Solar panel check up on our 13QBB

[Sylvain]

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

[Sylvain]

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

[Paul]

If you edit your post there is an option to rotate the pictures

[DavidM]

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

[Sylvain]

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.

[Sylvain]

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

[Powder Hounds]

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.

[DavidM]

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

[Sylvain]

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

[DavidM]

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

[Merlin]

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.

[Sylvain]

Thanks David and Merlin.  It does help a lot!

[Sylvain]

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

[Sylvain]

Second one

[DavidM]

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