Solar Question(s)

[ROXY6997]

Hi. I am new on here and am in the process of getting our teardrop built. I hope I am not beating a dead horse here by asking about solar, but I can't seem to find what I am looking for and I have tirelessly read through posts and websites. First, my goal is to have a free standing solar panel that I can bring out for longer camping trips to maintain our battery. We will primarily be running the fan and lights, maybe an electric blanket, and occasionally charging a phone if necessary. I prefer free standing because I can then move it where the sun is rather than leave it mounted on the teardrop. I am a MORON when it comes to electricity and solar, but I am trying soooo hard to learn...it is just a bit over my head, so bear with me please!

I primarily need some help in trying to determine the better solar option...a suitcase 100W solar kit with the controller mounted on the panels or a separate charge controller, which I would mount near the battery, and a single 100W panel? I was looking at the Renogy panels, as they appear to have good reviews, as well as decent performance for the price point. Also, the price difference between the two options should be minor, I think. The negatives on the suitcase kit for me is that the charge controller is mounted on the panel (I have read this is not as efficient, but a necessity to make an 'all-in-one' solar kit), as well as it is exposed to the elements. I wouldn't ideally leave the panel out in rain, but would rather not worry if a freak thunderstorm came upon us. Also, I have read that the charge controller in the Renogy suitcase kit is a piece of junk. There is a bit of a weight difference too, as the suitcase kit is heavier. If I just purchased the panel and built a stand for it, I could install a higher quality charge controller and that controller would be secure inside my battery box, so if someone decided to steal my panel, they would only get the panel, not the whole set-up...not that it makes a huge difference, since either way it sucks.

Also, while on the topic, anyone have ideas to prevent theft of the panels? We are out hiking a lot and I don't really want to leave it out all day while we are gone, but I may not have a choice on occasion if we need the battery charged. I have read a cable bike lock and anchor it to the tear frame or a tree or something, just as a deterrent.

I am also open to any other recommendations and I will continue researching and learning in the meantime!

Thanks for the help in advance!
Lisa

[vincigj]

I keep a loose panel. Actually bought two 20 watt units. Only use one so far. I installed a charge controller cheap from China. Also is a load monitor. I forget the volt level but if the battery gets too low the controller shuts off the load to save the battery allowing the panel to continue charging the battery back up. I always have a second option with me to recharge the battery separate from the tear. Either a electric charger or car taking it for a ride to charge when i get ice. I have small needs as we spend most camping time outside so small battery easy to move around.

[DrewsBrews]

No need to lug around the controller when it being secure by the battery is the more efficient option anyway. A larger single panel will probably end up cheaper and might be a bit more obvious if it tries to grow legs. That's my vote.

[tony.latham]

I've got 80 watts worth... 20 watts mounted to the tongue box...



It's chugging away, maintaining the battery 365 days/year. Inside the box are two 30 watters hinged together and the SunGuard controller near the 12V battery that's in there too.





Those folders haven't been out all summer, even though we've spent maybe 25 nights out this year.



BDOSBORN turned me onto his webpage showing one how to build your own folders: http://home.comcast.net/~bdosborn/Boxca ... Solar.html I used two parts of an old unused aluminum tripod for the legs. I've probably got $110 or so into them.

We don't use much juice. Charging phones, a couple of LEDs, a Fantastic Fan and we almost used our 12V electric blanket last night. Almost doesn't count. But I sure like that 20 watter so I can forget maintaining the battery between trips and during the winter.

Tony

[noseoil]

Not to hijack the thread (apologies), but is that a group 24 or group 27 battery in the tongue box Tony?

Also, which electric blanket did you get as I've read that some are pretty much junk, they work once then quit. Would the 20 watt panel bring the battery back if you used the electric blanket at night & had sun during the day in the fall or winter, or would you have to bring out the folding panel to be sure?

I'm going with a 100 watt panel on the roof, fixed mount facing up, & the charging module on the galley bulkhead under the counter near the battery (group 27 agm in a box). It's the Renogy el cheapo kit from Amazon. Actually getting close to being able to mount it soon.

[tony.latham]

Not to hijack the thread (apologies), but is that a group 24 or group 27 battery in the tongue box Tony?

Also, which electric blanket did you get as I've read that some are pretty much junk, they work once then quit. Would the 20 watt panel bring the battery back if you used the electric blanket at night & had sun during the day in the fall or winter, or would you have to bring out the folding panel to be sure?

