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Solar Installation On A 2015 17 Foot Spirit Deluxe

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#1 Rew

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Posted 13 April 2015 - 05:46 AM

I'm not an expert in solar...figuring this out as I go along with OTJ training and online research.  There doesn't appear to be a post on this forum that talks about what I have done so I thought I'd post it.  I'd love to get your feedback and questions.  This will not be a step-by-step guide...just a broad overview of what I used, where I put it, and how I did certain things.  I have a 2015 17 foot SD.

 

You need to consider three questions when considering solar:  how much energy do you need, how much can you generate, and how much can you store.  I made some decisions to reduce my power needs with LED lights, I have a low-power laptop, and the inverter I am using has low parasitic drain and an on/off switch.  I'll use LP to power the fridge, heat my water, and heat the cabin...all of these require 12v for circuitry, sensors, and fans/pumps, but the bulk of the energy requirements are handled by LP.  All in all, I figure I'll just need to regenerate 10-25 amp hours per day depending on outside temperatures...not much to worry about.  

 

There isn't a lot of real estate on the top of a Casita for solar panels, and with such a nice solid (i.e. waterproof) roof I wasn't interested in drilling holes to fix panels up there.  I found some flexible solar panels online, did some measurements, and found that I could fit two 50 watt panels on the roof of the casita...one immediately in front of the center fan and one between the fan and the roof heater/AC unit...without having to drill by using 3M VHB (very high bond) tape.  This tape has held for 1,400 miles so far so I have no concerns with its durability...plus the flexible panels are thin and do not generate much in terms of wind resistance.  Online I have found posts where people have also run sealant around the outer edge of the panels to support the 3M tape, but VHB tape is really tough and I think this is quite unnecessary.  These panels can flex up to 30 degrees and hug the slight contour of the Casita's mohawk perfectly.  The panel between the roof heater/AC and the fan is problematic...an entire solar panel loses efficiency when even a portion of the panel is in shadow, so in a typical day this particular panel is more likely to be partially shaded compared to it's more forward-facing partner.  I am not concerned about this because I only have the single Interstate group 27 battery to worry about, and with 100 watts of generating capacity I'll generate enough power, even if it is on a cloudy day.  For the first phase of this project I have permanently taped down only the front 50 watt panel as I want to see if that will be enough to keep my battery topped off.  The other panel is currently off and unplugged.  When connected, the two panels are strung in parallel with one another (to increase amp output and leave voltage the same as if only one panel were connected).

 

The charge controller is an area of discussion...most people will say get an MPPT controller over a PWM.  They are more efficient and you'll get more photons into your battery than with the cheaper PWM controllers.  I purchased an MPPT controller and do not believe it makes a difference in this particular application since I can generate more power than I need anyway, so efficiency gains are not important and simply costs more to implement, and I only have 100 watts to deal with.  What I do like about the MPPT controller I got, however, is that it came with a remote meter so I can read what I'm generating, battery SoC, and so on.

 

Where to run the cabling took some time to figure out.  I ran the MC4 cabling down towards the awning side and then toward the front where the grey water tank vent is.  From the closet I drilled two holes into that pipe and fed the cable down that vent and out through the holes.  When the temps improve here at home I'll add some silicone goop to seal around both sides of the wiring.  The MC4 cabling then goes down the outside of the PVC vent pipe to the floor of the closet, out under the wall the closet door is cut into, and under the wall for the bathroom and over to the driver's side of the trailer under the front dinette seat.  From there is was easy to run it alongside the rest of the wiring back to where the section of the compartment where the converter and water heater is.  I mounted the MPPT charge controller there using 3M velcro tape (it has held for 2,800 miles so far) and I used Anderson quick connecters for the wires going in and out...green to the panels, red to the battery.  There is only room to work in there one-handed, after all...so I wanted to make it simple.  I drilled two holes into the fiberglass battery box for the positive and negative MC4 wires going to the battery, attached directly to the terminals.  I plan to add an inline fuse shortly...this was recently pointed out to be something that I should do.  I soldered the ring terminals to the MC4 cabling.  

