Charging an Air from car cigarette lighter

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Charging an Air from car cigarette lighter

Based on my research, using a cigarette lighter adapter to charge an Air is not recommended. The car's circuit breakers might trip or the adapter itself would overheat.

I did read about DC to AC to DC inverters.

What about a Mophie? It probably wouldn't charge the battery, but would maintain the charge.

What does Apple recommend?

The following is a reply from a Mac forum that I'm on:

Personally, I don't trust the lighter adapters for charging even iDevices - my wife's phone blew a few fuses on my previous car - I bought her a small battery pack that can charge her new iPhone or iPad Mini at least twice while in the car. SO, that would not be an option for me.

But, there are more powerful battery packs that can charge a laptop - keep in mind the wattage needed (my MBPro has a 60 W charger) - there was a previous thread from a poster asking about the BatteryBox (shown below) that would serve your needs - not cheap (believe about $200) - assume that you've been googling similar products?

As to Apple's recommendation, this forum is not supported by Apple, so unless you join one w/ Apple technicians responding or visit an Apple store to ask your question, I cannot address your query - maybe others can? Let us know what you decide - good luck in your selection. Dave

P.S. I have a battery pack for my iPad, but have not used one w/ my laptop, so the above is not a personal recommendation for the product mentioned.

OK.A Mac forum recommended that I ask someone on an Apple forum. So, that's exactly what I'm doing.

Does Apple sell a car adapter/charger for a Mac laptop? I'm interested in getting a Macbook Air. One of the things that I want to do with it is use it as a GPS when I travel. Does Apple make a Mophie-like product?

Here's the situation. I considered getting an iPad Air2. I still might. I can pay Verizon $20/month to turn my phone into a hotspot. Then I connect my laptop to my phone & my phone connects to the cellular towers. I have an Android phone. I suppose that an iPhone would make the connection setup easier, but I'm stuck with my phone until October 2016. When my contract is up, I might get an iPhone instead of another Android. Verizon charges $10/month for tablet access to their network. So, it would cost me $30 to connect a tablet to their network. So, I have 2 options. Pay Verizon $20/month to connect my laptop to their network or pay them $30/month to connect a tablet to their network. I don't have a tablet so there's another option. Spend $800 on an iPad or apply the $800 towards an Air.

So, bottom line. Does Apple make a car charger/adapter for a Mac laptop or a Mophie-like device? Since the Air uses the MagSafe port, I wonder if I need an adapter for the adapter?! Like Lightning to MagSafe or USB to MagSafe.

Mac mini, OS X Yosemite (10.10.3)

Posted on Jun 27, 2015 10:15 AM

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Answer 1

Best reply

FoxFifth

Level 10

468,573 points

Jun 27, 2015 10:20 AM in response to macnerd48

Apple doesn't make the following but they do sell it for use in charging MacBooks. It is in the Apple Store: http://store.apple.com/us/product/TW696LL/A?fnode=5a

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Answer 2

OGELTHORPE

Level 9

57,305 points

Jun 27, 2015 10:21 AM in response to macnerd48

macnerd48 wrote:

So, bottom line. Does Apple make a car charger/adapter for a Mac laptop or a Mophie-like device? Since the Air uses the MagSafe port, I wonder if I need an adapter for the adapter?! Like Lightning to MagSafe or USB to MagSafe.

No, Apple does not make any such devices. Only third party vendors do.

The only 'practical' option is a 150w - 200w inverter from a 12v source. That will allow you to go from 12v DC to 120v AC to 16v DC. Unless you are in the backwaters of the Amazon, I personally would avoid it.

Ciao.

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Answer 3

macnerd48 Author

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31 points

Jun 27, 2015 12:07 PM in response to OGELTHORPE

I'm a bit confused.

I read my car manual & it states that as long as the device plugged into the power plug does not draw more than 10 amps then there isn't a problem. Well, according to Ohms' law, volts times amps equals watts. So, 12 volts times 10 amps equals 120 watts.

Is it the inverter that shouldn't draw more than 120 watts or is it the AC adapter or is it a combination of the 2? That's what confuses me.

The lowest power inverter on the Walmart website is 100 watts.

I have a 15" MacBookPro. I looked at the AC adapter & it has the following specifications:

Input: 100-240 volts at 1.5 amps.

Output: 16.5 - 18.5 volts at 4.6 amps.

So, doing the math - Input: 240 * 1.5 = 360 watts maximum; Output: 18.5 * 4.6 = 85.1 watts maximum. I think that the specs on my MBP for the AC adapter are 85 watts.

The output for the AC adapter is what I should look at, right?

The Air AC adapter is 45 watts. So, it seems to me that a 100 watt inverter would be enough to power either my MBP or an Air, right?.

