eagle1109
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But I thought that there would be like a boost converter with 2000W/220V = 9A
If this is all the information provided, then where did you get your current values from?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
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,
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.
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.So, for example, a normal car battery that is 12V, if we shorted the battery out, then what we get ? 12V/1ohm = 12A
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.
[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!
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.
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.
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