An AN challenge: Power my laptop

[mattf]

Unable to decide on the best way to power my laptop, I've decided to tap the brains of all you intelligent types here at Applenova. Brown-nosing out of the way ....

A bit of background:

Mrs f & I have recently decided to try a bit of travelling. I'm contracting these days, so it was an easy decision to make - I just find a contract in a part of the UK we want to visit, and 3 - 6 months later move on again. That could be anywhere from Cornwall to Shetland. To solve the accommodation problem, we went with a (some might think) drastic solution.

http://www.papercat.co.uk/personal/AN/rona_me_and_morgan.jpg

Rona The Big Green Van is our new home and she's a beauty. Actually, she's a tip at the moment, but whatever - we're happy with her.

Things she has:
A working engine
A working alternator
A bed / seats / table area
A cooking area
A desk
A 12V cigarette lighter socket in the cab


Things she doesn't have:
A fixed landline
Mains electricity
A leisure battery
A split charge diode (after all, without a leisure battery what's the point)
Any other method of charging the main battery / future leisure battery (e.g., solar panel, wind turbine, hamster wheel)
A 12V - 250V inverter


The problem:

You'll notice that, with the exception of the first item, the list of "Things she doesn't have" has a common element. The thing we do have is a recently acquired, second-hand, MacBook Pro (*) (with a battery that can hold about 80% of its original charge - IRL we seem to get 2 hours of working time - no bluetooth, no airport). In a nutshell, what we need is:

An internet connection
The ability to work on a laptop for 5 / 6 hours continuously (preferably more)


Half the problem solved:

An internet connection is actually relatively easy. We're going to use one of these these (http://threestore.three.co.uk/broadband/) For £7.50 a month, we'll have intermittent connectivity, anywhere we want (OK, anywhere we want that's got decent 3G coverage). Simple, and a bargain. Plus I can always use wireless hot-spots if need be.

What we're currently doing:

Fortunately, I'm able to recharge the MBP at work. I also get most of my browsing done at the office, although there are times when I need access at any hour. We also occassionally use hot-spots (cafes, pubs, etc) and the libraries in Shropshire - our current location - also have free internet wifi (although this isn't the case across all the UK). Unfortunately, this does leave Mrs f with infrequent internet connectivity, and since she also runs an online business (pretty small) this is proving problematic, to say the least.

The challenge:

So, what would you do if you were a stinky gypo desparately in need of an internet fix? Can you come up with a cheap(ish), reliable(ish), small(**) solution?


* I'm not adverse to changing the MBP for something else, as I've not had it that long. I love my iBook G4, but the battery lasts a whole two minutes, I can't run CS3 on it, and I need to test websites in IE (currently using parallels).

** Space is at a premium inside Rona. There is room under the bonnet for a leisure battery.

[Yontsey]

FIrst thing I would do is install a 2nd battery. This way you can wire it up to a capacitor and then to a distribution box and that way you can set up multiple power inverters in your van.

This way you can use regular wall chargers for everyday things. Just wire a cigarette lighter to the cables and wah-la. It should be a very simple process too. I use to run extra battery's and capacitors and what not for people in car stereo systems.

[atomicbartbeans]

Yeah, the most logical solution would be a deep-cycle battery and cheap inverter (make sure you get one with low-voltage shutoff protection). But unless you're going to be driving around a lot, you'll need another way to charge it. Simplest way would be a long extension cord (from someone's house etc) and charge controller, but if you're not running much more than the MBP, I'd consider a solar array - a 12 volt PV setup is cheaper than you might think, depending on the output you need.

[Dovek916]

I'd consider a solar array - a 12 volt PV setup is cheaper than you might think, depending on the output you need.

I think this is a very solid option, although I am not sure if they have batteries so that they can provide power w/o light. As for your internet problem, I think what you should do is add the max data plan to mrs. f's cell phone plan and have here use it as a modem. If she does not use it to much, that she won't go over her bandwidth limit and it will be cheaper than a cell card.

[mattf]

FIrst thing I would do is install a 2nd battery. This way you can wire it up to a capacitor and then to a distribution box and that way you can set up multiple power inverters in your van.

This way you can use regular wall chargers for everyday things. Just wire a cigarette lighter to the cables and wah-la. It should be a very simple process too. I use to run extra battery's and capacitors and what not for people in car stereo systems.

This is the way I'm thinking of going too. The biggest problem is recharging it.

Yeah, the most logical solution would be a deep-cycle battery and cheap inverter (make sure you get one with low-voltage shutoff protection). But unless you're going to be driving around a lot, you'll need another way to charge it. Simplest way would be a long extension cord (from someone's house etc) and charge controller, but if you're not running much more than the MBP, I'd consider a solar array - a 12 volt PV setup is cheaper than you might think, depending on the output you need.

