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Question: What wattage DC power inverter is required to charge a 15" MacBook Pro.

I am an over the road trucker. The inverter I use to keep my iPhone and various electronics charged does not provide enough wattage to keep the 15" MacBook Pro charged.

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Mar 13, 2018 9:10 PM in response to Kappy In response to Kappy

Kappy wrote:


85 watts is the regular charger's wattage.


I think that's only the output. There can be substantial loss from the input because of the conversion.


My 60W power adapter says output is 16.5V at 3.65A, which is 60.336W. However, the input says 1.5A at 100-240V. At minimum that's 150W (at 100V) although I'm pretty sure that it's a peak value. It obviously doesn't say how it scales with a typical 110-120V source like an inverter.


For the OP, what does it say on the power adapter for the input current? I'm thinking that you probably want at least 200W. Most inverters are rated for a specific steady output and a higher peak output.

Mar 13, 2018 9:10 PM

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Mar 14, 2018 7:18 AM in response to y_p_w In response to y_p_w

First thanks for the reply. I have at home (not in my possession here this minute) a 300 watt inverter. The reason it is at home is that the small Stanley 100 watt inverters that I have 2 of work fine for keeping the iPhone charged and TV working. It will charge the MacBook if it is the MB is shut off and hooked up to the Stanley for 20 hours! Therefore I was looking to purchase a bigger inverter and needed to know the minimum wattage I can use. (honestly I forgot about my 300 watt-er, or I'd have it with me and know if it is sufficient) What I DO know is that the MB Pro's charger is 85watt output, and the Stanley 100 watt inverters aren't going to get it done. So I'll be home Tomorrow or Friday and will at that time know via experimentation if said 300 is sufficient. I'll reply the results here as to possibly help someone else in a similar quandary. Thanks again.

Mar 14, 2018 7:18 AM

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Mar 14, 2018 9:03 AM in response to 1greg49 In response to 1greg49

1greg49 wrote:


First thanks for the reply. I have at home (not in my possession here this minute) a 300 watt inverter. The reason it is at home is that the small Stanley 100 watt inverters that I have 2 of work fine for keeping the iPhone charged and TV working. It will charge the MacBook if it is the MB is shut off and hooked up to the Stanley for 20 hours! Therefore I was looking to purchase a bigger inverter and needed to know the minimum wattage I can use. (honestly I forgot about my 300 watt-er, or I'd have it with me and know if it is sufficient) What I DO know is that the MB Pro's charger is 85watt output, and the Stanley 100 watt inverters aren't going to get it done. So I'll be home Tomorrow or Friday and will at that time know via experimentation if said 300 is sufficient. I'll reply the results here as to possibly help someone else in a similar quandary. Thanks again.


You've probably got a Level V efficiency standard power adapter. For anything providing 50-250W output, the requirement is for at least 87% efficiency. So theoretically it shouldn't require more than 98W input. But then you're dealing with all sorts of things including maybe a peak current when you first plug it in and maybe.


https://www.digikey.com/en/articles/techzone/2015/aug/efficiency-standards-for-e xternal-power-supplies


I would think that a 300W inverter would do it without any issues. 100W is really pushing the limits of the inverter with an 85W power adapter. In your case it doesn't seem to work. I had a 100W adapter, but I'm not sure where it is now. It about the size of a Compact Cassette case and had no cooling fins. The cables folded up took up more space than the actual inverter. I didn't use it for anything more than a cell phone power adapter.

Mar 14, 2018 9:03 AM

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Question: What wattage DC power inverter is required to charge a 15" MacBook Pro.