Date: Sun, 17 Jun 2007 08:26:06 -0700
Reply-To: Michael Elliott <camping.elliott@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Michael Elliott <camping.elliott@GMAIL.COM>
Subject: Re: Solar panels for your Vanagon..
In-Reply-To: <000301c7b0e4$9426eec0$0201a8c0@MASTERPC>
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Thanks for the correction.
--
Mike "Rocket J Squirrel" Elliott
71 Type 2: the Wonderbus
84 Westfalia: Mellow Yellow ("The Electrical Banana")
74 Utility Trailer. Ladybug Trailer, Inc., San Juan Capistrano
KG6RCR
Dennis Haynes typed:
> Lamp cord should be 18 gauge. Still to small for high current solar
> systems.
>
> Dennis
>
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
> Michael Elliott
> Sent: Saturday, June 16, 2007 10:58 PM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: Solar panels for your Vanagon..
>
> Hi Don,
>
> Right on. I can't tell if generator people are oblivious, inconsiderate,
> or some mixture of both.
>
> To others considering a solar rig, I would suggest using wire thicker
> than lamp cord to "remote" the panels. Low voltage systems are high
> current systems, so wire resistance wants to be low in order to get as
> much power from the panels to the battery. That means fat wire.
>
> Lamp cord is usually pretty skinny stuff, like 22 gauge. A 15-foot
> length of 22 gauge has about .36 ohms of resistance (send and return
> combined). In my system, the panels might be delivering 4.7A @ 17 volts
> in full sun. That's 80 watts. If I were using 15 feet of 22 gauge wire,
> the voltage lost due to wire resistance would be .36 x 4.7 = 1.7 volts.
> At 4.7 amperes, that's 4.7 x 1.7 = 8 watts lost as heat in the wire, a
> 10% loss.
>
> Standard North American-style household grade ac receptacles and plugs
> are supposed to have less than .03 ohm contact resistance -- when new.
> That adds .06 ohm more resistance to the mix, with an additional 1.3
> watts of loss.
>
> 11% may or may not be important, depending on your system. It's just
> something to consider. I wanted the freedom to locate my panels pretty
> far from the van, in case the good sunlight isn't conveniently close. I
> use 6 gauge wire, and a 40-foot extension. That's just .028 ohm, giving
> a loss of .6 watts passive wire loss. The PP75 Anderson Powerpole
> connectors have only .0002 ohm of resistance.
>
> --
> Mike "Rocket J Squirrel" Elliott
> 71 Type 2: the Wonderbus
> 84 Westfalia: Mellow Yellow ("The Electrical Banana")
> 74 Utility Trailer. Ladybug Trailer, Inc., San Juan Capistrano
> KG6RCR
>
>
>
> Don Hanson typed:
>> Solar is the way to go. I agree with Rocket J. Squirrel about having
> them "remote" from the van..Mine has about 15' of lamp cord hard wired
> into the panel and the controller. On the van, I have the female half of
> a regular plug..So that it won't short, from the auxiliary battery that
> the solar panel supplies. I have mine built into an "A-frame" plywood
> case.. Deployed to gather sunlight, it resembles one of those sidewalk
> sign boards you see sitting out front of store, etc. The base of this
> triangle become a cover for the front of the panel when folded up...All
> the cord goes inside, wrapped around a couple of cleats. I have a handle
> on the outside..So, when folded up, it is just a big double sided plywood
> book and very well protected for packing other stuff without worry of it
> harming the panel or the controller at all.
>> Dunno any of the numbers, but mine easily supplies my lights, my
> stereo and lap top, charges my cell phone and sometimes runs an inverter
> powered tool or two. I've spent months at a time in Baja without need of
> a generator, many times..I have one for the van, one for the Alaskan
> camper, and my wife just bought a travel trailer, also with a panel that
> works...until you forget to turn off a light or something...
>> I don't know why every RV doesn't use em..You can charge your system
> chock full when traveling, then when you stop to camp, stick out the panel
> and it will maintain the charge...But it seems some RVers just love the
> sound of their own generators...I see em drive into a camp area and
> immediately start the generator...Often.. We love (joke) this one guy we
> often see/hear in the desert at a spot we frequent...He fires up his
> generator outside his travel trailer, then leaves for the day! I asked
> him.."Hey Walt, how come you start your generator and leave?" He says, "I
> don't like all the noise"...Clueless!
>> Don Hanson
>>
>
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