 

I used zip tie anchors fixed to the roof with 3M tape to zip tie down all the loose wires on the roof.  The MC4 splitter (which allows both 50 watt panels to use the same MC4 wire going into the charge controller) I zip tied to the frontmost bracket for the awning...keeps it from flapping around while driving.  I zip tied the two MC4 wires going into the grey water vent pipe outside the Casita so that the little vent cap would stay down...the 10 gauge wire had a tendency to push the cap off on one side, so this keeps it in place.  I zip tied the MC4 wiring all down the vent pipe inside the closet, but once it was under the walls and out of sight I left it as-is.

 

I ran the remote cable up the small gap created by that partition between the bed and the dinette chair (opposite the stove in the SD).  I just leave the cable and the remote tucked down the gap between the mattress and the Casita wall...I don't need to check it often and did not want to drill holes in anything.  

Parts:

  • Renogy 50 watt flexible solar panel
  • Tracer 30 amp MPPT charge controller with remote (30 amp was overkill for what I currently have, but allows for expansion)
  • 50 feet MC4 10 gauge AWG cabling
  • Outdoor cable tie mount mounts (called cable tie anchors, find these in home depot, get ones rated for outdoor use)
  • MC4 connectors
  • MC4 crimp tool
  • Normal wiring tools (red knuckles, wire stripper, multi meter tester, and so on)

 

Some other things I've learned along the way:

 

  • Be careful of your positive and negative!  Learn to use a multi meter to accurately figure out what is what.  I tested and retested and found that I almost crossed my wires.  
  • Normal temps (0 - 80 F) will not affect solar generation capabilities, but lower temps means your deep cycle lead acid battery will have a significantly reduced capability for output.  At 15F our batteries may only be able to produce 40-50% of it's rated capacity...and since you shouldn't drop a lead acid battery below 50% that often, and these are 96 Amp Hour batteries by default...this leaves you with ~22 Amp Hours of power when it's really cold out (and when you need it most).  I had to keep my Casita plugged into shore power over this New England winter just because the battery really isn't designed to work well in cold conditions.  I plan to replace the battery with one made to work better in colder temps
  • Snow will significantly reduce generation capabilities on a roof-mounted system...down to zero.  If you want to generate power in the winter you'll either need to keep it clear or get yourself a portable panel that you can hook in and keep clear on the ground.  If you are camping in the winter you'll likely want to get a 120 watt portable panel to help get by several days of cloudy weather with much shorter generation days.  I purchased a Go Power! 120 watt portable unit for this purpose.  This is a powerful portable panel system and they sell a 7 pin trailer plug adapter so that you can hook it in without any wiring necessary.  I think it is pricey for what you get, and the charge controller built into the portable unit is not water proof (tho it is underneath the panel and will be protected from light rain)
  • The charge controller is in it's compartment fixed to the wall that separates the bed from the dinette chair.  I used used 3M tape to stick it to it...no drilling needed.  
  • I wish there was room for a single 100 watt panel up there but there really just isn't.  As solar technology improves in efficiency we will have more options to generate higher amounts of power with less space.
  • Read the 3M VHB directions carefully and install it accordingly.  I had everything installed inside the camper in December and then drove to Florida for vacation where I waited for a warm, sunny day to tape the panel down and give it the time it needs to cure (full day for me, but I think the instructions only call for 6 or so hours).  
  • I'm using a pretty long run of MC4 cable to the charge controller, something like 25 feet.  I used 10 gauge MC4 vs 12 gauge because of slightly less voltage drop (loss) with the heavier gauge cabling
  • Roof mounted panels provide power with no additional work required by you.  Portable panels need to be deployed manually and are at greater risk of being stolen.  I like shade over bright sun, so I'll be parking in there as much as I can, which will diminish my panel's generating capacity to some degree or another.  I hope to be able to still generate more than I need with the one 50 watt panel, but if not I'll stick on the 2nd 50 watt, and if that still isn't doing it I have the portable unit that I can stick out in the sun with a 30 foot extension cable connecting it to the front 7 pin cable

The results have been terrific.  Now that we are getting into more civilized temps and my battery is showing signs of working normally vs. diminished capacity due to the cold, I moved the camper off of shore power and have been testing it out.  The fridge is running (LP), the heat is on (LP), my inverter is on and keeping a laptop charged, and thus far the battery is easily charged each day after getting down to somewhere between 12.3 and 12.4 volts over night (somewhere around and between 70 - 80%...the suburban furnace is responsible for most of that).  

