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First use of Foldable Solar Panel


Simon 62
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So I bit the bullet and purchased a 100w foldable solar charger and went to use it at an off grid sight for the first time yesterday.  With the panel hooked up everything appeared fine.  In the early evening we had very bright sunlight and I noticed that inside the caravan on the control panel (2010 Swift Challenger) the 14v led was flashing and the 12v leisure system had switched off.  I tried to turn it back on by pressing the power button on the caravan's control panel but it wasn't having any of it.   I went outside to the the solar panel which was facing the sun and connected to the caravan's battery, and the solar charge controller was reading 22v.  I assume that means it was pushing 22v in to my battery which can't be good.  I laid the panel face down on the grass and disconnected it from the caravan's battery.  I was then able to put the 12v leisure power back on in the caravan.  I am now worried that there is something wrong with the charger controller and there is a risk that it may cook my battery.  Any thoughts or advice much appreciated.

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22v is a typical open circuit voltage for a panel.  My controller takes the battery to about 14.3 v then it reduces the voltage down to 13.8v which is its float voltage.  So it might depend where your over voltage cutout is. If it is  14V then it is in my opinion set a little low.  

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1 hour ago, Lost in the wilderness said:

Definitely sounds wrong. Should not get more than 14.5v going into battery 

I think the poster was saying the panel was producing 22v. It's the job of the controller to wind that down to the 12 or so volts to charge the battery...

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3 hours ago, Simon 62 said:

So I bit the bullet and purchased a 100w foldable solar charger and went to use it at an off grid sight for the first time yesterday.  With the panel hooked up everything appeared fine.  In the early evening we had very bright sunlight and I noticed that inside the caravan on the control panel (2010 Swift Challenger) the 14v led was flashing and the 12v leisure system had switched off.  I tried to turn it back on by pressing the power button on the caravan's control panel but it wasn't having any of it.   I went outside to the the solar panel which was facing the sun and connected to the caravan's battery, and the solar charge controller was reading 22v.  I assume that means it was pushing 22v in to my battery which can't be good.  I laid the panel face down on the grass and disconnected it from the caravan's battery.  I was then able to put the 12v leisure power back on in the caravan.  I am now worried that there is something wrong with the charger controller and there is a risk that it may cook my battery.  Any thoughts or advice much appreciated.

What make and model of solar charge controller do you have ?

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I am not sure what the make and model is but here is a picture.

20210918_161835.jpg

To clarify the 20v was what was displayed on the controller when connected ro the battery.  I thought that as the voltage that the charge controller was putting in to the battery.  I accept that the Voc should be 20v plus.  And why would the caravan 12v system not power up until I disconnected the solar charger.   Thank you to everyone for your input.  Can't find the "like" button atm.

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Have you set it all up properly or maybe changed something? it may be a simple configuration error. Double check the instructions or have a look on youtube there are lots of videos on that cheap and cheerful controller, example here

https://www.youtube.com/watch?v=EDl4cN1JREo 

 

As its supposed to be auto detect mind you!  What leisure battery have you got?

 

Search for "topcloud solar" on youtube for lots more 

Cheers, Martin

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Did you connect to the battery before connecting the panels?

If you connect the panels first then many controllers default to 24v . Connecting the battery first makes it default to 12v  .

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As far as I can recall I just followed the instructions which said, lay the panel face down, then connect to the battery and then pick up panel to face the sun.

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Maybe worth another try making sure you 

connect controller to the battery before you connect the panel to the controller. Might also be a good thing to reset the controller to factory default settings before connecting the panel.

I have seen similar problems quite a few times on boats when this has not been done.

 

ETA caravan would not power up as it was sensing high voltage .

Edited by Idleness
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To switch on:

Battery, panel and then load. 

 

To switch off :

Load, panel and then battery. 

 

My controller's display changes from Panel (PV), battery and load. The panel voltage is that put into controller, not to the battery. The battery is that sent to the battery by the controller. 

Graham

Unless otherwise stated all posts are my personal opinion 

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With most folding panels the controller is panel mounted and wired up, thus you can't power up the controller from the battery before the panel.

With a "12v Volt block of lead" loading it, it's going to be some impressive solar system that forces it up to 22 volts on the battery, the reality is it could not have done so.

The controller's LCD quite possibly can be indexed to cycle through reading, solar panel input and batt voltage, plus possibly the amps. It showing "batt" in the supplied photo, somewhat hints it can display more than "battery" voltage?

 

Seeing over 14 volts is in itself no surprise, the less so if the connection is made and broken. As the controller could then attempt, what a good smart charger will do , try a quick  pulsating high voltage "desulphation" phase. Mine, a Morningstar goes to 15.5 volts just as my CTEK MS 5 mains charger does. 

 

The time for concern is when these high voltages don't back off to "bulk", "absorption" and onto "float" levels as the charge progresses.

Edited by JTQ
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Thanks for the input.  The incident didn't occur yesterday with similar levels of brightness.  I remain concerned though as the 12v system on my caravan definitely locked out and would not switch back on until I disconnected the solar charger from the battery.  I am worried that one day I am going to come back to the caravan with a battery in flames.  I might get a new charge controller.

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1 hour ago, Simon 62 said:

I might get a new charge controller.

 

If you do, then that can come with several pluses :-

 

Many controllers feature an inbuilt temperature sensor, so being located near the battery the better the chances are it will "see" similar temperatures to the battery and so its inbuilt voltage to temperature algorithm better work as intended.

The more so in that a solar panel gets very hot, so mounting it on or near them is fundamentally destined to screw up that parameter, backing off the charge voltage prematurely.

 

The controller to battery cable can be short, so the voltage losses can be minimised. Again, the battery charge voltages achieved are going to be nearer where they ought to be; not the case where there are metres of cable out to the controller.

 

The controller would typically then be permanently connected to the battery that powers it. Thus, the plugging in and out of the panel will be made in the panel to controller input wiring; for all the controllers I know the "right" way round for the connecting and disconnecting sequence. [Only connect or disconnect a panel with a battery powered controller]

 

Then of course you can ensure you use a quality solar controller, and even wire the panels up to optimise particular panels and controller technologies.

 

 

Edited by JTQ
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I disconnected they built in controller on the back of the panel for the very same reasons, plus 5he fact that it was a cheaply pwm type anyway.  Solar now connects straight to the mppt in the van.  Which is near the battery and at the similar temp.  Result is a much better harvest of the power. 

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