RV Trip Planning Discussions

Go Back   iRV2 Forums > RV SYSTEMS AND TECHNOLOGIES FORUMS > Going Green
Click Here to Login
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
Reply
 
Thread Tools Search this Thread Display Modes
 
Old 06-16-2014, 10:27 AM   #1
Senior Member
 
SteveUpp's Avatar
 
Join Date: Nov 2013
Location: Fulltime Nomads
Posts: 203
Hybrid Solar / Shore Power Solution Wanted

I've been lurking around this forum for quite a while learning as much as I can about solar power for an RV. I am interested in going full-time in an RV but its quite a ways off.. so this is mostly just a question of curiosity at the moment.

I know that I want an RV with a good size solar array and battery bank to enable boondocking without needing to run a generator. With that much capacity (e.g. 1500-2000 watts), it occurred to me that this power will be wasted when I am plugged into shore power.

The inverter/chargers that I see on the market today will switch to shore power when AC power is detected and qualified and will put the inverter into standby mode. When that occurs the solar charge controller will fully charge the battery bank but the excess DC power produced by the panels will then go to waste as the MH will have all the AC circuits powered by the shore circuit.

What I would like to have happen, is that when I plug into shore power, I would like the inverter to actually detect and utilize excess solar power from the panels and only after the solar energy is insufficient would it draw current from the shore circuit.

Anyone aware of a combination inverter/charger and charge controller that could work together to prioritize solar energy over the shore power? I would assume that such a system would reduce the shore power utilization significantly thereby saving a little $, but also maximize the green power provided by the panels. I would be especially interested if the circuits not normally powered by the inverter (e.g. air conditioner) could benefit from the excess solar power coming in through the panels.
__________________

SteveUpp is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 06-16-2014, 12:04 PM   #2
Senior Member
 
JFNM's Avatar
 
Newmar Owners Club
Solo Rvers Club
Join Date: May 2013
Location: Mountain West
Posts: 1,178
Are you thinking that most/all shore power is metered?

I'm in the SW and have never been to a site with metered power, hence the question -not sure what the norm is.
__________________

__________________
JD - Full timer out west
Missy - 1998 MCI 102-EL3
JFNM is offline   Reply With Quote
Old 06-16-2014, 12:14 PM   #3
Senior Member
 
SteveUpp's Avatar
 
Join Date: Nov 2013
Location: Fulltime Nomads
Posts: 203
Quote:
Originally Posted by JFNM View Post
Are you thinking that most/all shore power is metered?

I'm in the SW and have never been to a site with metered power, hence the question -not sure what the norm is.
I have heard that some campgrounds do meter electrical usage, especially if you stay for an extended time (e.g. a month or longer). But even if the campground doesn't meter, I would still rather use green electricity available from the roof of my RV than the electrical power supplied by the campground. It seems to be good for everyone.

In many ways, I'd like my solar equipped RV to work like a grid-tied solar array, where the solar panels augment grid power to power the home or when excess energy is produced, push it out onto the grid.

Pushing power from the RV into the campground grid is icing on the cake. Even for a non-metered campground, having RVs with their own solar power generating electricity into the campground grid would be great for everyone.

I just hate to see green energy from solar panels being wasted.
SteveUpp is offline   Reply With Quote
Old 06-16-2014, 12:16 PM   #4
Senior Member
 
Join Date: Nov 2013
Posts: 931
Not at all sure why you would ever need to tie into shore power (except for a/c) if you plan to have 1500 to 2000 W of solar and equivalent battery source. We have 1420 W of solar and about 9500 W of LFP batteries and have not hooked in since system was fabricated a year ago. We do not even hook in when we are in an RV Park (which occurs only when we are near a large city and visiting friends/relatives as we are doing currently in Richland, WA).

We have used solar/batteries for a/c on several occasions for up to 3.5 hours (not at night of course) and 2000 W should suffice on solar alone for a single a/c unit.

Perhaps you should just hook into shore power when solar is insufficient such as needing to use a/c at night - and unhook during the day.

Reed and Elaine
Reed Cundiff is offline   Reply With Quote
Old 06-16-2014, 01:27 PM   #5
Senior Member
 
JFNM's Avatar
 
Newmar Owners Club
Solo Rvers Club
Join Date: May 2013
Location: Mountain West
Posts: 1,178
Quote:
Originally Posted by SteveUpp View Post
In many ways, I'd like my solar equipped RV to work like a grid-tied solar array, where the solar panels augment grid power to power the home or when excess energy is produced, push it out onto the grid.
I am certainly no expert but I do have a couple neighbors with grid-tie solar systems on their S&B. Those systems were very expensive and a great deal of effort went into getting the power company to approve them. So, I suspect grid tie is out in anything less than a permanent, approved system - just guessing though.

