Conext MPPT 60 PV MPPT Solar Charge Controller

http://solar.schneider-electric.com/product/conext-mppt-60-150/

Hi All,
I'm installing my 3rd PV system but my first one with any batteries. I set everything up and wanted to do a dry run with only two panels so that I can avoid a meltdown if possible. I connected the panels in my DC combiner box and with the breaker off, I get 107-109vdc. However, when I open the breaker and tie into the charge controller, the charge controller says "low light" and I get 0-1vdc. Any thoughts on why this might be?

Other possibly relevant info: 48v batteries. This is my panel, I have them two in series. http://sunelec.com/solar-panels/topoint-245w-solar-panel.html

Comments

  • BB.BB. Super Moderators, Administrators Posts: 29,321 admin
    Welcome to the forum Jestew!
    jestew wrote: »
    http://solar.schneider-electric.com/...t-mppt-60-150/

    Hi All,
    I'm installing my 3rd PV system but my first one with any batteries. I set everything up and wanted to do a dry run with only two panels so that I can avoid a meltdown if possible. I connected the panels in my DC combiner box and with the breaker off, I get 107-109vdc.

    I assume that you have two panels in series connected to one circuit breaker?
    However, when I open the breaker and tie into the charge controller, the charge controller says "low light" and I get 0-1vdc. Any thoughts on why this might be?

    We probably have a bit of terminology question here... In English/Engineering, we "close" switches to allow current to flow (in Chinese, my wife would say they "open the light" to turn it on, as in opening a faucet for water to flow--As I remember).

    So, you are "closing the breaker" to allow current to pass from the solar array to the charge controller's Vpanel input?

    The controller is reporting low light, and using a good quality meter set to DC you are seeing 0-1 volts at the input terminals of the charge controller.

    That sounds like you do not have good electrical connection between the solar array and the charge controller.

    In general, once you have (for example) direct early morning sun on the solar panels, they should generate enough current to bring the input voltage to the charge controller to over battery voltage. If the panels are in the dark, or you are doing your tests at twilight (or darker), there is not usually enough current to "wake" the controller.

    Do you have a DC Current Clamp Digital Multi-Meter (like this "good enough for our needs" meter from Sears--Note you have to learn to use the ZERO function for DC amps--It is not always obvious how to use it--At least to me it was not)?

    If you do not have a current meter, with everything connected, circuit breaker turned "on" (closed or making electrical connection), and good direct sun on the panels, use a volt meter to measure voltage across the various points in the system... For example:
    • On the charge controller: + to -, you see 0-1 volts
    • On the + output of the Combiner box circuit breaker: + to - you see 0-1 volts
    • On the + input of the Combiner box circuit breaker: + to - you see 1xx volts
    That would indicate that circuit breaker is passing current. By the way, what is the current rating (amps) of your circuit breakers?

    If:
    • On the + input of the Combiner box circuit breaker: + to - you see 0-1 volts
    That would indicate either the connections to your solar panels are not good (lose wiring, improperly crimped connector, or even a bad solar panel).

    You can connect a DMM set to 10+ amp full scale, and measure the short circuit current (Isc) of each panel... The current will vary depending on how much sun you have that moment--But anything >~2 amps probably indicates the panel is good (If you measure the panels separately, you can compare several--The average readings, vs one bad panel for example).

    You could set your meter to 10 amp DC current, and connect from + of the circuit breaker input and to the - of the return - buss bar (with one string of panels) and see what you read. Again, near zero amps with direct sun on the panels would indicate bad wiring or panel(s).

    You can short the output of a panel (or one series string of panels)--But be careful with the attached MC4 connectors. They do not like to be shorted while the panel has full sun on it... The small arcs can damage the thin gold surface.
    Other possibly relevant info: 48v batteries. This is my panel, I have them two in series. http://sunelec.com/solar-panels/topo...lar-panel.html

    I don't see anything wrong as you describe your setup... It sounds like a bad wiring connection between the solar array and the charge controller.

    A poor connection passes enough current to read with the volt meter, but as soon as a real load (the charge controller) is connected, the bad connection fails to pass any useful current.

    How much electrical experience do you have? The basics of PV Panels and your DC power system is very similar to working on a car or boat's 12 volt system... Just higher voltages (and much larger battery banks--Be very careful there--You can get 100's to 1,000's of Amperes into a dead short--And really ruin your day).

    The "magic" is the MPPT charge controller and AC inverters--They are really quite complex. In general, if you have good voltage/current to the inputs and outputs of those guys--They do work.

    Solar panels are not like Batteries--They are current sources--And while they sort of look like "solar batteries", solar panels are different enough that you can do different things (like measuring the DC short circuit current with a DMM) vs what you SHOULD NOT DO on a DC Lead Acid Battery bank (measure short circuit current here, at best you will end up with your DMM letting out its magic smoke).

    All of this is doable--I just want to be really sure you don't hurt yourself or get into trouble and cause damage.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Dave AngeliniDave Angelini Solar Expert Posts: 4,551 ✭✭✭✭✭
    jestew wrote: »
    http://solar.schneider-electric.com/product/conext-mppt-60-150/

    Hi All,
    I'm installing my 3rd PV system but my first one with any batteries. I set everything up and wanted to do a dry run with only two panels so that I can avoid a meltdown if possible. I connected the panels in my DC combiner box and with the breaker off, I get 107-109vdc. However, when I open the breaker and tie into the charge controller, the charge controller says "low light" and I get 0-1vdc. Any thoughts on why this might be?

    Other possibly relevant info: 48v batteries. This is my panel, I have them two in series. http://sunelec.com/solar-panels/topoint-245w-solar-panel.html


    There are 4 configuration screens that you must enter data. What did you enter? What Bill says. And when in doubt read the manual.. Go Warriors!
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • littleharbor2littleharbor2 Solar Expert Posts: 1,368 ✭✭✭✭
    jestew said:
    http://solar.schneider-electric.com/product/conext-mppt-60-150/

    Hi All,
    I'm installing my 3rd PV system but my first one with any batteries. I set everything up and wanted to do a dry run with only two panels so that I can avoid a meltdown if possible. I connected the panels in my DC combiner box and with the breaker off, I get 107-109vdc. However, when I open the breaker and tie into the charge controller, the charge controller says "low light" and I get 0-1vdc. Any thoughts on why this might be?

    Other possibly relevant info: 48v batteries. This is my panel, I have them two in series. http://sunelec.com/solar-panels/topoint-245w-solar-panel.html
    Your 60 cell panels are fairly low voltage for 60 cell panels these days. One problem I'm seeing is that two of these panels in series aren't going to give you a voltage high enough for the MPPT controller to process in a 48 volt system.

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric, 700 ah @24 volt AGM battery bank. Plenty of Baja Sea of Cortez sunshine.

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