 

In the picture below the wires are all over the place but this was right after I stuck it down.  The wires are currently tied up nicely using zip tie anchors that I stuck to the roof using 3M tape...I found these at Home Depot.  I'm ashamed that I didn't get the panel perfectly centered...so purists please withhold your anger =)

 

I'm sure I left things out but will answer questions and add/clarify as needed.  I'm making edits as I go along to correct grammar and add bits of detail.

 

Update April 15, 2015:  

I definitely need to connect the second 50 watt panel, bringing my total to 100 watts.  I'm getting around 2.1 amps with the one panel, and on a perfect day that won't be enough to back charge more than around 20 amp hours of battery.  With the two panels connect in parallel I'm seeing around 5 - 6 amps when both are in full sunlight.  

 

Turns out there may be a problem with charging when I connect my portable panel to the battery.  Having the two solar arrays with different charge controllers could make one (or both) think that the battery is far more full than it really is due to each misreading the incoming voltage.  Some charge controllers allow for multiple arrays on multiple controllers to feed one battery, allowing them to work in tandem.  I'm picking up a Morningstar ProStar controller to see if it'll fit on the portable panel when it is closed up....if so I'll change that one and the Casita's controller to the ProStar, allowing me to have up to 220 watts of generation if necessary.  I have a couple of other projects that I'll use the two extra controllers on.

Attached Thumbnails

  • IMG_1212 (2).jpg

Edited by Rew, 15 April 2015 - 10:35 AM.

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#2 garyeven

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Posted 26 May 2015 - 06:07 PM

I was wondering if you thought you could attach a second 50 watt panel to the top of the air conditioner housing. Seem that it's large enough.
Gary
Never mine, I crawled up there and looked and there is not enough room. Should have done that first.

Edited by garyeven, 28 May 2015 - 11:03 AM.


#3 araden

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Posted 27 May 2015 - 09:33 AM

Thank you for this post.  I was trying to decide on a solar set-up after my first couple of days off the grid.  I was considering the portable suitcase panels, but was concerned about theft and storage when not deployed.  This looks like a much cleaner way to go.


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#4 CA Birder

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Posted 04 June 2015 - 10:19 AM

I'm certainly not an expert either, but I have just set up a 90W system using a folding suitcase panel, a Morningstar Sunsaver 10A charge controller, and a Trimetric monitor. I'm confused though about one thing you said about using the Prostar and the one in the Casita to generate up to 220W. What do you mean by that? How do you get more wattage than the panels are rated at?

 

I was told too, that the charge controller should be as close to the battery as you can, with as large a wire that will fit, to reduce voltage drop.

 

I chose the folding suitcase type so that I can park in the shade and point the panel at the sun. I have a long cable to lock it down. It will at least keep the honest people from taking it. 

 

Mike


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#5 Rew

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Posted 11 June 2015 - 01:01 PM

I'm certainly not an expert either, but I have just set up a 90W system using a folding suitcase panel, a Morningstar Sunsaver 10A charge controller, and a Trimetric monitor. I'm confused though about one thing you said about using the Prostar and the one in the Casita to generate up to 220W. What do you mean by that? How do you get more wattage than the panels are rated at?

 

Mike

 

Hiya Mike...by this I mean to replace the GoPower portable 120 watt panel's charge controller with a ProStar model.  This unit connects to the Casita via the 7-pin plug in the front.  The ProStar that I have installed in the Casita is the one that controls the two flexible 50 watt panels on the roof.  The idea is that with the 120 watt portable unit + 100 watts on the roof I'll get 220 watts total since the two ProStars should play well together to charge the single battery.  Does this help?  I'll clean up my wording in the post above, thanks for the feedback!



#6 Rew

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Posted 11 June 2015 - 01:12 PM

Update on the installation so far:

 

I installed the second panel and wasn't happy with the results.  After troubleshooting with a multimeter I found the panel was defective.  Renogy promptly RMA'd it and the new panel has come in...it'll get installed this weekend.  They covered shipping both ways.  

 

The 3M VHB tape worked great...it has held the panels down flat and when I needed to remove the panel it came off with some prying.  I have ordered another length of it so that I can put the replacement panel on as well.  

