Tongue box & solar mods in progress: build thread -- advice & insults welcome

Discussion in 'Cargo Carriers / Bike Racks / Other Storage Option' started by unclemark, May 13, 2015.

  1. ajmaudio

    ajmaudio Member

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    gotta love the classic mppt/pwm debate. I'll share my brief thoughts. For smaller systems like my pop up I prefer to go with a good pwm and buy more solar to charge in less than great conditions. In our case we have a Bogart Trimetric meter, the complimenting SC2030 charger, 2-100 panels, and a single US Battery group 31. For those of you that want to have fine control of your charger and a great meter this is hard to beat. All parameters of the charger are controller from the meter. I feel like this is a very cost effective setup for what you get. I thought about doing 2 golf cart batteries but didnt want the weight. The decision to go overboard on solar a bit has proven to be very beneficial. We can charge on very overcast days. We power led lights, endless breeze fan all night and some day use, phones, laptops, water pump etc. Anyhow.... we certainly enjoy it!
     
  2. rabird

    rabird Howdy!

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    [;)]

    Intrigued with bogart's engineering and reasons (see C1) for going with pwm, 18 built in battery's charge profiles for various battery makers and the concept of 'finish' charge (IUI charging) when coupled to their monitor.

    Cell temperature in the range of PU camping is detrimental to peak power/MPPT.
    NOTC (nominal operating cell temp) is a test condition that shows how hot cell get with the back of the panel open to a breeze, even hotter flat roof mounted (add 25C-35C to ambient).

    I suggest this graph from victron should have its blue area expanded to 20C (0-10c ambient).

    [​IMG]
     
  3. ~erik~

    ~erik~ Active Member

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    Getting back to the OP's post of nearly four months ago...

    How's that project coming? Finished? Been waiting for some photos. :)
     
  4. unclemark

    unclemark Overland Park, KS

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    Argggh. So, okay, here's what happened:
    -- I gave up on building the box because the plywood was too heavy.
    -- Instead I built a cargo deck and attached two bins, a battery box, and the 1-tank propane rack.

    [​IMG]

    -- Square ubolts attach the sub deck to the trailer frame. Glue and screws hold the main deck to the subdeck. Diamond plate is in the sandwich to protect the wood of the subdeck from being torn up by the ubolts. Some routing occurred.

    [​IMG]
    [​IMG]
    [​IMG]

    -- I still don't have the 12V system finished, but I run off of battery and solar panel on all trips, including the one Friday and Saturday night when we were at a powered site.

    [​IMG]

    -- I got one 12v Crown 31DC130 battery. For our small electrical usage, I couldn't see doing more than that.
    -- I still have to get the MPPT Sunsaver solar controller programmed to allow 14.9V charging, per lifespeed's advice. I also have to install the Trimetic, if I can decide where to install it inside the camper. For now, I keep tabs on the battery and panel with PC interface for the Sunsaver.
    -- I'm set up to charge the battery from the panel while I'm on the road. A disconnect, unwinding of wires, and reconnect before cranking of the popup allows us to charge in the campsite as well. The panel is attached with two sets of brackets, one set (cut from c-channel aluminum) glued to the top of the popup, the other (z-brackets purchased from somewhere online) bolted to the panel. The two sets of brackets are bolted to each other. I wanted enough clearance to be able to get hands and tools under the panel and unbolt it to place it outside in winter while the trailer is stored inside. The bungy cords are the suspenders in my belt-and-suspenders system.

    [​IMG]
    -- The battery, panel, and loads all have exterior key switches on the side of the bin that holds my Sunsaver, my shunt, a fuse box, and an inverter. Also on that side of the bin is an all-weather 12V outlet with both USB outlets and a standard 12V outlet. Why is all this outside of the camper? Because it works great for us: I can fiddle with it during the daytime when there's plenty of light, I don't have to stand on my head to get to the components under a dinette seat, and if I do use the inverter overnight sometime the fan won't be very loud inside the camper.
    -- That said, the bin on the curb side is not waterproof, so I need another solution. Water came in on our Wisconsin trip during a couple of highway storms. No problems resulted to the electrical, but that's just luck so far. The bin that hasn't had holes cut in it didn't leak. Hmmm. I think the key switches are the worst leaks. I'm still figuring that out. I will probably put the switches on the other side of the bin inside their own box, so the shut-off is closer to the battery.
    [​IMG]
    I haven't done anything to it since June, but I'm sure I'll tear apart the component bin again this winter and redo it. After that, maybe I'll post pix of the electrical components.
     
