Help for a VERY beginner

ROXY6997

Hi everyone.  I am getting a teardrop built and I am trying to iron out what I want for a solar set-up.  I obviously don't have usage data, but at most I will be running a Fantastic vent, LED lights on the trailer, and maybe charging a phone.  I have no plans to run any refrigeration/air conditioning/heat, etc.  At most in the winter, I may add a 12V heated blanket.  I believe the battery going in is 100AH. I apologize for the loads of questions.  I have been researching solar stuff for hours and having no understanding about circuits and whatnot, I am just burnt out...though I have learned a TON thanks to this site.

That being said, I was hoping to get some feedback on my very limited plan and get some opinions.  It was recommended to me that I purchase the Renogy 100W suitcase kit.  I don't necessarily like the charge controller being mounted on the panel, both for efficiency and weather reasons.  My understanding is that it is better to mount the CC adjacent to the battery???  So my alternative was to mount a CC near the battery and purchase a 100W panel.  The battery will be inside a tongue box, is it safe to mount the CC in there too or is that not recommended?  I don't plan to mount the panel because I want to to be moveable, as we will likely park in the shade the majority of the time.  Is the independent panel set-up a better option than the suitcase kit?

Secondly, how important is an independent battery monitor?  I had looked at the Trimetric, but do I really need something like this or would the monitoring components of say the Morningstar Sunsaver 20 or Prostar 15 be sufficient for my needs?  Or if you have any better recommendations for me on monitoring usage or on a particular CC, please let me know.  I am sure I don't need more than a PWM.  At most, I MIGHT expand in the future to a second panel, but don't see the need now for our limited power usage.  I am praying that my builder knows all about the electrical components, like fuses, etc...so all I have to do is tell him exactly what I want installed and he can do it for me.  Otherwise, I am screwed LOL.  I am not sure about his experience with solar components.   

Lastly, if I cannot find an 'extension' cord to run from my CC to the solar panel, how hard would it be for someone with no electrical knowledge at all (ME!!!!) to make one?  I need to be able to move the panel some distance and was thinking about a 25ft cord.

Thanks so much for your time.
Lisa

waynefromnscanada

Oh my. You are biting off a HUGE mouthful considering your self admitted (as of now) lack of knowledge and understanding of things solar and off grid.  I'll touch on a few things for you to consider.
a) I don't like kits / packages etc which were put together just to sell. They tend to be aimed at those, like yourself, who have limited understanding of their needs, and often end up being a waste of money.
b) Electric blankets, 12 volt or otherwise, are NOT a small load for the size of system you are considering.  And I wonder about the power draw of your proposed "fantastic vent" as I have no experience with them.
c) Yes, the charge controller should be mounted near the battery, but not where it will be exposed to corrosive fumes from the battery. And cheap controllers are often worth little more than nothing when it comes to looking after your batteries.
d) Yes, you can make your own "extension cord" to go from panel/s to the charge controller, and also from the controller to the battery, but to be successful, the length of the cord must be known, as well as the max current in amps it must carry, as the longer the wire, the larger diameter it must be so as not to restrict current flow.
e) Re the battery being "inside a tongue box". Is this battery a flooded type (filled with liquid)? If so, it will release corrosive and stinky fumes and explosive gasses from time to time, so must be safely vented. And controllers / inverters must not be inside the box with the battery if this is the case, otherwise acid fumes will greatly shorten their lives. Also these devices need free air to keep from overheating.
d) Re: "I am praying that my builder knows all about the electrical components", Do NOT bet on it. Carpenters and plumbers usually know very little about things electrical, and even a lot of electricians are unfamiliar with off grid solar.
f) And finally, Good Luck.

Mountain Don

The aforementioned fantastic vent is a std RV item. They can draw up to 3 amps operating on high speed. If we assume high speed and round up to 3 amps and run the fan for one hour we have consumed 3 AH _amp hour) of power from the battery.

Assuming the TD manufacturer is using a lead acid battery, flooded or sealed, only a maximum of 50% of its capacity should be used before a recharge, if we want reasonable life from the battery.  So, with that 100 AH (assumed to be 12 volts) battery you would have 50 AH usable.  50 / 3 = approx 16.6  on high speed. More at lower speeds.  LED lights don't use much and charging a phone once in a while does not use much either.   So that gives you an idea of what you might expect as well as the method to estimate needed battery capacity. 

