new solar install - Fiberglass RV


Reply
 
Thread Tools Search this Thread Display Modes
 
Old 03-15-2012, 09:50 AM   #1
Senior Member
 
cpaharley2008's Avatar
 
Name: jim
Trailer: 2016 2ndGen Escape19 Prairie Schooner pulled by 2014 Dodge Ram Hemi Sport
Pennsylvania
Posts: 6,398
Registry
new solar install

I decided to install a new battery tongue box and mount my 30 watt solar on it vs on the roof. No holes, no leaks. I installed marine 12v outlets and plugs.
Attached Thumbnails
DSC01055.JPG   DSC01056.JPG  

DSC01058.JPG   DSC01059.JPG  

__________________

__________________
cpaharley2008 is offline   Reply With Quote
Old 03-15-2012, 09:51 AM   #2
Senior Member
 
cpaharley2008's Avatar
 
Name: jim
Trailer: 2016 2ndGen Escape19 Prairie Schooner pulled by 2014 Dodge Ram Hemi Sport
Pennsylvania
Posts: 6,398
Registry
Three more pictures
Attached Thumbnails
DSC01060.JPG   DSC01061.JPG  

DSC01063.JPG  
__________________

__________________
cpaharley2008 is offline   Reply With Quote
Old 03-15-2012, 09:53 AM   #3
Senior Member
 
Name: Roger
Trailer: U Hall VT
Michigan
Posts: 394
Registry
Smile

Very nice, nice job!
__________________
Roger Kimble is offline   Reply With Quote
Old 03-15-2012, 12:06 PM   #4
Senior Member
 
Name: john
Trailer: scamp 13
Michigan
Posts: 1,320
i think i will get a solar panel. i plan on having it loose and set it up with adjustable legs sort of like a tilted table. it will have an outlet to plug into to charge the battery when we are boondocking. since we don't use much power, mostly a light for a little in the evening. it should be able to recharge during the day . or at least extend the charge.
being able to move it to take advantage of clearings in the leaves and a better angle towards the sun should help. and when we don't need it it can stay at home.
__________________
john warren is offline   Reply With Quote
Old 03-15-2012, 02:23 PM   #5
Senior Member
 
Name: Rene
Trailer: Bigfoot 2500 truck camper
British Columbia
Posts: 233
Simple and relatively inexpensive install. Great job. I am getting supplies together ATM to solar charge my boler. Your installation highlights a simple way to keep wire runs short. Losses from panel to controller, inverter and battery can be high if the wires are too long or too small a guage. At least 10 gauge wire is required for most installations and wire runs should be in the 6-12 foot range. Check out a table on recommended wire sizes and lengths.
__________________
Rene is offline   Reply With Quote
Old 03-15-2012, 03:41 PM   #6
Senior Member
 
honda03842's Avatar
 
Name: Norm and Ginny
Trailer: Scamp 16
Florida
Posts: 7,300
I'm not too sure that these huge wire gauges are needed for short runs like 10 feet.

16 gauge wire has a resistance of about 0.05 ohms per 10 feet. A 30 watt solar panel produces no more than 3 amps. That represents a voltage drop of 0.15 volts.

Is this correct?
__________________
Norm and Ginny

2014 Honda Odyssey
1991 Scamp 16
honda03842 is offline   Reply With Quote
Old 03-15-2012, 03:59 PM   #7
Senior Member
 
Name: Rene
Trailer: Bigfoot 2500 truck camper
British Columbia
Posts: 233
I honestly don't know how to do the calculation. I use the tables which call for 2% or less voltage drop. I am using 10 gauge wire. My controller recommends up to 6 gauge and runs of no more than 6 feet between the battery and controller. Lots of systems perform poorly due to small wire. The bigger the better when it comes to 12 volt wiring although there are real limits when it comes to practical application.
__________________
Rene is offline   Reply With Quote
Old 03-15-2012, 06:20 PM   #8
Senior Member
 
Jon Vermilye's Avatar
 
Name: Jon
Trailer: 2017 Escape 21
Oswego, NY
Posts: 1,407
Registry
The Powerstream site has a good calculator for voltage drop. Scroll to the bottom of the page, stick in your information & it does all the work.
Jon Vermilye is offline   Reply With Quote
Old 03-15-2012, 06:57 PM   #9
Senior Member
 
honda03842's Avatar
 
Name: Norm and Ginny
Trailer: Scamp 16
Florida
Posts: 7,300
Solar Panel Wiring

The thread got my curiosity up since I've never measured the voltage drop.

