Solar controller question - help please

Discussion in 'Solar Power' started by Mr Mousy, Oct 2, 2016.

  1. Mr Mousy

    Mr Mousy Funster Life Member

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    First things first... I know nothing about solar systems or electrical things other than turning something on and off.

    The Moho has a 100w solar panel fitted with a controller and display as shown below.

    Even in the bright sunshine (when in France in the summer) I thought the output was not very great - 4a ish.

    So to my questions...

    Do solar panels output deteriorate over time? The panel is about six years old. If I replaced it would the output improve?

    The current controller is 20ah (whatever that means) the user manual says it is suitable for one 100w panel.

    If I swapped to a MMPT (?) controller would it substantially improve the performance? I have no idea what the difference is between MMPT and a standard unit.

    We have two x 125ah batteries plus the standard engine battery.

    The 0.4a and 19.3v was this evening as the sun went down. The 7.3a is the maximum it has ever delivered.

    We are fortunate that the van also has an Efoy system, however I would love to have free electricity!

    20161002_174749.jpg 20161002_174946.jpg

    20161002_174948.jpg
    20161002_174952.jpg
     
  2. DP_JAY

    DP_JAY Funster Life Member

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    What we don't know is the battery voltage. As the battery voltage rises so the charging amps falls.
    With a voltage of 12v I would expect 6A plus. but with 13v maybe 2A in the same light.
     
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  3. Mr Mousy

    Mr Mousy Funster Life Member

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    @DP_JAY thanks for the quick reply. I will check the battery display and report back.
     
  4. Taran_Las

    Taran_Las Funster

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    Martin,

    If your batteries are nearly full and you are not drawing a heavy load your panel will not show a large input amperage figure.
     
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  5. andy63

    andy63 Funster

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    hi.. your figures don't seem too bad.. the best output you could expect from a 100w panel would be in the order of between 5 and 6 amps i think... and that would have to be under good sunlight with the battery in need of that sort of output.. a controller rated at 10amps would do a 100w panel... if yours is a 20a controller it would comfortably take another 100w panel ..
    andy
     
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  6. jollyrodger

    jollyrodger Funster Life Member

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    I have the same controller,and in Javia Spain now so plenty if sun ,but with 200w of solar and 3 x 110amp batts .
    both batteries in your pics show batteries full charged .the red lights. are they fixed red (charging)
    or flashing red( fully charged )
    and in float mode ,? Personally I see an mppt controler as an unnecessary expense ,but my opinion only.
     
    Last edited: Oct 2, 2016
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  7. Mr Mousy

    Mr Mousy Funster Life Member

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    Thank you all for your replies.

    The red lights were flashing - which you say is fully charged.

    The voltage of the batteries is okay 13 ish - the hymer display shows 90% charged.

    I don't understand why the % charged does not go back up to 100% as it does when on hookup or if I turn the Efoy on.

    Any ideas?

    @jollyrodger @Taran_Las @andy63


    .
     
  8. jollyrodger

    jollyrodger Funster Life Member

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    Last edited: Oct 2, 2016
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  9. Bobby22

    Bobby22 Funster

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    An MPPT regulator is most suited to 170 watts and above. Your PWM controller is best for lower than 170watts.
    Unless you are using a inverter your system looks a good setup.

    4amps with a roof mounted panel, ie not square on to the sun, is a decent return with a 100w panel.
     
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  10. andy63

    andy63 Funster

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    if i understand you your asking why the power management system doesn't show an increase in battery capacity when charged by the solar but does when you are on edu or efoy .i would its because the solar is wired directly to the battery and not through the shunt which records current flow in and out of batteries... so your solar isn't been recorded the way its wired...all i can think of. and hope I've understood your question..
    andy
     
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  11. DavidG58

    DavidG58 Funster

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    did that help Martin?

    more importantly did anything not work on your last trip?

    leave well alone, as in Yorkshire, if it ain't bust don't try and fix it (y)
     
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  12. jollyrodger

    jollyrodger Funster Life Member

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    Manuals link now both working
     
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  13. Stealaway

    Stealaway Funster

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    How flat do you allow the batteries to go? If you are plugged in regularly you don't need solar. Run the batteries down to 12 ish volts and see how much charge you get. You might see 10amps plus.
     
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  14. Taran_Las

    Taran_Las Funster

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    To prove Andy's theory do you know if your eFoy system is plumbed through your electroblock?
     
  15. Mr Mousy

    Mr Mousy Funster Life Member

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    David, you of course are correct. I should only think about these things when they do not work at all.

    I really appreciate all your input to my questions. I think @andy63 may have sussed it as the solar input does not go through the electrobloc and therefore does not show on the maintenance display. Maybe i should judge the state of my battery charge by the voltage and not the % charge shown by the control panel?

    @jollyrodger Thanks you for the user manuals
     
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  16. Mr Mousy

    Mr Mousy Funster Life Member

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    Phil, yes the Efoy is connected to the electrobloc.

    @Taran_Las
     
  17. andy63

    andy63 Funster

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    I asked a question on a thread a while back about the problems of connecting solar direct to batteries and not through power management systems... my power management panel had a max solar capacity of 120w I was told and I had 280w to install.
    I was told that as long as the system didn't monitor and calculate the current in and out to determine batery condition then I should be OK. .. and so far so good....but in your case the system does check these things and your solar isn't taken into account....
    Point I'm trying to make rather badly is do you know if it does cause a problem... ie can you be sure your batteries do get a good and full charge on hook up as the system will see the elevated battery voltage from the solar connection and adjust charge rate to suit...
    again hope you get what I'm trying to say and hope someone may be able to give a better explanation of possible problems with such a set up..
    Andy..
     
  18. Bobby22

    Bobby22 Funster

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    Andy would the system top up to full during darkness on EHU or would it not be long enough to fully condition the battery bank?

    I ask this as i have mine on hookup at home with 120w solar.............would it be best to switch solar off at controller in this situation?
     
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  19. andy63

    andy63 Funster

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    Hi Bobby. . Seems logical that it would charge fully on hook up off the built in charger..
    Again can only comment on the charger in my camper..
    It takes around 4 hours to reach a float charge after the bulk and absorption cycles... its a sterling charger and rated at max 20A.. I quite often just leave it on float for the day and the power management snows a charge of 200 to 400ma during that time...
    The new van I have no idea what it's doing as I've not had the time to check things out and it doesn't have a pmp in it yet... that allows me to see things other than voltage at a glance..
    Andy.
     
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  20. Bobby22

    Bobby22 Funster

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    Hi Andy i was looking at an MT-50 , it plugs straight into my controller, to see the inputs, condition and the like cheap on ebay. Are they any good?
     
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