Just wondering if there is a way to charge my laptop battery during a power outage. I have a bunch of 18650 cells laying around. I’ve done some research and it doesn’t look like I can charge it via USB using a charger like the Xtar WP2 II. Seems like that can only recharge a cell phone. Any ideas?
If you have a car. 
But then I can’t browse this forum from the comfort of my sofa. (21% battery remaining)
car battery and an invertor or charge it in your car and then take it inside
Yep, a car charger setup for your laptop is the esaiest way. You will need a very long CAT6 cable (300 foot max length) or drive to a place that has a free unsecured Wi-Fi router. McDonalds, Starbucks, your neighbor’s unsecured wireless router, etc. Don’t know what kind of cellphone you have but I can use mine (AT&T) to connect via a USB cable between the phone and my computers. Plan ahead. This will happen to you again.
i asked this in the other thread with no reply. if I buy an extra $100 regular lead acid 12v car battery, does anyone know approximately how long it would power a typical 150watt inverter to feed a typical 65watt notebook power brick? after the 12v car battery is drained, you can put it in the trunk of your car and charge it in parallel when you drive. but the main question is, approximately how many hours will this extra battery, outside the car, power the computer?
Dynamo bicycle hub or and old schwinn generator and pedal your @$$ off
I had a friend that did that, only he used a ~20Ah, 14V SLA cell. He plugged it straight into the ~14V input on his laptop. His DSL router also ran off 15VDC so he could run for at least 2-3 evenings completely off the grid so long as his ISP and land lines were in-tact. IIRC he used a battery space SLA trickle/conditioner. IIRC he explained it as a microprocessor controlled wall-wart type charger that continually monitored battery charge status. I guess alternately you could manually charge the cell every other week.
That’d be really slick doing that with an Optima deep cycle or marine cycle battery. You could run for a week or 2 at least completely off the grid.
Someone double check me on that… I am pretty sure he was not using a power inverter of any type to power the laptop power supply. It was just 14.5V straight between the SLA and laptop. IIRC his PC was a pre-lenovo Thinkpad
Buy a deep cycle battery if you're planning on draining it ,, if you drain a regular car battery you'll just do permanent damage to it . You'll also need a isolation diode ?? to keep from one battery stealing a charge from the other puts the juice in but doesn't let the other battery rob it ..(sort of )
http://www.fridge-and-solar.net/dual_bat.htm
Add a solar panel or a windmill and you're the man .
Don't ask me about the math :) there are losses in the connectors... in the inverter , in the conversion from DC/to AC,in the line ...etc etc etc ..
- You will want a deep-cycle battery for this task, as a regular (cranking) battery will fail after relatively few complete discharges. These are usually found in boating or home-power applications
- A decent battery has around 85-100 amp-hours. Multiplying voltage, we get 85 x 12 = 1020 (or 100x12=1200)
- At max draw of 150W, you would get (1020/150=6.8 hours) to (1200/150=8 hours)
- At lower consumption levels, you could possibly double these numbers. Using a DC/DC charger with fewer losses, 20 hours, or more, seems very possible. My new laptop uses between 18W and 35W, depending on type of use.
- Please remember that you will also need to power your modem and router to stay online, if that’s your goal. In addition, the ISP may or may not be up during a local power outage, rendering this exercise moot.
120V x 1.4A = 168W
84W/12V = 14A (DC)
14A X .1 (inverter consumption, estimated) = 1.4A
total DC load = 15.4A
1000AH/40 (max recommended discharge for lead acid = 40%) = 400AH
400AH/15.4A = 25 hours
You could discharge it further, but if you're planning on doing this frequently, it will adversely affect your battery's longevity.
thanks chiX, Boaz, Kramer for the quick numbers. I'm looking at this thread and everything is symmetrical. chiX has 2222 posts, boaz has 2727 posts and kramer 888. somebody buying a lottery ticket? :)
http://astore.amazon.com/newworldsolar-20/detail/B007VPQP5Q
Get solar 
I just went and got 6 145 watt panels.
Gonna get six more if they still have some come payday.
Using a inverter to feed power brick would be very ineffective, instead you should get 12V -> 19V (or 20V for some notebooks) DC/DC synchronous boost converter (and get plug which’ll fit your laptop’s socket somewhere), that’ll give you ~90% efficiency in best case (using inverter & power brick would give you 60-70% in best case, and even less in worst).
This will be much more efficient however it will require some searching to find one for your computer.
I don't know what phone you have but I used to have a at&t phone that I could get unlimited data for 10 dollars and then i would tether it to my computer. Naturally it is more expensive with a smart phone. If you want I could pm you the instructions on how to do it.
I thought some computers could be charged via USB,e.i. 5volt.
First and second generation Ipads and with Asus laptops with some app???
Lennart