Ammeter wiring

Discussion in 'OnBoard Electronics & Controls' started by CarbonFootprint, Jul 4, 2016.

  1. CarbonFootprint
    Joined: Nov 2009
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    Location: Northern Scotland

    CarbonFootprint Ill-Advised Boat Modifier

    Hello,

    I'm looking for some advice on wiring up an ammeter on my boat.

    [​IMG]

    I have two batteries in parallel that are connected to my outboard starter solenoid via a thick starter cable. Both batteries have isolator switches between them and the engine/instrument panel.

    My outboard setup uses the starter cable also as the charging cable, which is nice, as it saves on expensive thick wire, but is proving tricky from a wiring point of view.

    I'm currently thinking of connecting the ammeter between the batteries, but this would only show me the current drawn by one of the batteries, not both.

    Is there a better way to wire up the ammeter that doesn't involve breaking into the starter cable?

    I've been sat on the floor of my boat pondering this all day...

    Thanks for any suggestions :)
     
  2. CDK
    Joined: Aug 2007
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    Location: Adriatic sea

    CDK retired engineer

    The only way to wire an Ammeter is to cut the connection between alternator and starter relay in the outboard and add an external wire from the alternator to the battery. It doesn't need to be as heavy as the starter wire because it will never carry more than 40 Amps.

    In new installations nobody uses Ammeters anymore because of the heavy wiring and/or losses. A voltmeter showing the range of 10-15V is much easier to implement.
     
  3. CarbonFootprint
    Joined: Nov 2009
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    Location: Northern Scotland

    CarbonFootprint Ill-Advised Boat Modifier

    Hi CDK,

    thanks for that - it's certainly a thought.

    To be honest, I should have thought about this before I made up a new instrument panel and fitted an ammeter into it...perhaps I'll just take it out and fit a clock or something :)

    Thanks for your advice :)
     
  4. BertKu
    Joined: May 2009
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    Location: South Africa Little Brak River

    BertKu Senior Member

    Hi Carbon Footprint, I would not wire a fixed ampmeter in anyway, but to get an ampmeter which sensor clamps around a wire. In this way you are able to measure any current at any time. the question is, are you willing to keep the ampmeter close to the batteries. If not, you need to go CDK's way. Bert
     
  5. BertKu
    Joined: May 2009
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    Location: South Africa Little Brak River

    BertKu Senior Member

    Something like this or a cheaper one. If there is a need of measuring any current anywhere, any size, this is the way to go.

    http://www.mantech.co.za/Images/Products/TG311CD.jpg

    Bert
     
  6. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Agreed and "inductive" ampmeter is a lot easier to do, though neither are particularly difficult. A voltmeter shows potential energy, an ampmeter shows kinetic which is less useful in daily use.
     
  7. BertKu
    Joined: May 2009
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    Location: South Africa Little Brak River

    BertKu Senior Member

    Hi PAR, Indeed, he should have both. At least he can then see what is leftover in the battery/ies and also what the present current consumption is. Bert
     

  8. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    If the system is small and fairly conventional, I'd opt for the voltmeter, as it's more practical, but if the system is larger, more complex and has a significant bank of batteries, gen set(s), etc., I'd have a separate "status" panel, that would likely include several gauges, charging and switching options, etc.
     
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