Hello everyone,
Has I mentioned in my " new member" post, we received our 2013 13QBB a few weeks ago. There is a lot of that things that needs attention. I decided to start with the solar panel installation. The first thing I noticed is that the panel itself was not secured properly to the roof. It's a rigid 185w panel that was only glued to the roof with construction adhesive! Four hockey pucks were used at each corners of the panel as supports (see photos)! This morning I removed everything from the roof and my goal is to reinstall it properly with aluminium brackets.
Now my question to the solar professional of this forum! I noticed that my panel was only producing between 0.2 and 0.5 A this morning in full sun. The voltage was around 44v. At 0.3A it means about only 13watts. It sounds a bit low don't you think? The sun was not very high though. I'm just wondering if my panel could be defective.
The other thing I was also considering would be to replace this rigid panel with 2 flexible 100W panels. They would be lighter and more aerodynamic. Is this a good idea?
Please feel free to let me know what you think.
Sylvain
One more.
Third one one.
Construction adhesive and hockey puck once removed from the panel!
P.S. I'm not sure why the images are uploading sideways?
Theoretically if the battery is full the amperage would be zero because there's no where for the voltage to go. How did you measure the amperage?
Two 100 watt 12 volt panels could be wired to give you significantly more amperage then your current panel and more amperage means faster charging so that would be a plus in my book.
Quote from: MitchB on April 22, 2019, 01:00:23 PM
Theoretically if the battery is full the amperage would be zero because there's no where for the voltage to go. How did you measure the amperage?
Yes the battery was full. That's probably why I was reading only 0.3A. The amperage reading was from the display that is connected to the solar regulator.
Yes, if the battery was full, the amps from the solar controller will be low. Most controllers have LEDs which will tell you if the controller has switched to "float" which it does when the battery is full.
If you want to check how your panels are really doing then let the batteries run down to about 50% and try again. The solar controller will first go into "bulk" mode which pushes all the amps it can. Then after a fixed time, usually 30 minutes, it switches to acceptance where it slowly raises the charging voltage where it peaks out at about 14.5 and then switches to float. During acceptance you will measure declining amperage as it gets closer to full.
I don't quite understand what MitchB is saying about wiring two 100 watt panels to get more amps than your current panel. Yes it will be a little more than the 185 amp panel, but not much. Maybe he is thinking about reduced voltage drop in series- see below.
I actually like flexible panels a lot. They are thin and weigh 1/3 as much as rigid ones. That means for a portable installation you can store them behind a couch or bed and easily pull them out and hook them up. They have recently gotten cheaper, about $1.25 per watt, maybe lower. I am helping a Class A RV friend install two flexible panels. He will not mount them to the roof, so he can place them anywhere in a sunny spot. That is the big downside to permanently installed panels. We always look for shady campsites and rarely get any sun on the trailer.
He is installing his two 175 watt flexible panels with 50' of 8 gauge MC4 cables so he can place them in the sun. He might even get another pair of 50' MC4 cables so he can reach farther. With his two watt 175 panels he will wire them in series if the spot he places them in has full sun. If not he will wire them in parallel with Y connectors, so that shading of one doesn't affect the output of the other panel.
A slight downside is when he does put his panels on the roof if he has full sun they will be laying on the roof and won't have an air circulation space underneath. Solar panels lose output the hotter they get so you want to keep them as cool as possible with about a 1" air gap underneath.
He should complete the installation in a week or two and I will report how they work.
David
Hi Sylvain, this reply is in regards to the 1 image per post. Please disregard this if the 1 image per post was intentional, but the "images are uploading sideways" comment caught my eye. This shouldn't be happening given the current forum software. Anyhoo, in case you were wondering how to add multiple photos, click on (more attachments) to bring up another Choose File box.
Since I usually want to annotate photos, the easiest way for me is to bring them into PowerPoint, do the annotation thing and save the slides as individual PNGs before uploading. As I found out recently, saving as JPGs can cause uploading issues. For reasons far beyond my IQ to understand, PNG is the preferred format for the Web.
Looking forward to following your fixing and mod journey. GK
Good for you to be checking the installation! That was an awful and dangerous method of installing a rigid solar panel.
A panel with those parameters (voltage output) can't effectively use just any old charge controller. It needs to be an MPPT controller (maximum power point tracking). I wonder if your system has that, given the sloppy nature of the mechanical installation.
I do highly recommend flexible panels and not permanently mounting them. I use a Renogy 100 watt flexible panel and with a long wire attaching it to the controller I can get it in the sun for best performance. By being able to put it directly in the sun, I need only one 100 watt panel for all my electrical needs (except of course the appliances that can't be used off the grid like microwave and A/C. I'll dig up the post with my installation and put the link below.
