Solar panel charging?

jmcowdjmcowd Registered Users Posts: 8
How do I test to see if my pre-installed RV 175W solar panel is charging? Please, I need simple instructions.

Comments

  • Alaska ManAlaska Man Solar Expert Posts: 252 ✭✭
    Put a tester on it if you don't have it metered. Your Charge Controller should tell you if and what is being produced.
  • verdigoverdigo Solar Expert Posts: 428 ✭✭
    What else does the system consist of? Charge controller, batteries, inverter, ect...............
  • jmcowdjmcowd Registered Users Posts: 8
    The system has a 175W solar panel mounted flat on top of the RV. There is a controller (an inexpensive MPPT), and the battery. A few days ago the controller quit having any LED readout. Have been trying to troubleshoot, but this is all new and to be honest.... I am not too swift with electrical stuff. I muddle through, but only with very specific direction. Thank you.
  • BB.BB. Super Moderators, Administrators Posts: 32,007 admin
    My suggestion is for you to get a (relatively) cheap DC Current Clamp DMM (like this one from Sears). Learn how to use it (put it on your car's battery, turn on head lamps, start engine, let idle, etc.). With the Sears unit, it works well, but the "zero" DC current button is a little bit odd (compared to other meters) in how it works--However it is fine once you understand it (DC clamp meters "zero drift" over a minute or so--It is the nature of the beast--AC current clamp meters work differently and don't have a drifting zero issue).

    When you get the DC Current Clamp meter--You zero it and clamp across each major + wire in your system. On the wire from the solar array, on the + wire from the charge controller to the battery bank, etc.

    In general, if the MPPT controller is not showing any lights--It is probably not charging.

    What you can try (without a meter):
    • Disconnect the positive wire from the solar panel (to charge controller).
    • Disconnect the positive wire from the battery (to solar charger).
    • Wait several minutes (don't know if it matters--everyone just waits for electronics reset).
    • Connect the Battery to charge controller first.
    • Connect the solar panel to charge controller second.
    • See if works.
    Note, you may see some smaller sparks... If this bothers you, do the connections at night or cover the solar panel with a dark blanket/tarp. Of course, always be careful when working around batteries. There is hydrogen present that sparks can cause an explosion (take of rings, where glasses/goggles/face shield/old clothes/etc. when working around batteries). Be careful with wrenches to not short circuit the battery bank (use electrical tape to insulate other end of wrench/screw driver shank, if needed).

    In general, if the charge controller "went bad"--Then you need a new one. There is not usually anything you can fix inside.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • jmcowdjmcowd Registered Users Posts: 8
    I really appreciate the detailed information. I have a voltmeter that I did check the battery. However, everything was installed and sealed. The item you suggested may be more useable since everything is sealed. The MPPT that is on the system is questionable according to some information i have been reading. Invested in a better one that should hopefully be here early next week.
  • jmcowdjmcowd Registered Users Posts: 8
    I did try the reset you mentioned. I would really like to try to see what is coming from the solar panel.
  • BB.BB. Super Moderators, Administrators Posts: 32,007 admin
    In an emergency--You can put the solar panel directly to the battery bank (run a short jumper from the Vpanel+ to the Vbatt+ on the charge controller). Monitor battery voltage and disconnect when done.

    If you have sealed/agm batteries, you really do not want the battery voltage to exceed ~14.4 volts -- If you charge much above that voltage for more than a few minutes, you run the risk of damaging and/or over heating the batteries.

    Another quick check... Measure the Vpanel voltage on the controller and the Vbatt voltage on the output. We can probably make some guesses if there is any charging going on or not with those voltages...

    Vpanel should be around 14.5 to 17.5 volts if there is charging going on. If you see >20.0 volts, the panel is probably not charging (assuming a Vmp~17.5 volt panel).

    On the battery side, below 12.7 volts, the battery is not charging. below ~12.0 volts with no loads, the battery is going to be damaged if not recharged soon.

    Between 12.7 and 13.6 volts, the battery is "floating" (maintenance charging). From ~13.8 to 14.4 volts (seale batteries), they are charging. >~14.4 volts, they are over charging.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • ApplesApples Solar Expert Posts: 39 ✭✭
    If you have sealed/agm batteries, you really do not want the battery voltage to exceed ~14.4 volts -- If you charge much above that voltage for more than a few minutes, you run the risk of damaging and/or over heating the batteries.


    Good advice as always. AGM are also known as VRLA (valve-regulated lead acid) batteries. They are sealed and are "recombinant" batteries.. If overcharged, they will vent, ruining their ability to re-combine hydrogen and oxygen to maintain their {starved-} electrolyte volume. I say "volume" because even if the battery case is cracked from damage, these batteries won't leak electrolyte. U.S. Fed DOT does not require they be handled as HAZMAT. (Too, these are not! "gel" cell batteries)

    That said, there are exceptions to the AGM charge voltage rule... perhaps only one exception, but an exception nonetheless: Odyssey-made batteries, for example. See Pages 12, 13 and 14 in this linked PDF.

    http://www.batteryplex.com/sheets/Od...n%20Manual.pdf

    I use an Odyssey/Sears DieHard Platinum Group 31, a 100Ah AGM in my small camp trailer's solar electric power system and as such I've reprogrammed my SunSaver MPPT 15L to absorb at 14.7 and for longer than 3 hours (now six, since the prior bulk phase takes less than two hours) ending with a 13.6 V float stage.
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