Date:         Thu, 11 Nov 2010 11:26:23 -0500
Reply-To:     David Beierl <dbeierl@ATTGLOBAL.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         David Beierl <dbeierl@ATTGLOBAL.NET>
Subject:      Re: Solar Power Charger for Van Camping
Comments: To: Pat Sloan <pmsloan@SHAW.CA>
In-Reply-To:  <568767C8F8944EC58EB90EAFC832B5A7@OwnerPC>
Content-Type: text/plain; charset="us-ascii"; format=flowed

At 09:15 PM 11/10/2010  -0800, Pat Sloan wrote:
>Thank you very much, Mike. I've had a quick look at the mrsolar page and
>have saved it for when I have more time to figure it all out. The thing is,
>for me, I read about the ThinkGeek thing and they describe its capacity in
>terms of 20,000 mAh.

Actually that's kind of scary -- why are they saying 20,000
milliamp-hours when they could say 20 amp-hours the way normal people
would?  The main page gives me the feeling that they're trying to
blow smoke somewhere I don't want it.

However the details/specs page is more forthcoming.  This thing is
basically a multi-voltage battery power supply for laptops and
smaller electronic gear.  It has about the same capacity (74
watt-hours*) when brand new as an extra-large (nine-cell) laptop
battery.  Just like the laptop battery, the capacity will start
dropping immediately and will get down to half in a few years.

*That's 74 watts for rather less than an hour (technical stuff you
don't want to know right now), 7.5 watts for ten hours, one watt for
?85? hours.

The solar panel is rated to charge the battery in ten hours, they
say.  It might possibly do that at noon in the Sahara Desert, but I
doubt it.  I'm guessing more like thirteen hours in full sun.

This is a perfectly worthy device, or could very well be, but it's
mainly an AC-powered auxiliary battery with flexible outputs for
various electronic gadgets -- and a solar panel for backup or
low-drain use like charging cell phones and the like.


>  Then I go to the mrsolar site and they're talking in
>terms of watts and volts and AC. Since I don't really understand what any of
>those things are, I throw up my hands, place my brain in Park, and go off
>and do something else.

FWIW, I sympathize.

>They will sell a lot more solar items generally, when people don't need a
>journeyman's certificate to decide what to buy.

Ouch.  It isn't going to happen.  Any time you're rationing a scarce
resource you have to know something about it, and solar power and
battery capacity are both scarce resources.  Slightly off the point,
but -- my brother's 35-foot diesel RV came with a nylon "briefcase"
twelve inches thick, containing twelve inches of manuals.  To operate
the thing correctly you'd better have read at least six inches of them.

People here, me included, can help you with watts and volts and stuff.

Yours,
David