Here ya go; post #29
https://aluminumcamperforum.com/index.php?topic=164.msg7557#msg7557
If you get two 100 watt panels and wire them in parallel then the amps will be additive vs. wiring them in series where the voltage is additive.
As an example if you get two 100 watt panels that are rated at 5.2 amps (it will state it right on the panel) when you wire them parallel you'll get 10.4 amps (in the perfect world). That's a pretty good jump over the single panel you have now that is rated at 5.76 amps.
As Merlin said, an MPPT charge controller will convert some of your excess voltage into amperage. In my opinion the 36 volt panel you have now isn't particularly well suited for a small single panel system like you have, your plan for two 100 watt panels is good and if it were me I'd wire parallel and be happy. In fact I did that very thing going from a single 70 watt panel to two 60 watt panels.
Quote from: MitchB on April 22, 2019, 04:09:21 PM
If you get two 100 watt panels and wire them in parallel then the amps will be additive vs. wiring them in series where the voltage is additive.
As an example if you get two 100 watt panels that are rated at 5.2 amps (it will state it right on the panel) when you wire them parallel you'll get 10.4 amps (in the perfect world). That's a pretty good jump over the single panel you have now that is rated at 5.76 amps.
As Merlin said, an MPPT charge controller will convert some of your excess voltage into amperage. In my opinion the 36 volt panel you have now isn't particularly well suited for a small single panel system like you have, your plan for two 100 watt panels is good and if it were me I'd wire parallel and be happy. In fact I did that very thing going from a single 70 watt panel to two 60 watt panels.
I'll jump in here for a moment and DavidM can fill in more details. The parameter you're missing in the math is the voltage difference. Start wit the total watts output and figure from there. When you do that, 200 watts is not much more than 185 watts. Divide BOTH by the same voltage to get a comparison of amps. V X A = W. A = W / V.
Except that in this case he's got a 36 volt panel so 185/36 vs 200/17 (or whatever the 12 volt panels will be). The difference is significant.
Yes, as Merlin said.
In addition the solar controller, assuming it is rated for the additional voltage, will convert the series voltage to greater 12V amps. Wiring two nominal 12V panels in series is functionally identical to a single nominal 24 V panel.
A word about the nominal term used above. When solar panels first came out for charging batteries they were typically made with 36 solar cells. The 36 cells results in a maximum open circuit voltage of about 21 and a maximum power point voltage of about 17 which a MPPT controller converts to 12-14 volts for battery charging. But you can also connect such a panel directly to a battery and it will charge it at whatever voltage its current capability will achieve and it will also over charge with no controller. That is why we have controllers.
A 24V nominal panel has double the cells and all of the voltages noted above are doubled. The MPPT controller converts these voltages to what the battery needs and does so very efficiently. You can also hook a 24V panel directly to a battery and it will charge it again at whatever voltage its current capability will achieve, but it will REALLY over charge your battery once it gets full and the voltage starts spiking way beyond. 12V.
Finally a pulse width modulation controller if it is rated for the higher voltage can be hooked up to a nominal 24V panel and charge a battery just fine. But here you are wasting about half of its current output due to how the PWM controller operates. It just pulses faster with a higher voltage and those pulses waste at least half of the amperage capability of the panel.
Always use a MPPT controller on 24V nominal panels.
Whew. Time for a beer!!!!
David
Quote from: MitchB on April 22, 2019, 06:02:59 PM
Except that in this case he's got a 36 volt panel so 185/36 vs 200/17 (or whatever the 12 volt panels will be). The difference is significant.
Like I said above the extra voltage of 36 is directly converted by the MPPT controller to extra current to the battery which will be somewhere between 12 and about 14V. Think of a MPPT controller as a very efficient DC transformer.
David
Thanks everyone for your input! I wasn't expecting that much reply so fast! It's very intersting information. I like the idea of having a panel installed on the roof since it does keep my battery always fully charged when the trailer is in my driveway or when I'm on the road. My controller is indeed a MPPT and it can handle up to 260W so I was thinking about adding a portable panel to my set up so I can move it in a sunny area if needed. I really like the idea of the flexible panel on the roof since they would be lighter and I would not have to drill trough the roof to install them.
Thanks again.....Sylvain
Quote from: GrampaKilt on April 22, 2019, 03:02:20 PM
Hi Sylvain, this reply is in regards to the 1 image per post. Please disregard this if the 1 image per post was intentional, but the "images are uploading sideways" comment caught my eye. This shouldn't be happening given the current forum software. Anyhoo, in case you were wondering how to add multiple photos, click on (more attachments) to bring up another Choose File box.
