Simple, portable laptop system (help!)

System
System Posts: 2,511 admin
in Solar Beginners Corner #1
Hi All,

I've been scouring the internet for days, can't find any simple, straightforward advice on rigging up a system to power a netbook computer.

Here are the specs:

Small netbook with 19V, 2.1A input (the adapter draws 100-240V, 1.2A)

Here is the question I can't find an answer to: Can I power this with a 12V deep cycle battery and inverter? How many amp hours would be reasonable for the battery capacity? What rating would the inverter need to have (think cheap!)?

And lastly, what panel setup would be appropriate to charge the battery (assume average North American sunlight)? Could I buy a cheap 12V 7W panel? Could I buy two of them and link them somehow? Would I need a charge controller with such low amperage?

I know this is a simultaneously pissy and amateur post, but I think a good answer would be able to help a lot more people than just myself in the long run. Thanks in advance!
· Share on Twitter

Comments

  • AntronX
    AntronX Solar Expert Posts: 462 ✭✭
    #2
    Re: Simple, portable laptop system (help!)

    What is the purpose of powering this netbook from solar? What is the runtime per day? Is it one-off deal or you are making many of solar netbooks? It it goign to be portable setup?
    · Share on Twitter
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #3
    Re: Simple, portable laptop system (help!)

    Lap top will draw ~50 watts.

    Given a 4 hour run time, that is 200 watt hours /day.

    To power that you will need ~100 watts of panels, given an average of 4 hours of good sun, about what one can expect on average.

    A 12 volt battery, using 200 wh would use ~16 ah/day. To keep a battery in the good range of of discharge (not below ~75%) on average, you would want a battery of ~ say 80-100 ah.

    You can buy a 7 watt panel, but it isn't going to do anything except keep a battery float charged if there is no load.

    Personally, I would consider getting a Plane/auto adapter for the lap top instead of an inverter. A sine wave inverter running at only ~50 watts is going to run fairly inefficiently. Just run directly off the 12volt battery, and it will use less power net/net.

    What is it you are trying to achieve?

    Tony
    · Share on Twitter
  • AntronX
    AntronX Solar Expert Posts: 462 ✭✭
    #4
    Re: Simple, portable laptop system (help!)
    jackgrump wrote: »
    ...Can I power this with a 12V deep cycle battery and inverter? ...

    You could, but that would not be very efficient. It's better to skip using inverter and PSU, and go with 12V to 19V DC-DC converter. You would need 18Vmp solar panel, small charge controller, battery (AGM or Lithium) and DC-DC converter. Here is PST-P90W 90 Watt converter for $50, way cheaper than sine wave inverter.
    · Share on Twitter
  • System2
    System2 Posts: 6,290 admin
    #5
    Re: Simple, portable laptop system (help!)

    Thanks very much for your answers so far everyone.

    I will be using the netbook for probably 4 hours every other day (about 12 hours per week) - however with a low backlight, no sound or video, etc, to do translation work). The small battery that comes with the netbook can power it for my use for about 5 hours. Basically, I need my 12V deep cycle to charge the laptop battery, or maintain it during laptop use.

    I assume I can also (bulk) charge the 12V battery from the truck's cigarette lighter while driving, to supplement the panel's input?

    With a 12V-19V converter, would it be possible to make a linkage: panel->converter->charge controller->laptop, and skip the external battery?
    · Share on Twitter
  • AntronX
    AntronX Solar Expert Posts: 462 ✭✭
    #6
    Re: Simple, portable laptop system (help!)
    jackgrump wrote: »
    ...With a 12V-19V converter, would it be possible to make a linkage: panel->converter->charge controller->laptop, and skip the external battery?

    If you only want to recharge laptop's internal battery from solar, in theory, you could get by without charge controller, dc-dc and battery. You would need the device connected between solar panel and laptop, that would limit voltage to 19V and disconnect solar panel when voltage falls below certain point. This method is not reliable. There needs to be energy storage buffer to keep solar panel always under load, and to regulate sporadic voltage conditions from solar panel. This would provide steady power source for dc-dc converter.

    Another possible solution is to tap into laptop's battery pack and charge it directly from solar, instead of internal charger and 19V source. That would require some electronics to be engineered for this application. That may also confuse battery monitor in the laptop. So the answer is, stick to original idea of PV>controller>12V batt>DC-DC>laptop.
    · Share on Twitter
  • dwh
    dwh Solar Expert Posts: 1,341 ✭✭✭
    #7
    Re: Simple, portable laptop system (help!)