  5. rabird

    rabird Howdy!

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  6. unclemark

    unclemark Overland Park, KS

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    If I were starting over, I'd buy the cheapest battery I could find, just for practice. I suspect that I'll not get my money's worth from this battery because there are too many new habits to learn to take good care of a battery using solar alone and really not much time to learn them during a camping season, even if you're out 19 nights and counting.
     
  7. rabird

    rabird Howdy!

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    solar makes a great maintainer. minimum daily charge with a rest overnight.
     
  8. unclemark

    unclemark Overland Park, KS

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    As predicted, I modified my tongue storage again.
    [​IMG]Tongue storage on Flickr
    Top right bin has everything I need to unhook and set up: tool bag, chocks, levelers, headlight (for my head), crank handle, gloves, knee pads, knit cap, dog leash.
    Bottom right bin has socket set, torsion wrench, bottle jack, roadside repair stuff.
    Upper left bin will probably have gizmos, coleman fuel, charcoal, lighter fluid, hatchet, etc.
    Bottom left bin has my solar converter, switches, fuses, inverter.

    I hope I can stick with this one for a while. I know I'll have to strip it next fall to repaint the cargo deck, but I think I'm done dreaming up ways to put it back together differently.

    By the way, the pic is from last weekend's camping trip at Hillsdale Lake State Park south of the Kansas side of the KC metro area. Well, it's probably part of the metro area, to be honest, but I'd rather tell myself I got out of town. I manipulated the lighting on the pic, so the grass is not the same color that I saw in person.

    Yes, I know I'm missing a PVC cap. Thanks for mentioning it.

    The goal of this project was to create space for a battery and for storage. The deck provides a platform to add these items, and it helps us haul less stuff inside the TV. I think we're going to like it.
     
  9. Haybale

    Haybale I'd rather be camping!!

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    Awesome!!
     
  10. lifespeed

    lifespeed Member

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    Looks nice! That is a lot of solar panel for a single battery. Bet it charges quick.
     
  11. unclemark

    unclemark Overland Park, KS

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    Thanks!

    Thanks! You know, I'm still figuring out how well it's working. I have the Trimetric installed, so I can keep an eye on usage and charging. I haven't been disappointed at all: The battery fully recharged both days this weekend. Our biggest usage was down to 81 percent on Saturday night with two 12V electric blankets running. When I get around to buying and installing a furnace we'll learn a lot more. Also, contrary to your advice, I might dream up a tilt system for the panel. AS big as it is, operating the panel at a fraction of its capacity means I'm missing a lot of energy. I'm thinking of replacing the nut-and-bolt fasteners in the brackets with something with quick-release and/or pivot capabilities. Maybe I'll put carabiners in six holes and padlocks in the other two. As I set up, I'll pull all the fasteners except the two on the most-southerly side of the camper, which will serve as hinges. I'll have to figure out a kick stand for the north side.
     
  12. Haybale

    Haybale I'd rather be camping!!

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    I would go for another battery, possibly in the pup (near a vent) and never worry. I would only worry about the tilt panel if you plan to use a lot of power during the day.

    As for the hinging, I would keep it a bolt system, as a carabiners would allow the panel to be bouncing and could damage it or the roof. And for tilting, would you have to able to tilt in any direction? Or do you always camp with the pup in the same orientation to North?
     
  13. unclemark

    unclemark Overland Park, KS

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    I'll have to watch my use and figure out if I need another battery. It won't happen this year, I don't think, but maybe someday.