Thanks for the information GK. I was indeed trying to upload multiple images and I tried the "more attachments" button but it didn't work. The problem might be my old iPad though. I'll try again next time!
Sylvain
Quote from: DavidM on April 22, 2019, 02:34:32 PM
Yes, if the battery was full, the amps from the solar controller will be low. Most controllers have LEDs which will tell you if the controller has switched to "float" which it does when the battery is full.
If you want to check how your panels are really doing then let the batteries run down to about 50% and try again. The solar controller will first go into "bulk" mode which pushes all the amps it can. Then after a fixed time, usually 30 minutes, it switches to acceptance where it slowly raises the charging voltage where it peaks out at about 14.5 and then switches to float. During acceptance you will measure declining amperage as it gets closer to full.
That's great information David, thanks a lot! I didn't have look at the solar controller since it's located under the bed but I will next time.
Do you have any brands of flexible panels to suggest or can I just use the Chinese flexible panels available on Ebay?
Thanks again.......Sylvain
If you edit your post there is an option to rotate the pictures
Quote from: Sylvain on April 22, 2019, 07:16:09 PM
Do you have any brands of flexible panels to suggest or can I just use the Chinese flexible panels available on Ebay?
Thanks again.......Sylvain
I am quite confident that rigid solar panels made by the Chinese are every bit as good as ones made in America. Heck the Chinese make most of them used throughout the world.
I am a bit less confident about flexible panels, mostly because they are a tiny part of the solar panel market and AFAIK they are all made by the Chinese, so you probably don't have a choice.
Amazon currently has 100 watt flexible panels from Renogy, a big Amazon supplier and WindyNation an on line solar retailer who has been around for a while. I would trust those brands more than no names.
My Class A RV friend bought 175 watt flexible panels from Amazon by a no name supplier- no doubt Chinese made. I will let you know how they work out.
David
Quote from: Paul on April 22, 2019, 08:31:22 PM
If you edit your post there is an option to rotate the pictures
Thanks Paul, I just rotated the pictures. I had to do it on the computer though since the "rotate" option is not available when I use my iPad.
Quote from: DavidM on April 22, 2019, 08:45:47 PM
Quote from: Sylvain on April 22, 2019, 07:16:09 PM
Do you have any brands of flexible panels to suggest or can I just use the Chinese flexible panels available on Ebay?
Thanks again.......Sylvain
I am quite confident that rigid solar panels made by the Chinese are every bit as good as ones made in America. Heck the Chinese make most of them used throughout the world.
I am a bit less confident about flexible panels, mostly because they are a tiny part of the solar panel market and AFAIK they are all made by the Chinese, so you probably don't have a choice.
Amazon currently has 100 watt flexible panels from Renogy, a big Amazon supplier and WindyNation an on line solar retailer who has been around for a while. I would trust those brands more than no names.
My Class A RV friend bought 175 watt flexible panels from Amazon by a no name supplier- no doubt Chinese made. I will let you know how they work out.
David
Ok, thanks again David. I may also keep our rigid panel since we already have it and the quality seems to be good.
Sylvain
My main concern with adhesive flexible solar panels is heat. Increased heat will result in reduced performance. Now take into account the aluminum roof surface that we have and how hot it gets up there. No air circulation under the panel, hot climates, not sure how long they would last? They certainly have advantages over tempered units but I would be cautious.
Using the flexible panels in a portable fashion is very clever, no heat issues, no low hanging trees, easy to move around.
Just my opinion.
Flexible solar panels mounted on a flat surface will certainly be hotter than a rigid panel mounted with a 1" air gap. But it may not be a deal breaker. Solar panels have a temperature power coefficient of about 0.5% per deg C.
So if the flexible panel is 20 deg F hotter than a rigid panel then its power output would be 0.5*20*5/9= 5.5% less, 11% less for 40 deg F hotter which is all I can see ever happening.
Willl 40 deg harm the panels long term. I have no idea. I do know that earlier very flexible panels that you could roll into a 1' cylinder did degrade rather significantly over time. Not sure it was heat related, more time I think. I had several of these which were almost worthless after ten years, most of which was sitting in my garage.
David
Great information again, thanks.
I may have to replace our battery (70Ah). I was thinking about a 105-130Ah battery bank. Is a 185Wh panel powerful enough for a 130Ah battery?
Sylvain
Quote from: Sylvain on April 23, 2019, 09:48:25 AM
Great information again, thanks.
I may have to replace our battery (70Ah). I was thinking about a 105-130Ah battery bank. Is a 185Wh panel powerful enough for a 130Ah battery?
