Laptop Charge While Camping; Long Term (Newbie Question)

I must say that I was thrilled to have found this forum! I've been reading posts for the past hour now, but still have questions. I don't mind researching and becoming informed on the subject (book recommendations are welcome), but I've found this all a bit overwhelming and am not sure where exactly to start.

I will am volunteering at a somewhat remote campsite in B.C., Canada all summer. (Campsite is 18km outside of Fruitvale, 20 minutes West of Creston and about an hour South of Nelson). I am a freelance writer, so I'll need to access my laptop 4-6 hours a day. It runs at 60W, I think - the power cord says the following: INPUT 100-240V - 1.9A, 50/60Hz, OUTPUT 16V 4.5A. I've also got a 150W (300 amp) Power Box from Motormaster with adaptors. We'll have a car onsite, and will be hitting town probably twice a week.

From my calculations (and correct me if I am wrong), I should be getting a 60-80W panel (or combination to create that amount of wattage) that is element-ready.

Have I got this right? Will I need anything else? Should I do some further reading? Thanks so much for your time.

Comments

  • System2
    System2 Posts: 6,290 admin
    Re: Laptop Charge While Camping; Long Term (Newbie Question)

    What make and model of laptop?

    Mike
  • crewzer
    crewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    Re: Laptop Charge While Camping; Long Term (Newbie Question)

    Sorry about this question dropping through the cracks... Is this previous discussion at all helpful?

    Regards,
    Jim / crewzer
  • System2
    System2 Posts: 6,290 admin
    Re: Laptop Charge While Camping; Long Term (Newbie Question)

    First, I apologize for not responding sooner! I checked back for a while, and then forgot to. I was very happy when I saw not one, but two responses.

    Make and Model: IBM Thinkpad R40

    I did review that posting, and thank you for sending me the link. However, that person is looking for something not terribly portable; we are camping at a remote location (although with a car) and can't lug around a 75W panel (which is what I've estimate I'll need at this point in time). Affordability is key as well, so although the thin rolled panels (I can't remember their official names, sorry) are very appealing, I've only found them in the $300 USD range for about 15W at this point... but then again, that's why I posted here originally. I assumed either (a) I am miscalculating, or (b) I've not found a source of information that would fill in the cracks, so to speak.
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Laptop Charge While Camping; Long Term (Newbie Question)

    use the car's electrical system by plugging into the cigarette lighter adaptor. this should be good for a short while even without starting the car as it should allow the laptop's battery to chargeup without a dangerous drain to the automotive battery. if going to charge the laptop up several times be sure the car battery can take it without stranding you. once you know your limit you know you can't go beyond a certain point without restarting the car to recharge the automotive battery.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Laptop Charge While Camping; Long Term (Newbie Question)

    Other than trying to do this with a 80 watt+ solar panel, possibly a storage battery, and inverter/converter for you laptop... You are correct that you are not going to find much out there that will reliably and cheaply power any electronic equipment that consumes more than a little bit of power.

    Even running an inverter off of your car battery, you will only be able to run the laptop for a couple of hours before the car battery starts draining below 80% capacity (probably around 200 Watt*Hours)--which will damage the battery over long term use.

    You could get a storage battery that you can drain to 50% capacity, and charge it when driving the car--but a "car sized" storage battery is only going to give you 500 Watt*Hours of energy before you should recharge it. May be 10 hours of use.

    For reliable, and fairly cost effective power, a small generator is still probably going to be your best bet. Honda makes a range of small and very quiet generators (1kW, 2kW, 3kW) that should run you around $700 USD for the 1kW and ~$900 USD for the 2kW version (in the US, I purchased my 2kW unit from www.mayberrys.com).

    http://www.hondapowerequipment.com/gensup.asp

    Fuel wise, according to Honda's numbers, the eu2000i uses, at low power, about the same amount of fuel per kW generated as the smaller eu1000i (but generates much more electricity for the same fuel usage). Depending on your needs, you can probably run the laptop for an hour or two on batteries and on the generator for a couple of hours and charge at the same time. In theory, 1 gallon of gasoline should give you about 2.8 to 5.8 kWhrs of electricity--the equivalent to 5-10 car sized storage batteries. In either generator, if it is just your laptop plugged in, they will run for around 15-16 hours per gallon of fuel.

    Hmmm... Lets try another tact (running a generator several hours per day may not be what want). Looking at the IBM web site, the new versions of the Think pad should last around 8-10 hours per battery charge using the extra capacity battery option...

    http://www.pc.ibm.com/us/accessories/battery/alldaycomputing.html
    http://www-131.ibm.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=-840&langId=-1&partNumber=92P1119&storeId=10000001

    The larger batteries recharge in 4.3 to 12 hours (laptop off vs on?). The battery (above link) is rated at 4.5 amp*hours at 14.4 volts = 65 watt*hours. If your laptop will run for 8 hours on a charge, then the average consumption is around 8 watts.

