Solar not Ready - R-pod Owners Forum

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toddrich

Newbie

Joined: 16 Aug 2018
Location: WA
Online Status: Offline
Posts: 4

Topic: Solar not Ready
Posted: 16 Aug 2018 at 6:50pm

I have a 2011 177 that is not solar ready. I currently have a small panel that (12 W) that I used on my previous trailer. It just does not seem to help much since it claims to output 650 mA. I would like to mount a bigger panel to my roof but am not sure what i need. I am pretty handy and can handle doing the work myself. There are trips where I dry camp for 10 days. Do I need a panel & controller? Any suggestions?

Ben Herman View Drop Down

Senior Member

Joined: 26 Apr 2018
Location: Gr Junction, CO
Online Status: Offline
Posts: 355

Posted: 16 Aug 2018 at 8:05pm

I've had good experiences with a Renogy suitcase unit, 100 watts with built in controller. Generates enough juice to keep the battery fully charged every day. Might be better prices out there but here is the unit::

https://www.renogy.com/products/solar-panels/folding-solar-suitcases/?gclid=CjwKCAjwwdTbBRAIEiwAYQf_E1dRW5-8rYilzq6u4MryhufgJ9WHCObwznvqgqct7i_SCGSy9kNzNxoC0iAQAvD_BwE

fwunder

Senior Member

Joined: 04 Oct 2013
Location: New Jersey
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Posts: 1676

Posted: 16 Aug 2018 at 8:14pm

The newer Renogy 100 watt Eclipse suitcase is smaller, lighter and comes with a waterproof controller.

Sooo tempting...

https://www.amazon.com/dp/B01NADR1CI

fred

2014 RPod 178 => MyMods and Buying Habits
2008 4Runner Limited 4.0-liter V6
Yes, those are wild ponies dining on grass while dumping tanks!

offgrid

Senior Member

Joined: 23 Jul 2018
Online Status: Offline
Posts: 5290

Posted: 17 Aug 2018 at 6:58am

Hi toddrich,

Here are some thoughts on adding solar to your rpod. You probably should do a little thinking regarding what kind of usage you will be making of electric appliances in you rpod and where you will be camping. If you're on hookups then none of this matters. If you're off grid and a relatively heavy energy user like I am then I would start with a dual battery installation, then add solar.

If you nearly always camp under tree canopies without direct solar access then its probably not worth bothering with solar, PV modules just don't perform well under these conditions. Even partial shade causes a severe reduction in performance because the cells in the modules are in series so shading one cell pretty much blocks the output of the whole module. Then you also have the issue of how to maintain battery charge over a series of cloudy days.

in this scenario just get a generator and run the battery charger with it for a couple hours a day (depending on your usage) instead. Generator type and size will depend on whether you want to run your air conditioner and/or microwave directly from it which are the loads in your trailer which require and AC power source. You can switch to a 12Vdc TV set pretty cheaply and easily if you use that a lot.

If you do mostly camp in direct sun and in sunny weather then by all means go for the solar installation. Keep the genny for cloudy day backup and for when you are camped under trees.

I'd suggest you try the dual battery installation first and determine how long that lasts for you before deciding how large a solar array you need. If you install say a dual 210 amphour battery bank and it gets down to one light on your led display after about 48 hours then you would roughly need about 200 watts of PV (unshaded, summer conditions). Shut off all your loads and charging sources and wait half an hour before checking the display. If you get down to the same state of battery charge after one day then you'd need double that and half that if it takes 4 days.

Double these estimates for late fall/winter conditions (less sun in winter of course). Also, your electrical loads will be different in cooler weather (more lighting, heater usage, probably more entertainment usage, less fan usage).

This gets technical but you could also try to estimate your daily electrical load. In case anyone is interested, here are measured current draws from my rpod:

single led lite		0.2
dual led lite		0.4
bath lite		0.3
outside lite		1.4
small 12V fan		0.5
fantastic fan h		2.8
fantastic fan m		1.9
fantastic fan l		1.3
fridge 12V (don't use except when driving!)		10.7
water pump		5.0
TV 12V (I replaced the 120Vac TV with one of these, easy mod)		1.5
Audio unit		0.4
heater (when on only)		2.0
water heater (when on only)		0.6

You would need to estimate how many hours (or fractions of an hour) each device was operating, multiply by the current draws, and add to get a 24 hour total. As a shortcut, if you take that calculated amphour total and multiply by 3 that is roughly the size of solar array you'd need for summer unshaded conditions. For example, I use about 75 amphours/day in the summer so I'd need about 225 watts.

Note that I am not including the microwave and air conditioner here. These use a LOT of power and would require a large DC to AC inverter to run. You could consider this for the microwave if it got light usage but just use the generator for the air conditioner if you have to run it when not on the grid. There are posts on generator requirements and air con mods you can study if you want to do that.

For larger scale solar applications, say above 200 watts or so, consider buying one or more residential style PV modules as they are far less expensive than the RV kits. If you have light electrical loads and can get by with one of the portable RV kits then great, do that.

