Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×
 


Reply
 
Thread Tools Search this Thread Display Modes
 
Old 07-03-2020, 09:16 PM   #1
3 Rivet Member
 
2020 20' Bambi
Clayton , North Carolina
Join Date: May 2020
Posts: 229
Solar and Relevance to Long Off-Grid Trips

Folks, I am reading as much as possible but I have some logic issues. On the Zamp website related to portable units they tend to imply the bigger units are better for longer off-grid trips. I sent this email to them but would like to hear anyone else’s thoughts on my logic.

Zamp: On your website, in the product promo for the 230 Watt portable you state “ Our biggest, most powerful portable solar kit generates 230 watts at 12.6 amps—enough for large RVs and long off-grid trips.”

What does the size have to do with length of trip in relation to your reference to “long off-grid trips”? If the solar panel is only generating energy when the sun is out, which occurs on a partial daily cycle, and it only charges the battery to top it off daily, depending sun exposure and your usage, it has to repeat the process daily, regardless your trip is 2 days or 20 days. So in fact it is only enough for charging daily regardless the length of your trip and the length of your off-grid trip is irrelevant with respect to the size of the unit since the limiting factor is your battery bank size, useage and the fact the charge controller cuts off to prevent overcharging. Am I not correct? If incorrect, please explain if you don’t mind so I am clear about the panels.

ASForum folks, am I missing something here?
smsasf is offline   Reply With Quote
Old 07-03-2020, 10:04 PM   #2
Boondocker in Training
 
2020 27' Globetrotter
Los Angeles , California
Join Date: Jul 2020
Posts: 8
You aren't missing anything except perhaps a realistic expectation that they would not use cute marketing language in advertising . I've had these same thoughts as a solar fan, but it's not false advertising.

The main reference too big RVs is that it's over 200 watts.

What scares me more is when people think they will get the advertised max every time they point it at the sky.

Edit:
Unless you know how much power you use daily, it's effectively impossible to guess how big you want to go with the solar.
__________________
Camping David

Shelter: 2021 - 27 Globetrotter FB Twin
Tow Mule: 2020 - Ram 2500 Power Wagon
CampingDavid is offline   Reply With Quote
Old 07-04-2020, 05:39 AM   #3
3 Rivet Member
 
2020 20' Bambi
Clayton , North Carolina
Join Date: May 2020
Posts: 229
Quote:
Originally Posted by CampingDavid View Post
You aren't missing anything except perhaps a realistic expectation that they would not use cute marketing language in advertising . I've had these same thoughts as a solar fan, but it's not false advertising.

The main reference too big RVs is that it's over 200 watts.

What scares me more is when people think they will get the advertised max every time they point it at the sky.

Edit:
Unless you know how much power you use daily, it's effectively impossible to guess how big you want to go with the solar.
Camping David, Thanks for your thoughts. I can agree related to the part of the quote referencing bigger RVs. But the part that suggesting having a larger watt panel allows for longer off-grid trips is coming fairly close to false advertising. At least it is very misleading. Given two RVs with same power consumption needs sitting at same boondock location, with two AGM 24T batteries and same daily sun if a 180 watt solar panel keeps the batteries fully charged each day until sundown then having a 230 watt solar panel does the same but produces excess power that can never be used by the batteries and that additional 50 watts does not allow you to take longer off-grid trips. Being honest with myself, I was not smart enough to think this through prior to buying the 230 watt portable when there is very high probability a much smaller unit would suffice. The “longer off-grid trips” reference was a driving force in my hasty purchase.
smsasf is offline   Reply With Quote
Old 07-04-2020, 06:05 AM   #4
"Cloudsplitter"

 
2003 25' Classic
Houstatlantavegas , Malebolgia
Join Date: Jun 2007
Posts: 19,977
Images: 1
welcome Aboard 👍

Quote:
Originally Posted by smsasf View Post
Folks, I am reading as much as possible but I have some logic issues. On the Zamp website related to portable units they tend to imply the bigger units are better for longer off-grid trips. I sent this email to them but would like to hear anyone else’s thoughts on my logic.

Zamp: On your website, in the product promo for the 230 Watt portable you state “ Our biggest, most powerful portable solar kit generates 230 watts at 12.6 amps—enough for large RVs and long off-grid trips.”