*nods*. Again, this is what I've been thinking of, but the biggest problem is daylight. If I'm up North during the winter, we get down to around 6 hours of daylight. The amount of charge we'd get into the deep-cycle battery would be neglible. In a case like that, a portable wind turbine would be far more effective (we get a damn sight more wind than sun in Scotland). I'm trying to keep away from relying on cables to other people's houses - just a personal thing.

I think this is a very solid option, although I am not sure if they have batteries so that they can provide power w/o light. As for your internet problem, I think what you should do is add the max data plan to mrs. f's cell phone plan and have here use it as a modem. If she does not use it to much, that she won't go over her bandwidth limit and it will be cheaper than a cell card.
:lol: Not in this country! Seriously, mobile broadband prices (since I'm already a 3 customer, I'd get 3GB cap on a £7.50 p/m plan. That's a bargain) have plummeted over here recently. And it gives us the freedom to have the laptop / internet access with either one of us.

Anybody got any thoughts on whether a MacBook would be less power hungry than the MBP? I'm thinking I could sell the MBP for at least half of the cost of a new MB...

[atomicbartbeans]

*nods*. Again, this is what I've been thinking of, but the biggest problem is daylight. If I'm up North during the winter, we get down to around 6 hours of daylight. The amount of charge we'd get into the deep-cycle battery would be neglible. In a case like that, a portable wind turbine would be far more effective (we get a damn sight more wind than sun in Scotland).
This (http://store.altenergystore.com/Wind-Systems/Wind-Turbines-Electric/Southwest-Windpower-Turbines-Parts/Air-X-Wind-Electric-Turbines/Southwest-Wind-Power-Air-X-Wind-Turbine-Land-400W-12V/p1429/) might be what you're looking for then. :) 13 pounds is super light for a wind turbine - it would be simple to construct a collapsible van-top mast to get it 30-40 feet in the air. That model has a charge controller built into the unit, so I assume you can just connect it to the battery. I'd study a mean wind speed (http://www.bwea.com/images/misc/noabl_c.gif) map (along with the graph on the turbine's page) to get an idea of how much power it'll realistically crank out. Of course, you could supplement it with a small PV system if you don't think it'll be enough (but for just a laptop computer I'm virtually certain it's sufficient alone).
I'm trying to keep away from relying on cables to other people's houses - just a personal thing.
I agree - you don't want to be dependent on others, and building something that uses the environment would be damn cool.
Anybody got any thoughts on whether a MacBook would be less power hungry than the MBP? I'm thinking I could sell the MBP for at least half of the cost of a new MB...
Not significantly - maybe an average of 10-11 watts versus 14-15 for a MBP.

Also, as a motorhome enthusiast (I'm currently building mine) may I ask what the layout inside is like? What have you figured out for showering, eating, etc? Let us know how the whole thing goes. :)

[zippy]

This (http://store.altenergystore.com/Wind-Systems/Wind-Turbines-Electric/Southwest-Windpower-Turbines-Parts/Air-X-Wind-Electric-Turbines/Southwest-Wind-Power-Air-X-Wind-Turbine-Land-400W-12V/p1429/) might be what you're looking for then. :) 13 pounds is super light for a wind turbine - it would be simple to construct a collapsible van-top mast to get it 30-40 feet in the air.

Or, you could get this (http://www.windenergy.com/products/air_x_rv.htm) for it.

[Yontsey]

This is the way I'm thinking of going too. The biggest problem is recharging it.

With the capacitor though, it wouldn't necessarily be draining the battery all the time. That's the point of a capacitor. The battery charges the capacitor so that whatever you're pulling from it doesn't come directly off the battery.

I would think unless you're running some hardcore shit off there, you would be fine. Just get a 1 or 2 farad capacitor and you should be gravy.

[Dorian Gray]

How often does Rona have her engine started? For example, do you drive the van to work every day (if so, how long is the drive)?

If it's driven regularly you could add a deep-cycle leisure battery (and split-charge diode) and recharge it from the existing alternator. You might need to fit a larger alternator, depending on your driving time. Older vehicles like Rona often had smaller alternators than they would have if they were sold today, so you might not have much leeway for demands beyond simply charging the starting battery on short trips.

Charging a second battery from the engine/alternator and powering the laptop with a cigarette-lighter adaptor will have the lowest initial costs, but if you find yourself running the engine just to charge the battery, the high price of diesel will rapidly add up. Running the engine more would also be pretty stupid from an environmental point of view.

