Table Of ContentRVers·
Guide to
SOLAR
BATTERY
CHARGING
12volt DC-120volt AC Inverters
by Noel and Barbara Kirkby
Second Printing 1990
aatec publications
PO Box 7119, Ann Arbor, Michigan 48107
313 9951470
Copyright © 1987 by Noel and Barbara Kirkby
Library of Congress Cataloging-in-Publication Data
Kirkby, Noel.
RVers' guide to solar battery charging. 12 volt DC-120 volt Ac.
Includes index.
1. Recreational vehicles--Batteries. 2. Solar batteries.
I. Kirkby, Barbara.
II. Title.
TL298.K57 1987629.2'542 87-19611
ISBN 0-937948-08-X
All Rights Reserved
No part of this publication may be reproduced or transmitted in any form or by any means,
electronic or mechanical, including photocopy, recording, or any information storage and
retrieval system, without the written permission of the publisher.
Manufactured in the United States of America
Printed and Bound by Mitchell-Shear, Inc., Ann Arbor, Michigan
Cover Design by Carl Benkert
The authors and aatec publications assume no responsibility for any personal injury, property
damage, or other loss suffered in activities related to the information presented in this book.
Noel and Barbara Kirkby live in a solar home in the desert foothills
near Phoenix, Arizona. They travel each summer in an RV, and
found that the traditional methods of battery charging did not meet
their needs. The search for a better method began, and resulted in
the purchase of a solar electric system. Their present RV is com
pletely independent electrically. It is an example to those seeking
peace and freedom from engine generators and crowded camp
grounds.
Noel and Barbara's experiences and their efforts in research
ing and designing their own system led to the creation of their
business-Kirkby Solar Electric-which designs, tests, and con
stantly improves solar equipment for the RV. They now manu
pow
facture, package, and distribute the RV POWERPAC™ and
ER GUARDTM, and publish a semi-annual newsletter, Solar
Electric Update, to share the new information and helpful hints
generated by the many solar and soon-to-be-solar RVers through
out the country.
This book is dedicated to our beloved parents
Samuel and Ruth Kirkby
and
Glenn and Jewell Warren
whose love for the great outdoors introduced us
to the RV lifestyle during its infancy
And to our three children
Doug, Kim, and Steve
who have shared many an RV adventure with us
and who, in turn, will be
passing on this love to the next generation.
Contents
Our Solar Experiences ... ... .... ............. vii
Introduction .. ... .... .... .... .. .............. 1
2 Understanding Electricity .... .. .... .. ..... ... 11
3 Batteries and Conventional
Charging Methods ....... ... : ............... 23
4 Using Solar Electricity in the RV ... ..... ..... .49
5 The RV Solar System ........ ...... ..... .. ... 71
6 Basic RV Wiring and
Solar System Installation .. .. ... ..... . .... .. 101
7 DC-AC Power Inverters. . . . . . . . . . . . . . . . . . .. 125
Appendix A: Solar Cell Technology ..... .... ... 151
Appendix B: Resource List .. ....... ..... ..... . 155
Index ....... ... ... ......................... 161
/
OUR SOLAR EXPERIENCES
by Barbara Ki rkby
Noel and I have been serious RVers since 1966, and trips of
extended length have been an important part of our family life. We
started with a 12-foot trailer and, as our three children grew, we
graduated through a succession of larger trai lers to our present class
A motorhome.
In 1977 we learned all about dry camping, or "boon
docking," when we spent six months at the base of the Sierras
beside a delightful trout stream. Our greatest concern was battery
power for the water pump, lights, and heater, and we found that
even strict conservation practices were not enough to maintain an
adequate power supply.
We used three batteries in rotation with the tow vehicle
battery and had to drive endless mi les just to get a half-way charge.
Buying a generator only created more headaches in the form of
annoying adjustments, repairs, noise, and fuel handling. When the
snow arrived, we could not keep up with the demands of the
furnace blower and acquired a catalytic heater that proved to be a
big help in keeping our electric consumption down. But, there still
had to be a better way to charge those cold batteries.
vii
Solar was the answer! Our first solar charging system, in 1979,
introduced us to a concept of RV independence that still amazes
me. Two solar panels flat atop the roof quietly generated enough
power to meet the basic energy needs of our family of five. Since
that time, remarkable breakthroughs, especially in high-efficiency
inverters, have added even more exciting dimensions to our RV
adventures. With our inverter we now have 120-volt utility-like
current at will-even when camped independent of electrical
hook-ups for an entire summer. By simply adding two solar panels
and deep-cycle batteries, a total of four each, we can produce and
store a surplus reserve of power.
We easily meet our 12-volt needs and have plenty of power
left to run the inverter, which in turn supplies 120-volt current for
our microwave, vacuum, blender, hair dryer, sewing machine,
and even power tools. Our POWER GUARD regulator/meter
set-up is an indispensable aid for monitoring our private "power
company." It tells us how much we are storing and how much we
are charging at any given time, and so helps us gauge howextrava
gant we can be or how conservative we must be in our power
consumption.
Recently, our motorhome broke down in the most desolate
part of Death Valley. What a place to discover that the alternator
and bracket had broken away from the engine, leaving the bolts
sheared off in the engine block! Our solar panels generated the
electricity that allowed us to remove the broken alternator and
continue on the road to home for convenient, and inexpensive,
repairs.
When Noel was first searching for a photovoltaics source, I
recall that my attitude was skeptical at best. To hear him explain it,
some magical piece of glass would soak up the sun's energy and
abracadabra ... all the power our RV would need. Well, since
1979 we have been using these "magical, silent, maintenance-free
generators" in our RV and for supplemental power in our home.
Now I not only enjoy all the comforts of our solar-powered RV, but,
with Noel and our three teenagers, understand and enthusiastically
endorse the benefits of this simple technology.
viii
We wrote this book for the RVer who seeks the independence
and comfort we have found. Even though it contains lots of techni
cal detail, the basics are included, too. We remember what it was
like when we hardly knew a watt from an amp, and no one could
answer all our questions. You'd be surprised at the number of
people on the road who ask us how much hot water our panels
produce. A little reading and research will clear up many miscon
ceptions about what solar power can do-and how much it will
cost.
We have tried to include all the information you will need to
investigate, decide, size, select, purchase, and install solar compo
nents or packaged systems in your RV. If you have diffiCulties or
questions, just write or phone us. We're always glad to hear from
other RVers-to offer technical assistance and share the benefits of
solar battery charging. We hope you enjoy the book!
ix