There's certainly nothing wrong with using 6 or 10 gauge wire though I expect it's not necessary for a 30 watt solar panel. Though I must admit it would minimize the voltage drop.

I have two 40 watt panels. I wired them with 16 gauge wire. From my solar controler to my battery is in the 8-10 foot range. The drop is 0.2 volts measured with a digital volt meter. This takes into account all contact resistance between wires and terminals.

As an interesting side bar, a 10 amp auto fuse has a 0.1 volt drop at 10 amps.

To insure a realistic reading I took measurements while drawing between 3 and 4 amps from the solar panel/battery.

One interesting aspect of at least of my solar panels is that the wire size is substantially less than 10 gauge coming from the panels.

We have been running almost wholely off our panels and they seem to easily meet our needs with the battery fully charged by noon. The biggest continuous current draw, particularly in the west, is the two fans that blow air over the fridge's coils. With these fans we are capable of keeping our temps in the high 30s F.

The solar panels are humming in the AZ sunshine. Totally unlike New England. Here no matter the temperature the Sun shines brightly virtually every day.
__________________
Norm and Ginny

2014 Honda Odyssey
1991 Scamp 16
honda03842 is offline   Reply With Quote
Old 03-15-2012, 09:45 PM   #10
Senior Member
 
Name: Rene
Trailer: Bigfoot 2500 truck camper
British Columbia
Posts: 233
Nice calculator, Jon. When I ran my numbers it all came down to the amperage for sure. Using the amperage specs from my panels, they will be putting out about 4.5 amps each. Depending on whether I use 1 or 2. Will probably use both if I can fit them on properly. Using a 10 amp load, 10 guage wire can run 12 feet one way and just come in at about 2% drop. Then you have to consider the load of the inverter, again short and large wires are the key.
__________________
Rene is offline   Reply With Quote
Old 03-15-2012, 09:58 PM   #11
Senior Member
 
Name: Rene
Trailer: Bigfoot 2500 truck camper
British Columbia
Posts: 233
Quote:
Originally Posted by honda03842 View Post
The thread got my curiosity up since I've never measured the voltage drop.

There's certainly nothing wrong with using 6 or 10 gauge wire though I expect it's not necessary for a 30 watt solar panel. Though I must admit it would minimize the voltage drop.

I have two 40 watt panels. I wired them with 16 gauge wire. From my solar controler to my battery is in the 8-10 foot range. The drop is 0.2 volts measured with a digital volt meter. This takes into account all contact resistance between wires and terminals.

As an interesting side bar, a 10 amp auto fuse has a 0.1 volt drop at 10 amps.

To insure a realistic reading I took measurements while drawing between 3 and 4 amps from the solar panel/battery.

One interesting aspect of at least of my solar panels is that the wire size is substantially less than 10 gauge coming from the panels.

We have been running almost wholely off our panels and they seem to easily meet our needs with the battery fully charged by noon. The biggest continuous current draw, particularly in the west, is the two fans that blow air over the fridge's coils. With these fans we are capable of keeping our temps in the high 30s F.

The solar panels are humming in the AZ sunshine. Totally unlike New England. Here no matter the temperature the Sun shines brightly virtually every day.
Between the abundant sun shine and your conservative needs, it is obviously working for you Norm! I don't know the exact output of your panels in amps so I have no idea if your wire is within 2% voltage drop. In your case it may not matter.
__________________
Rene is offline   Reply With Quote
Old 03-15-2012, 10:10 PM   #12
Senior Member
 
Jon Vermilye's Avatar
 
Name: Jon
Trailer: 2017 Escape 21
Oswego, NY
Posts: 1,407
Registry
I feel it is wise to think about voltage drop differently when looking at recharging batteries, particularly from solar. The acceptable 3% for home & industrial wiring means the incandescent lamps will be a bit dimmer if they are on a fully loaded circuit (something that is rare). Under most actual conditions home wiring (as well as the 12v wiring in your trailer) are not loaded anywhere near capacity, so the real voltage drop will be far less than the calculated.

