Best Solar Power for Macbook Pro and Cell Phone?

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tylerrr
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Best Solar Power for Macbook Pro and Cell Phone?

Post by tylerrr » Wed Aug 03, 2016 10:02 am

Can someone tell me a good option if I want to start charging my iphone and Macbook pro via solar?

I'd like to hang the panel out my apartment window sometimes, but also have solar power on trips in my car.....

From what I see, most of the portable solar panels you can fold up and carry in a backpack are not powerful enough to charge my Mac laptop.

thanks for any advice on this.....


Toska2
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Re: Best Solar Power for Macbook Pro and Cell Phone?

Post by Toska2 » Thu Aug 04, 2016 8:52 pm

http://wagan.com/wagan-tech/solar-produ ... el-37.html
Or better
http://m.homedepot.com/p/Coleman-18-Wat ... /203241551

And two cheap SLA batteries that are in power packs 7-9 amp hours, a plastic ammo box and an inverter. Or use the car cigarette outlet as an inlet. A MacBook won't harm a car battery if you charge it a few times. Two SLA batteries are $30 vs $100+ for lithium ion

Batteries are rated by amp-hours. This is based on an 8 hour draw down to a certain voltage. This isn't linear, a higher amp draw means a much shorter period before it's dead. A MacBook pro charger is 60 watts or 12 volts 5 amps for one hour. Your battery rating should be 9 amp-hours or more for that amp draw.

Unsolicited honest opinion? Buy a cheap 100-200 watt car ($30 ish) inverter for the car trips. The car battery can handle it and, if you're worried, add a second one in the trunk

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Re: Best Solar Power for Macbook Pro and Cell Phone?

Post by henrik » Fri Aug 05, 2016 4:25 am

The type and size of the panel you need largely depends on where you are or expect to be going.
http://www.nrel.gov/gis/solar.html

I've had good experience with these, but they were bought and tested with Central Africa in mind.

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Re: Best Solar Power for Macbook Pro and Cell Phone?

Post by tylerrr » Fri Aug 12, 2016 2:04 pm

thanks for the ideas. I may message a couple of you!

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C40
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Re: Best Solar Power for Macbook Pro and Cell Phone?

Post by C40 » Fri Aug 12, 2016 3:52 pm

Note just incase you're wondering - a Macbook pro is very difficult to charge without using an AC inverter and then the Apple AC to DC converter. There is a voltage/amps/resistance test that occurs between the computer and the charger before the charger will put out amps of any significance, so if you try to use a DC to DC converter hooked up to a 12v source, it's not going to work. Someone did a test of the charging system and put a detailed report on the internet, which if you're interested can be found with some googling. (I was wanting to charge my Macbook pro without having to use the inverter, but gave up on the idea once I saw how complicated the charging system is).

The phone - that's no problem, you just need a little USB thing that you can wire straight to a 12v battery. (For example, these work: https://powerwerx.com/panel-mount-dual- ... igh-output (Their lower amperage version works ok also.. I haven't checked how many amps my cell phone can actually take and I just use either one) )

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Re: Best Solar Power for Macbook Pro and Cell Phone?

Post by C40 » Fri Aug 12, 2016 3:53 pm

To add - I don't believe something like that Goalzero product will work for you. For your laptop, you'd need one that has a inverter and outputs AC. Also, if you want to learn how to build it, building your own system from components will usually cost much less than Goal Zero products.

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Re: Best Solar Power for Macbook Pro and Cell Phone?