 

I upgraded the battery to a Lifeline 31XT.  It was a tight squeeze but it fit in without much trouble...just make sure you are not putting too much strain on the wiring or pinching it on the installation.  The metal bracket that holes the factory battery in place has to be removed in order to fit this battery.  The 31XT was a bit pricey, to be honest, but it is American made, has a great reputation, and increases my capacity from 96 amp hours to 125.  

 

Velcroing the charge controller to the storage cabinet wall hasn't worked out...it keeps dropping off, so I have screwed it in.  Out of sight anyway, plus I don't plan to not have a solar controller in there anyway.  



#7 Va Hillbilly

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Posted 13 June 2015 - 05:57 AM

Rew, my experience has been somewhat similar to yours. Like you I installed a 50 watt panel on the roof in front of the fan vent. The exception was I used a monocrystaline panel. I used VHB tape to attach the panel. Like you I ran the power cable down the vent instead of drilling any holes. I have a Liberty and because I mounted the controller underneath the furnace it was a shorter run to use the black tank vent as my conduit.

My controller is a Morningstar 15A MPPT unit. All wiring to and from the controller was 8 gauge marine wire using Anderson connectors. After contacting Interstate technical support I adjusted the controller to output 14.8 volts bulk charge to fully charge the lead acid battery.

It sounds like our power usage is similar to yours. I found the 50 watt panel capable of fully recharging my 85 ah battery with some exceptions. These being spring and fall with the lower sun angles, shady camping locations, and protracted overcast conditions. In general though the roof mounted unit was super convenient and typically was turn it on and forget it during camping trips.

To address those periods when the roof mounted unit could not bring the battery to full charge I purchased a 100 watt panel that can be used to minimize shade effects and bring the battery back to full charge quicker. I use a 30' eight gauge marine cable with Anderson connectors fo this as well. Installed a "pigtail" 8 gauge cable from the solar controller to the Casita power door beside the water heater. The remote panel is connected through this door power opening to the controller. Both panels are running through the common controller and should one panel be shaded and the other not it still gets power from the the active panel.

In preparing for a trip to Alaska last year I was concerned about extended overcast conditions as well as low sun angle. To address this in installed two 6 volt golf cart batteries in the bed of my pickup. This brought the combined total battery capacity to about 300 ah. The bed mounted units were connected into the vehicle charging system and was tied into the 7 pin trailer connector. This allowed for charging when we were out driving and the camper parked.

I installed switches that allowed for either the Casita battery or the six volt batteries or combined to be brought online. The Casita battery is monitored by a Victron power monitor. The six volt batteries only have a voltmeter.

We spent almost 5 months on the Alaska/western U.S. trip last year year and did not need 110 volt power for charging. The state of charge never dropped below 80%.

Like you stated in your original post my experience has been a lot of OJT and Internet research. We are now stariting our fourth season using solar and my experience so far has been favorable. I am sure if we camped in the hotter areas of the country we would need a generator to run the AC but so far we have either avoided the hot areas or stayed at Campgrounds with electrical hookup. I tend to use elevation and or latitude to avoid the need for AC.

I did not mean to be so long winded but for anyone reading these posts and are just starting down the solar path perhaps they might find something useful and perhaps avoid a do over. As my findings and installation is similar to yours there are some differences as well. As there is no single "right answer" those following us will do what fits their unique needs. Thanks for outlining your experience. When I was into the research phase of my solar education it was post like yours I was seeking.

Edited by Va Hillbilly, 13 June 2015 - 06:32 AM.

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#8 SoloMatt

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Posted 15 June 2015 - 05:28 AM

^Very useful! Thanks!