The exceptions? Because of the cost & efficiency, inverters are often sized as small as possible so they very often closer to maximum load for wiring capacity. Since many have built in electronics to disconnect them when the battery voltage drops below a set point, oversized wiring is necessary to prevent voltage drop in the wire from looking like a depleted battery and shutting down the inverter before the battery is really down.

The other exception is the wiring from a solar panel. At the time you need it most (bright sun) you will be drawing continuous calculated amperage. If you use the standard tables to determine wire size you will be losing unacceptable amounts of the panel output to heating the wiring.

In the case of a solar charging system every amp hour you put back into the battery is less time you need to run a generator, or the lower wattage solar panel you need to replenish your batteries. While you can certainly go overboard with wire size, every percentage of voltage drop is costing you amp hours getting back into the battery. You only have so much sunlight...

Panels are getting more efficient and less expensive, so I suspect it won't be all that long until just putting a higher wattage panel will be less expensive than going to oversized wire, but I would shoot for less than 1% for a current installation.

Although he does go on, if you want some interesting opinions on RV solar installations, try reading Handy Bob's Blog. A bit of overkill for the shorter wiring distances in our smaller trailers and lower power systems, but good stuff.
Jon Vermilye is offline   Reply With Quote
Old 03-15-2012, 10:28 PM   #13
Senior Member
 
Name: George
Trailer: Waiting for the Sprinter van and designing the converion modules.
Oregon
Posts: 629
Quote:
Originally Posted by honda03842 View Post
The thread got my curiosity up since I've never measured the voltage drop.

There's certainly nothing wrong with using 6 or 10 gauge wire though I expect it's not necessary for a 30 watt solar panel. Though I must admit it would minimize the voltage drop.

I have two 40 watt panels. I wired them with 16 gauge wire. From my solar controler to my battery is in the 8-10 foot range. The drop is 0.2 volts measured with a digital volt meter. This takes into account all contact resistance between wires and terminals.

As an interesting side bar, a 10 amp auto fuse has a 0.1 volt drop at 10 amps.

To insure a realistic reading I took measurements while drawing between 3 and 4 amps from the solar panel/battery.

One interesting aspect of at least of my solar panels is that the wire size is substantially less than 10 gauge coming from the panels.

We have been running almost wholely off our panels and they seem to easily meet our needs with the battery fully charged by noon. The biggest continuous current draw, particularly in the west, is the two fans that blow air over the fridge's coils. With these fans we are capable of keeping our temps in the high 30s F.

The solar panels are humming in the AZ sunshine. Totally unlike New England. Here no matter the temperature the Sun shines brightly virtually every day.
Hi Norm,

Did you connect your panels in series or parallel?; you had that option with MPPT controller. Connection in series increases voltage but reduces current consequently reduces demand on wiring. This benefits wiring between solar panels and charge controller only.

George.
__________________
GeorgeR is offline   Reply With Quote
Old 03-15-2012, 10:35 PM   #14
Senior Member
 
Name: Rene
Trailer: Bigfoot 2500 truck camper
British Columbia
Posts: 233
Yeah thats the guy I read already. Handy BOB (angry Bob?) So good I think I will read it again. It may be overkill for some more casual RVers but if you are off the grid or a hardcore boondocker or wannabe like me it makes a lot of sense. Thanks again Jon.
__________________

__________________
Rene is offline   Reply With Quote
Reply

Tags
solar


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
New solar install.... cpaharley2008 Modifications, Alterations and Updates 212 01-05-2013 07:17 PM
My solar Install Rodger Modifications, Alterations and Updates 15 09-28-2011 12:17 PM
Solar install, need tape Perry J Modifications, Alterations and Updates 8 09-18-2011 09:00 AM
A new way to install AC Jacob S. Modifications, Alterations and Updates 12 02-21-2010 08:51 AM
A/C install Legacy Posts Care and Feeding of Molded Fiberglass Trailers 8 12-15-2002 08:49 PM

» Upcoming Events
No events scheduled in
the next 465 days.
» Virginia Campgrounds

Reviews provided by


Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 10:13 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.