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My car has a wall-style AC receptacle in it. It is merely marked 110V 150W. It is not mentioned in the owner’s manual. I’m curious if it can safely power this laptop power supply: enter image description here

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2 Answers 2

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It can't because 130 W is how much the adapter can supply not how much it consume. Your car's plug only supply 1.35 A 110v but adapter needs 1.8 A (198 W ) .

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  • \$\begingroup\$ Mordecai is right, but only in regards to maximum power. If your laptop is only drawing half that (e.g. 65W) then that would not be a problem. \$\endgroup\$ Aug 20, 2019 at 1:51
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    \$\begingroup\$ That may be true - but the current will vary with the AC supply voltage which can be down to 100V or up to 240V. The 1.8A is the maximum. The efficiency of the power supply is probably in the 90% region so it could require up to about 145W when outputting maximum power. If it took 198W in that would mean that there is about 70W being dissipated - it would overheat with that much. The bottom line answer is that there isn't really enough info, it may be ok. \$\endgroup\$ Aug 20, 2019 at 2:24
  • \$\begingroup\$ I believe unused 70 w is reactive power which returns back to outlet but even it's not used it required without it device won't work properly. Also I'm repairing these kind laptop adaptors in store and by my experience they are quite dangerous to risk it . He asked if it's "safe " to use , so its not safe no matter what.Any mistakes can damage the adapter, car or laptop's power supply . \$\endgroup\$
    – Mordecai
    Aug 20, 2019 at 2:47
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Strictly from an engineering standpoint, you have an outlet that says it can supply up to 150 watts, and a load that claims to only need 130 watts.

So, it may work. There's all sorts of caveats (like, the power supply may take some inrush current above what the outlet can supply), but unless someone's been messing with your car electrical system it's probably safe to try.

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  • \$\begingroup\$ by multiplying 19.5V times 6.67 A - the listed output, it is clear that the 130W is what the power supply outputs, not what it needs. \$\endgroup\$ Aug 19, 2019 at 23:50
  • \$\begingroup\$ @GeorgeWhite - although you are strictly correct the 130W is the MAXIMUM the supply outputs, the PC may not consume anywhere near that much normally. If the battery in the notebook is charging at high rate and it is being used then it may take that much. Since the efficiency will probably be about 90% it will require about 145W input at max output. There is also the issues of inrush and power-factor that may require extra capability from the outlet. \$\endgroup\$ Aug 20, 2019 at 2:28
  • \$\begingroup\$ I agree completely that it will most likely work ok. \$\endgroup\$ Aug 20, 2019 at 4:24

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