If the maker uses a typical RV battery box on the tongue they are vented. As was mentioned no other electric devices or parts should be in the battery box.

As for panels being bolted to the roof or portable it is a matter of personal choice. Mine are bolted to a rack on the trailer roof. I know folks with portable ones. Half the time we end up camping in the sun and that is good for the panels on the roof.  The other half time I grumble and praise the shade depending on whether I'm thinking keeping the trailer cooler w/o A/C or thinking about charging the battery.  I see campers with portables but have not heard of thefts. So I wonder?  I have had other camping stuff disappear so have not wanted to go with portable PV.  Time for a personal decision and G/L.  

 Does the TD manufacturer belong to the RVIA?  If so it will follow all the prescribed rules. If not, you are are your own. A responsible builder should build a safe unit. Should. .....  Does the TD come equipped with any AC power hardware / wiring?

 For a simple TD, IMO, you don't need a battery monitor like the Trimetric.  If not programmed well and adjusted from time to time meters can provide false information and an unwarranted sense of security.  If the battery is an FLA get a good hydrometer.  If the battery is sealed you can't use a hydrometer and can not tell the health of individual cells.  You must only go by voltage and there are pitfalls with that.  IMO, sealed batteries also may provide a false sense of security. There are some advantages to be sure, but to keep a battery healthy it is better to be able to open the cell and use a hydrometer. 


As waynefromcanada mentioned you can have a "extension" cord between PV panels and the CC. To properly choose the maximum amps, the operating voltage of the PV must be known as well as distance. 

ROXY6997

Thanks for the feedback on that stuff.  I know it would be an easy out to just buy one of those suitcase kits, even though they aren't efficient, but I am really interested in trying to learn and do things the right way.

westbranch

If the CC has read outs like a Midnite Kid you might consider having the CC mounted inside so you can easily monitor the charge stage and Voltage

or better yet, for a lower cost and PWM, The BRAT... http://www.midnitesolar.com/productPhoto.php?product_ID=615&productCatName=Charge Controllers - Brat&productCat_ID=49&sortOrder=1&act=p

The BRAT is probably a better fit as long as you don't plan on expanding too much but I think you would have trouble exceeding the input limits.
http://www.midnitesolar.com/pdfs/spec_sheet_brat_frontBack.pdf

hth

ROXY6997

Thanks.  I will look into the BRAT.  If I mount my CC on the interior, I would run a cable to use a plug in for the portable solar panel wiring.  Any recommendations on a connector that would maybe mount on the exterior of the trailer with weatherproof protection when it's not in use?  The panel I was looking at has MC4s off the panel and I will run a 25ft 10# wire from there (it's a 100W panel).  I just need to decide what the best means of connecting it to the trailer end is.  I am not too keen on putting a hole in the trailer unless it's one that can be sealed.  I like Anderson Power poles, but I am not sure how to leave these accessible on the outside of the trailer without them just hanging there or being unprotected.  

FYI, the battery will still go in the tongue box, but it will be inside a separate battery box and the tongue box will be vented  

Mountain Don

The Brat is weather resistant; wires through compression seal fittings on the bottom edge. I painted the shell of my Brat to match the trailer, leaving a view port for the LED indicators. It is all but invisible from a few feet away. Our panels are not portable so I was not concerned wioth howto couple / detach.  The wires are run inside by running down the exterior wall in a small diameter metal tube. Like conduit but not "official" conduit. The wires run around the bottom and up through the floor. 

I like Anderson Power Poles as they offer polarity keying. 

K4KMG

Don't be fooled by the hype for the 'fantastic fans'. They are LOUD! (at least my new one is) I put one in the bedroom of my toy hauler, (which I live in), and it's just too loud to use while trying to sleep.  Look into the O2Cool's. Much quieter and much more energy efficient. I bought the ac/dc version and plug it in wherever needed. At night I just sit it on the bed next to me. Works great and I don't have to worry about energy use.

ROXY6997

I had read that too about the fantastic fans.  So, instead of being thorough and researching other options, I was lazy and just paid the money to upgrade to their 12 speed option.  I have heard that the low speeds on that one are much quieter and it's far more energy efficient, pulling only .9-2amps for the whole range of speeds (if I recall).  I liked that I could either push air out or pull it in to the sleeping area.  Hopefully it works as planned!  Thanks for the warning K4KMG.