Posted on

Renogy 100 watt lightweight solar panels

Renogy 100 watt lightweight (previously known as “flexible”) solar panels have been a great choice for cruising sailboats until recently.  Unfortunately, we have experienced excessive failures on them (but not on the rigid, aluminum frame, glass top Renogy panels), and so have discontinued selling them.  In talking to the company reps, they said the panels are in the process of redesign, and I look forward to selling them again when the new model is available.

If you own these panels, you need to be aware that there is a possibility of one portion of one cell overheating and damaging the material under the panel. The cells are those black, nearly square, ~4 inch patches, and there are 32 of them.

I recommend checking the cells for discoloration or small areas of disturbed material.  If you have an infrared thermometer, you could check the temperature of each cell, looking for one cell that is significantly (more than 15 F degrees) hotter than the others.  My experience has been that the cell overheating occurs as soon as a new panel is placed in service, that is put in sunlight and producing energy, so if yours are more than a day (one period of sunlight) old, they are probably OK.  However, it is possible that a panel that has been in service for some longer time could overheat.

Renogy recommends that there be an air gap under the panel.  This will help the panel stay cooler and lessen the normal effect of heating during operation which reduces the output.  My experience has been that this will not effect the overheating issue.

Another issue is low or no output.  Renogy reports that bending the panel excessively can damage the current carrying parts and result in very low or no output.  Their fix for this is to put an aluminum backing sheet under the panel to reduce its flexibility.  My opinion is that this sheet will not help prevent output problems if the panel is in service, nor will it prevent overheating.  It would reduce the flexing that could occur during shipping and installation, but removing a panel to install the sheet could cause the problem you are trying to avoid.  My experience is that the sheet will not prevent a cell overheating.

Renogy has been very good about replacing panels that fail.  Their customer support has been very good, and I expect they will fix the problem, and take care of any customer concerns.   If you own these panels, I recommend you test them for output and for an area of higher than normal temperature, but there is no reason to replace them with more of the same until updated panels are available.

We have 100 watt semi-flexible, lightweight panels from another CHinese manufacturer that I feel confident in.

Posted on

defining amp-hours

We need to be speaking the same language in order to communicate.   I know there is a lot of confusion on this, so please allow me to attempt to clarify; amp-hours is energy, amps is power (when both are referenced at the same voltage).  You can think of amps as “instantaneous”, that is, the number of electrons flowing.  Amp-hours is power times time, which equals energy.  We usually talk in terms of amp-hours per day, in order to determine the overall energy used, generated, or stored.  
An electrical engineer will point out that this is not correct, that watts is the way to measure power and watt-hours is energy, and they would be technically correct, but we use amp-hours because it is more convenient and plenty close enough.

John
Posted on

Wind Generators – AC v. DC Output and Blade Design Effects

Thank you for the mostly accurate article about wind generators in the
Feb, “All At Sea”.  I do want to point out some things you said which
are generally accepted as true, but like many urban myths, are not.

First was your statement that the generators with A/C output are more
expensive (“because more components are necessary”).  It’s the same
number of components.  The KISS is the only one that makes the
conversion to D/C in a remote location, and it is less expensive than the other high-output wind generators..

The smaller bladed wind generators do not start turning in lower wind
speeds.  The Air X, for example, needs 12 knots to start turning.  The
generators with more than three blades start turning in lower wind
speeds, not because because the “blades are lighter”, but because there
is more torque placed on the shaft by the multiple blades.  As usual,
compromises must be made, and the generators with more than three
blades (GWMTTB) are not as efficient in higher wind speeds.  The big
advantage to GWMTTB is the effect of surface area and drag.  In higher
wind speeds, GWMTTB have more drag due to larger surface area, which
tends to limit the maximum speed (RPM), a big advantage for generators
designed for use on farms in England, which is where most of them come
from.  They also do not “cut in” at lower wind speed.  They (generally)
start turning at lower wind speed.  Generator voltage is a function of
RPM and load.  “Cut in”, sometimes called “start up” speed is the wind
speed where generator RPM produces voltage above battery voltage to
start charging, and some manufacturers use 12 volts (which in my
opinion is too low).

The amount of energy a wind generator can produce is a function of
blade swept area, with a slightly larger diameter significantly
increasing swept area.  If you look at the power curves, you will see
that “generators with smaller blades” do not produce more power in “10
to 15 mph”.

Hotwire Enterprises
102 W. Fulton St.
Tarpon Springs, FL 34689
(727) 943-0424
hotwiregam@aol.com
www.svhotwire.com

Posted on

Home Power Magazine

If you are thinking of using wind or solar power and want to learn more, you should have this magazine.  Every issue has an article about a real life installation.  Solar power, solar hot water, electric cars, NEC code info.   Fairly technical, but written for the general public.

see www.homepower.com   or call for the latest.  $7  BUY NOW

Posted on

12 & 24 Volt Refrigeration Manual

12 & 24 Volt Refrigeration ManualKollmann Book    $30.00
by Richard Kollmann

Richard Kollmann is the go-to authority when it comes to marine or RV refrigeration. If you’re adding or changing the refrigeration on your boat, you should get this book. This $30 investment can save you hundreds of dollars and hours of aggravation!