I'm going with a 100 watt panel on the roof, fixed mount facing up, & the charging module on the galley bulkhead under the counter near the battery (group 27 agm in a box). It's the Renogy el cheapo kit from Amazon. Actually getting close to being able to mount it soon.

It's a Group 27 and more than we need. When it's on its spiral, I'll downgrade to a Group 24.

This is the blanket we use: http://www.amazon.com/Trillium-Worldwid ... ic+blanket

As you can see, it's 58" x 42" so is on the small size for a queen sized bed. And I can't find a larger one. (We used to have a 12V mattress pad in our old 4-wide, but we could feel the wires and didn't care for it.) This blanket has a 30/45 minute timer for preheating under a down comforter. I've been known to turn the timer back on in the morning, prior to getting up when its frosty. So we're not using it to burn all night. If I recall, it draws about 4-5 amps/hour.

We just got back from a two-nighter at 6500' and about 46º north. Ice in the dog bucket in the mornings. The low's must have been in the upper twenties. We didn't use the electric blanket. Had we fired it up, we would have used about ... I dunno, six amps at most using the timer. For two nights I wouldn't have gotten the folding panels out. Either way, by the time we're home, the battery is topped off.

I'm sure that 20 amp panel was doing it's best, but at ... I perhaps six amps per day based on sun/shade/intermittent clouds, I wouldn't rely on it for bringing the battery up if we were aggressively using the blanket for two or three nights with a morning kicker.

We had both door windows cracked a bit above the mattress and the fan vent opened a couple of inches. We were fine snuggled under a thick down comforter with a second thinner comforter "just in case" ––which wasn't needed. Even wile exhibiting a high bare-skin ratio during an after-midnight arc into the pine needles.

Tony

[ROXY6997]

No worries about hijacking!! All information is valuable in my book!!! Tony, have you had any issues with corrosion/fumes from mounting your charge controller in the same compartment as the battery? I know morningstar recommends against it, but it is quite honestly the most convenient place to put it IMO. IF I decide it's safe to mount it in the tongue box with the battery, I plan on mounting it on the opposite side, just to keep it away from the fumes as much as possible. I was only planning on putting one vent for battery fumes in the tongue box, would that be sufficient or should I do more? I know they make sealed battery boxes with a hosed vent, but I would have to deal with getting it to my builder or installing myself, which is not a good idea because my "handy" skills are beyond lacking. I think venting is sufficient, but unsure how many. I don't know my battery type off hand yet.

I saw your set-up Tony and I really liked it. It looks awesome. I thought about mounting the 20W in the same manner as you, but I haven't committed yet.

I was trying to figure out if I placed a charge controller with a digital display inside the cabin (to monitor things) how I would do an easy plug in for a solar panel on the outside of the teardrop? Any ideas? Also, I keep going back and forth on getting a Trimetric mounted...then I don't have to worry about trying to install a charge controller inside as much, though that also presumes I can mount the charge controller inside the tongue box safely with the battery. With my low power usage, anyone have an opinion about the necessity of something as detailed as a trimetric? The fact that I can see my amp hour usage is so neat, but I am not sure if it's worth the expense.

Thanks again for everyone's help.

[noseoil]

The usual setup for venting a battery uses fresh air from below & a vent out the top to clear the gasses. It's hydrogen gas, so it's lighter than air & will escape out the top if there's a hole in the bottom to allow for the chimney effect to take place. Doesn't take much for it to work, small hose or tubing with a compartment is all it needs.

[tony.latham]

I am not sure if it's worth the expense.

I keep an eye on my resting voltage. Plus I have a G.T. Power Analyzer that tells me how many amps I'm drawing and the total since I've unhitched:



They're $20 on Amazon. http://www.amazon.com/Amps-Power-Analyz ... r+analyzer



The SunGuard controllers are set in epoxy so there's no way they could be a source for spark and shouldn't have a problem with corrosion. Glancing over their instruction manual, I don't see where Morningstar suggests it needs to be isolated from the battery. In fact it says it should be in a "similar thermal environment."

Tony

[MtnDon]

charge controller in the same compartment as the battery? I know morningstar recommends against it, but it is quite honestly the most convenient place to put it

Morningstar and other manufacturers will not cover acid fume damage under warranty. Even if the problem was not caused by that exposure they could claim it as a contributory cause and void their warranty. That sort of damage becomes obvious if there is an issue. I have seen damage that was caused by acid fume damage, to the inside of a metal enclosure.