It kind of sounds like you should wire your RV so that the AC units are powered from shore power and everything else is thru an inverter/battery bank. Then, you are always using your solar power. Maybe a manual plug that is moved if you have 'emergency' need of shore power in the house. Another option would be an additional AC sub-panel that feeds only a couple of sockets (for electric heaters or whatever).

The solar numbers mentioned previously are impressive - I have a 650 watt system and never need to plug in/run generator (in the SW with lots of sun). However; I run my fridge on propane. I can imagine a residential fridge and lots of house heater use could cause the demand to skyrocket (and, obviously, AC - but that is way out of my league)).

A possibility (that someone smarter than me would have to validate) would be to set your shore power charger voltage level to something lower than the solar charge controller. The goal would be to have the solar charge controller supplying all power (during daylight) and then the charger would kick in when solar power drops off. You could almost set it to a hair above battery voltage and it would never actually charge the batteries, just provide some power when it was in demand (I think). Of course, this would have you consuming shore power at night instead of battery power - a switch on the charger would take care of that (but not automatic). The fun thing with electronics is that most anything is possible, you just have to decide if the cost and/or effort is worth it.
__________________
JD - Full timer out west
Missy - 1998 MCI 102-EL3
JFNM is offline   Reply With Quote
Old 06-16-2014, 02:05 PM   #6
Senior Member
 
Kevin-B's Avatar
 
Join Date: Apr 2014
Location: Henderson, NV (Las Vegas)
Posts: 140
Why not wire the system so only the AC is only powered by the shore power and everything else is off the batteries & inverter?
__________________
- AD USAF Security Forces/Combat Arms (3P071B) - 19+ years of serving our great country and counting.
- 2009 Gulfstream Vista Cruiser Mini 4232
Kevin-B is offline   Reply With Quote
Old 06-16-2014, 02:33 PM   #7
Senior Member
 
vsheetz's Avatar


 
Fleetwood Owners Club
Ford Super Duty Owner
Join Date: Jun 2012
Location: SoCal
Posts: 14,704
I agree, why not be greener by using solar even when on shore power. I seldom turn on my converter/charger, even when on shore power. DC systems operate from batteries and solar charges batteries.

Also I don't plug in at home since adding solar, saving a few bucks a month of home electric bill (actually, I have 28 250w panels on the sticks and bricks as well - grid tied, with (-)$179.00 electric bill last year).
Attached Files
File Type: pdf VSheetz - Solar Setup for my RV v1.1.pdf (473.7 KB, 39 views)
__________________
Vince and Susan
2011 Tiffin Phaeton 40QTH (Cummins ISC/Freightliner)
Flat towing a modified 2005 Jeep (Rubicon Wrangler)
Previously a 2002 Fleetwood Pace Arrow 37A and a 1995 Safari Trek 2830.
vsheetz is online now   Reply With Quote
Old 06-16-2014, 03:44 PM   #8
Senior Member
 
SteveUpp's Avatar
 
Join Date: Nov 2013
Location: Fulltime Nomads
Posts: 203
Thanks for all the feedback...

I am looking for something fully automatic...like the way that grid-tie systems are fully automatic and utilize the PV array to meet all residential demand until the demand is too high at which time the inverter begins pulling from the grid.

My plan is to get a large (45ft) MH with lots of roof space for high efficiency residential panels (just as an example: 5 or 6 Sunpower X21-345 panels).

When on shore power, I'd prefer not to cycle the battery bank and would rather automatically fully utilize every solar watt for all MH AC demand including up to 3 air conditioning units that are typically on a MH of that size. I know 2000 watts isn't enough for all 3 air conditioners, but it will put a dent into the shore power demand that they would otherwise require. I'm hoping not to be in climates that require 3 air conditioners running continuously too often

I believe that current RV electrical system designs simply don't account for this and that's a missed opportunity.

Hey - Magnum Energy if you are listening maybe this is something to consider for your next generation inverter/charger? The BEST solution I think would be to integrate the transfer switch/energy management system and interverter/charger with MPPT(s) solar controllers so that the whole system works together to fully utilize solar capacity and use shore power only when necessary.

With 2KW of solar, you need more than one (current generation) MPTT controller anyways, so making it possible to network all these components together into one integrated system would in my opinion be quiet compelling. You already need all these subcomponents... make them communicate together into one whole system and you've got yourself a customer.