#9 C.FiberglassFreedom

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Posted 20 June 2015 - 09:14 PM

Rew, my experience has been somewhat similar to yours. Like you I installed a 50 watt panel on the roof in front of the fan vent. The exception was I used a monocrystaline panel. I used VHB tape to attach the panel. Like you I ran the power cable down the vent instead of drilling any holes. I have a Liberty and because I mounted the controller underneath the furnace it was a shorter run to use the black tank vent as my conduit.
My controller is a Morningstar 15A MPPT unit. All wiring to and from the controller was 8 gauge marine wire using Anderson connectors. After contacting Interstate technical support I adjusted the controller to output 14.8 volts bulk charge to fully charge the lead acid battery.
It sounds like our power usage is similar to yours. I found the 50 watt panel capable of fully recharging my 85 ah battery with some exceptions. These being spring and fall with the lower sun angles, shady camping locations, and protracted overcast conditions. In general though the roof mounted unit was super convenient and typically was turn it on and forget it during camping trips.
To address those periods when the roof mounted unit could not bring the battery to full charge I purchased a 100 watt panel that can be used to minimize shade effects and bring the battery back to full charge quicker. I use a 30' eight gauge marine cable with Anderson connectors fo this as well. Installed a "pigtail" 8 gauge cable from the solar controller to the Casita power door beside the water heater. The remote panel is connected through this door power opening to the controller. Both panels are running through the common controller and should one panel be shaded and the other not it still gets power from the the active panel.
In preparing for a trip to Alaska last year I was concerned about extended overcast conditions as well as low sun angle. To address this in installed two 6 volt golf cart batteries in the bed of my pickup. This brought the combined total battery capacity to about 300 ah. The bed mounted units were connected into the vehicle charging system and was tied into the 7 pin trailer connector. This allowed for charging when we were out driving and the camper parked.
I installed switches that allowed for either the Casita battery or the six volt batteries or combined to be brought online. The Casita battery is monitored by a Victron power monitor. The six volt batteries only have a voltmeter.
We spent almost 5 months on the Alaska/western U.S. trip last year year and did not need 110 volt power for charging. The state of charge never dropped below 80%.
Like you stated in your original post my experience has been a lot of OJT and Internet research. We are now stariting our fourth season using solar and my experience so far has been favorable. I am sure if we camped in the hotter areas of the country we would need a generator to run the AC but so far we have either avoided the hot areas or stayed at Campgrounds with electrical hookup. I tend to use elevation and or latitude to avoid the need for AC.
I did not mean to be so long winded but for anyone reading these posts and are just starting down the solar path perhaps they might find something useful and perhaps avoid a do over. As my findings and installation is similar to yours there are some differences as well. As there is no single "right answer" those following us will do what fits their unique needs. Thanks for outlining your experience. When I was into the research phase of my solar education it was post like yours I was seeking.


Could you offer more information on your setup, pictures would be a blessing. Was the wiring done yourself, if so could you explain more about it. Any information is appreciated.




-Charlie

#10 Beetlefreak

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Posted 21 June 2015 - 09:14 AM

I believe I have also been down a similar road as others that have posted.  My first installation was 2 - 50 watt panels and a second 12 volt battery.  I mounted 1 panel in front of the roof fan and another in back of it.  There really wasn't room in back and the shadow from the air conditioner negated a lot of the benefit from the second panel. (mistake #1)  I also ran the #10 cable from the 2 panels down the vent pipe and under the galley in our Liberty to the Go Power controller mounted next to the power panel and then on to the batteries. (mistake #2)  I should have made a more direct route for heavier gauge wire and keep the controller closer to the batteries.  Our is a 2010 Liberty Deluxe and it has one of the older converters that will over charge the batteries if left plugged into shore power for extended periods of time.  (mistake #3)  I was still working at the time so the Casita sat in the garage plugged in and it boiled both batteries.

 

There were probably other minor mistakes but those 3 were enough to take me back to the drawing board for another design.

 

After calculating how many watts I planned to consume and calculating how many amp hours I would need to run all of the things I wanted to run (lights, fans, water pump, TV, computer, phone chargers, rechargeable tooth brushes, amplified speakers etc.) I decided to install 2 - 6 volt golf cart batteries.