These larger modules operate at higher voltages than the smaller (nominally 12V) modules. You can get MPPT type charge controllers to optimize power extracted from the module and to step down the module voltage to charge your 12V battery bank. You will need a charge controller regardless of which module type you get anyway.

I haven't yet added solar to my rig as I just got it this spring and I want to assess my fall and winter usage first, so I don't have any specific recommendations for solar installation hardware yet, but larger modules/systems are generally roof mounted, they are really too big and heavy to be considered very portable. In the meantime I just use my 2kw generator, and will continue to carry it after I install solar for use when I am camped in the shade or run into prolonged periods of cloudy weather.

1994 Chinook Concourse
1995 RV6A Experimental Aircraft
2015 Rpod 179 - sold

GlueGuy

Senior Member

Joined: 15 May 2017
Location: N. California
Online Status: Offline
Posts: 2654

Posted: 17 Aug 2018 at 9:02am

Originally posted by fwunder

The newer Renogy 100 watt Eclipse suitcase is smaller, lighter and comes with a waterproof controller.

Sooo tempting...

https://www.amazon.com/dp/B01NADR1CI

fred

The main attraction to this is the very compact size when folded up, and $440 is not a terrible price. BUT... These days solar panels can easily be gotten for about 75 cents per watt (I've seen promotions as low as 40 cents per watt). That, and a decent MPPT controller is less than $100. Add $25 for wire and connectors, and you're up to about $200 for a DIY setup (that might not be foldable). So the question you have to ask yourself is whether the folding option is worth $240?

bp
2017 R-Pod 179 Hood River
2015 Ford F150 SuperCrew 4WD 3.5L Ecoboost

geewizard

Senior Member

Joined: 16 Apr 2017
Location: Spokane
Online Status: Offline
Posts: 347

Posted: 17 Aug 2018 at 9:41am

I chose to make my own portable setup because I think the commercial suitcase solar panels aren't very good. I would not put a solar panel on the roof because of mounting issues and most importantly, when you park in the shade, you obviously have no solar! By using a portable solar panel and 50' cable, you can put the solar panel in the sun and move it around for maximum solar input. Put money into a good MPPT solar controller, it's worth it.

See my post in the thread below for details on what I did. You can PM me if you want.

http://www.rpod-owners.com/forum_posts.asp?TID=9728&KW=&PID=91400&title=rpod-177-battery-box-mod#91400

2021 Winnebago Micro Minnie 1708FB
2017 R-Pod 177 (Blue) HRE SOLD
2004 Outfitter Apex 8 camper
2014 Toyota Tundra DC

fwunder

Senior Member

Joined: 04 Oct 2013
Location: New Jersey
Online Status: Offline
Posts: 1676

Posted: 17 Aug 2018 at 5:29pm

Thanks for the tips guys! I do like a challenge, but that Renogy Eclipse is a sweet little package and I got a lot of challenges. Smile

Perhaps both of you guys could list the parts for the setups you put together? That would be great.

Thanks!

fred

2014 RPod 178 => MyMods and Buying Habits
2008 4Runner Limited 4.0-liter V6
Yes, those are wild ponies dining on grass while dumping tanks!

toddrich

Newbie

Joined: 16 Aug 2018
Location: WA
Online Status: Offline
Posts: 4

Posted: 17 Aug 2018 at 6:51pm

Thanks for the responses.

I already have dual marine deep-cycle batteries from Costco but last week, when dry camping, we had inclement weather and all the kids packed into the rPod for warmth with the heater going. Little did I know they were also all charging their phones. The next day, both batteries were down under 11 V. I tried to get the little panel to bring it back up (I don't have a generator) but it wouldn't handle it. So I ended up plugging in the truck and idled for about an hour to help get through the next couple days. I managed, and now that I am home they are both charged up but I think it is time to upgrade.

I have had a chance to research and compare prices & features. The 2 below are very similar except the big difference is the Eclipse is 30A and the Waterproof one is 20A. I had to look at each of the user manuals to find the differences. There are other differences but I think I may go for the Waterproof one since it is much more than I have now and under $300.

https://www.amazon.com/Renogy-Monocrystalline-Foldable-Waterproof-Controller/dp/B01NADR1CI/ref=sr_1_1?s=lawn-garden&ie=UTF8&qid=1534465382&sr=1-1&keywords=Renogy%2B100%2BWatt%2B12%2BVolt%2BMonocrystalline%2BFoldable%2BSolar%2BSuitcase%2Bw%2F%2BVoyager&th=1

https://www.amazon.com/Renogy-Monocrystalline-Foldable-Waterproof-Controller/dp/B079JVBVL3/ref=sr_1_1?s=lawn-garden&ie=UTF8&qid=1534465382&sr=1-1&keywords=Renogy%2B100%2BWatt%2B12%2BVolt%2BMonocrystalline%2BFoldable%2BSolar%2BSuitcase%2Bw%2F%2BVoyager&th=1

I will take your advice on not mounting it and just keep it separate and portable. I also found it simple to just connect it to one of the batteries rather than fuss with running wires & connectors.

offgrid: I really appreciate all the data, I admire you for taking the time to test them all. Do you have a separate ammeter attached to your e-box? Very impressive.