What does the size have to do with length of trip in relation to your reference to “long off-grid trips”? If the solar panel is only generating energy when the sun is out, which occurs on a partial daily cycle, and it only charges the battery to top it off daily, depending sun exposure and your usage, it has to repeat the process daily, regardless your trip is 2 days or 20 days. So in fact it is only enough for charging daily regardless the length of your trip and the length of your off-grid trip is irrelevant with respect to the size of the unit since the limiting factor is your battery bank size, useage and the fact the charge controller cuts off to prevent overcharging. Am I not correct? If incorrect, please explain if you don’t mind so I am clear about the panels.

ASForum folks, am I missing something here?

Last Season we did a 7k Cross Country without deploying our 360w of Zamp Suitcase.🤔

It really depends how long you are not moving. Four days our longest without shore power.
The rest of the stationary time we did have SP.

Bob
🇺🇸
__________________
"You don't know where you've been until you leave, enjoy life" RLC
ROBERT CROSS is offline   Reply With Quote
Old 07-04-2020, 06:30 AM   #5
3 Rivet Member
 
2015 25' Flying Cloud
Gainesville , Florida
Join Date: Aug 2016
Posts: 117
Anyone who has 'solar' on the roof knows that panel production is heavily dependent of sky conditions. The used AS I purchased in 2016 came with ~ 160 Watts of panels that are managed through a Zamp 5 stage controller.

During the day the controller tallies the amp hours delivered by the system. The day to day variations in output are significant. Large solar farms utilize advanced camera systems to track clouds in order to predict output variations.

On an RV scale how long you can boondock on a set of panels is heavily dependent on weather, sky conditions, and probably time of year. I suspect many people walk into this process without understanding the variablities in play.

Best of luck in developing your solar solution. There is lots of expert comments on these boards about solar systems. Lots of great lessons to be learned.
Specsalot is offline   Reply With Quote
Old 07-04-2020, 09:36 AM   #6
3 Rivet Member
 
chugchug's Avatar
 
2018 25' International
Belmont , California
Join Date: Dec 2017
Posts: 150
Images: 5
It is clearly a marketing department issue. They needed to differentiate the larger product from the smaller one and it flows well to say that the larger product is for larger/longer applications.

You need to evaluate your needs. What you need and what the solar system generates are wildy variable depending on season, lifestyle and weather. In my opinion, solar can provide what you need some of the time. You will still need a generator every so often. The bigger the solar the less often you will need to run the generator.
chugchug is offline   Reply With Quote
Old 07-04-2020, 09:36 AM   #7
Half a Rivet Short
 
2017 30' Classic
2022 Interstate 24X
Carlisle , Pennsylvania
Join Date: May 2017
Posts: 15,674
Hi

Bigger is always better

If you are out for a weekend, you start with fully charged batteries. The *assumption* is that your batteries are "ok" for at least two days. In this case, the solar only has to "make up" for about half a day (or less). It's more a "just in case" than a "gotta have".

If you are out for weeks at a time, the math is a bit different. The same batteries are not enough to run for a significant fraction of this time. You *must* get enough out of the solar every two days to keep things going.

If you are in the shade and it's cloudy / raining solar isn't going to do much for you. It's very easy to "loose" a day this way. Now your setup has to produce two days of power in one day.

If the shade in your campsite is pretty deep, you may only get half what you expect ( I've seen a *lot* less than that ...). Double the panel size again.

If it's late (or early ) in the year, the sun isn't up as long. It's angle is not at all ideal for roof mounted panels. Double (or triple) the panel size vs high summer out in the desert.

The more you travel, the more you will run into all this stuff.

Bob
uncle_bob is offline   Reply With Quote
Old 07-04-2020, 10:06 AM   #8
Rivet Master
 
AirMiles's Avatar
 
2018 27' Globetrotter
Apollo Beach , Florida
Join Date: Feb 2017
Posts: 1,401
Excellent answer Uncle_Bob. I will add that my goal with solar is to produce enough AH each day to fully charge the batteries and live continuously without the need of shore power or generator charging. I use the energy that my panels produce.

When I'm camped under a fairly thick canopy of shade trees, my usage may be as little as 25AH per day. Keep the lights off, use fantastic fans sparingly. Don't camp there if you want to watch the NASCAR races on TV over the weekend. Better not use the furnace.

When I'm camped where I get six hours, or more, of good sunshine. Turn on the fans to stay cool. Turn on the inverter and watch TV. Use the vacuum cleaner. Charge up all the battery powered appliances. Use all those cool indirect lights on the Globetrotter. Heck, turn the refrigerator to DC during sunlight hours to save some propane. 150AH of use in a day, no problem, the batteries will still be fully charged by evening. Then run the furnace all night long and repeat the process the next day.