Post by _JT » Sun Oct 09, 2016 3:29 pm

Toska2 wrote:http://wagan.com/wagan-tech/solar-produ ... el-37.html
Unsolicited honest opinion? Buy a cheap 100-200 watt car ($30 ish) inverter for the car trips. The car battery can handle it and, if you're worried, add a second one in the trunk
This is a terrible idea. Cheap inverters put out a modified square wave, rather than a nice clean sine wave. When you take that square wave AC and rectify it back to DC (done by the macbook charger), you overheat components inside of the charger that aren't meant to do that. This is a quick recipe to a charger "mysteriously" dying.
C40 wrote:Note just incase you're wondering - a Macbook pro is very difficult to charge without using an AC inverter and then the Apple AC to DC converter. There is a voltage/amps/resistance test that occurs between the computer and the charger before the charger will put out amps of any significance, so if you try to use a DC to DC converter hooked up to a 12v source, it's not going to work.
Not sure where this info comes from, but I do exactly the thing you're saying won't work. I built a DC->DC converter that steps up my 12V solar system up to the 18V DC required by the macbook. The system isn't fully operational at the moment, but when I tested it it successfully charged my laptop with no issues.

Bona fides: electrical engineer/off grid tiny house builder

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Re: Best Solar Power for Macbook Pro and Cell Phone?

Post by C40 » Sun Oct 09, 2016 11:04 pm

_JT wrote:
C40 wrote:Note just incase you're wondering - a Macbook pro is very difficult to charge without using an AC inverter and then the Apple AC to DC converter. There is a voltage/amps/resistance test that occurs between the computer and the charger before the charger will put out amps of any significance, so if you try to use a DC to DC converter hooked up to a 12v source, it's not going to work.
Not sure where this info comes from, but I do exactly the thing you're saying won't work. I built a DC->DC converter that steps up my 12V solar system up to the 18V DC required by the macbook. The system isn't fully operational at the moment, but when I tested it it successfully charged my laptop with no issues.

Bona fides: electrical engineer/off grid tiny house builder
Oh, cool. What year is your computer? Macbook or Macbook pro?

I believe I was basing what I said off of what I read here:
http://www.righto.com/2013/06/teardown- ... gsafe.html

Specifically, this part:
website linked above wrote: When the Magsafe connector is plugged into a Mac, a lot more happens than you might expect. I believe the following steps take place:
  • * The charger provides a very low current (about 100 µA) 6 volt signal on the power pins (3 volts for Magsafe 2).
    * When the Magsafe connector is plugged into the Mac, the Mac applies a resistive load (e.g. 39.41KΩ), pulling the power input low to about 1.7 volts.
    * The charger detects the power input has been pulled low, but not too low. (A short or a significant load will not enable the charger.) After exactly one second, the charger switches to full voltage (14.85 to 20 volts depending on model and wattage). There's a 16-bit microprocessor inside the charger to control this and other charger functions.
    * The Mac detects the full voltage on the power input and reads the charger ID using the 1-Wire protocol.
    * If the Mac is happy with the charger ID, it switches the power input to the internal power conversion circuit and starts using the input power. The Mac switches on the appropriate LED on the connector using the 1-Wire protocol.
I've been charging my computer using an inverter. If I could charge it straight DC, I could reduce my inverter use to very little, and the computer would charge quite a bit more efficiently.

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Re: Best Solar Power for Macbook Pro and Cell Phone?

Post by 7Wannabe5 » Mon Oct 10, 2016 7:58 am

I use KingSolar 6o watt portable panels and RAVpower 23000mAh bank with 20 volt option. Not the cheapest solution, or a completely self-reliant without grid access solution, but works great for wide variety of needs. The bank is rather heavy, but it is slim enough to fit in the smallest utility bag (AKA man purse)that I carry, and the panels are very light and small enough to fit in the smallest backpack. They both come with a variety of well-functioning jacks and jills. The panels can charge the bank in a few hours, and the bank can provide enough power to meet my desire for laptop, cell phone, usb fan and bright led light bulb usage for at least a day or two, when used in conjunction with the device batteries.

Unfortunately, portable power banks are not cheap enough to warrant even the purchase of the smallest coffee in order to suck "free" energy from cafe jacks, and the sun does not always shine in Michigan (sigh.)

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Re: Best Solar Power for Macbook Pro and Cell Phone?