    At 8 watts, that is quite a small load, and a storage battery, car battery or even buying a couple extra batteries to recharge on the way to town and back may be a good deal. I would feel pretty safe charging two of these batteries without starting the car ((good for 16+ hours of run time). A Honda 1000 watt generator would be way overkill if you did not need the electricity for anything else.

    Unless you have found a 12 VDC to Laptop adapter, you would probably be better off getting a small 200 watt inverter that can connect to the car/battery and just charge the laptop directly. To see what your "real" power usage would be in this case, I would suggest you get a hold of a power meter, like the Kill-A-Watt (~$34 USD) and measure your true power consumption. It appears your supply is sized to run both the laptop and charge the battery at the same time (rated for a worst case use--makes sense).

    http://www.amazon.com/gp/product/B00009MDBU (Kill-A-Watt meter at Amazon)

    If you were going to be in the bush, away from gas/electricity for a long time, it might be worth trying to figure out if you could run the laptop directly off of a Solar PV panel--but you would probably need to contact IBM (or an electrical engineer) to see if the laptop's input would be compatable with the solar panel's output (wide voltage range and less than full current output). You could also look for a 12 VDC charger for the batteries themselves.

    And, running for a few days on the Kill-A-Watt meter will help you see how much power is affected by your use (bright screen in day, lots of power, typing at night with screen backlight set low, much less power, etc.). You might be OK just running off a trolling motor battery that you charge once a week.

    Your thoughts on how you would like to proceed from here?
    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Laptop Charge While Camping; Long Term (Newbie Question)

    bb,
    you misunderstand me in my saying to use the car battery. i never said use an inverter, but to use those dc to dc converters that matt and brock were talking about. this would recharge the internal laptop battery so there's no hours on end being talked of through an inverter that would drain the car battery too far. if it can be done with a 12v pv it can be done in a car. recharging the car battery is a matter of starting it up and running it for a short time.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Laptop Charge While Camping; Long Term (Newbie Question)

    Hi Niel,

    I did not think I was in disagreement with you Niel... I suggested the inverter/converter assuming that both would be similar solutions. The "car converter" has, of course, some sort of buck/boost/inverter type circuit. And wether or not it would be more energy efficient to go 12 vdc to 110 vac to 16 vdc or just 12 vdc to 16 vdc via a car/laptop converter depends on the individual designs -- but it would probably be better to obtain the 12 vdc converter. And it would be best to measure using a volt/amp meter.

    The "hours on end..." of use would apply to operating the laptop itself (4-6 hours per day of the user) and, if the internal batteries are used, IBM (see battery link) says that it takes 4.3 to 12 hours to charge the internal laptop battery. Either use would require many hours of some sort of power. Charging the car battery (assuming a 20% capacity, 200 watt*hour discharge) would probably take an hour (+/-) of idling or driving to fully charge back to full capacity.

    And, in any case, we where writting our posts at the same time and I did not see your's (or address any of its points) until after I posted mine (got the new post warning)... I was just using both user information (72 watts 4-6 hours per day 450 watt*hours) and IBM's information (8 watts * 6 hours = 50 watt*hours or almost 1/10 the amount of power originally assumed) to form a couple of options (generator if 72+ watt load, batteries/solar if 8 watt load) and leave it to Bonny to tells us how she (?) wishes to proceed from here.

    The current crop of laptops from IBM use only and average of 8 watts (if the battery link is correct--did not find the R40 information but am assuming it is still close), and if I was on a trip where solar was much preferred over generators and/or storage batteries, it is very possible that connecting a (as an example) twenty watt 12 volt (actually ~17 volt) solar panel directly on the 16 vdc laptop input (with an 18 volt zener diode clamp and a Schottty blocking diode to protect the laptop) may actually be enough to charge/support the battery/cpu during the day and use the laptop in the evening. Using the laptop in the evening/night is also energy efficient because of the lower use of backlight.

    Of course, not having the laptop (perferably a cheap EBay purchase to test on), solar panel, and bench top lab supply in front of me--it would not be possible for me to guarantee that any non-standard DC input configuration for the laptop is safe and reliable. Failing that, then going back to an AC or DC power input brick with a hybrid solution of solar/generator and/or battery is the only off-the-shelf solution I can think of.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Brock
    Brock Solar Expert Posts: 639 ✭✭✭✭
    Re: Laptop Charge While Camping; Long Term (Newbie Question)

