It all depends on the brand of laptop that you have purchased and the type of battery that it uses. Your battery hours range between 3 and 7 hours depending on how good the batteries life is for that particular laptop system.
That battery model will give about 1.5 hours of battery life before needing to be recharged.
I imagine it started with rechargeable batteries and someone just personified the concept to include people needing energy.
Sony claims that its standard battery for the VAIO VGN-P530H/Q provides 4 continuous hours of running time before needing a recharge.
Yes. Use a volt meter. A general rule of thumb is if the battery voltage is 95% or above of the maximum voltage, the battery is excellent. 90% is good but needing recharge (if rechargeable.) 80 to 90% is poor. Below 80% is very poor.
the average time it takes for most rc racing boats before needing a recharge is about 30 mins depending on how long you charged it before you used it. http://www.bananahobby.com/rc-watercrafts-high-speed-racing-boats.html
Anything needing 12V to operate.
Test the battery at a local place such as advanced auto. They do it free.
none it is a double wall socket needing system
The idea of needing to fully discharge the battery on phones is a common misconception based on older setups. The modern cellphone has no need to "exercise" it. Use the phone as you need it, and the battery will be fine.
start back at the battery, are the leads corroded? is there a clicking noise when the starter is engaged but the starter wont turn? are the leads from the battery to the starter in good condition. Usually any sign of a white powder around the battery or a lot of dirt is a sign of needing attention. The clicking could be a starter relay aor the starter itself needing replacement.
Connect positive cable of donor battery to battery of car being jumped. Then connect negative cable to negative battery post on the donor car and lastly to a ground point on the car needing the jump start, normally the engine. Do not connect to negative post of battery needing a jump start. Let donor car run for about 5 minutes and then attempt to start. The instant the engine starts reverse the procedure to disconnect the jumper cables.
Could be anything from needing a simple recharge to a bad compressor. Take it to a service shop (any side shop should be able to help you)