Post by _JT » Mon Oct 10, 2016 6:41 pm

C40 wrote:
_JT wrote:
C40 wrote:Note just incase you're wondering - a Macbook pro is very difficult to charge without using an AC inverter and then the Apple AC to DC converter. There is a voltage/amps/resistance test that occurs between the computer and the charger before the charger will put out amps of any significance, so if you try to use a DC to DC converter hooked up to a 12v source, it's not going to work.
Not sure where this info comes from, but I do exactly the thing you're saying won't work. I built a DC->DC converter that steps up my 12V solar system up to the 18V DC required by the macbook. The system isn't fully operational at the moment, but when I tested it it successfully charged my laptop with no issues.

Bona fides: electrical engineer/off grid tiny house builder
Oh, cool. What year is your computer? Macbook or Macbook pro?

I believe I was basing what I said off of what I read here:
http://www.righto.com/2013/06/teardown- ... gsafe.html

Specifically, this part:
website linked above wrote: When the Magsafe connector is plugged into a Mac, a lot more happens than you might expect. I believe the following steps take place:
  • * The charger provides a very low current (about 100 µA) 6 volt signal on the power pins (3 volts for Magsafe 2).
    * When the Magsafe connector is plugged into the Mac, the Mac applies a resistive load (e.g. 39.41KΩ), pulling the power input low to about 1.7 volts.
    * The charger detects the power input has been pulled low, but not too low. (A short or a significant load will not enable the charger.) After exactly one second, the charger switches to full voltage (14.85 to 20 volts depending on model and wattage). There's a 16-bit microprocessor inside the charger to control this and other charger functions.
    * The Mac detects the full voltage on the power input and reads the charger ID using the 1-Wire protocol.
    * If the Mac is happy with the charger ID, it switches the power input to the internal power conversion circuit and starts using the input power. The Mac switches on the appropriate LED on the connector using the 1-Wire protocol.
I've been charging my computer using an inverter. If I could charge it straight DC, I could reduce my inverter use to very little, and the computer would charge quite a bit more efficiently.
Mine is an aluminum unibody MBP from 2011 or so. I know the charger does all sorts of fancy sensing stuff, but when I hooked it up to my homemade charger* it charged with no issue. At least on a short term basis (the solar power isn't all hooked up yet, so I just function tested it). Beyond just needing to use your inverter less, you'd extend the lifespan of your charger by several years I'm guessing. Unless your inverter is an honest to god pure sine wave inverter.

*basically I bought an adjustable 12VDC --> 14-20VDC board off of ebay (made in china for about 3 bucks), and then mounted it in a box. Wired a 12VDC auto-type hookup on the in, and a magsafe2 cable on the out (which I scavenged from an old dead charger I had). Once I get my stuff all hooked up for real and do more testing on the charging I can send you the build details if you're interested.

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Re: Best Solar Power for Macbook Pro and Cell Phone?

Post by C40 » Mon Oct 10, 2016 10:33 pm

_JT wrote:
Mine is an aluminum unibody MBP from 2011 or so. I know the charger does all sorts of fancy sensing stuff, but when I hooked it up to my homemade charger* it charged with no issue. At least on a short term basis (the solar power isn't all hooked up yet, so I just function tested it). Beyond just needing to use your inverter less, you'd extend the lifespan of your charger by several years I'm guessing. Unless your inverter is an honest to god pure sine wave inverter.

*basically I bought an adjustable 12VDC --> 14-20VDC board off of ebay (made in china for about 3 bucks), and then mounted it in a box. Wired a 12VDC auto-type hookup on the in, and a magsafe2 cable on the out (which I scavenged from an old dead charger I had). Once I get my stuff all hooked up for real and do more testing on the charging I can send you the build details if you're interested.
Mine is newer. Are you saying the 2011 version also does the high resistance and voltage adjustment thing as described by the website I quoted? If so, that gives me some hope for mine.

Please do let me know after some more testing how it works out. I was planning to do exactly what you described but that website I linked discouraged me enough to abandon it.

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Re: Best Solar Power for Macbook Pro and Cell Phone?

Post by bryan » Tue Oct 11, 2016 1:55 am

This may be more up to date: http://www.righto.com/2015/11/macbook-c ... html#ref16

Really odd Apple doesn't put out a DC charger. I wonder why? Would be interesting to compare/contrast the DC signals from an authentic Apple charger and the other crap you can buy (if there is anything fancier than a 1s delay in charging).