Then like Uncle_Bob said, all of this depends on the month of the year. Summer months are sunnier, with longer days, and better sun angles. I could get by on half the panels in the summer than in the winter.

Bottom line for me is to buy as many solar panels as will fit on the roof, can be stored if portable, or you can afford. Then live on the power that is produced.
__________________
2021 Northern-Lite 10-2 & F350 DRW PSD, 600W Solar/Victron/600A BattleBorn
146 nights 31,000 miles (first 10 months!)
Sold: 2018 GT27Q, 74 nights 12,777 miles
Sold: 2017 FC25FB, 316 nights 40,150 miles
Sold: 2013 Casita SD17 89 nights 16,200 miles
AirMiles is offline   Reply With Quote
Old 07-04-2020, 11:30 AM   #9
3 Rivet Member
 
2010 25' FB Flying Cloud
Powell , Ohio
Join Date: Feb 2005
Posts: 115
Bottom line is larger watt panels provide a larger margin to obtain enough power to get you through more days. I have the 230 Watt zamp portables with lithium batteries and have gone 10 day in the west running the furnace and cpap machine each night. Temps at night were in the low 30 degrees. The lithium’s accept charge more easily than Lead Acid batteries and I believe that it the reason we did well on the trip. We did have sunny days and was able to move the panels to the sun. Don’t know if this helps but are my thoughts.
tbaugh is offline   Reply With Quote
Old 07-04-2020, 12:09 PM   #10
1 Rivet Member
 
2015 20' Flying Cloud
Las Vegas , Nevada
Join Date: Feb 2015
Posts: 8
I RV off the grid more than not in my Flying Cloud 20 - and at least once a year for a full month without moving.

You need DIRECT SUNLIGHT for a few hours to recharge half-depleted batteries. Adding panels will not help much if you don’t get direct sunlight. Extra panels will reduce the charging time which is very long if not in the sun. I use two Zamp 160w panels, mostly so I don’t have to be around to continually move a single one into direct sunlight. 160w kept in the sun for a few hours will do the trick. Its more critical to get that direct sunlight than buying a bunch of extra panels. Again, DIRECT SUNLIGHT!

While in direct sunlight, you can run the fans on high, use the inverter, and take a luxurious shower. When not, I suggest running one fan on low, inverter off, and water pump sparingly to assure you can run the furnace to keep you from freezing at night.

For example, I spent a month in Yellowstone in a mostly shaded spot. With two panels and planned noontime returns to the campsite to avoid crowds and get the maximum positions for the panels on sunny days, I used less than 2 gallons of gas to run the generator after cloudy days for the entire month.

If you are moving every day or two, your tow vehicle will provide somewhere in the order of 1200w for charging. So, a couple hours on the move will charge them right back up.
Paultower is offline   Reply With Quote
Old 07-04-2020, 02:08 PM   #11
:SPACE A" S/O 11 Air19745
 
guskmg's Avatar
 
2006 34' Classic S/O
Fort Worth , Texas
Join Date: Feb 2007
Posts: 1,766
In advertising "puffing" is legal, but I'm not sure about politics.
guskmg
guskmg is offline   Reply With Quote
Old 07-05-2020, 09:59 PM   #12
Boondocker in Training
 
2020 27' Globetrotter
Los Angeles , California
Join Date: Jul 2020
Posts: 8
I am sympathetic to your complaints about advertising. It's bad advertising, but not technically "false" advertising as defined to a point where you could force a change.

I always take my generator and hope I don't have to run it. I would love to be fully energy independent, but I can't control the sun and sometimes can't set-up with clear sky access (nor do I want too.)
__________________
Camping David

Shelter: 2021 - 27 Globetrotter FB Twin
Tow Mule: 2020 - Ram 2500 Power Wagon
CampingDavid is offline   Reply With Quote
Reply


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
Seeking solar and battery advice: fixed-location off-grid airstream paulbmccarth Generators & Solar Power 29 06-16-2016 01:16 PM
Off Grid Solar Trailer silverwoman Generators & Solar Power 36 07-15-2012 08:27 PM
The relevance of CB as a technology Jammer Phone, CB & Ham Radio 44 05-29-2012 09:00 AM


Featured Campgrounds

Reviews provided by

Disclaimer:

This website is not affiliated with or endorsed by the Airstream, Inc. or any of its affiliates. Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.



All times are GMT -6. The time now is 12:33 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.