Playing with Solar

[RogerDat]

Originally Posted by Steve Outlaw

That's strange you should mention that story, Roger. I was actually remembering it as I wrote about "absorbing" the electricity. As I remember, he designed some kind of copper coils on tall towers on either side of the companys right of way and just captured what was being "lost". The courts did uphold that he was not stealing.

Could well have been copper coils, my memory was of some sort of wire on poles. Was thinking it was wire livestock fence but it was a long time back and some days I'm doing good to remember where I parked the car. I would think copper coils would work better.

You know the real icing on the cake would be if the shadow from the towers fell on your solar panel and interfered with charging the camper battery.

[Raz]

Originally Posted by RogerDat

I would think copper coils would work better.
.

You'd be correct. Put a conductor in a varying
magnetic field and you will "induce" a voltage across that conductor. Coiling the wire increases the length of the conductor and the voltage. What the farmer made was a transformer. A Mr. Faraday figured it out in the 1800's. Raz

https://en.m.wikipedia.org/wiki/Fara...w_of_induction

[Scamper Jim]

After doing some reading about solar, I find there is not much discussion about the quality of the solar panels themselves, even in Handy Bob’s. That is, with either mono or poly, have the panels become a commodity item where they are all pretty much the same in power-producing ability, or are they like controllers, where differences in quality is all over the place.

I am looking at a portable 100w system that folds and has a stand as I want, but the controller looks like it was made by Hasbro. If the panels are all pretty much the same, could I buy the system and just upgrade and relocate the controller so it works better? Or since the controller is Mickey Mouse, should I assume the solar panels are also?

[Carol H]

Originally Posted by Scamper Jim

That is, with either mono or poly, have the panels become a commodity item where they are all pretty much the same in power-producing ability, or are they like controllers, where differences in quality is all over the place.

Jim I do not believe that all solar panels have the same power producing ability . They do have different output ratings depending on what they are made of or under what conditions they will be operating.

You may have seen this already but a good write up on the differences is called Which Solar Panel type is Best? Mono vs Polycrystalline vs Thin Film.

[Paul Braun]

I have done as you are planning. I purchased a folding panel(s) totaling 120 watts from Solar BLVD. It was sold as a kit complete with 14 gauge wire, alligator clips for your battery and a pretty nice nylon carrying case. The only difference from your plan is my controller was stamped "Disney", made in India.

I cut everything off that was attached and tossed it out, including the rather fragile legs, controller and wire. I saved the panel and the carrying case. A carrying handle was attached along with two latches, not bad quality. The handle is nice because the unit is heavy and bulky, I might guess 25 lbs complete.

I left the wire connecting the two panels and installed an extension cord connector on the panel. I have a similar outlet installed on the outside of my Escape with the opposite gender. I now use 12 gauge extension cords of varying length to connect the panel to the trailer. I could use 10 gauge but cost and weight discouraged me. It could be easily done in the future by purchasing a different extension cord. This extension cord doubles as a hook up for campsites that have power and the power pedestal is out of reach of the built in cord.

From this external connector on the Escape everything is 8 gauge to the controller and then to the battery.

As far as quality of panels, this is hard to measure. Panels give a output rating but none of them achieve this rating. My panels are Polycrystalline and do seem to perform as advertised. I have been able to regularly charge my dual 6 volt Interstate batteries at 15.3 volts and hold it for two hours; it does take all day in full sun however. I do not like the weight of the panels but do like the heavy duty frame they have, a must for portable units that are free standing. I can live with the weight.

If I take the panels out of the case they travel very nicely in the wardrobe closet on my Escape 21.

[MyronL]

Keeping my two booked 50 Watters on the ground outside. Been doing great, but noticed today (?) ...stopped producing. And that's 10 gauge wire to the Morningstar controller.

[Scamper Jim]

Excellent information from all three of you.

Carol, the take-away from that article is stated very succinctly, and answers it for me that there is no use in getting overly concerned about trying to buy a super-duper expensive panel technology because they all still have low efficiency anyway. Just chasing a couple of percent increase in efficiency. That's what I liked finding out.

“Typically, the efficiency of commercial solar panels operates in the range 11-15%.”