"Voltaic Systems" seems to come up in google searches..

If you go the diy DC-DC route you should understand what might happen if you supply more or less than the specified voltage/current to your devices (or variances, noise in those values from your source). You should also understand how this can realistically happen and how to test that it's not the case. (this seems like a popular DC-DC thing that could work: https://www.amazon.com/Geeetech-Convert ... B008NKNHSG).

If you aren't 100% on it, you should stick to tried-and-true off-the-shelf stuff, no matter how easy others tell you it is.

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Re: Best Solar Power for Macbook Pro and Cell Phone?

Post by _JT » Tue Oct 11, 2016 4:07 pm

C40 wrote:
_JT wrote:
Mine is an aluminum unibody MBP from 2011 or so. I know the charger does all sorts of fancy sensing stuff, but when I hooked it up to my homemade charger* it charged with no issue. At least on a short term basis (the solar power isn't all hooked up yet, so I just function tested it). Beyond just needing to use your inverter less, you'd extend the lifespan of your charger by several years I'm guessing. Unless your inverter is an honest to god pure sine wave inverter.

*basically I bought an adjustable 12VDC --> 14-20VDC board off of ebay (made in china for about 3 bucks), and then mounted it in a box. Wired a 12VDC auto-type hookup on the in, and a magsafe2 cable on the out (which I scavenged from an old dead charger I had). Once I get my stuff all hooked up for real and do more testing on the charging I can send you the build details if you're interested.
Mine is newer. Are you saying the 2011 version also does the high resistance and voltage adjustment thing as described by the website I quoted? If so, that gives me some hope for mine.

Please do let me know after some more testing how it works out. I was planning to do exactly what you described but that website I linked discouraged me enough to abandon it.
It does, but IIRC from my reading those things actually happen at the magsafe charging port itself (it's got a tiny circuit board inside of it), so as long as the port senses a safe voltage level coming it supplies the MBP battery. You've got me curious again, so maybe next week when I go back to my cabin I'll try a longer charging test.
bryan wrote:This may be more up to date: http://www.righto.com/2015/11/macbook-c ... html#ref16

Really odd Apple doesn't put out a DC charger. I wonder why? Would be interesting to compare/contrast the DC signals from an authentic Apple charger and the other crap you can buy (if there is anything fancier than a 1s delay in charging).
Because there's no real demand for one. Standard car alternators won't really be able to charge laptops (my laptop draws like 5A @ 12VDC), and there just aren't that many people who understand why they need such an animal who live with DC power.

If you go the diy DC-DC route you should understand what might happen if you supply more or less than the specified voltage/current to your devices (or variances, noise in those values from your source). You should also understand how this can realistically happen and how to test that it's not the case. (this seems like a popular DC-DC thing that could work: https://www.amazon.com/Geeetech-Convert ... B008NKNHSG).

If you aren't 100% on it, you should stick to tried-and-true off-the-shelf stuff, no matter how easy others tell you it is.
Too true! I have a few different digital voltage meters wired in to my system, and also have the ability to adjust DC output voltage to my MBP via the magic box I built. Should be much, MUCH better for it than charging DC -> AC, AC -> DC like a lot of people do with an inverter.

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Re: Best Solar Power for Macbook Pro and Cell Phone?

Post by bryan » Tue Oct 11, 2016 6:47 pm

_JT wrote: Standard car alternators won't really be able to charge laptops (my laptop draws like 5A @ 12VDC)
Last I checked most car alternators are >100A @ ~14V?

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Re: Best Solar Power for Macbook Pro and Cell Phone?

Post by _JT » Wed Oct 12, 2016 12:08 pm

1) Your accessory loads aren't the main things alternators power, and
2) Really, I misspoke. The alternator is certainly one limiting factor (anyone who's done car stereo installs will tell you alternator upgrades are a pretty standard part of running a speaker amp), but even beyond that is the wiring to your 12V sockets. Consistent drains of 5-10A is probably going to blow fuses/fry wiring in a standard car. Work trucks and delivery vans might have upgraded wiring, though.

