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How to connect a magsafe to a solar panel

How to connect a magsafe to a solar panel

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Asked by: Guest | Views: 227
Total answers/comments: 4
mcgyver89 [Entry]

"Here's where I think your problem lies...

Mac computers draw a fair bit of current. If you look at your magsafe puck it's likely 60 or 85W (i think) and 35ish for the macbook air. In order to get 60W from a solar panel, you're looking at something the size of your computer desk (2ftx3ft minimum). The Gorilla charger looks to put out about 10W. So, will your computer register that it's ""charging"", probably. But this is likely not the case. It only registers that because your magsafe is plugged in and there is SOME current coming from it, but not enough to actually run your computer. I don't know what the actual draw is on a macbook but it's more than 10W (Volts X Amps). So, when you're running off of your solar panel you're actually drawing most of your power from your battery and only a tiny bit from the panel. The net result of this is that you actually kill your battery. Not sure why, it just does. Same goes if you try to charge a macbook pro with a macbook/macbook air charger. The current isn't sufficient, and because of that it draws strangely on your battery and WILL kill it. My friend has gone through 3 macbook pro batteries because he was using a 60W charger rather than a 85W. Took him 3 batteries to figure out why they were dying after only a week.

If you do want to charge your macbook with a solar panel, I'd only do it if your computer is off. I think this should work to slowly recharge your battery.

My theory behind this method. Lithium batteries die when they drop below a certain voltage. Your computer knows this and shuts down before you get into this critical phase of the battery cycle. When you use your solar panel your computer ""thinks"" it's charging properly and therefore doesn't shut down when the battery gets critically low (because a normal mac charger has enough current to power your computer and charge your battery at the same time). Your makeshift charger cant perform both of these tasks because it doesn't pump enough juice. As a result, you constantly drain your battery (albeit slowly because the solra charger is aiding a little) below it's safe range. Inevitably, your battery drops below the critical voltage (something like 2.8v per lithium cell) and it will never charge again.

Does using a solar charger always kill your computer battery, no, but more than likely it's going to dramatically shorten the life of it.

Cheers

W"
mcgyver89 [Entry]

"This one is tough. I looked up the Solar Gorilla and they make you buy a $60 adapter. There is a solar power ""generator"" from Voltaic Systems that costs $500, so that is spending more money if you return the Gorilla.

If you can try to make a jumper from 10 or 12 wire and alligator clips and make connections on pins until you have the power you need. It may be as simple as clipping to the regular 2 prong wall plug.

If you have a multimeter this may be the way the way to test the output of the solar panel prior to hooking up to the actual computer.

That being said, I hope you can do it so you don't have to spend another dime!

Regards,

Frank"
mcgyver89 [Entry]

"Solar panels put out DC electricity

Look at what your AC/DC power charger for you computer put out for DC.

V is voltage

A ( or I) is current in amperes

W is watts (power)

W=VA

For example a MacBook. A 16.5 V 3.65 A is required to charge the battery. To find the power (W) 16.5 X 3.65 = 60.225, this the power required and is also the power of the solar panel you will need a 12V 60W rated solar panel

You can also make a solar generator, a solar panel+ charge controller + a deep cycle battery and a power inverter."
mcgyver89 [Entry]

"I live off-grid. I have a MacBook Pro 17"" (model A1261) which requires a 85W power supply. I also have a Solar Gorilla and a Power Gorilla which I used for a summer before I got the main solar system up and working.

You can't run the laptop directly off the Solar Gorilla because the power supply is too variable. There's a massive difference in what a panel can output in full sun and what happens when clouds pass over. The idea is to charge a battery (ie. the Power Gorilla) with the panel and then use the battery to run/charge your devices. The best use of the combo I found was to remove the laptop's battery and run the computer directly off the Power Gorilla. It doesn't draw a constant 85W and the bulk of the draw is for battery charging, so avoid processor-intensive operations and you can get a reasonable amount of time out of it. And I did shell out for the 3rd party MagSafe connector Solar Gorilla supply."