You could try a micro wind turbine (as used on sailing boats) but would it not be a problem to be seen parked in an urban area with a mast and turbine? May attract unwanted attention. You might also have problems finding stable airflow in a built-up area like the one in the photograph.

Good quality solar cells like the Siemens SM55 produce useful power even on cloudy days, though by useful I mean ~20% of direct sun output. That might still be enough if you have a big battery to even out the peaks and troughs. A panel could be discreetly placed on the roof of the vehicle when parked.

My PowerBook G4 uses about 10 watts with the screen on a dim setting and reduced processor power, surfing the web (with Flash off). This is probably better than a MBP or maybe even a MacBook, but it's definitely more than a MacBook Air at idle. And it's surely much, much more than an Asus EeePC or similar. If you could find something that draws 5 watts you'd more than double your surfing time, once you've figured out a way to charge a battery.

[Ashka]

We are on the road in New Zealand, a 7 meter motor home has been home for the last 18 months.

I use a 14" G4 1.42 GHz 1 gig ram (Leopard) iBook and a Lind iBook~ PowerBook 12 volt car adapter model AP2425-523G3 which powers and recharges the iBook via a normal 12 volt cigarette lighter socket. This is more than enough power for the iBook or a Power Book but not enough for a MacBook. I would need a 100 watt Sine wave inverter via the 12 volt socket for an intel MacBook. Home work done for new Mac :)

Two 125W Solar Panels power the deep cycle house batteries ~ the truck also powers the house batteries via a second alternator.
Lights, fridge & water pump run on 12 volt, gas for cooking & water heating plus a diesel heater (Diesel truck)

To start with I used a 3G blue tooth phone & 3rd party modem script to get online. This sort of worked :) with a small data plan on my phone. I now use a USB Vodem via Vodafone ~ still on the 3G / 2G mobile network with a larger data plan.

All the best...

[mattf]

*small bump* - haven't been online much recently....

How often does Rona have her engine started? For example, do you drive the van to work every day (if so, how long is the drive)?

Yeah, this is a problem, as day-to-day she's driven for short distances only (3 - 15 miles). Occassionally (like every few weeks) we'll do a longer journey to see friends or family, but I know we're going to need a supplementary power source for a leisure battery.

You could try a micro wind turbine (as used on sailing boats) but would it not be a problem to be seen parked in an urban area with a mast and turbine? May attract unwanted attention. You might also have problems finding stable airflow in a built-up area like the one in the photograph.

You raise a good point there (about unwanted attention). But she's soon going to have a chimney poking out of her, so may as well be hung for a sheep as a lamb. :)

TBH, the photograph shows the only time in the last two months that we've stayed in a built up area (we've even stayed in the centre of Edinburgh and still had green fields all around :) ), so I don't think airflow stability will be too much of a problem.

Good quality solar cells like the Siemens SM55 produce useful power even on cloudy days, though by useful I mean ~20% of direct sun output. That might still be enough if you have a big battery to even out the peaks and troughs. A panel could be discreetly placed on the roof of the vehicle when parked.

I'll take a look at the Siemens, thanks.

My PowerBook G4 uses about 10 watts with the screen on a dim setting and reduced processor power, surfing the web (with Flash off). This is probably better than a MBP or maybe even a MacBook, but it's definitely more than a MacBook Air at idle. And it's surely much, much more than an Asus EeePC or similar. If you could find something that draws 5 watts you'd more than double your surfing time, once you've figured out a way to charge a battery.

Hmm, not sure I could convince Mrs f to let me buy a MBA, but I'll tell her you recommended it ;)

We are on the road in New Zealand, a 7 meter motor home has been home for the last 18 months.

I use a 14" G4 1.42 GHz 1 gig ram (Leopard) iBook and a Lind iBook~ PowerBook 12 volt car adapter model AP2425-523G3 which powers and recharges the iBook via a normal 12 volt cigarette lighter socket. This is more than enough power for the iBook or a Power Book but not enough for a MacBook. I would need a 100 watt Sine wave inverter via the 12 volt socket for an intel MacBook. Home work done for new Mac :)

Two 125W Solar Panels power the deep cycle house batteries ~ the truck also powers the house batteries via a second alternator.
Lights, fridge & water pump run on 12 volt, gas for cooking & water heating plus a diesel heater (Diesel truck)

To start with I used a 3G blue tooth phone & 3rd party modem script to get online. This sort of worked :) with a small data plan on my phone. I now use a USB Vodem via Vodafone ~ still on the 3G / 2G mobile network with a larger data plan.

All the best...

Thanks Ashka, that's useful information and good to hear from a fellow traveller. Although Rona's definitely a smaller sister to your truck, measuring in a paltry 14' LOA