    He said netbook, not laptop. My Acer Aspire One ZA3 draws less less than 15w when the battery is charged. Not sure how much it draws when it is charging, but the I think it's probably under 25w.

    Adjust calculations accordingly. :D


    EDIT: jack, here's a link to a post I made not long ago. Might give you some ideas:

    http://forum.solar-electric.com/showpost.php?p=58906&postcount=10
    · Share on Twitter
  • System2
    System2 Posts: 6,290 admin
    #8
    Re: Simple, portable laptop system (help!)

    Thanks a bunch for all the help, guys. I'll post back here when I get the system up and running, or blow up my laptop - either way.

    One last question: is there a way to charge a 12V deep cycle battery from the cigarette lighter in my truck? I assume the battery doesn't draw current like a load, but when the alternator is running at speed, the voltage is high enough to bulk charge? I suppose I'd put my charge controller between the cigarette lighter and the battery, too, but I honestly don't understand the dynamics of such a system.

    Any ideas much appreciated as always! Thanks
    · Share on Twitter
  • AntronX
    AntronX Solar Expert Posts: 462 ✭✭
    #9
    Re: Simple, portable laptop system (help!)

    Just charge your laptop from 12V plug via DC-DC converter. Charging the battery from cig. plug is possible as long as you limit charging current below 10A. Plugging in discharged 12V battery directly into the plug will result in blown fuse, because the battery will most likely pull way more than 10A without current regulator in line.
    · Share on Twitter
  • RWB
    RWB Solar Expert Posts: 168 ✭✭✭✭✭
    #10
    Re: Simple, portable laptop system (help!)

    You do not need a inverter and the AC Adapter.

    Your netbook will run for 5 hours off on fully charged battery. That battery is probably a 20-50 Wh battery.

    Here is a system that would probably run your net book for 10 hours and recharge in peak sunlight in 3 hours everyday.

    http://www.powerenz.com/store/index.php?_a=viewProd&productId=173

    I have tested many different small portable systems and the one above is my favorite by far because its so small yet still very usable due to its many voltage outputs. The solar panel also has the best high heat performance we have tested to date due to its Unisolar cells.

    If a grand is to much the Ultra Light system is the next best option if your wanting small and light weight but its going to take 5-6 hours to recharge if you upgrade to the 20w panel. The 10w panel is going to take 10 hours/2 days to fully recharge the battery from dead.

    You can remove the link mods if you think this is not ok.
    · Share on Twitter
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #11
    Re: Simple, portable laptop system (help!)

    Someday some company is going to build a netbook with a solar panel built in that will recharge the battery every time you close it up and put what power it can in when open. Just watch. :D
    · Share on Twitter
  • AntronX
    AntronX Solar Expert Posts: 462 ✭✭
    #12
    Re: Simple, portable laptop system (help!)
    RWB wrote: »
    http://www.powerenz.com/store/index.php?_a=viewProd&productId=173

    That is one pricey little setup. You can power a lot more than little netbook with $1000 of conventional solar components.
    · Share on Twitter
  • RWB
    RWB Solar Expert Posts: 168 ✭✭✭✭✭
    #13
    Re: Simple, portable laptop system (help!)
    AntronX wrote: »
    That is one pricey little setup. You can power a lot more than little netbook with $1000 of conventional solar components.

    Just depends what the buyers needs are.

    Its a ready to go package that is better than any other option your going to find in its weight class.

    I've been using this setup for almost a year straight now and it has never failed me.

    I agree that you could build something cheaper but more than likely its going to be much bigger and heavier and not near as convenient to use.

    I'm always looking for the best portable setups out there and so far that system is my favorite small system I have ever used, and its my favorite because it actually works as its supposed to and has a quick dead to full recharge time, a perfect package in my opinion.

    We have lots of cheaper heavier systems if price is a concern.
    · Share on Twitter
  • System2
    System2 Posts: 6,290 admin
    #14
    Re: Simple, portable laptop system (help!)

    Heartily agree with AntronX. I admire the weight and size specs on that system, but it's a cold $900 above my budget!

    For $1000 I'm visualizing my off-the-grid dream house :)
    · Share on Twitter
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #15
    Re: Simple, portable laptop system (help!)
    jackgrump wrote: »
    Heartily agree with AntronX. I admire the weight and size specs on that system, but it's a cold $900 above my budget!

    For $1000 I'm visualizing my off-the-grid dream house :)

    For your off-grid dream house you'd better plan on multiplying that $1,000 by 10. :cry:
    · Share on Twitter

Categories