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Re: Best Solar Power for Macbook Pro and Cell Phone?

Post by bryan » Wed Oct 12, 2016 1:21 pm

OK.

A lot of cars have accessory power ports (12V sockets) that are on a 15A fuse. But yeah, obviously you should be checking the wiring and complimentary fuses for anything you are plugging in. If it's stock you can pretty safely just plug and play and not worry about things until a fuse goes.

I'm am in "van living mode" (as well as @C40 I assume) and was working from the basis that you have your own power circuits, like a $battery_voltage, 75-150A 0 awg cable, fused just after battery terminal, running to a voltage regulator circuit, voltage dividers, and new fuse box etc.

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Re: Best Solar Power for Macbook Pro and Cell Phone?

Post by _JT » Wed Oct 12, 2016 8:25 pm

Yeah, that's a different scenario than me (10 year old Honda Pilot).

My primary concern is charging via an inverter, since I wouldn't charge in my car regardless.

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Re: Best Solar Power for Macbook Pro and Cell Phone?

Post by _JT » Tue May 02, 2017 9:00 pm

C40 wrote:
Mon Oct 10, 2016 10:33 pm
_JT wrote:
Mine is an aluminum unibody MBP from 2011 or so. I know the charger does all sorts of fancy sensing stuff, but when I hooked it up to my homemade charger* it charged with no issue. At least on a short term basis (the solar power isn't all hooked up yet, so I just function tested it). Beyond just needing to use your inverter less, you'd extend the lifespan of your charger by several years I'm guessing. Unless your inverter is an honest to god pure sine wave inverter.

*basically I bought an adjustable 12VDC --> 14-20VDC board off of ebay (made in china for about 3 bucks), and then mounted it in a box. Wired a 12VDC auto-type hookup on the in, and a magsafe2 cable on the out (which I scavenged from an old dead charger I had). Once I get my stuff all hooked up for real and do more testing on the charging I can send you the build details if you're interested.
Mine is newer. Are you saying the 2011 version also does the high resistance and voltage adjustment thing as described by the website I quoted? If so, that gives me some hope for mine.

Please do let me know after some more testing how it works out. I was planning to do exactly what you described but that website I linked discouraged me enough to abandon it.

Well, it took me longer than I thought to get my cabin electrical system all up and dialed in, but it is now. Yesterday I charged my MBP fully off the cabin electrical system (12VDC) and my DC --> DC converter box I built. No issues. Highly recommend.

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Re: Best Solar Power for Macbook Pro and Cell Phone?

Post by _JT » Tue May 02, 2017 9:00 pm

C40 wrote:
Mon Oct 10, 2016 10:33 pm
_JT wrote:
Mine is an aluminum unibody MBP from 2011 or so. I know the charger does all sorts of fancy sensing stuff, but when I hooked it up to my homemade charger* it charged with no issue. At least on a short term basis (the solar power isn't all hooked up yet, so I just function tested it). Beyond just needing to use your inverter less, you'd extend the lifespan of your charger by several years I'm guessing. Unless your inverter is an honest to god pure sine wave inverter.

*basically I bought an adjustable 12VDC --> 14-20VDC board off of ebay (made in china for about 3 bucks), and then mounted it in a box. Wired a 12VDC auto-type hookup on the in, and a magsafe2 cable on the out (which I scavenged from an old dead charger I had). Once I get my stuff all hooked up for real and do more testing on the charging I can send you the build details if you're interested.
Mine is newer. Are you saying the 2011 version also does the high resistance and voltage adjustment thing as described by the website I quoted? If so, that gives me some hope for mine.

Please do let me know after some more testing how it works out. I was planning to do exactly what you described but that website I linked discouraged me enough to abandon it.

Well, it took me longer than I thought to get my cabin electrical system all up and dialed in, but it is now. Yesterday I charged my MBP fully off the cabin electrical system (12VDC) and my DC --> DC converter box I built. No issues. Highly recommend.

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