what solar setup for pure boondocking, 12+ hrs/day laptop?

[Kaylee]

Overview:

I'm planning to spend this summer (starting in mid-May) boondocking (at altitude (CO/etc)), mainly to do a Noise Detox, and work on some computer based Passion Projects.
This will be mostly Work Mode, though I figure I'll take Scenic/Languorous Journeys while relocating every two weeks, and will probably have to hit town once per week mainly for water.
After the initial stressful decision, I'm definitely looking forward to it. I've never been to the Rockies!

I've already given notice to my landlord, it's been rented, so the s&b departure date is set in stone.
I have some flexibility in when I go to the mountains, and do have some life admin tasks I'll be taking care of before it gets too hot at low altitude.

My main Critical Path item is power.

I'll be doing this in my existing car (old but reliable budget stationwagon), and if things go well, would eventually switch to a van.
I'd like a system that's car-friendly (compact, simple), which will also scale nicely to a van.
I prefer to pay more & fewer times with less frustration, rather than pay smaller amounts more times with more frustration.


Show me The Numbers!

My initial usage is expected to be:

• laptop: 12 hours / day
  
• hotspot: 0.5 - 2 hours / day
  
• mostly trivial weekly recharge of: generic tablet, cellphone (pay-as-you-go-flip), batteries (camera, flashlights).
  

Initially, I'll probably be less than 12 hours/day, as I acclimate.
After about a month or two, if everything goes well (Noise Detox wise), I expect to do some laptop 16 hour days, about 1-3 days/week.
If needed, I'd upgrade then, based on actual usage data.

All of my intended-use devices have AC only power cords.
I have two laptops (will only use one at a time, t'other will nap).
Here's sundry info on the newer laptop's power cord:

45W
input 100-240V ~ 50-60Hz 1.1A
19.5v == 2.31a

My head's spinning from reading lots of articles, and watching lots of Youtube vids (on my Roku - I don't stream on dev laptops).
The most interesting/useful YT I've seen is the solar setup for "pam on the lam".
Like me, she's a middle aged female Newbie (albeit Muggle-not-Geek) who started in her car, and wanted simple & reliable power.

I looked up her gear on Amazon:

• $340 Suaoki 400 watt generator (after a $20 coupon & recent price drop)
  
• $189 Suaoki 200 watt generator
  
• $175 Allpowers 80 watt solar panel (folding)
  
• $175 Suaoki 60 watt solar panel (folding)
  

I also found several other folding/compact solar panels, some of which come with laptop DC cords.

After checking out other vids, I'm sold on the small form factor and simplicity of an all-in-one LiIon battery/generator. I also love the form factor of the folding solar panels.

I'm tentatively planning to buy the 400 W gen/bat (tomorrow am?), and one folding solar panel (by end of week?).
I'm open to buying a 2nd smaller gen/bat and/or panel, after about a month (or from the beginning if enough Geeks recommend it).
I will monitor & evaluate performance, I just want some confidence that I'm starting with "enough" to be, um, Fully Functional.

Here's my key questions:

1. Would a 400 watt "generator"/battery be enough for my "initial" intended usage?
   
2. What size solar panel should I get? Is 80-100 W enough? Any specific brand/unit recommendations?
   
3. I gather I'll save some power by directly using DC instead of AC. Does anyone have a lookup site for the correct power cord? Are there any risks to the laptop of going that route?
   
4. Has anyone used Suaoki? What's been your experience? Is there something "better", that will last longer?
   
5. Sanity Check: apparently one can not use the Suaoki's AC outlet while it's charging, so I'd have to charge hotspot/tablet/phone/etc at night. Is there a workaround? That's not a big issue, it's just one of the few cons that stood out.
   
6. Any other advice?
   

Thanks a ton in advance!

Note that I am a software engineer, but I'm... not an-an-an electrician.
Plus I'm in my 50s and it's been a loooooong time since I did anything electrical related. :\
I can do numbers, just help me with the formulae & heuristics.

[whisper:]
How many software engineers does it take to change a lightbulb?
...
ZERO, that's clearly a hardware problem.
[/whisper]
[whisper:]
Beware of programmers carrying screwdrivers.
[/whisper]

[Mr.LooRead]

None of your choices will migrate with ease to a van.