    I'm not sold on the carabiner idea, partly for the reason you mention.
    This outfit has several options for quick-release pins.
    http://www.pivotpins.com/index.html
    I haven't picked out a favorite yet, but I figure if the diameter of the fastener is matched well with the holes in the brackets I can probably get a snug enough fit to eliminate bounce.

    I think I'd need to be able to tilt any direction and get my bearings at each campsite, either while I'm booking online, or with my compass app on my iPhone after I've arrived at the site. Each of the four sides of the panel has two attachment brackets. During set up, I'd have to identify the most south-ish (or southeast-ish) side with my compass, unfasten the other three sides of the panel, lift the unfastened sides of the panel to an angle determined beforehand from Internet research, and deploy my kickstand.
     
  14. Damuta

    Damuta New Member

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    Unclemark

    I've been going through the forums looking for ways to mount my solar array to my Coleman abs roof. So far yours is the closest thing I've seen. (It appears to be abs) could you share with a bit more detail how you have secured you panel to you roof.

    Much appreciated

    Mike aka damuta
     
  15. unclemark

    unclemark Overland Park, KS

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    Funny, I thought my roof was ABS too, until I started working on it. I formerly had a sailboat with an ABS hull, and it looked like the same stuff until I started drilling. It's painted aluminum with a foam core. Gosh, I can't remember the name of the two-part epoxy that I used on the solar panel brackets, but it was the strongest I could find. It was probably a Loc-Tite product, perhaps a 3500 psi epoxy resin. In fact, the 1200 psi product shattered almost immediately when I used it on two brackets after I run out of the stronger stuff. On that ABS boat hull, I used epoxy resin to fill cracks, and it took well and did not ever weather or wear away. Your mileage may vary, of course.

    To get more thoughts: Try searching for "epoxy" using the forum search engine, or search for " ABS" using a space in front or "ABS roof"
     
  16. ribs1

    ribs1 Member

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    This is very similar to my system and I believe pretty much ideal for most popup campers. There is no reason to go mppt for a system less than about 450 watts.
    Personally I have 2 trojan t105 on my tongue. For those worried about weight I would go with a true deep cycle battery like the Trojan t-1275. This is a 12v golf car battery and true deep cycle. I had one in my last camper and loved it. 150ah I think.

    Back to the controller and such. I believe there is no battery system currently on the market than the Bogart sc-2030 controller paired with the trimetric monitor.
     
  17. ribs1

    ribs1 Member

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    Tilting is over rated. Once you get your Trimetric running you will probably realize that you are often getting very close to the rating on your panel without tilting. I have a panel that is rated at 8 amps and I often get around 7 amps when the sun us overhead and bright. Sometimes more. The only time tilting is a real advantage is in the winter.
    You don't need another battery it sounds like. When your battery dies in a few years replace it with a Trojan T1275 or similar true deep cycle.
     
  18. ribs1

    ribs1 Member

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    The best way in my opinion to mount a solar panel to an ABS roof is to use the brackets from AM Solar and the VHB tape that comes with them. After that coat the whole bracket foot with Sikaflex 221.
     
  19. Damuta

    Damuta New Member

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    Thanks mark! I'll search on that and look into the resins. Thanks ribs1 also for the lead.. I have been looking all these things over. I plan on 4 100w panels on top. Extremely yes but dry and boondock is the plan. I've thought about it a lot and I'm thinking my abs roof is 16yrs old don't drill it! I'll be using a resin or the like to secure the rails then attach the panels.
     
  20. unclemark

    unclemark Overland Park, KS

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    Reviving an old thread with an update: The Crown battery is now dead -- I got 86 nights of camping from that 31DC130 over 3 years and 3 months, but I messed up and let it get too discharged last weekend on a camping trip with too much excitement, including a breakdown of my TV at the campsite just as I was ready to leave. My dealer no longer carries 12V Crown batteries, so at the moment I have a sealed Group 31 under the ElectroLife/Goodwill brand. I just got it today, but I probably will not install it and will instead swap it out for a Trojan Reliant 31-AGM, disregarding the concept expressed in the message quoted above. Still mulling it over.
     

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