Question for Mac Users

Discussion in 'Computers' started by Molls-Phot, Oct 22, 2009.

  1. Molls-Phot

    Molls-Phot Funster

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    With one photographer and one writer we both have MacBooks (magsafe versions) that are pretty much in constant use. We are getting our first campervan in a few weeks and are trying to work out the best solution for keeping the laptops fully charged while on the road that does not involve EHU/campsites.

    We reckon a dedicated leisure battery connected to a 300W pure sine wave invertor should do the job. We are aware that a solar panel and portable generator are alternatives but too expensive to go for until we have tried cheaper means first.

    My question is are there any other solutions that we may not have thought of? What are the experiences of other MacBook users with power issues?

    Thanks,

    Gary
     
  2. 6pm Cowboy

    6pm Cowboy Read Only Funster

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    Got me going there :Smile:

    I always champion the mac but mine is an IMac.

    Keeping laptops topped up has been discussed so I am sure someone will be along with an answer.
     
  3. scotjimland

    scotjimland Funster Life Member

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    Hi

    Much depends on how long you will be in one location, the size of the leisure battery(s) and the load from the Macs ..

    I will use some arbitrary figures to give an example..

    Lets assume you fit another 85ah battery in parallel with the existing 85 ah one , that gives you a total of 170ah .. as you should never discharge below 50% that gives you a useful supply of 85ah

    Two Macs ( not certain about your Macs, check the back to see the wattage ) lets say 90watt each = 180 watts total.

    Ignoring the losses from the inverter , that puts a load of 15A on the batteries .. (180/12) so they will be down to 50% in about 6 hrs or less...

    That doesn't take into account any other loads , water pump, lights, TV , radio etc .. so it could be as little as 4 hrs

    As engine alternators are not good chargers even after a full days driving they will not be fully re charged. at best about 80%

    So.. I suggest you fit the biggest batteries possible.. 2 x 110ah if you have the space.. and have a small suitcase genny for charging, say 1kw.

    You also need to check the MH on board charger, it may not be a proper multi stage charger, if so, you need to instal one to get max charging from the genny.


    I hope that helps,

    jim
     
  4. JeanLuc

    JeanLuc Funster

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    I use a 15" MacBook Pro with 85 watt magsafe adapter. In the motorhome I use it for viewing DVDs and occasional work so not as heavy use as you. My solution was to install a 150W pure sine wave inverter powered by the standard leisure batteries. You might need a 300W version to power 2 Macs simultaneously, but a good quality inverter will have a bit of peak 'headroom above its rated level. The Sterling model I use can handle a peak of double its rating.
    If you start with the MacBook fully charged, I find it takes little power to keep it that way. If it runs down, then clearly, it needs more input to re-charge the Mac battery. If you are on the move quite frequently, the MH leisure batteries will be re-charged and I would not have thought you would need a dedicated leisure battery for the Macs, assuming you have sufficient standard battery power (2 x 110 Ah in my case).

    I posted a document detailing my installation in the downloads section (left hand side of the 'Fun' home page under resources). It is in one of the miscellaneous sections (in case the link below does not take you there automatically.

    Philip

    >>Installing a small inverter<<
     
  5. Molls-Phot

    Molls-Phot Funster

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    Many thanks for the advice so far.

    I forgot to mention that we anticipate moving between locations each day and we certainly won't be static for more than 36 hours. I have the 15" MacBook Pro and measured its peak current at 29W. The other is a MacBook which I assume will use the same or less power.

    As we reckon you can never have too much power we will likely go for another leisure battery, which we will have professionally installed along with a Sterling as they look the best available. It will also be useful for charging camera batteries and the toothbrush!

    All will become clearer when we actually get the van!
     
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