Sylvain
Well, that really isn't an answerable question. The real question is with X amp hours of DC usage each day, is a 105-135 Ah battery big enough and will a 185 watt panel recharge it fully each day.
Said another way, what is the maximum amp hours I can use each day and live with a 105-130 Ah battery and a 185 watt panel.
Since you want to limit the discharge of your house battery to 50% for best life the battery will support 50-65 Ahs of use each day. That is a lot for a camper. We use 10-15 Ahs each day but no furnace or TV use.
Your 185 watt panel will supply about 60 Ahs on a sunny day, but you need to allow for a few cloudy ones, so in order to fully recharge your battery each day on average I would keep the Ah use down to 40 or less each day.
Hope this helps.
David
Quote from: Sylvain on April 23, 2019, 09:48:25 AM
Great information again, thanks.
I may have to replace our battery (70Ah). I was thinking about a 105-130Ah battery bank. Is a 185Wh panel powerful enough for a 130Ah battery?
Sylvain
Just as a point of reference, I use two 105Ah 12 volt batteries which gives me a usable battery capacity of 105 Ah @ 12 volts. I have a 100 watt flexible, mobile panel that keeps the batteries fully charged pretty much every day. I use two batteries just for some reserve capacity in case of a series of cloudy days. Otherwise, one battery would be enough to get me through the night. You might want to consider where and when you camp too, because late fall, early spring camping in cloudy parts of the country will need more capacity.
Thanks David and Merlin. It does help a lot!
Hello everyone,
Did some more work in the Livin Lite today. I took some photos of the solar charge controller wiring. Everything seems fine but for one wire. There is this black wire loosely connected to the + output of the solar charge controller (see photos). It goes to the RV converter?? Why would someone send some power from the solar charger controller to the RV converter? Can anyone help me on this one?
Thanks........Sylvain
Second one
Well, first of all that is an abominable installation with the insulation cut on the red wire and the stripped end of the black wire wrapped around the cut. So, STOP, don't use it and get a real PV electrician (marine electrician's are pretty good at this kind of stuff) to fix it.
Your solar controller looks like there are two breakers on either side of the controller, probably added on by the installer. The controller's inputs and outputs are on the bottom and the red input and output leads go to their respective breakers on the left and right sides and then to the solar panel and the battery. I see no real safety reason for those breakers. You should have a breaker or fuse near the battery on the red wire but you didn't supply a picture of that.
Who knows what the black wire from the converter wrapped around the insulation cut is for. I haven't a clue. How do you know that it goes to the converter? What is the significance of the red wire you have an arrow pointed to in your second pic of the back of the converter?
Whoever wired this needs to be shot.
David
Yes David, it's abominable. Just remember that the solar panel was glued to the roof on four hockey pucks with construction glue!!
The black wire really goes to the converter. I forgot to mention that it started as a black wire at the solar charge controller and it ends up being red at the converter. That's the red wire that you see at the back of the converter on the second photo. The black wire probably wasn't long enough to go all the way to the converter so he connected a red wire to the black to make it longer.
I'm a electronic technician so I should be able to re-wire everything properly. I was just curious about that wire going to the converter? Is there any reason someone would need to have a connection between the solar charge controller and the rv converter?
There is no fuse at the battery. I believe the 15A breaker at the solar charge controller output is doing that job. The wire from the panel to the controller and from the controller to the battery is 10awg. The distance between the controller and the battery is only a few feet.
Thanks......Sylvain
OK, good you have the skills to do this right. Here is what I would do:
Remove the black wire wrapped around the red one and pull it back to the converter, and disconnect it. Tape up the insulation cut. I see no reason for a separate wire to the converter. The converter was already wired to the battery, right?
My 2013 16TBS had no fuse between the battery and the converter. That is very poor practice but lots of RV builders do it. The wire to the converter on mine goes about ten feet underneath the trailer. It is exposed and if a rock hit it, dinged the insulation and shorted to the frame it could possibly burn up.
So I installed a water proof 30A breaker within a foot or so of the battery on the positive wire. It also serves as a disconnect. This is what I used: https://www.amazon.com/gp/product/B00DIGK346/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1. I used the defunct break away battery box (I wired the breakaway switch directly to the house battery) and it makes a good place to bring all of the wires together.
Then wire your converter, and the solar controller's output to the downstream side of that breaker. Then you will have a safer system.
David
Ok, thanks a lot again for all the information David. Yes my converter is connected (from the factory) to the battery. I don't think there is a fuse between my battery and the converter on my trailer too. I may install something similar to you. Do you have a photo of that set up in your battery box? That would be great!