“The efficiency of solar panels goes hand in hand with purity, but the processes used to enhance the purity of silicon are expensive. Efficiency should not be your primary concern. As you will later discover, cost-and space-efficiency are the determining factors for most people.”

“Monocrystalline solar panels are based on the highest-purity silicon available. This makes them the most efficient solar panel type available for homeowners."

Solar panels based on polycrystalline silicon are usually not quite as efficient as monocrystalline, but there is not that much of a difference."

Paul, that is the type of system I am looking at, and knowing that you got it to work satisfactorily is what I was hoping to find out, and I like your dual-use of an extension cord. That has to be some kind of a first for someone to respond with actual experience with an identical unit, and not wander off on a discussion of the efficiency of the solar panels on the Mars lunar lander or something.

I will probably follow through next summer and get that system and make the necessary modifications as you and Myron did. I am looking at two controllers on eBay that have integral monitoring systems of both input and output voltage and amps:

http://www.ebay.com/itm/30A-DIGITAL-...-Charger-Steca

and

http://www.ebay.com/itm/LCD-30A-Sola...-With-Dual-USB

By the way Myron, your photo illustrates another advantage of having a portable system; you don't have to climb up on the camper to brush off the snow or clean the glass.

Jim

[Paul Braun]

Jim
I looked at one of the models of controllers you listed. There were a ton of different models, I did not explore but this one. Several things struck me: a really nice interface with the LCD screen, second I was unable to determine if it allows you to change the voltages you want to charge at. Not just bulk, absorption and maintenance but to set the voltages for those levels. The description states "Adjustable charging & discharging parameter", not sure just what that means. Finally, I would want to be sure the unit would accept 8 gauge wire, that is the recommended from controller to battery.


As an aside, the one issue I have with monitor screens on the controller is the need to keep the controller within three feet of the battery and yet have it mounted in such a way that one can read it.

[MyronL]

Here's my controller, in the tongue box. It came with a remote display (wire installed after pix taken) which is inside the trailer.

[Scamper Jim]

Paul and all,

I sent off an email yesterday to the “LCD 30A Solar Panel ...” guy regarding the same question, as well as some others. I received the following response this morning:

It's a pleasure to serve for you.

You can look up our listing about all you have questioned, if there is no description, then it can't be changed.

If there are any more concerns, please feel free to contact us.
Have a nice day!
​vita

Wow, he sure sold me, NOT! Those questions are not answered in the listing, that's why I asked him. Sounds like he has never opened a box of what he is selling or have any experience with it, just selling without a clue what gets shipped to him. I am still waiting for an answer from the other guy ($79 unit). Will let you know if the parameters are adjustable.

In addition to the usual list of techi-specs for the controllers, I am specifically looking for controllers that have the following features:

LED monitor screen
Parameters monitored: Battery voltage, Battery SOC, Voltage from solar panel at controller, Voltage at battery from controller, Amps from panel, Amps at battery from controller, Amps being used by appliances.
3-stage charge, and the Bulk ___ Abs ___ Float ___ charge voltages
Controller adjustable parameters, (e.g. voltage settings at battery)
Aluminum heat-dissipating back plate, not plastic
Temperature compensation
#8 gauge or larger wire at terminals

Are there any other features you think should be added to the list?

[MyronL]

Here's a breakdown on what my remote display shows. I think this is the barebones model.

[Franswa]

it looks like as soon as controllers get a little upscale they offer the capability to monitor two battery banks (like Myron, your controller is gonna read your two six volts as ONE battery, no?)....

off the top of my head I'm trying to imagine a situation where one would have two banks of batteries....and can't really find one....if it's for boats, where you have a start battery and a house battery (bank) I kinda think that's a little redundant anyway because in "real world" use the engine gets run at regular intervals and the start battery gets a more than adequate recharge when that happens....

just more "bells and whistles", or what??

[MyronL]

That's right, it has the capability of hooking up to and reading two separate batteries. My two 6 volt batts read as one. Redundant for my application, yes. I only got this duo controller because it came packaged with the remote, (25 ft, I think, of wire) which I found out sells separately for $81.

