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Engine charging incompatability with solar panel

Discussion in 'Technical Discussion' started by katieorielly, Jun 7, 2008.

  1. katieorielly, Jun 7, 2008
    #1
    katieorielly

    katieorielly New Member

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    Kinsale, Ireland
    :confused: I have a Volvo MD2040 which on start up wants to charge about 6 amps. But after fitting a solar panel (and controler) the charge from the engine is restricted to about 1 amp. Remove the solar panel and the low engine charge rate continues at about 1 amp. Stop the engine and remove the solar panel and the engine will then charge 6 amps. The engine generates a voltage of 14.2V, the solar panel on its own generates about 13.5V. How can I connect the solar panel so neither interferes with the other?
  2. K1W1, Jun 7, 2008
    #2
    K1W1

    K1W1 Senior Member

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    Hi,

    I am not an electrician but I have a reasonable amount of electrical experience I would say that you need to separate the two charging devices from working at the same time.

    You will need to fit a switch or relay that opens the charging circuit for the solar panel when the engine is running and closes when the engine is off.

    I think what is happening here is you have the two voltage regulators fighting each other.

    Maybe someone who has had the the same experience or a more in depth electrical knowledge can add to this thread.
  3. Castlerock, Jun 7, 2008
    #3
    Castlerock

    Castlerock Senior Member

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  4. Capt J, Jun 7, 2008
    #4
    Capt J

    Capt J Senior Member

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    The solar panel is interfering with the voltage regulator on the alternator of the Volvo. There are a few ways you can fix that. One is the isolator that someone mentioned and probably the easiest. The other is that you can install a diode I believe in line that cuts the current from the solar panel? Another would be a relay that you can wire so that when the motor is running it cuts the power from the solar panel line. Although I know a lot about electricity I am not a marine electrician.