I suggest one size 24 marine/rv battery in a plastic box.
A $20 solar controller with integral 12V (2) and 5V(2) outputs (1 amp load@) mounted to the top of the battery box.
Two 50watt framed panels with ground mount multi-angle brackets with MC4 "Y" connector

[Riverman]

My Dell laptop is rated for 45-watts, but it's plugged into 120v. power right now and pulling 28-watts, since the battery is fully charged.

Of course, it will use more watts when charging the battery and running the laptop at the same time.

[Trebor English]

Get a "Kill A Watt" either from Harbor Freight, Ace Hardware, Home Depot, Lowes, or Amazon.  You unplug a device, plug in the Kill A Watt then plug the device into the Kill A Watt.  Use the device and the Kill A Watt will tell how much power you used.  Check while the laptop is battery charging, computing with a charged battery and both.  

Once you know how much you use, you can figure how much battery you want in order to cover rainy days.  The amount of solar has to be more than you use, even in winter, plus enough to recharge discharged batteries.  

"Solar Generator" boxes sell you a $65 battery as 400 watt hours" for $400.  The 400 watt hour battery will die very quickly unless you limit the discharge to half, 200 watt hours.

[Trebor English]

Here's sundry info on the newer laptop's power cord:

45W
input 100-240V ~ 50-60Hz 1.1A
19.5v == 2.31a

The input power is 100 × 1.1 = 110 watts.  The ouput of the power cord brick is 19.5 × 2.31 = 45.045 watts.  What the computer actually takes will be less than 45 and much less than 110.  

You can  power the brick with 120 volts made from 12 volts from the battety using an inverter.

If the computer is using 30 watts the brick will take 36 watts of 120 volts.  Verify this with your Kill A Watt.  The conversion loss is likely 20%.  The inverter will take 43.2 watts from the battery.  Remember the 20% loss.  To run the computer 12 hours will take 518.4 watt hours so you need a 1036.8 watt hour battery.  You, being a software person, could round that off to 1024.  

The 2 step process, 12 to 120 and then 120 to 19.5, can be improved.  Go to Amazon and search for "car charger" and your computer brand and model.  Those are a power supply brick that runs off 12 volts directly.  There is a 20% loss once instead of twice.  So the computer takes 30 watts and the car charger takes 36 watts.  12 hours use requires 432 watt hours instead of 518.  The battery you need is 864 watt hours instead of 1024.  The solar panels you need get reduced by 20% also.  

Using a car charger eliminates the inverter use for the lap top and saves 20% on everything else.  All the money to buy equipment is just credit card numbers into web pages.  That's software.  The car charger brick is a hardware solution.  

The battery size you are likely to get is about 100 amp hours, 1200 watt hours, about $100.  An 864 watt hour battery is not ging to happen.  The 1200 watt hour battery will last longer with the car charger.  It will recharge quicker.

[Trebor English]

Often people who are new to battery powered living kill their first batteries in less than a year by undercharging.  That makes the price of the first battery tuition.  I suggest you use a low cost battery to minimize the amount of tuition you pay.  

AGM batteries are 150% to 200% the price of the least expensive flooded lead acid.  For the higher price you don't have to spend 5 minutes per month topping off with distilled water.  

It sometimes happens that you get conflicting symptoms and you aren't really sure what's happening with your system.  If you have a flooded battery you can use a $10 hydrometer to measure the specific gravity of the electrolyte.  That tells you the state of charge by directly measuring how much sulfur is in your sulfuric acid.  Battery voltage is easy to measure and many people use that to estimate state of charge.    It is not the same.  If your battery is partly sulfated it charges quickly and seems good but dies quickly.  The voltmeter is no help.  The solar charge controller does stuff too.  Only the hydrometer is a direct measure of the electrolyte.  

If you get a Suaoki or Inergy battery you can't see what's going on.  That makes it difficult to detect and diagnose problems.  

Consider:  
Battery
https://m.samsclub.com/ip/duracell-marin...rod3590216  
It is $95, $25 - $30 more without a trade in, and it is 105 amp hours, 1260 watt hours.  

Plastic box
https://www.amazon.com/NOCO-HM318BKS-Sna...B004W5SGBO  
$9  

Www.BatteriesPlus.com has group size 31 batteries and boxes.  Prices are similar.

