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Thread: Charging a laptop from a bike - Inverter or ???

  1. #16
    criminaldesign
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    Exactly what I'm dealing with.

    Being a remote working graphic designer, I'm able to travel when I like for the most part but have no way to charge the macbook when on the road, other than the above mentioned of the hotel or wherever you may be. I zip tied a $5 dc power outlet on the bike for the phone.

    When I stop, outlets are usually my main concern. I've pulled 8 hr work days at coffee shops truck stops and rest stops always keeping plugged in for the precious juice, not knowing what later is going to be like. I've crushed the 5hr battery life the laptop says is left in 3.

    But there's always the moment where I'm in the middle of nowhere sitting by a creek or somewhere in the plains, or by tent making a final change to a graphic, attach to email and the comp dies before it sends. Race against time.

    McDonalds and such used to be a guarantee for electric, here recently it seems the outlets have vanished, leading me to believe they don't appreciate my visit and my electric needs.

    I've kept an eye out for a macbook safe charger, but afraid of whats out there as I can't risk loosing work.

    Question, in this supposed mobile culture and access to anything with your fingers, why hasn't apple covered this? It's their fault we're all in this position of living by the gadget.

    For the mean time, it's wall sockets for me and the continual search goes on....

  2. #17
    Registered User richardak's Avatar
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    I picked up an external battery pack for my MacBook Pro at batterygeek.com. It'll charge up the internal battery almost twice per charge. plus it has a USB port to charge my phone. BTW, the Mac chargers are 19.5 vDC which may be why their airline/car adaptor will power the laptop but not charge the battery.
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  3. #18
    Cam Killer marchyman's Avatar
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    Quote Originally Posted by richardak View Post
    I picked up an external battery pack for my MacBook Pro at batterygeek.com.
    Did you mean http://www.batterygeek.net/ ???

  4. #19
    Unfunded content provider tommcgee's Avatar
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    Quote Originally Posted by criminaldesign View Post
    I've kept an eye out for a macbook safe charger, but afraid of whats out there as I can't risk loosing work.
    There is one in the Apple Store:

    Kensington Inverter
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  5. #20
    Registered User richardak's Avatar
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    Quote Originally Posted by marchyman View Post
    Yep, that's the one. I have the 130 watt-hour model with the USB port. Back when I ordered it they still had the option of shipping with a Apple Mag-Safe connector. I heard that Apple made them stop.
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  6. #21
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    Quote Originally Posted by tommcgee View Post
    My white MacBook has a 10.8V battery. My 2010 MacBook Pro has an internal battery, but both machines use the same Apple Magsafe Charger. It's a good bet that the MacBook Air also has a 10.8V battery.

    There's a small switching power supply inside the Apple power brick, and as I say, it prolly deals fine with inverter input. The big problem with the damn thing is the output cord. The strain relief does not do a proper job. YouTube is loaded with videos about how to fix the cable. Most start with a dremel tool. The thing was not designed to be serviced.
    The voltage required to charge that battery from the DC input on the laptop might be more than twice the battery voltage. Unless you want to remove the battery to charge it, look at the DC OUTPUT of your AC adapter. That will have to match when you charge the laptop.

    Or look to see if the input voltage is mentioned on the laptop itself.

    -Don-

  7. #22
    Unfunded content provider tommcgee's Avatar
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    Quote Originally Posted by DonTom View Post
    The voltage required to charge that battery from the DC input on the laptop might be more than twice the battery voltage. Unless you want to remove the battery to charge it, look at the DC OUTPUT of your AC adapter. That will have to match when you charge the laptop.

    Or look to see if the input voltage is mentioned on the laptop itself.

    -Don-
    Good point. If we could only get all laptop vendors to mark voltage and current requirements on their products. Chargers usually ARE marked. I don't think I've ever seen a 2X difference in voltage between battery installed in device and charger, 1.5x is more typical. The battery voltage and charger voltage is much closer when charging a standalone battery.

    After you have a charger with the right voltage, and you MUST match charger voltage with device voltage, what's equally important is to match charging current because if the charger can't provide enough of that, the battery will not fully charge.

    My battery comment was about two different Apple products that use the same input connector. I should have been clearer and more specific. Apple does make three versions of its magsafe charger, a 45 watt, a 60 watt, and an 85 watt. The difference is the current capacity -- all three output the same voltage.

    I get bit by this once in awhile because there are at least half a dozen different Apple laptops in the house. They look identical, but if you pick the 45 watt version when you need the 85 watt version, the battery voltage will never make it to 100%.
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  8. #23
    Cam Killer marchyman's Avatar
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    Quote Originally Posted by tommcgee View Post
    My battery comment was about two different Apple products that use the same input connector. I should have been clearer and more specific. Apple does make three versions of its magsafe charger, a 45 watt, a 60 watt, and an 85 watt. The difference is the current capacity -- all three output the same voltage.
    The labeling on the 45 watt charger for my MacBook Air says 14.5 volts at 3.1 amps. If I ever decide I want to charge the laptop on the bike I'll buy an inverter. In the 20 years I've been carrying a laptop I've not yet needed to charge it on the bike. I think that just means I've not done any long, camping only trips.

  9. #24
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    Quote Originally Posted by tommcgee View Post
    There's nothing inherently wrong with an inverter, it's just that there's a lot of cheap crap out there. You gotta choose carefully.
    Do I need to lookup the lighter insert style inverter we have from Wally World to make certain it isn't on your "cheap crap" list (and has the curved waves , not square)? FWIW, I didn't choose it and never had the papers either.Thus to avoid frying our laptop?

  10. #25
    Registered User naddy100's Avatar
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    Quote Originally Posted by kantuckid View Post
    Do I need to lookup the lighter insert style inverter we have from Wally World to make certain it isn't on your "cheap crap" list (and has the curved waves , not square)?
    This is my question as well. I have a 175W inverter.
    http://www.radioshack.com/product/in...odsInSession=1

    It doesn't say sine wave, so I figure it isn't.

    I picked up a $10 Phillips surge protector, but reading the fine print, it seems to be more interested in protecting against *surges,* which I suppose to be different from square waves. So, the surge protector may not be helpful.

    The inverter has a fuse.

  11. #26
    Unfunded content provider tommcgee's Avatar
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    I'd trust the RatShack inverter over the one from WallyWorld. As to square waves, that's how they work. All inverters produce them. The good ones have filtering to take the edge off, so to speak. You can see this stuff on an oscilloscope, but they aren't exactly household items.
    Salty Fog Rally 2007, 2009, 2011, 2012, AND LOOKING FORWARD TO 2014!

    -Tom (KA1TOX)

  12. #27
    BUDDINGGEEZER
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    I have a Black and Decker 100W inverter. I haven't used it on a lap op but the package says "powers and recharges laptops, electronics and more"

    Output wave form: modified sine wave (whatever that means.

    Ralph Sims

  13. #28
    criminaldesign
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    Quote Originally Posted by tommcgee View Post
    There is one in the Apple Store:

    Kensington Inverter
    perfect, thanks tom. h

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