Charge from 6hp Tohatsu

Discussion in 'OnBoard Electronics & Controls' started by 23feet, Jun 19, 2015.

  1. 23feet
    Joined: Dec 2014
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    23feet Junior Member

    Hello folks,

    I am going to connect the charge connections from my 6hp Tohatsu outboard to my 30 amp hour AGM boat battery. The battery drives the vhf and tiller pilot. The outboard charge output does not have a voltage regulator - is it OK to connect the outboard output direct to my battery?

    Many thanks,
     
  2. gonzo
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    gonzo Senior Member

    It is not ideal, since it could overcharge the battery. Also, check if it is a charger (DC) out, or a light power supply (12V AC)
     
  3. 23feet
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    23feet Junior Member

    Thanks Gonzo. The charge source is a rectifier. The part diagram is attached.
     

    Attached Files:

  4. 23feet
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    23feet Junior Member

    Sorry, I guess that wasn't clear. As an electronic ignoramus, does that mean that the rectifier is a charger?

    Thanks
     
  5. CDK
    Joined: Aug 2007
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    CDK retired engineer

    The rectifier output is your source of charge current. There are several reasons why it is not regulated, one of them is the limited amount of available current.
    Overcharging a battery is not completely impossible though highly unlikely if there is any equipment connected to the battery.
     
  6. BertKu
    Joined: May 2009
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    BertKu Senior Member

    Looking at your diagram, and the T wiring coming out, it looks like that it also could be a voltage regulator. The only way to check this is to connect this to your battery and measure the voltages on the battery and on the output of your 6Hp engine alternator part. If the OPEN voltage (i.e. nothing connected) is below 13.8 Volt, you can be assured that it will not harm your battery, if it is 14.4 Volt, you need to have your equipment switched on, to ensure no overcharging of the battery like CDK said. If it is higher than 14.4 Volt, at OPEN voltage, nothing connected, you need to ensure that your battery does not overcharge by exceeding the 13.8 Volt.

    Thus, you check the voltages coming out your outboard. 1) open voltage, 2) battery connected should be approx. 14.4 Volt 3) battery connected and equipment switched on , the voltage should be not more than 14.4 Volt.
    If it is different, let us know.
    bert
     
  7. 23feet
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    23feet Junior Member

    Thanks folks - much appreciated.
     
  8. 23feet
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    23feet Junior Member

    Ok, final question. Can the rectifier output from the outboard affect or do damage to a solar panel also connected to and charging the battery?

    Thanks
     
  9. gonzo
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    gonzo Senior Member

    No, it won't be a problem.
     
  10. BertKu
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    BertKu Senior Member

    The best is to ensure that you have a diode between the solar panel and the battery to avoid the battery discharging when it is dark. If the panel is a 10 watt panel, A 2 Ampere or 5 Ampere diode is fine. A diode has the same function as a rectifier. For a 30 watt panel, a 5 Ampere diode and for a 80 watt panel a 10 Ampere diode. Any diode as long it is greater than 20 Volt. However your rectifier is connected between your "alternator/generator" of your 6Hp engine. While the diode/rectifier for the solar panel must be between solar panel and battery or controller or regulator, whereby the cathode is in the direction of the battery/regulator. The ring on the diode must be at the side of the battery. (most diodes has a black ring indication that is the cathode side). Bert
     
  11. 23feet
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    23feet Junior Member

    Thanks BertKu,
    Would a simple solar charge controller like the RDK 8 amp (West Marine) do the same job as a diode?
     
  12. BertKu
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    BertKu Senior Member

    The website answers your question. Yes according to the product information, it is protected against discharging. Thus you don't need a diode. Bert

    >>>>>> Product Description for the RDK 8 amp (West Marine)

    Any solar panel that is rated 12W or higher requires the use of a charge controller to regulate the current and voltage to the battery. Charge controllers are able to prevent 12V batteries from overcharging or discharging, and reduce overall maintenance to help prolong battery life. Choose this 8A plug-n-play charge controller for up to 120W of solar charging. They work with all 12V batteries and solar panels <<<<<<<
     
  13. 23feet
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    23feet Junior Member

    The outboard is putting out 7 volts at idle. When I increase the rpm the voltage DROPS to around 1 volt and stays there. Clearly some sort of a problem, but stumped.

     
  14. BertKu
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    BertKu Senior Member

    OK, you have a problem. Please disconnect everything from the outboard. Measure the open Voltage. If it is still 7 volt? , it looks like you have a 6 Volt system. If it jumps to 14 Volt, something is wrongly connected.
    Please do above first, then we take the next step and see how you should connect it. .
    Bert
     

  15. BertKu
    Joined: May 2009
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    BertKu Senior Member

    You have everything disconnected and have only the outboard running? i.e. the T unit is NOT connected, nothing at all . Like I wrote to you, OPEN VOLTAGE means absolute nothing connected. What is the outboard giving you. 7 Volt?
    Bert
     
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