I do agree that actually grid-tieing the RV to the campground grid is unrealistic for now.
SteveUpp is offline   Reply With Quote
Old 06-16-2014, 03:45 PM   #9
Senior Member
 
SteveUpp's Avatar
 
Join Date: Nov 2013
Location: Fulltime Nomads
Posts: 203
Quote:
Originally Posted by Kevin-B View Post
Why not wire the system so only the AC is only powered by the shore power and everything else is off the batteries & inverter?
It may sound rediculous, but I don't want to throw away solar watts. If the PV array can supply 500W to the AC units.. then that's 500W less energy pulled from the grid.
SteveUpp is offline   Reply With Quote
Old 06-16-2014, 05:33 PM   #10
Senior Member
 
vsheetz's Avatar


 
Fleetwood Owners Club
Ford Super Duty Owner
Join Date: Jun 2012
Location: SoCal
Posts: 14,704
Hybrid Solar / Shore Power Solution Wanted

I see the goal, and appreciate the thinking. However, as for manufacturers providing such a solution in a package, what is the ROI that will drives sales to justify? Most CG stays with power hookup include non metered power. And most RV'ers won't cost justify the large PV system to support this. Maybe an idea ahead of its time and the cost reduction curve of PV equipment.
__________________
Vince and Susan
2011 Tiffin Phaeton 40QTH (Cummins ISC/Freightliner)
Flat towing a modified 2005 Jeep (Rubicon Wrangler)
Previously a 2002 Fleetwood Pace Arrow 37A and a 1995 Safari Trek 2830.
vsheetz is online now   Reply With Quote
Old 06-16-2014, 06:05 PM   #11
Senior Member
 
Join Date: Feb 2002
Location: Aguanga, CA, USA
Posts: 239
I had a similar desire with a decidedly smaller solar array (300 watts), and come up with a simple (I like simple), albeit somewhat different, solution.

I simply got a digital appliance timer (Home Depot) and plugged the converter into the timer. The timer is set to turn on about sundown and off about 11 PM. That way I use solar all day and every evening the batteries get topped off by shore power if the solar panels were not able to during the day. It does a pretty decent jobs of "steering" the electric usage to solar and automatically taking any excess electric consumption from shore power. You want a timer that has an internal battery for it's clock, of course, so you can lose shore power and not lose the time setting.
jspande is offline   Reply With Quote
Old 06-20-2014, 04:10 PM   #12
Registered User
 
Join Date: Feb 2013
Posts: 472
I think you answered your own question. You need a grid tie inverter
Fl_Richard is offline   Reply With Quote
Old 06-22-2014, 08:07 PM   #13
Senior Member
 
Bumps's Avatar
 
Winnebago Owners Club
Join Date: Sep 2013
Location: FTer Class of 2015 Origin: Evergreen, Colorado
Posts: 1,560
I pursued this dream last summer. I found some systems that would do this, but they were too large for a motorhome ... and too expensive for my budget. I even consulted with an electrical engineer who was eager to take on the project, but he was going to be a pretty spendy option, too. I agree with the "green agenda," but opted to simply manually switch power sources (when I have those options). I'll be following this thread, however, just in case somebody comes up with an affordable, practical, automated solution (with a touchpad user interface!). Thanks! \ken
__________________
Ken, Deb, & Gadget (WIT Club, FMCA, SKP, and grateful volunteers with Habitat for Humanity and SOWERs), traveling in a well-behaved 2005 Winnebago Vectra 40FD w/1100w solar, some gee-golly-whizbang, and a TRAILERED 2015 Cherokee TrailHawk toad.
Bumps is offline   Reply With Quote
Old 06-22-2014, 11:07 PM   #14
Senior Member
 
SteveUpp's Avatar
 
Join Date: Nov 2013
Location: Fulltime Nomads
Posts: 203
Glad to know others share the same hope that a solution will present itself.
__________________

__________________
Steve & Karen Upp
2019 Newmar New Aire 3341 (1620W solar, 1200AH Lithionics LiFePO4 Batteries)
2019 Jeep Wrangler Unlimited Rubicon (4 cyl Turbo)
SteveUpp is offline   Reply With Quote
Reply

Tags
power, 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
Generator / shore power question Tom222 RV Systems & Appliances 6 06-08-2014 06:05 PM
Solar power of the future. Thought this might be of interest to the Solar power puris IMDSailor MH-General Discussions & Problems 1 04-17-2014 04:31 AM
Shore power from gas generator? DynastyJim RV Systems & Appliances 8 03-15-2014 08:41 PM
Solar Power - Generator - Inverter Question Rossi6998 Boondocking 7 03-09-2014 12:06 PM
Shore power cord 2013 BayStar ICUMobile Ch Newmar Owner's Forum 7 01-21-2014 08:27 PM

» Featured Campgrounds

Reviews provided by


All times are GMT -6. The time now is 02:20 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
×