Answered

Disconnected solar panels - Renogy support

Posted by SpinnerUp

Nov 8, 2019 at 11:52am

My deep cycle AGM battery manufacturer(FullRiver) recommends that their batteries be disconnected from solar charging systems if there will be little/no discharge on them for an extended period of time.. Does anyone have any authoritative information about damage or reduction in life/efficiency of my 160 watt Renogy panels if disconnected from the system over the winter months? Should their be a resistor/load connected to the panels + and - so that there isn't an open circuit? Hopefully Renogy support staff will chime in on this.

Thx


Posted by tattoo

Nov 8, 2019 at 2:30pm


Nov 8, 2019 at 11:52am SpinnerUp said:


 Hopefully Renogy support staff will chime in on this.


Since you want renogy to answer this they will be by in a few days I'm sure......


But if it was me I would leave everything hooked up and running, battery and all.........


You can leave the panels unhooked from the CC but DON'T leave them hooked up to the CC without the battery in the system.....


Best of luck..............

Posted by tattoo

Nov 8, 2019 at 2:32pm

By the way why not leave a light on, on a timer?

Posted by Spinnerup

Nov 8, 2019 at 8:43pm

Per Fullriver, low discharge rates below 0.7% of the C20 spec causes a higher rate of sulphation in the middle of the plates resulting in decrease in capacity. Their AGM's have a 6 month storage life below 86F from a full charge. Batteries are pulling less than .5A average during bulk. They also advise that a battery maintainer during storage is unnecessary, just check OCV periodically. I'll leave the batteries disconnected after flipping the double pole breaker off on the panel outputs. As far as the panels being disconnected, I've seen a lot of folks say it's not an issue, I'd just like to hear it from the "horse's mouth" though. It's kind of like asking for opinions on what's the best brand of engine oil :). Thanks for the input tattoo. 

Posted by tattoo

Nov 9, 2019 at 4:48am


Nov 8, 2019 at 8:43pm Spinnerup said:


  I'd just like to hear it from the "horse's mouth" though. It's kind of like asking for opinions on what's the best brand of engine oil :). Thanks for the input tattoo. 


Your welcome,


I totally understand wanting to hear from them, I'm sure they will be along shortly......


Best of luck.....

Posted by bupkis

Nov 10, 2019 at 5:16pm

panels not being connected to anything is a non issue, there is no circuit so there is no power created.

While I would likely keep em hooked up (possibly change boost/absorption time to a few minutes) there is no issue with disconnecting the panels then the controller and letting your batteries rest making sure to giving them a charge it they do discharge.

Since a charge controller 'turns the panel(s) OFF' to limit power/overcharging, as a maintainer the panel is 'disconnected' most of the time.

Posted by mediadogg

Nov 11, 2019 at 8:55am


Nov 8, 2019 at 11:52am SpinnerUp said:



My deep cycle AGM battery manufacturer(FullRiver) recommends that their batteries be disconnected from solar charging systems if there will be little/no discharge on them for an extended period of time.. Does anyone have any authoritative information about damage or reduction in life/efficiency of my 160 watt Renogy panels if disconnected from the system over the winter months? Should their be a resistor/load connected to the panels + and - so that there isn't an open circuit? Hopefully Renogy support staff will chime in on this.

Thx



Here is how I would think about it: what are the panels connected to before purchase? Yes, they are typically not in the sun while waiting to be installed, but I don't recall seeing any warnings on the box or instructions about pre-installation precautions. So, the authoritativeness of my thoughts comes only from deduction based on observation. Another thought: many installations, especially commercial ones, include a PV disconnect switch. I don't ever recall seeing them include any sort of load or ballast to prevent extended open circuit operation. Again, merely an observation.

Posted by tattoo

Nov 11, 2019 at 9:42am

mediadogg Avatar

Nov 11, 2019 at 8:55am mediadogg said:

  Again, merely an observation.


And it's a damn good one if you ask me!!!!!!!!!!!!

Posted by Admin

Nov 11, 2019 at 1:20pm


Nov 8, 2019 at 11:52am SpinnerUp said:

My deep cycle AGM battery manufacturer(FullRiver) recommends that their batteries be disconnected from solar charging systems if there will be little/no discharge on them for an extended period of time.. Does anyone have any authoritative information about damage or reduction in life/efficiency of my 160 watt Renogy panels if disconnected from the system over the winter months? Should their be a resistor/load connected to the panels + and - so that there isn't an open circuit? Hopefully Renogy support staff will chime in on this.

Thx





What size system do you have? We would normally recommend to disconnect your system (PV and controller) from the battery bank if they will be in storage for an extended period of time.

Posted by Spinnerup

Nov 11, 2019 at 7:39pm

Hi Renogy Admin,


I have 2 Renogy 160w panels attached to a pair of FullRiver DC220-6 deep cycle batteries. As noted in my initial post, FullRiver recommends disconnecting the batteries if they are going to be unused for an extended period of time. My concern is with any possible degradation of the panel's efficiency if left disconnected from the charge controller for an extended period.


Thx

Posted by bupkis

Nov 12, 2019 at 5:02am

Unless you move em to a controller environment their natural degradation will continue connected to not.

Posted by Admin

Nov 12, 2019 at 11:08am


Nov 11, 2019 at 7:39pm Spinnerup said:

Hi Renogy Admin,


I have 2 Renogy 160w panels attached to a pair of FullRiver DC220-6 deep cycle batteries. As noted in my initial post, FullRiver recommends disconnecting the batteries if they are going to be unused for an extended period of time. My concern is with any possible degradation of the panel's efficiency if left disconnected from the charge controller for an extended period.


Thx




If the panels are cycling throughout normal operating conditions, then they are technically degrading. You would need to cover up the panels and disconnect them from your battery bank.

Posted by Spinnerup

Nov 12, 2019 at 7:48pm

The panels would be completely open circuit, disconnected from the charge controller with the batteries disconnected on the other side of the charge controller. The panels would not be supplying any current to anything. However, they will still be mounted on the top of my van exposed to sun for the next few months. My question is, again, will the panels being disconnected like this be subject to any enhanced degradation due to the fact that they are sitting in the sun disconnected from everything?

Posted by tattoo

Nov 12, 2019 at 8:23pm


Nov 12, 2019 at 7:48pm Spinnerup said:



 My question is, again, will the panels being disconnected like this be subject to any enhanced degradation due to the fact that they are sitting in the sun disconnected from everything?


I believe Renogy answered your question above.......... But I will put it below just in case you missed it....... And by what they said the answer is yes since they said you need to cover them up...........


If the panels are cycling throughout normal operating conditions, then they are technically degrading. You would need to cover up the panels and disconnect them from your battery bank.

Posted by bupkis

Nov 13, 2019 at 5:05am

panels degrade <1% a year and I would assume most of the P/N junction (where power is made) degradation happens in full light like summer. I'd also assume that environmental degradation is more in the summer (thermal cycle, humidity UV etc).

So you are worried about 3 months of degradation in the winter (low angled sun ...)? If ya find any testing that can quantify degradation while not in use let us know.


Posted by mediadogg

Nov 13, 2019 at 5:57am

Here is a typical Renogy solar panel warranty. Keep in mind that manufacturer warranties are notoriously conservative. They expect (and need) for the products to perform far better.

WARRANTY INFORMATION
Panels
25-year power output warranty: 5 year/95% efficiency rate, 10 year/90% efficiency rate, 25-year/80% efficiency rate

5-year material and workmanship warranty

  •  Detailed Answer above 

Login or Signup to post a comment