Thanks again. I am sold on this forum to get information. I will add some of my mods as payback.

offgrid

Senior Member

Joined: 23 Jul 2018
Online Status: Offline
Posts: 5290

Posted: 18 Aug 2018 at 7:27am

toddrich,

I just used a clamp-on digital meter, it used to be the dc clamp-ons were very expensive, now the Chinese ones are under $40 and work just fine for non professional use. Only took a few minutes to get all the current draw data.

https://www.amazon.com/gp/product/B077ZS5RR4/ref=oh_aui_detailpage_o06_s00?ie=UTF8&psc=1

The heater fan and solenoid use a couple of amps when operating as you can see, the cell phones really shouldn't be a lot. So I'm a little puzzled by how your dual battery system discharged that much in a day. Did you have the cell phones on an inverter running through wall warts? If so then I'd suggest installing cig lighter and usb ports and charging them directly. I used this:

https://www.amazon.com/gp/product/B01B79F8CW/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1

and found a place to tap 12V for it at the feed to the audio system in my 179. Ran this through the wall behind the TV. Easy mod. Replaced the 120 Vac TV with a dual 12V/120V one as well. Very inexpensive these days.

If you really took fresh fully charged dual batteries down below 11V in 24 hours then that's around 150 or more amphours per day. If that's what you want your solar system to provide you will need much more than 100 watts. That will give you maybe around 30 AH on a good day. And you said there was inclement weather than day, which means little to no solar recharging.

I'm not trying to turn you off to solar, far from it. I've worked in the solar industry for over 35 years so I am a true believer. Just want to be realistic about what you can expect to achieve with a small solar system and the effects of bad weather and shade on performance.

For the kind of conditions and electrical loads you're describing, a generator is really probably the way to go. Even if you mounted a 350 watt residential module on the roof of the Rpod it wouldn't do much for you on a bad day. I converted my Honda EU2000i to propane so I wouldn't need to handle gasoline. Got a long heavy gauge extension cord for it. If you place it far from the campsite with the exhaust facing away you can barely hear it.

I've also used my tow vehicle alternator for recharging and that's really not a bad way to go either. Modern engines sip fuel at idle and if you set it up right (direct heavy gauge bolted cable connection from TV to trailer) you can get 40-50 amps charging current, which is more than the little rPod charger will provide via a generator. Either way you are looking at several hours of engine operation to recharge 100+ amphours.

One other comment about dual battery systems. Its preferable to use 2 6V batteries in series because that way the batteries stay balanced. If you are using 2 12V batts in parallel, take the + lead from one batt and the - from the other. Otherwise one of the two batteries will always be handing more of the load.

Best of luck!

1994 Chinook Concourse
1995 RV6A Experimental Aircraft
2015 Rpod 179 - sold

offgrid

Senior Member

Joined: 23 Jul 2018
Online Status: Offline
Posts: 5290

Posted: 18 Aug 2018 at 9:33am

The lowest cost per watt solar modules are large commercial/residential ones which are in the range of 250-350 watts and often under 50 cents per watt. The 12V battery charging modules are still quite expensive as they are made at much lower manufacturing volumes. Meaning that you can usually buy a 250-350 watt module for about the same $ as a 100-120 watt module. BTW, run away from the so called "flexible' modules. They're not.

PV modules are Chinese for the most part but its not rocket science to make a reliable PV module these days. There are several reputable manufacturers. These are big, the 300 plus watt ones are typically about 76 by 39 inches and weigh about 50 lbs. Not something I personally want to carry around or find a place to store while on the road.

So I plan to roof mount at least one of these. Solar is roof mounted on RVs all the time. Note that the length of these modules is almost exactly the same as the rpod box width, so it should be possible to mount them edge to edge. I need to learn more about the structural design of the rPod roof edges. Anyone know how the walls and roof are connected and what is going on structurally there?

The large modules are all high voltage (typically operate at 30-40Vdc) so as another poster recommended, an MPPT controller is required. MPPT is max power point tracking, meaning that the controller maintains the solar module voltage at the optimum point to extract as much power as possible, and then steps this voltage down to the battery voltage. The controllers used in the Renology and other portable kits are PWM, (pulse width modulation) which simply connects the nominally 12V solar modules to the battery directly. These controllers are cheaper and don't optimize the solar module output. But they are also simpler controllers so tend to be a bit more reliable.

In the end it comes down to the electrical load you are trying to cover, how often you camp under shade, and what you plan to do in bad weather. Personally, living in coastal NC where we get some pretty bad weather sometimes, I will continue to carry my generator with me regardless of what size solar system I end up installing. I view the purpose of the solar as reducing my generator fuel and runtime costs over the long term. Not to mention that my DW really wants her air conditioning sometimes and I need the generator for that Wink

1994 Chinook Concourse
1995 RV6A Experimental Aircraft
2015 Rpod 179 - sold