Not everything we should do is convenient. As individuals we can choose to take chances and I am sure often come out okay. Some charge controllers are sealed but most have venting where fumes could enter.


There is also the question of whether or not the CC will be sufficiently cooled when it is enclosed in a box. At times a CC will be producing a noticeable amount of heat. Under some charge conditions the battery itself produces heat.

~~~~~~~~~~

The reason a similar thermal environment is recommended with some CC is that they have a temperature sensor in the CC. That helps the CC determine what voltages to charge with as the battery temperature changes. However that presupposes that the battery is atthe same temperature as the controller. That is not necessarily always true. The better CC will have a remote temperature sensor placed with the batteries so the CC itself can be in any temperature.

[ROXY6997]

AHHH...so many options, I am paralyzed by the choices I have to make!

Thanks again for everyone's help. I want to note that I saw the rule about not mounting charge controllers near the battery on several forums, as well as in some of the user manuals for 'some' of the morningstar controllers. Coincidentally, this was not the case with the Sunguard manual, so you are right Tony. I know little about this stuff, so I have been relying heavily on the opinions of others, which is not always the best decision and often conflicts LOL. From there, I research. Unfortunately, the Sunguard is too low amperage for my needs, particularly if I choose to add more panels. I will look into that monitor though!!!

For the battery box issue...if my battery is in a vented battery box and in the tongue box, I would just need to have a hole low on the tongue box and a vent up high to get adequate ventilation, correct?
Just want to make sure I am understanding. I wish I had the specs on the battery, but I will get that soon.

Where does everyone mount their charge controllers? I have seen numerous in the tongue box with the battery, despite the air flow concerns. IN my scenario, with the battery in the tongue box, I would think the galley is WAY too far away from the battery for it to be a good choice of a mounting location. I could put it on the outside, if I got a wetherproof version, but I am not super keen on that idea since I don't really want attachments on the exterior. Lastly, I could place it inside the cabin, but then I have to find wall space where we won't bump it (in a 5x8), as well as find a means of hiding the wiring since everything attached on the front side of the charge controllers I have been considering. I don't really want to run the wiring in the cabin, but I also feel a hole in the wall so the wiring can be installed behind the paneling is not aesthetically ideal. Any tips?!?

Thanks,
Lisa

[noseoil]

My battery box is mounted in the galley. It takes up more room than is necessary & eats up some useful space, but this was my decision on where to put it. Here's the mock-up a shot of how it sits & the breather tube off of the top of the box. The bottom of the box has an opening for fresh air, there's an opening through the deck under the box.



The charge controller will be mounted on the galley bulkhead above the battery box. The breather tube has a cover plate on the passenger side.



There's no reason you couldn't do something like this inside the tongue box. A simple plywood box with a lid, epoxy coated inside, with a couple of holes for breathing & a smaller tube would suffice and work just as well. It just has to be functional, not fancy. Mine is a "store bought" box, but plywood still works well for most things.

[MtnDon]

In my scenario, with the battery in the tongue box, I would think the galley is WAY too far away from the battery for it to be a good choice of a mounting location.

If the wires between the CC and the battery are sized for the distance and the maximum charging amperage, that can be completely satisfactory.

[pete49]

My set-up is similar to a couple here. I have a 20watt on the tear which just goes and goes and a 120watt foldout similar to Tony Latham's just bigger as I use it in the caravan (travel trailer?) as well though that's not been used for a while as we now just use the tear since the boy left home . Battery is a sealed 120 amp hour deep cycle in the galley similar to nose oil's and to date never had a problem with lack of lights
Pete

[ROXY6997]

I have spent the last 2 hours reviewing battery ventilation set-ups LOL

That is what I am looking at now for an option, to set-up an external ventilation for the battery in the tongue box. If I do the Prostar15 charge controller, I am leaning toward mounting it in the tongue box, presuming the battery is vented. If I do the Trimetric set-up for battery monitor and their solar controller, which I am debating as a splurge, I feel I have more options. I could either mount the charge controller in the tongue box, so it's near the battery, or because the battery monitor is shunted (if that's even a word) and the controller "talks" to the battery monitor, they say you can mount the charge controller anywhere between the battery and battery monitor and it should still be just as accurate. YAY! Down to two choices!!! Either way I will vent the battery somehow. I could also consider completely relocating the battery to the galley like noseoil's.

I know you probably get tired of the questions...so thanks soooo much for everyone's help!