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re: the 18 watt uni-solar panels, and pv general info
15 mar 1999
tex wrote:
>...i use a 300 watt whisler modified square wave inverter and it runs
>even my 31 inch tv, 22 watt flourescent lights, what have you. since
>it is only about an amp of charge...
charge is just a certain number of electrons, measured in coulombs, as
warren and i both attempted to teach you in yesterday's postings. an amp
is 1 coulomb per second. current is the time rate of change of charge,
like power, the time rate of change of energy. talking about an amp of
charge is like saying your car goes at a speed of 22 miles, altho
talking about an amp-hour of charge makes sense.
no one is exempt from occasionally uttering nonsense, tex. the misfortune
is to do so solemnly (moliere?), or over and over and over, in your case.
consider this quote from page 12 of the *38th edition* of the excellent
little book, _wiring simplified_, by h. p. richter and w. c. schwan:
when we want to measure a quantity of water, we talk of "gallons"; the
absolute measure of a quantity of electrical power is the "coulomb."
this mistake was fixed in the 39th edition. it's amusing that it took
37 years for someone (me) to notice it, with a new edition each year :-)
>...be sure and put a high current rated diode in series with the
>battery charge input so you don't have the pv act as an electrical load
>at night...
some pvs and charge controllers have built in blocking diodes or relays.
>power loss with the reverse diode is so small it may be considered
>insignificant, on the order of a few miroamps (for the 2.5 amp, 1 kv
>diodes i bought for about $1.49 at radio shack). they have about 1 volt
>(measured 0.8 vdc) voltage drop, btw, which can be sigificant in hot
>climes..
a 0.8 volt drop wastes about 0.8/12 = 6.6% of the power in a 12 v system,
and a 100v diode is likely to have a smaller voltage drop, and it seems
worth buying a $5 0.2 v schottky diode instead. and the diode voltage
drop goes down with increasing temperature. pv power does too, altho pvs
tend to produce more power in warmer climes with more sun.
>*any arguments with this post, nick!??*
just a few gentile corrections. we are here to help you.
it is our fondest hope that someday you will be able to
open your mouth without talking nonsense.
nick
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