I was recently charging my battery outdoors when it started to rain.
I became concerned, because I know that water conducts electricity.
Is it very unsafe to connect a charger to a battery in wet conditions?
Please don't tell me to experiment...I'd rather not. :)
The rule is: Don't charge in the rain. Actually water
doesn't conduct electricity very well. If it did, every time it
rained all the power lines would short out. Salt water is an exception.
It turns out people are better conductors of electricity than water.
So if you reach into or touch water that is covering an electrical
appliance, the electricity finds an easy path to ground through
This is why our battery chargers have a grounding conductor, and
so should your extension cord and outlet. It is why hair dryers
now come with ground fault detectors built in; to turn them off
if they fall in a bath tub.
Remember this, if an electrical appliance falls into water do not
reach in to get it. Unplug it first. Why you ask, because the electricity
will go from the water into your arm and kill you.
So what should you do if during charging it starts to rain? Unplug
your extension cord from the outlet. Then don't use the charger
until it's dried out. By the way, before using an extension cord,
check it over for cracks in the insulation. If there are any, don't
"I enjoyed visiting your Web site. At work, several of people
on staff were discussing charging a battery and the effect that
placing a fully charged battery on concrete would cause the battery
to lose its charge.
Their statement is that a battery placed directly on concrete will
quickly discharge, while a battery placed on a 2x4 above the concrete
will not discharge as quickly."
My opinion is: The only way to resolve this question among friends,
in order to stay friendly, is to take two matched batteries, place
one on concrete and one on a board. In other words, use the scientific
method. Try to get everyone involved to sign off on the test protocol
first to avoid further infighting. It is my experience that this
matter cannot be resolved among friends by theoretical discussion
alone.:-) Let me know what you find out.
Suggestion for further work, is a board necessary? How about plastic
film, wax paper, metal foil, etc. Have fun.
Theory guides, but experiment decides.
"I wish to know if running vehicle in the daytime with headlights
on reduces gas-mileage and the battery life time, and how much."
If the headlights are on, the dashboard lights and the car's rear
lights are on too. Assume the current drain is 20 amperes, more
or less depending on the type of car. That will be about 240 watt-hours
for each hour of driving time. That energy has to come from somewhere.
Your gas-mileage will decrease. How much, I leave as an exercise
for you, dear reader, to figure out for your car.
The effect on battery life should be nil. Two factors most responsible
for decreases in battery life are high temperatures, and frequent
deep discharges of the battery.