[Paul Braun]

Monitoring two banks of batteries maybe necessary (desired) on pushers where there maybe house battery, battery for generator and vehicle battery. I also noticed in working with different controllers that many of them have the capability to work with wind power. There are different settings for charging via wind. What ever, I noticed my Trimetric Battery Monitor has this capability as well, it seems it was not as full functioned for the second battery as the first.


Myron, that remote screen is a very useful add on. Plus that name Morningstar is usually on the short list for a top performing model.


Jim, I believe there are many controllers that will meet those specifications. I had a need for high voltage charge rates as I am using dual six volt Interstate batteries (the same is true for Trojan) and they recommend charge rates of 15.3 volts. I only found two models that fit that bill. If you do not need the high charge rates than there are many choices with Morningstar being on the top of my list. You might check to see what your battery manufacturer recommends for charge rates to be sure the controller can be set accordingly.

[MyronL]

Here's my home-boy "kit." Two panels booked with hinges plus support brackets.
A little heavy, yes. Polycrystalline Panels by ML Solar, draw latches by Lowes.

[padlin00]

Jim, a couple controllers to check.

Bluesky 3000i (MPPT)
Trimetrics sc-2030/tm-2030 (PWM)

6 months or so ago they were the only ones I could find that allowed the battery voltage to be set high enough for Interstate and Trojans.

[RogerDat]

Originally Posted by Myron Leski

Here's my home-boy "kit." Two panels booked with hinges plus support brackets.
A little heavy, yes. Polycrystalline Panels by ML Solar, draw latches by Lowes.

Do the panels stay in the case or is the case just for convenient transport? Either way that looks like a nice set up.

In a 13 ft. Scamp it can be tricky to find a place to stow a good sized panel for transport, two panels in a case opens up some additional possibilities.

[MyronL]

Thanks. Does take a few minutes to set up.

[Scamper Jim]

Thank you Bob and Deb,

It's amazing what one finds when looking for something else. The more you look, the more you find!

I also received a response from Net Meter Solar regarding whether or not the parameters can be adjusted. as stated in their listing. They confirmed that they can not be adjusted. The up and down buttons are only for scrolling through the menu.

They seemed to be fairly knowledgeable about solar systems and didn't feed my a line, so it occurred to me to asked them about the use of my Honda 1000w generator to recharge the battery if the weather was bad and not sufficient charging from solar panels, and if the charging would damage the controller.

Their response was:

Dear jim,

Regarding the subject of external charging source our experience has been mixed. We have some customers who have reported problems with the unit operating in RVs and have the AC power hooked up which damaged the controller. But we also have other customers that have been using it that way with no reported problems.

If you put a disconnect switch between the battery and controller that would definitely do the trick. But if you are going to do that I would recommend you getting a STDP switch and disconnect both the battery and solar panel from the controller at the same time. You only need to disconnect the positive of the battery and the positive of the panel by connecting them to each set of pins. The switch would have 4 pins with two set of isolated switch lines. It would not be good to have a charge controller connected to a panel with no battery.

What is your intended use for the system? What is the load and how many panels are you going to have?
- net meter solar

Wow, so it looks like any other charging source whether from a generator, shore power with converter & charger, or power line from tow vehicle could damage some solar controllers.

Has anyone had any experience or heard anything about this?

I contacted Renogy regarding their PWM30LCD controller. Their manual says, and they confirmed it in a phone call, that the battery can be charged with a generator with no damage to the controller. Looks like that's another issue to be checked before buying a controller.

[Timber Wolf]

Originally Posted by Scamper Jim

If you put a disconnect switch between the battery and controller that would definitely do the trick. But if you are going to do that I would recommend you getting a STDP switch and disconnect both the battery and solar panel from the controller at the same time. You only need to disconnect the positive of the battery and the positive of the panel by connecting them to each set of pins. The switch would have 4 pins with two set of isolated switch lines. It would not be good to have a charge controller connected to a panel with no battery.

That is VERY good info and some I had not heard before. With my currently planned wiring setup a switch such as he describes would entail more wiring than I want to do. Also, I plan on pretty large wire from the controller to the battery and a suitable switch for that size wire may not be feasible. What is feasible are fuses that can be pulled and/or just unscrew the wing nut and take the wire off the battery. Of course one should “kill” the panel array to the controller first THEN the controller to battery line. Oh well, maybe the Sun will always shine and this will not be an issue.