A 100 watt solar panel is just over $100 and a solar charge controller is $20.  Mine came with 2 usb ports.  A 400 watt 120 volt inverter is $25 at harbor freight.  

Putting the battery in the box all by yourself is assembly.  Some software people know what assembly is and how it is different from high level languages.  Suaoki and Inergy are higher level credit card invoices.

[Blacktank]

12 volt laptop charger? and skip the inverter

[tx2sturgis]

What about keeping food cold and keeping yourself warm?

Do we need to figure in power needs for those devices?

In the mountains, and probably with shading from trees, you may end up with less, or much less, solar input than you expect. Cloudy, overcast days, and poor weather for many days, can mean a lack of solar energy input. 

A small, quiet gasoline generator might be needed as a backup in your situation.

[sternwake]

A couple of quick estimations and calculations
Your one laptop, can pull a maximum of 45 watts. Actual running wattage in your usage is unknown, until you do the Kill a watt thing.

But lets say it consumes on average, with an altready full laptop battery, 20 watts and add in 5 more for inverter or car adapter(DC to DC adapter inefficiency) though the car adapter will be significantly more efficient.

so 25 watt hours each hour just for the laptop.

Keep in mind this is an estimate filled with assumptions. My laptop requires a 90 watt adapter, right now it is using 34 watts to type this, which is more than my fridge consumes when the compressor is running. If I am spinning a DVD, it is about 60 watts, streaming videos over the internet about 55 watts.

So 25 watts times 12 hours = 300 watt hours consumed by the laptop

300 watt hours is about 24.6 amp hours as 12.2vDC

A group 27 battery has about 100 amp hours capacity, and one should try not to use more than 50 of those each day.

I'd say on a good sunny long summer day, re-aiming a 100watt panel at the sun 4 or 5 times, you should be OK, as long as other loads are not too significant.

I'd go for at least 200 watts of solar though, and perhaps a group 31 battery that can be from 100 to 130 Amp hours, as the ideal sunny day with often reaimed panels is usually a pipe dream jumped upon by those with too much idealistic hope.


The suaoki things are obviously not generators, they are overpriced batteries with inverters, but well marketed.

Plug your laptop make and model into Amazon electronics and add 'car adapter'.

Mine looks like this:


https://www.amazon.com/CHARGER-Latitude-E4300-E4310-Adapter/dp/B0046HU670/ref=sr_1_fkmr1_1?s=electronics&ie=UTF8&qid=1525233176&sr=1-1-fkmr1&keywords=dell+e5500+laptop+car+adapter

really for 22$ it they are a no branier, especially for a 45 watt laptop. Over 60 watts and the ciggy plugs will become problmeatic and fail much more quickly.

Mine must be at least 7 years old, and uses about 10 less watts than if I were to use my 400 watt PSW inverter to power the original power brick.

Inverters are great at allowing users to overdeplete batteries and they can vary wildly in their efficiency. Modified square wave inverters can also have a very poor waveform, and some power bricks/wall warts will run significantly hotter, and heat is wasted energy, and heat is cumulatively damaging to electronics.

I would not cheap out on the inverter, if you decide to use an inverter instead of a DC to DC car adapter.

Many people also tend to buy a much bigger inverter than they actually need to power what they want. A 200 watt inverter powering a 100 watt load will be usually significantly more efficient than an 800 watt inverter powering a 100 watt load. Now the person occassionally needing to power an 4.5 amp 115vAC Angle grinder can benefit from a 800 watt inverter, but the person only needing to power a 45 watt laptop will not.

I've seen some brag about having a 2500 watt inverter, on a group 24 battery, that could power 2500 watts for about 0.6 seconds before the low volatge alarm sounded and the inverter quit. it can be like a drag racing car which uses 20 gallons to run the quarter mile, then putting in a 5 gallon gas tank and filling it only half way.

[Scott7022]

I won't add on the above other than to endorse the 12v to 12v laptop straight DC. I bought one for my YARC camp run and it kept my little MAC happy. My big one well...It just kinda worked and I was running little foldable panels, highly efficient, but still lacked in wattage and dedicated attendance to sun angle.
Scott No pay attention to SUN No movies for YOU!
Doug and the Bleeps stepped up to help my catastrophe LOL!