 

I didn't want to fool around with storing and positioning portable panels so I came up with a design that allowed me to put enough panels on the roof to keep the batteries charged even in less than optimum conditions.  I think one of the rookie mistakes others make is to calculate how many watts of solar they need based on data provided by the manufacturer that is achieved under ideal conditions.  Then when we get out in the real world where there is shade and cloudy days and low sun in the winter, a couple of rainy days or dirty panels and now we don't have the ability to return the batteries to 100% charge.  I settled on a design that utilizes the 2 - 50 watt panels that I had plus 3 additional 100 watt panels.  Sounds like a lot and I suppose my needs are greater than some but if you consider the factors I mentioned and the fact that the panels are positioned to collect the suns rays at all different angles, I doubt if at any given time I am using the equivalent of 200 watts worth of panels.  The beauty of the designs that I don't have to consider orientation to the sun when I camp.  We have used this setup in all conditions including full shade campsites, multiple rainy days in a row, cloudy days and 9 weeks on the road last winter where more than half of the time we were boon docking with no hookups.  That reminds me of mistake #3 - remember the converter.  I disconnected it.  All of my 12 volt needs are provided by the sun - even when we have hookups.  Now that I am retired the Casita sees a lot less garage time but when it is there I use a 2 amp trickle charger to keep the batteries charged.

 

There are a lot of details to the system I have been using for over 18 months that I won't go into here but if you are interested I can answer questions and provide more detail.


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#11 BillG

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Posted 06 July 2015 - 01:13 PM

My Patriot is parked up in the woods this week so I can't look at it right now. If I were to run the wires from the solar panel in thru the power cord door to the under-stove compartment, is there access from there over to the battery? Could I just leave the controller connected to the battery all the time and then have pigtails I could pull out thru the power cord door and connect to the solar panel? I'm headed back up this weekend and I'd love to know what tools to take along. Thanks for any help!!!

#12 Va Hillbilly

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Posted 06 July 2015 - 06:53 PM

My Patriot is parked up in the woods this week so I can't look at it right now. If I were to run the wires from the solar panel in thru the power cord door to the under-stove compartment, is there access from there over to the battery? Could I just leave the controller connected to the battery all the time and then have pigtails I could pull out thru the power cord door and connect to the solar panel? I'm headed back up this weekend and I'd love to know what tools to take along. Thanks for any help!!!


I can't address the patriot part of the question as to wire routing inside the camper but on leaving the controller connected, this is essentially what I do. My roof mounted panel is connected to the solar controller all the time. The output from the controller goes to a switch that allows the converter to the battery to be turned on and/or the output from the solar controller to be turned on to the battery. The portable panel cable when needed comes through the power door to an Anderson connector installed on a pigtail which connects in parallel with roof mounted panel.

My normal camping operating mode is to have both the converter and roof mounted panel connected to the Casita battery all the time. If I need more power which is not often I just connect the portable panel to the pigtail. I typically leave the roof panel connected in even if connected to 110 volt power. This can actually help to fully recharge the battery. The converter installed to 110 volt only charges the battery at 13.7 volts which makes it difficult to fully recharge the battery. To get the last 10-20 % of battery capacity in a reasonable amount of time the charging voltage needs to be up at 14.8 volts which the solar panel is capable of.

#13 Rew

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Posted 03 August 2015 - 04:51 AM

August update:  I'm traveling around with the two 50-watt panels (one forward the roof exhaust fan and one between that fan and the AC unit).  These are connected in parallel to a three-way MC4 splitter.  The 120 watt portable panel's charge controller was changed to a Morningstar one, but I didn't seem to get the full benefit of the two roof panels and the portable connected at the same time (two charge controllers charging the same battery seems to not work well).  So I just bypassed the portable panel's charge controller and installed a short quick connect extension off of that to just behind the awning.  I then built a 20 foot MC4 extension cable and that is what connects to the extension using an anderson pole connector.  This puts all the panels on the same array, in parallel, going into the Morningstar PS15m controller.  Since all of the panels have the same voltage output and the total amperage will be below the 15 amp limit of the charge controller this was OK/safe to do.  When all panels are connected and in perfect sun I'm getting > 8amps.  In short, I have two 50 watt and two 60 watt panels all hooked up in parallel to the same controller.  

 

I wish I had some sort of digital logger to track the power being generated over time.  It would be neat to see what that would tell me.  

 

Fortunately the two 50 watt roof panels have been sufficient to allow me to use the camper for > 30 days without plugging it in.  Sometimes the power gets to around 70-75% (12.3 - 12.39 according to the meter I have in the 12v outlet above the bed) volts after an evening of running the fridge on LP, the smoke/monoxide detector, Xantrex 1000 watt inverter, a small fan, and the roof exhaust fan.  I imagine that if I had grey skies for a couple days I'd need to hook up the portable panel.  

