Controller won't show charge with coach battery's connected.

[dmotwell]

I am installing an 18 watt solar panel to maintain batteries while in storage, etc. All wiring was done correctly with polarity confirmed. When I tried to hooked up controller it did not show charge. After much personal conversation, I disconnected the coach batteries from the trailer and hooked up the controller. It is now showing charge. and is charging the batteries.

I have no issues with trailer that would indicate a wiring issue. IT is a 2014 FC 30 foot Twin bed.

What is going on???

[Ag&Au]

An 18 watt solar panel is in my opinion, just barely enough to keep the batteries charged with no load on them. However it is apparently inadequate to keep the batteries charged while they are connected to the trailer circuitry. Even when everything is turned off there are still small current loads being drawn by several of the electronic devices on the 12 volt circuit. My solution: Either get a more robust solar cell or be sure absolutely everything (including the converter and inverter if you have one) except the solar controller is disconnected from the batteries, when you expect them to be charged with the solar controller.

Ken

[dmotwell]

Are you saying that the controller won't allow the batteries to charge because the panel is too low a wattage? Or am I missing something. It seemes that it would charge, but never reach full capacity. In this instance the controller shuts off when I hook it up to the batteries, unless I disconnect them from the coach. The the controller lights up and the batteries charge.

[Ag&Au]

Originally Posted by dmotwell

Are you saying that the controller won't allow the batteries to charge because the panel is too low a wattage? Or am I missing something. It seemes that it would charge, but never reach full capacity. In this instance the controller shuts off when I hook it up to the batteries, unless I disconnect them from the coach. The the controller lights up and the batteries charge.

I understand what you are saying. I am saying that I believe the coach circuitry is drawing more current that the solar charger can deliver and the controller is shutting down. This may be because there are devices on the 12 volt circuitry that are still drawing current even though their power switch is off (this is not uncommon) and/or there are devices that are still functioning. Even the output of your shore power converter probably has some small leakage current when you are not hooked to A/C.

Keep in mind that the absolute maximum your 18 watt panel can deliver is 1.5 amps. That is with everything absolutely perfect and lossless (that is not presently possible) including sun intensity and angle. The controller is obviously also using some of the available power also. So I am guessing you have a fraction of an amp to really try to charge with. I still say you probably (I'm guessing) need around at least a 50 watt panel and controller to keep you batteries charging while they are connected to the trailer loads.

Ken

[dmotwell]

Thank you. I will consider a larger panel. But for now I will leave the system the way I have it. Not perfect, but it will do what I need.

Thank you again

Dave

[dmotwell]

I have been told that the issue maybe related to a false polarity. How do you check for and resolve a false polarity issue?

[xrvr]

This is usually caused by false info about global warming and the ice caps, hence false polarity!?sorry, bad day, jim

[Ag&Au]

Originally Posted by dmotwell

I have been told that the issue maybe related to a false polarity. How do you check for and resolve a false polarity issue?

Before you find out how to check for it, I suggest you get whomever told this to tell you what it is and how it may pertain to your problem . I've been around electricity and electronics for quite a while and do not know what false polarity is in regards to electricity. I do know that it is a term used in the philosophy of politics.

Ken

[dmotwell]

I have been medically challenged for the past months and have not gotten back to your response to my issue.
I installed a 50 watt panel and the issue seems to be resolved. I want to thank you for your response. I'm now a happier camper.

Dave