Not particurally well written or edited, this independent information is not available antwhere else, and is invaluable to anyone purchasing refrigeration for their boat.  Richard has been around marine refrigeration for a long time, and is not afraid to tell you what he likes or dislikes about the various manufacturers.  He has done a lot of independent testing of the various systems, and the results are in this book.

BUY HERE

Posted on

Yoga Onboard

Yoga Onboard: a guide for cruisers and live-aboardsYogaOnboard    $22.95
By Kim Hess

buy now

This is the most beautifully inspiring yoga how-to book I’ve ever seen. Just looking at the pictures and reading the quotes make me feel more relaxed! Her pages are stiff so they don’t easily blow in the wind while you’re working out on deck, and they’re glossy so you can quickly wipe off stray water droplets.

The organization is simple. The positions and stretches are for everyone. And she shows you how to use parts of the boat to assist you, which makes lots of sense!

A fine book to have on board for stress reduction and injury prevention!!!

Posted on

Marine SSB Radio for “Idi-Yachts”

Marine SSB Radio for “Idi-Yachts”    $29.95
HF Radio E-Mail for “Idi-Yachts”    $29.95
by Capt. Marti Brown

buy now

For readers who are intimidated by all the technical jargon on these subjects, Marti’s books explain in simple layman’s conversation the how/why/when of successful operation of your marine radio for monitoring weather and maintaining contact with friends and family. Excellent resources by a knowledgable technician!

Posted on

Spanish for Cruisers & French for Cruisers

Spanish For Cruisers  (2nd Edition – NEW!!)   $31.95
French For Cruisers    $29.95
by Kathy Parsons

Useful resource books for boaters in countries where Spanish or French are spoken! Each contains not only basic conversational words and phrases but also (more importantly) vocabulary specific to boat parts and jobs, including exploded diagrams of important systems along with the names of the various pieces. Handy to have even if you’re fluent!!

sample page

Guys, if you think you’re covered in this department because your wife is a native Spanish speaker from Panama or the Dominican Republic or wherever, … think again!  Does she know all the technical words for the engine parts or electrical components?  Do your friends’ English-speaking wives or partners know all the technical names in ENGLISH? These books will make their value OBVIOUS to you once you get to French-speaking or Spanish-speaking countries!

An Embarrassment of Mangos
by Ann Vanderhoof
$14.95

A great read!! Ann is a writer by profession (former editor of Cottage Life magazine and contributor to Port Guides) and put together a great story! We actually met these fun folks in Grenada back in 1996 when we were all exploring the island for the first time! We shared an anchorage with them and rode around together in Cat-Eye’s “maxi-taxi” for an overview of the island. A more positive-thinking couple would be hard to find, and the uplifting attitudes come through in her book. It’s a story of their journey from Toronto through the Caribbean, learning about their boat, meeting people and making friends. It’s a comedy. It’s a tale of island history. It’s a collection of island recipes she learned along the way. It’s also her personal discovery that boundaries and limits are set within our own minds and that we can pick them up and move them around any time we choose. The book defies categorizing and is even enjoyed by the guys!  John says, “If you have a special lady friend, and want her to go cruising with you, this is the book you should buy for her to read.”

Home Power Magazine    $7

If you are thinking of using wind or solar power at home or at your small business and want to learn more, you should have this magazine.  Every issue has articles about real life installations.  Solar power, solar hot water, electric cars, NEC code info, geothermal, and other energy-related topics.   Fairly technical, but written for the general public.
See www.homepower.com   or call for the latest issue.  $7  BUY NOW

Posted on

An Embarrassment of Mangoes

An Embarrassment of Mangos
By Ann Vanderhoof
A great read!! Ann is a writer by profession (former editor of Cottage Life magazine and contributor to Port Guides) and put together a great story! We actually met these fun folks in Grenada back in 1996 when we were all exploring the island for the first time! We shared an anchorage with them and rode around together in Cat-Eye’s “maxi-taxi” for an overview of the island. A more positive-thinking couple would be hard to find, and the uplifting attitudes come through in her book. It’s a story of their journey from Toronto through the Caribbean, learning about their boat, meeting people and making friends. It’s a comedy. It’s a tale of island history. It’s a collection of island recipes she learned along the way. It’s also her personal discovery that boundaries and limits are set within our own minds and that we can pick them up and move them around any time we choose. The book defies categorizing and is even enjoyed by the guys!  John says, “If you have a special lady friend, and want her to go cruising with you, this is the book you should buy for her to read.”

$14.95