 

The 50 watt panel between the AC and exhaust fan vent doesn't do much for much of the morning and late afternoon due to shadows from the Maxxair vent cover or the AC unit.  Overall, however, I still think it was worth installing because when it often gets good sunlight for several hours, adding maybe an additional 3-6 amps to the battery that wouldn't otherwise be there.  It makes me happy when I see 4.3 amps being generated.  

 

VA Hillbilly mentions this too...that even though the two 50's are flat mounted on the roof and one of provides power much less than the other, the panels up there are really convenient and I don't even think of them anymore.  If I have a choice of how to park the camper I'll try to angle it east/west to minimize shadows.  

 

The VHB adhesive has thus far held up well for 4,000 miles.  I have been able to remove the panels after installation without damaging the roof.  

 

Rew


Edited by Rew, 04 August 2015 - 11:25 AM.


#14 garyinpreskitt

garyinpreskitt
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Posted 12 June 2017 - 02:46 PM

August update:  I'm traveling around with the two 50-watt panels (one forward the roof exhaust fan and one between that fan and the AC unit).  These are connected in parallel to a three-way MC4 splitter.  The 120 watt portable panel's charge controller was changed to a Morningstar one, but I didn't seem to get the full benefit of the two roof panels and the portable connected at the same time (two charge controllers charging the same battery seems to not work well).  So I just bypassed the portable panel's charge controller and installed a short quick connect extension off of that to just behind the awning.  I then built a 20 foot MC4 extension cable and that is what connects to the extension using an anderson pole connector.  This puts all the panels on the same array, in parallel, going into the Morningstar PS15m controller.  Since all of the panels have the same voltage output and the total amperage will be below the 15 amp limit of the charge controller this was OK/safe to do.  When all panels are connected and in perfect sun I'm getting > 8amps.  In short, I have two 50 watt and two 60 watt panels all hooked up in parallel to the same controller.  

 

I wish I had some sort of digital logger to track the power being generated over time.  It would be neat to see what that would tell me.  

 

Fortunately the two 50 watt roof panels have been sufficient to allow me to use the camper for > 30 days without plugging it in.  Sometimes the power gets to around 70-75% (12.3 - 12.39 according to the meter I have in the 12v outlet above the bed) volts after an evening of running the fridge on LP, the smoke/monoxide detector, Xantrex 1000 watt inverter, a small fan, and the roof exhaust fan.  I imagine that if I had grey skies for a couple days I'd need to hook up the portable panel.  

 

The 50 watt panel between the AC and exhaust fan vent doesn't do much for much of the morning and late afternoon due to shadows from the Maxxair vent cover or the AC unit.  Overall, however, I still think it was worth installing because when it often gets good sunlight for several hours, adding maybe an additional 3-6 amps to the battery that wouldn't otherwise be there.  It makes me happy when I see 4.3 amps being generated.  

 

VA Hillbilly mentions this too...that even though the two 50's are flat mounted on the roof and one of provides power much less than the other, the panels up there are really convenient and I don't even think of them anymore.  If I have a choice of how to park the camper I'll try to angle it east/west to minimize shadows.  

 

The VHB adhesive has thus far held up well for 4,000 miles.  I have been able to remove the panels after installation without damaging the roof.  

 

Rew

 

Rew,

I check this forum every now and then to see if someone has come up with a novel way to add several hundred watts of solar power to our Casitas.  I like what you did and compliment you on a well thought out and installed system.  I usually set my systems up in a provisional way and can take a while before I permanently install them simply because I have trouble deciding where to mount stuff!  I have seriously been considering panels as awnings for all the windows, but I can see that I'm probably not going to get anywhere with that anytime soon!  I'm still using portable panels.   A few things caught my eye as I was reading about your system I believe you might want to consider.

 

First, in nearly every instance an MPPT charge controller is used, panels are connected in SERIES within the input limits of the controller given the combined open circuit voltage of the panels.  Is there a special reason you connected yours in parallel?  You are no doubt doing better than with a PWM controller with your panels in parallel, but falling pretty short of realizing the full potential of the MPPT controller.   With the panels in series, you should see a marked increase to the battery under conditions you are currently reporting less than desirable results.  It will be particularly important in heavily shaded or inclement weather conditions.  I can offer that from past experience.   If you can swing getting the portable panel in series with those, considering the input limits of the controller, so much the better.  You might find less of a need to include the portable panel in the mix with the 2 rooftop panels in series.