    Another crazy idea might be to throw a given size panel on the cars main battery and use the inverter to charge/run the laptop. You could use a true deep cycle battery, but that would add cost and weight. It's not the most ideal, but might work. Going back to say a daily load of 200w/h and assuming 4-5 hours of sun you need to just add about a 50w panel to the car battery and your good to go. I would add a smallsunsaver or similar controller just in case.
    3kw solar PV, 4 LiFePO4 100a, xw 6048, Honda eu2000i, iota DLS-54-13, Tesla 3, Leaf, Volt, 4 ton horizontal geothermal, grid tied - Green Bay, WI
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Laptop Charge While Camping; Long Term (Newbie Question)

    that would work too brock. you know everybody does have to back up and take a good look at the batteries in a laptop. we're talking at the most around 5ahrs. this won't do much to a car battery as far as draining it goes and as wattage for a pv is concerned you could probably get away with an even smaller pv than 50w if it's connected up to the car battery. this one 50w pv is a good portion of the entire capacity of a laptop battery. typical may be 4.5x14.4=64.8w. add about another 20% or so for conversion and charging losses for about 80w total to charge it up. even a unisolar 32 with a small sunsaver would do it if connected to the car battery for at least 3hrs of the day. there's no getting around a voltage converter for you bonny as you will have to have one. your computer manufacturer may make one.
  • System2
    System2 Posts: 6,290 admin
    Re: Laptop Charge While Camping; Long Term (Newbie Question)

    I have a lot to read up on and process here, so give me a day or two to look into it before I can reply with any sort of coherence.

    And yes, I am female. :)

    The newer IBMs do have 4-7 hour battery run times; mine only came with a refurbished battery that lasts about an hour or two depending on several variables, although I can upgrade to one of the newer ones. (eBay link... http://cgi.ebay.com/NEW-Hi-Cap-LiON-Battery-for-IBM-ThinkPad-Laptop-R32-R40_W0QQitemZ6883415228QQcategoryZ14298QQrdZ1QQcmdZViewItem)

  • System2
    System2 Posts: 6,290 admin
    Re: Laptop Charge While Camping; Long Term (Newbie Question)

    Another addition; the Motormaster Power Box that I have already purchased (I *think*) will work as a converter. Canadian Tire won't let me link directly to the product, but here is the generic blurb:

    The Motomaster Eliminator 300W PowerBox is easy-to-use and designed for years of reliable service.

    Provides 120V AC household power, 12V DC power
    Built-in 150W inverter with grounded outlets provides household power, anywhere, anytime
    Sealed, non-spillable 12 amp-hour AGM battery
    Reverse-polarity detector for safely jump-starting your vehicle
    300A booster feature boosts vehicles' dead batteries; jumper clips designed for easy storage on the unit
    Built-in light provides illumination in emergency situations at home and on the road
    LED indicator for monitoring the battery charge level
    Overload and over-temperature protection to ensure longer inverter life
    Recharge from household current or from a vehicle
    Powers camcorders, video games, stereos, 13" TV, as well as runs fans, computers, laptops, portable stereos, and clock radios

    I had planned to set up a solar panel to the MotorMaster box to recharge it as needed, and then run the laptop from the outlet as required to juice up the battery. Then I realized I needed some input... and found this forum.

    Again, I'm learning everything from scratch; three weeks ago I didn't know anything about anything! *laugh* Give me a day or two to figure it out.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Laptop Charge While Camping; Long Term (Newbie Question)

    The power box will work fine... If the battery is rated for 12 amp-hour that is 12a*12v*1h=144 watt hours. You will only want to use 1/2 of that (so that battery will last), giving you 72 watts. You should be able to run your laptop for 4-10 hours safely (depending on the laptop's load), or recharge your laptop battery a couple of times. (it would be nice to have a current meter to measure how much power you are really using).

    Go here and look at the solar panels:

    http://store.solar-electric.com/instock.html

    A 12 volt (really around 16-17 volts DC), 20 to 50 watt unit should be fine.

    And, assuming your power box does not have a 12 vdc charge controller, you should purchase something from this page:

    http://store.solar-electric.com/mochco.html

    Even the smallest on this page (4.5 amps) will work for up to 80 watts of solar panel. The least expensive one here is $30 and has for wires to connect... Two to the solar panel, two to the battery.

    http://store.solar-electric.com/sg-4.html

    If you were going to build your own battery box, and/or wanted to monitor your load (like how much current your laptop is drawing), you could go with this unit:

    http://store.solar-electric.com/pros30solcha.html

    It looks very nice--has a digital meter for you. However, it is probably way overkill for your application at $155 (and can handle ~180 watts of solar panels). But it also has a battery temperature monitor--very worth while for good battery life (again, really for larger battery systems).

    Also, when you are storing your battery box for more than a week or so without charging (or solar charging), I would disconnect (or use a switch) to make sure that the solar charger does not slowly discharge your battery (for example, the small SunGuard will discharge your battery box over a couple of months without sun).

    Have Fun,
    -Bill

    PS: Might as well add, this solar panel might be very nice for your application. 64 watts (a bit on the large size) but is not made of glass--so is better for packing and camping. Price per watt (how you should price all solar panels) is very good (20 watt glass panel is ~$200 or just under $10/watt, the 64 watt ~$375 or ~$6/watt). These panels are somewhat larger because they are not as efficient at generating electricity (although, they are supposed to work better in hot weather than the crystalline types).

    http://store.solar-electric.com/unus64wathfi.html

    The company also makes a 32 watt panel (and smaller). You can probably call NAW&S, or others, and see if you can find the 32 watt version if the 64 watt is too big to lug around.

    -BB
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset