Solar Powering a 17" MacBook Pro

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Level 1

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Solar Powering a 17" MacBook Pro

Hello,

I'm attempting to solar power my 17" MacBook Pro while away tent camping. I have a Brunton 52 Watt folding solar array, Brunton 12V DC-to-AC inverter, Solar controller, cigar plug cable for output from solar array. The output from the solar aray in full sun is 24V DC. I can lower the voltage to 14V if I cover up 2/3rds of the cells.

I've connected the DC side of the 12V inverter to the solar array and the AC side to the MacBook Pro power brick. The inverter is between the solar array and the MBP. With solar array in full sun and connecting the three pieces, there is no AC power output from the inverter going to the MacBook Pro brick. Can anyone answer why I have no 120V output from the AC side of the inverter to the MBP?

Thanks,

Peter

MacBook Pro, Mac OS X (10.6.8)

Posted on May 23, 2012 1:02 PM

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Answer 1

Csound1

Level 9

60,063 points

May 23, 2012 1:03 PM in response to Starfield14

I suggest contacting Brunton and asking them.

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Answer 2

OGELTHORPE

Level 9

57,329 points

May 23, 2012 2:01 PM in response to Starfield14

I think the right way to approach your objective is to include a storage battery in your set up.

Solar panel>Battery (possibly a voltage regulator)>Inverter>MBP power adapter.

Covering a part of the solar panels will just reduce the output.

Ciao.

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Answer 3

Starfield14 Author

Level 1

0 points

May 23, 2012 2:16 PM in response to Starfield14

I went ot the Brunton website and Support answered my question. Apparently, the output from my 52 Watt 12 VDC Brunton solar array is not enough to become meaningful DC for the MBP after being converted to AC and then DC again. I need to keep the system DC-to-DC (no inverter, no AC). The DC to AC to DC process lowers the entire current too much. I can do this by purchasing an after-market (Chinese) MBP 12VDC Car Charger which will plug into the solar array directly (via its cigar plug cable) and power/charge the MBP the same way as it would from a car's 12V cigar output.

Thanks,

Peter

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Answer 4

Courcoul

Level 6

18,684 points

May 23, 2012 4:44 PM in response to Starfield14

I guess the first stumbling block is that you have one of those "Carrier Class" Macs, a 17". Starting from the fact that the power supply needs an 85W capacity, the solar panel was not going to cut it. Maybe a "Pocket Destroyer Class" 13" MBP (65W) might have eked thru. Or even a "Torpedo Boat Class" MB Air (45W). Cause no matter how much battery buffering you add, if the power input doesn't at least equal the drain, no solar solution is going to work.

What about taking a wind powered generator as a supplement? Great for harnessing the growl of the grizzly when it strolls by for a visit...😝

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Answer 5

steve359

Level 6

17,187 points

May 23, 2012 4:54 PM in response to Starfield14

With slight tongue-in-cheek ... a portable fusion reactor from the Enterprise would be helpful.

But seriously ...

My work PC only has a 2-prong polarized plug for the wall. The 85W adapter for my MBP has 3 prongs which is a clue about the power draw.

Additionally, some have reported their MBP drawing so much power that even on the wall plug the internal battery is needed to supplement the power needs. Granted, they were running very much at the time, but a USS Reagan class carrier can require more than a few watts.

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Answer 6

OGELTHORPE

Level 9

57,329 points

May 24, 2012 2:55 AM in response to Starfield14

If you are going to use your MBP power adapter you are forced to do the DC to AC conversion and deal with the inherent power loss (10%-15%).

You need to calculate the real world output of the solar panels (not the advertised figures) and take into account that the amperage will fluctuate with weather conditions and panel orientation.

My guess is that you will need a minimum of 5 amp output (using 24 v output panels) plus a fudge factor to take into account less than optimum conditions. The good news is that more panels can be added if the need so requires.

Good luck.

Ciao.

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Answer 7

OGELTHORPE

Level 9

57,329 points

May 24, 2012 3:01 AM in response to steve359

steve 359, greetings: May I point out that the CVN 76, Ronald Reagan is a Nimitz class carrier. No such thing as a Reagan class carrier.

I'm just being a picayune donkey so don't take this seriously.

Regards.

Ciao.

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Answer 8

eww

Level 9

53,052 points

May 24, 2012 3:08 AM in response to Starfield14

I've never heard of any really backpackable solar panel array that can come close to powering any Macbook Pro while it's in use. They can be used to charge the battery, usually quite slowly, when the mahine is shut down or sleeping, but that's all.

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Answer 9

wjosten

Level 10

95,369 points

May 24, 2012 3:36 AM in response to Starfield14

You need to have a battery between the Solar Panel & you're MacBook Pro. The battery will provide a stable power source at the correct voltage. I don't know of any Mfg., that makes kits for computers, that would recommend trying to do things they way you're trying to.

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Answer 10

steve359

Level 6

17,187 points

May 24, 2012 8:57 AM in response to OGELTHORPE

OGELTHORPE

Good to know the proper classification, thanks.

I knew I was a little off (in more ways than one ...) about that.

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