 

Second, the Lifeline 31XT looks to be an AGM.  While still a lead acid battery, AGMs, especially those spec'd for deep cycle service, are special animals.  I am more familiar with the Odyssey and Optima charge requirements along with a few others and from what I've seen of the Lifeline technical materials, there are many similarities with all of them.  While Lifeline appears to specify nominal flooded absorption and float voltages @ 77F, they do call for a higher “boost” voltage more akin to the recommended Odyssey absorption voltage of 14.7 volts when the Lifeline reaches a state of charge of 75%.  Since you are recharging daily from a state of charge of <75%, you might want to talk to Lifeline about optimizing your charge controller for 14.7 absorption voltage.  I would hope the Morningstar will let you do that.  I would leave the float at 13.3 per the Lifeline spec.   That MPPT charge controller should be temperature compensated as well.  If there is a sensing cable that you can attach to the battery so the controller can adjust charging voltages accordingly, I recommend you add that.  You want to be sensing BATTERY temperature instead of ambient.

 

The voltage levels used to determine the state of charge (SOC) for deep cycle AGM batteries is different from flooded batteries.  I believe the measurements you are using are based on a FLOODED battery state of charge curve.    A fully charged Lifeline 31XT is 13 volts.  The 31XT is considered to be at 75% SOC at 12.5 volts.  At the voltage levels you are reporting (12.3-12.39) the actual state of charge is considerably lower for your 31XT.   According to the Lifeline technical materials, this would call for at least a boost charge, which as previously mentioned, you might be able to coax out of your Morningstar MPPT controller.  

 

AGM mfrs of good repute offers extensive technical information on how to care for their batteries.  AGMs can be more sensitive to a "walk down" of their rated capacity if depth of discharge and commensurate charging practices are not observed.  A forty page technical manual for Lifeline batteries is available from their website.


Edited by garyinpreskitt, 12 June 2017 - 02:51 PM.

  • kgraggio likes this

#15 Rew

Rew
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Posted 14 June 2017 - 08:15 AM

Garyinpreskitt...

 

Thank you so much for taking the time to write your recommendations.  I did a little looking around at the manuals for both my charge controller (morningstar PS15m) and Lifeline 31XT battery.  It's been a while since I dove into this project so I need to do a bit of reading, research, and experimentation.

 

The charge controller allows me to set it to one of three battery types.  From the manual found here:  http://www.windandsu...tar-Manual.pdf:

------

 

8.2 SELECTBATTERYTYPE

The Battery Type rotary switch allows selection of 1 of 3 charging algorithms. These are broadly defined as the following battery types as noted on the lower label:

  1. Gel: Some gel and other battery types recommend lower regulation voltages and no equalization. This setting regulates to 14.0V (for a 12V battery).

  2. Sealed: AGM, “maintenance free“ and some types of gel batteries. Regulates to 14.15V (12V battery) with 14.35V boost charging.

  3. Flooded: Vented cells that require water to be added. Regulates to 14.4V with 14.9V and 15.1V equalizations (12V battery). 

------

 

I believe I have it set to "Sealed".  As you pointed out, this regulates to lower than the 14.4 that Lifeline appears to recommend in their manual for 77F.  Setting this to "Flooded" would raise those values and perhaps coax more out of the charge controller.  The manual I found online is here:  http://lifelinebatte...ical-Manual.pdf.  Section 5.4 "Charging" has Table 5-1, which shows the various absorption and float voltages based on temperature.  

 

I'm going to do a few things the next time I'm out there:

 

1) Hook up the temperature sensor.  I have one but forgot about installing it.  It needs to be soldered on the board.  I have the equipment and enough experience to muddle my way through that without destroying anything.

2) Call Lifeline and get any recommendations from them

3) Experiment with different charge controller settings and monitor the results

 

Again, thanks!  

Rew


Edited by Rew, 14 June 2017 - 08:16 AM.






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