the output current.

Your charger has an OUTPUT rating of 180W (19.5V * 9.23A) so at full load the input would also be 180W meaning from 12V it must draw 15A. (12V * 15A = 180W)

The inverter has an OUTPUT rating of 2000W (220V * 9A) so the input at full load would also be 2000W meaning from 12V it must draw 166.6A (12V * 166.6A = 2000W)

If you are powering your charger from the output of the 2000W inverter, the load on it would be at most 180W so the input current to the inverter would still be 15A.

In real life, the inverter and charger are not 100% efficient. Using realistic figures instead of the advert, assume 80% efficiency so for a given output power, the input power would be about 20% more input needed to get the same power out, the remainder mostly being lost as heat.

Most car accessory sockets are rated for 10A so the limit of power you can take from them is 12V * 10A = 120W as marked on your console. As long as the load power from the inverter doesn't cause it to take more than 120W it will work. Taking into account the efficiency loss, you can probably take about 100W from the inverter output when plugged into the socket before blowing the car fuses.

If you need more power, you have to run thick cables back to the battery terminals so you bypass the 'weaker' cables fitted to the car. Doing that will significantly increase the current you can draw from the battery but of course it will run down faster.

Brian.

betwixt said:

You are confusing the power, voltage and current.

If you assume it is 100% efficient, and it certainly isn't, the input power from the car battery would be the same as the output power at 220V.

Power = Volts multiplied by Amps (W=V*I)

So the input voltage multiplied by the input current would be the same value as the output voltage multiplied by the output current.

Your charger has an OUTPUT rating of 180W (19.5V * 9.23A) so at full load the input would also be 180W meaning from 12V it must draw 15A. (12V * 15A = 180W)

The inverter has an OUTPUT rating of 2000W (220V * 9A) so the input at full load would also be 2000W meaning from 12V it must draw 166.6A (12V * 166.6A = 2000W)

If you are powering your charger from the output of the 2000W inverter, the load on it would be at most 180W so the input current to the inverter would still be 15A.

Click to expand...

Oh wow, the input must draw 166.6A to deliver 2000W at output !

So at most input max current is 10A, and I think at many cases input unit won't allow for 10A to prevent blowing the fuse, right ?

So it could be around 9A in best cases, then what current I might get at output ?

In real life, the inverter and charger are not 100% efficient. Using realistic figures instead of the advert, assume 80% efficiency so for a given output power, the input power would be about 20% more input needed to get the same power out, the remainder mostly being lost as heat.

Most car accessory sockets are rated for 10A so the limit of power you can take from them is 12V * 10A = 120W as marked on your console. As long as the load power from the inverter doesn't cause it to take more than 120W it will work. Taking into account the efficiency loss, you can probably take about 100W from the inverter output when plugged into the socket before blowing the car fuses.

Click to expand...

So I might get like 100W on output ? I hope it's enough to run the laptop's charger.

If you need more power, you have to run thick cables back to the battery terminals so you bypass the 'weaker' cables fitted to the car. Doing that will significantly increase the current you can draw from the battery but of course it will run down faster.

Click to expand...

I don't think I want to do that, but I actually have audio wiring kit, 5CH amplifier and a subwoofer.

Actually the power wires must or should be taken from the main battery directly to power up the amp, but a nice thing is that the battery is in the trunk, so I don't have to take along the car.

Hi,

I actually got the inverter, and tried it and it worked and started to charge my laptop which is a pretty good thing.

I like it, it has a fan for cooling, universal output plug and a USB.

A word of caution - that does not look to be capable of anything like 2KW, in fact it looks remarkably like my 300W inverter.

Also, there seems to be a problem with the heat sinking. If you look at the right side there are four black devices sitting against the side of the box, they are the inverter switching transistors and under load will get very hot. The back two are clamped to the side of the box with a bar to ensure good heat transfer to the box wall but the clamp on the near two transistors is not fitted properly. It should be rotated 90 degrees and the screw tightened so it holds the transistors tight to the box.

Brian.

There's a 40A fuse in the 12V input, so surely less than 500 W.