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Answer 4

OGELTHORPE

Level 9

57,305 points

Jun 27, 2015 1:14 PM in response to macnerd48

Apologies. I am one with MBPs using 85w chargers, so my orientation when writing my response did not take into consideration the MBA 45w charger.

You math is fine except it does not take into consideration the 10%-15% loss each time you convert from DC to AC and AC to DC. All inverters are not created equal and what it says on the box may not be what you get. I ran into that problem a few years ago. The best I could do was about 75W AC from a 12v system not constrained to a 10amp output limitation. I returned that particular Inverter.

Ciao.

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Answer 5

carl wolf

Level 6

14,625 points

Jun 27, 2015 2:12 PM in response to macnerd48

Another consideration is the waveform that the inverter produces. The electricity from an ordinary AC outlet is a sine wave. Electronic inverters approximate a sine wave, using electronic circuits. The problem is that, under load, the waveform distorts. Some inverters provide an AC output that is more square than sine, and others produce an output that is more triangle than sine.

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Answer 6

macnerd48 Author

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31 points

Jun 27, 2015 3:40 PM in response to OGELTHORPE

You math is fine except it does not take into consideration the 10%-15% loss each time you convert from DC to AC and AC to DC. All inverters are not created equal and what it says on the box may not be what you get. I ran into that problem a few years ago. The best I could do was about 75W AC from a 12v system not constrained to a 10amp output limitation. I returned that particular Inverter.

I hadn't considered that.

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Answer 7

macnerd48 Author

Level 1

31 points

Jun 27, 2015 3:44 PM in response to carl wolf

Another consideration is the waveform that the inverter produces. The electricity from an ordinary AC outlet is a sine wave. Electronic inverters approximate a sine wave, using electronic circuits. The problem is that, under load, the waveform distorts. Some inverters provide an AC output that is more square than sine, and others produce an output that is more triangle than sine.

I read about that while researching power inverters. An inverter that outputs a sine wave would be more expensive, but it would be a good idea to get one to avoid damaging a $1,200 laptop!

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Answer 8

macnerd48 Author

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31 points

Jun 27, 2015 5:08 PM in response to macnerd48

It looks like I'll have to return to the proverbial drawing board!

I read on the 'net & this forum recommends a power inverter with sine wave output. I haven't been able to find one.

I can get a Mophie or Mophie clone for an iPad, but not for a laptop. I read on Wikipedia that Apple doesn't license the MagSafe connector or the patent.

DARN!

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Answer 9

macnerd48 Author

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31 points

Jun 28, 2015 1:10 PM in response to macnerd48

Another thought has occurred to me. I wonder how long the battery will last when the Air is in Sleep Mode. Would it be days, weeks, months? Won't OSX shut down the Air when the discharge level of the battery gets to a certain point?

I really don't need a power inverter. I won't be spending months out in the middle of nowhere. I was just curious.

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Answer 10

macnerd48 Author

Level 1

31 points

Jul 4, 2015 7:03 AM in response to carl wolf

The output from an AC outlet is not clean. There are power surges & brownouts & noise on the sine wave. I wonder if the output from an inverter would be similar.

Are there car power inverters that have a sine wave output rather than square or triangle wave? Are you aware of any?

I know that I can power the new MacBook from a Mophie. I've seen it on websites. Just connect the MacBook to the Mophie with a USB-C to USB-A adapter cable. The Mophie probably wouldn't be able to supply power for very long, though.

So, to get or not to get a car power inverter. That is the question. Apologies to Shakespeare!

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Answer 11

OGELTHORPE

Level 9

57,305 points

Jul 4, 2015 7:09 AM in response to macnerd48

If the inverter in question puts out a pure sine wave, the the DC input issue is of no consequence. Among inverters, the pure sine wave ones will be the more expensive ones.

Ciao.

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Answer 12

FoxFifth

Level 10

468,573 points

Jul 4, 2015 9:04 AM in response to macnerd48

The Kensington converter is sold by Apple for use with Mac notebooks. http://store.apple.com/us/product/TW696LL/A?fnode=5a

It was designed by Kensington for use with any brand of laptop or notebook: http://www.kensington.com/us/us/4470/k38037us/auto-air-power-inverter-with-usb-p orts#.VZgAsniBVSU

There may be better options in terms of noise but they will likely be larger in physical dimensions.

It is a modified sine wave converter.

I have used modified sine wave converter with a variety of devices for years with never a problem.

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Answer 13

carl wolf

Level 6

14,625 points

Jul 5, 2015 3:21 AM in response to macnerd48

The power from an AC outlet is very clean. Within reason, the Apple power adapter will handle power surges, noise, and brownouts without any problem - the adapter has over-voltage, over-current, and thermal protection built-in. Any happenstance that can't be handled properly will cause the power adapter to shut down. It can be reset by unplugging, waiting 60 seconds, and then plugging the power adapter back in. The same problem is likely to occur with non-sine wave voltage input.

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