Thanks a lot........Sylvain
I for sure agree with DavidM. Yikes. I wonder what other dangerous connections were made in that installation? In addition to the bad connection, that mysterious black wire is not protected by the circuit breaker, but nothing else may be protected by those breakers either. I don't know how DC circuit breakers work, but those are wired backwards according to the installation instructions for Midnight Solar breakers. I looked up the installation instructions for that controller too, just to check on in/out connections. If you could definitively find out what the black wire is connected to, we might be able to help some. For example, if it goes to the converter, which terminal? I sure can't think of a purpose for that. All things considered, take DavidM's advice and get pro help. You don't want to do any accidental welding or start any fires with the high current from the battery (says the voice of experience).
Thanks for your reply Merlin. Thanks for pointing out the fact that the breakers are connected the wrong way. I'll have a look at them. I checked the rest of the wiring it it looks fine. It's a very simple system and there is not much wiring. As soon as time allows I would like to open the back of the converter and see where that wire is connected. I'll let you know. I already disconnect that weird wire. Everything seems to work fine eventhough it's disconnected. I sent a message to the previous owner about that wire but he didn't replied.
Thanks..........Sylvain
I did the same thing as DavidM and installed a breaker in my battery box. This one also serves as a convenient on/off switch. They come in different amperage ratings.
https://www.solar-electric.com/mrcb-30-amp-dc-circuit-breaker.html
Ok thanks. I'll do the same thing. I couldn't find the same breakers on Amazon Canada that you and David suggested. I found this one though. Would it work?
T Tocas 30 Amp Surface-Mount Circuit Breakers with Manual Reset for Auto Boat Marine, 12V- 48V DC, Waterproof https://www.amazon.ca/dp/B07D7T3ZR5/ref=cm_sw_r_cp_tai_l6YXCbSA06D2V
Thanks......Sylvain
Is this the proper way to cennect it? I would install the circuit breaker less than 12" from the battery.
Your breaker looks fine, and cheaper too!! Your installation diagram is good too.
David
You say full sun but most likely is not given the morning sun. You also need to understand the load on the system to get a good panel output reading. Google "effects of shading on solar panels" etc.. Partial shading of even one cell may reduce its power output. Because all cells are connected in a series string, the weakest cell will bring the others down to its reduced power level. Much depends on how the panel was manufactured but lower cost panels will see the type of drop you are seeing. Also lower sun angle will greatly reduce the output. Solar cells also degrade over time. The panel rating is with direct overhead full sunlight no shade. I have 6 of the sun power cell flexible 100W panels mounted to the roof of my Campsite 21RBS. When I first installed my system I would see ~30Amps in full overhead sun. After a storm of with 3/4" hail stones I see a 20% degradation in my system. I can see some small dents in the panels plastic. I would not recommend these flexible panels. They are expensive per watt and IMO do not hold up. Doing some searches on Amazon I see many framed, more cost effective panels that will hold up to hail etc.
Quote from: DavidM on April 29, 2019, 02:38:37 PM
Your breaker looks fine, and cheaper too!! Your installation diagram is good too.
David
Great, thanks David!
Quote from: Bluewaterbound on April 29, 2019, 03:00:37 PM
You say full sun but most likely is not given the morning sun. You also need to understand the load on the system to get a good panel output reading. Google "effects of shading on solar panels" etc.. Partial shading of even one cell may reduce its power output. Because all cells are connected in a series string, the weakest cell will bring the others down to its reduced power level. Much depends on how the panel was manufactured but lower cost panels will see the type of drop you are seeing. Also lower sun angle will greatly reduce the output. Solar cells also degrade over time. The panel rating is with direct overhead full sunlight no shade. I have 6 of the sun power cell flexible 100W panels mounted to the roof of my Campsite 21RBS. When I first installed my system I would see ~30Amps in full overhead sun. After a storm of with 3/4" hail stones I see a 20% degradation in my system. I can see some small dents in the panels plastic. I would not recommend these flexible panels. They are expensive per watt and IMO do not hold up. Doing some searches on Amazon I see many framed, more cost effective panels that will hold up to hail etc.
Thanks for the added information.
I finally found where that fishy cable was connected in the RV converter. It was connected to the battery terminal inside the converter (photo). I really can't understand why he would have connected that wire there??
Sylvain
No reason, it was just a redundant parallel connection to the battery The real problem was that screwy splice. If it had come loose and there was no fuse/breaker at the battery, it could have touched ground and at best burnt the cable, at worst burned up your camper.
David
And I found another screwy splice really close to the converter on another wire. I did use heat shrink to protect those splices. Everything is fine now!