PV Gap

Robin Said:

Alternative Camping Heater Source Other Than Propane?

We Answered:

The normal alternative to propane in camping is white gas (name in US at least) which has the great advantage over propane of not requiring a heavy container to contain the pressure. It has a lot of Btuh's in liquid form and can be carried in a thin metal container (or some plastic containers) Many stoves and heaters are available that run on white gas/Colman fuel/camping fuel.
But the real answer is to not try to heat a space that is separated from the cold by a thin layer of nylon or canvas. Instead, put your money into properly rated sleeping bags and clothing to match the temperatures you will encounter and use the tent to keep off the wind and rain.

Aaron Said:

Is there any way you can host your own cellular plan?

We Answered:

Simple answer is no. There are very basic and limited plans you can purchase nowadays.
Everyone thinks they need a cell phone. If you can't deal with the costs, get a house phone and voicemail setup so that people can call you at home.

Joan Said:

Do you believe we should store food/water/ammo or is that an over reaction?

We Answered:

sounds like you're squared away to me. better to have something you don't need then need something you don't have. of course we all hope such measures are not needed but in these tumultuous times it's not a bad idea. i also agree with a previous response....i wouldn't let too many people know about your preparations.

Louis Said:

physics problem battery charging?

We Answered:

You purchase a solar panel and charge controller that is rated to produce 30 watts (in full sunlight). You want to use it to charge a very large L-16 (400AH capacity, 12 volt) deep cell battery. Because the battery would be damaged by being fully discharged, you never discharge the battery past the 50% level. If you want to fully charge the battery (bring it from 50% to 100% capacity), how many hours of full sunlight do you need?

Power = Energy ÷ time
A 30 watt charger produces 30 Joules of energy per second
Energy = 30 * time

A battery stores energy.
Energy = Power * time
Power = Volt * Amp
Energy = Volt * Amp * seconds

A 400 amp * hour 12 volt battery can store (12 V * 400 A * 3600 s) = ___ Joules of energy


At 50% capacity, Energy = 0.5 * (12 * 400 * 3600)

Energy produced by solar panel = energy stored in battery

30 * time = 0.5 * (12 * 400 * 3600)
Time =

Lucille Said:

I wrote an essay on electric cars and how we should start adopting them. Constructive Criticism Please?

We Answered:

I think you've tried really hard here so well done on that! There are a few problems with the essay though I'd like to highlight.
- Although electric cars are more expensive to buy from a dealership, they outperform regular petrol cars. - In this sense what does "outperform" mean? Are you referring to physical/economical performance? Can you provide a source which backs this up?
- Electric cars are said to have a whopping fuel economy of 188 mpg - Aside from again not highlighting a source for this figure, this is nonsensical. Electric cars cannot be measured in "miles per gallon" as they do not take gallons! Should be "equivalent of" or some such term.
- These cars are much cheaper to maintain than gasoline cars - again, no source of figures to back this up.
- They age much slower - no, everything ages at the same rate. I think what you mean is that electric motors have a longer serviceable life than internal combustion. Again, source required.
- “The Environmental benefits of E.V.’s are dubious,” stated a California Newspaper in 2003 when GM was about to end their line for the all electric EV1 - not sure what this adds?

Let me ask you another question. As most electricity in the world is generated by burning fossil fuels by switching all of the worlds cars to use electricity are we not just moving the pollution from the car to the power station? Can the electricity network handle the increased demand? Surely we need to fix the power plant problem first?!
You're really good at writing but unfortunately you've not convinced me to give up my petrol powered car yet!