need some advice, just fixed my solar panels

[Halifax Sailor]

Hi all, although I've had solar on my boat since i purchased (7yrs), have never had to do anything to it as it has worked. Kept my batteries charged even during the winter. This sailing season however, it didn't seem to charge well and when I hauled the boat, removed the panel and took apart. Discovered it was only producing between 1.5-3 volts in full sun. Now really disassembled, found 2 really bad connections. Resoldered, and WOW, panel now produces up to 24v in full sun. I do have a charge controller, but my question is....do some panels produce 24v? and if this is normal, when I connect to my system will my charge controller hold it to 12v approx so I don't blow up my batteries? Haven't had any other issue until I lost the voltage this season, always had full charge on the batteries when at mooring. So any advice or answers to my questions would be appreciated? Some of these may sound a little naive but have never had issue so first time to repair this part of my boat. I do have the option of purchasing new from Oceanplanet but if this is fixed then would rather save the boat dollars for new sails.

[sy_gilana]

All panels put out more than nominal V when open circuit.
Your reg will drop the V to the correct value provided you connect BATTERY FIRST, then panels.


Check your user manual just to be sure.

[Halifax Sailor]

Thks for quick reply, will follow the battery first then panels. Do you know of any way to check how many amps the panels would be outputting? I have a pretty good meter .........would putting all circuits on and then running a test on what the panel is putting in do it?


https://cdn.greenlee.com/resources/images/c35959c4-22f7-4bb6-acff-e78e251f8baf" alt="600 AMP AC + DC TRUE RMS CLAMP METER (CALIBRATED)"/>

[Dsanduril]

There are two quick tests for solar panels to see if they are up to spec; open circuit voltage (Voc) and short circuit current (Isc). For open circuit voltage measure the two leads on the panel while it is not connected to anything. Sounds like you’ve already done this. Should take very little sun to reach nominal Voc. To measure short circuit current connect the panel to itself (plus to minus). Put your clamp meter on the wire. Expose the panel to bright sun normal to the plane of the panel. This will give you Isc. It may or may not match specs depending on how much sun you had at the time of measurement.

For any panels over ~18Voc you are probably better off putting in an MPPT controller that can take advantage of the higher voltage. But even a PWM controller will restrict the high panel voltage so that the batteries only see what they need. Confirm, however, the highest voltage the controller can accept.

Panel voltages these days vary a great deal with many running from 30 to 50V.

[Edit] looks like the Greenlee may only do AC current, depends on exact model.

[Halifax Sailor]

Thks so much for the info, thats why I belong to this forum. Going to the boat today, will let you know.

[freakytiki]

I have 2 solar panels and 2 battery systems. One for the starter battery and one dedicated to lights and stereo. Both panels put out 18+volts , but as long as you have a controller..OK