Tech help needed.

Discussion in 'Tech/Mech General' started by Wildman, Nov 30, 2014.

  1. Wildman

    Wildman Read Only Funster

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    I am looking for a relay that includes one pair of normally open contacts and one pair of normally closed contacts. i.e two independant switches. To take the max charge current from the alternator (which will be the greater of the two feeds). The idea being to switch off the solar feed to the regulator when the engine is running so that neither feed confuses the other.not sure what the max charge amps could be from the alternator, with or without a B2B charger fitted.
    Anyone any suggestions as to part numbers/location etc.
     
  2. pappajohn

    pappajohn Funster Life Member

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  3. tonyidle

    tonyidle Funster

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    Neither feed will confuse the other. Whichever is providing the highest voltage at any given moment is the one doing the work: the other will be doing nothing. You don't need added complication in the form of a relay.
     
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  4. Wildman

    Wildman Read Only Funster

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    if the solar is charging at over 13v then the alternator regulation kicks in and thinks the battery is almost fully charged and reduces output accordingly or they both reduce output. as the respective regulators see the other voltage and confuse the charge for battery level and even after an 8 hour run batteries are not recharged.
    Your hypothesis would apply if both voltage sources passed through a single regulator however there are separate regulators in the solar and the alternator.
    However am ready to be convinced I am wrong.
     
    Last edited: Nov 30, 2014
  5. mjltigger

    mjltigger Funster

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    I've proved often that I'm useless at this sort of thing but I was told all I needed to separate multiple charging inputs was a diode
     
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  6. pappajohn

    pappajohn Funster Life Member

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    Actually, thats a very good point......but.....

    You cant put a blocking diode in a charging circuit.....the charger, or in the case of solar...the regulator, needs to monitor the battery voltage state or it will continue to charge after the battery has reached capacity.
    a diode would stop the charger mnitoring the battery.
    .
     
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  7. Wildman

    Wildman Read Only Funster

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    so what is the general consensus of opinion am I correct or mistaken, come on Eddie banned bits you are the hexpert.
     
  8. movan

    movan Funster Life Member

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    Crumbs, not being sarcastic, honest. You lot arn't half clever... I havn't got a clue what you are talking about... Anyway, hoping this post bumps it up a bitz.
     
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  9. Techno

    Techno Funster Life Member

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    The alternator works at 14.4 volts this will put any solar regulator into float mode 13.2/13.4volts
    Usually the alternators target voltage is a minimum of 13.8 and thus it will keep up output (current) to achieve that.
     
    Last edited: Dec 1, 2014
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  10. Wildman

    Wildman Read Only Funster

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    solar has an input voltage of approx 17v and regulator maintains 13.8v on the battery as well. How does the alternator decide if the voltage is sees is the solar or battery level. I seem to remember you have a posh Ctec system that sorts it for you.
     
  11. eddievanbitz

    eddievanbitz Trader - Funster

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    I wouldn't bother to be perfectly honest unless, I was designing a bespoke system from scratch. What sort of wattage are we talking about?

    Eddie
     
  12. Techno

    Techno Funster Life Member

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    Get a better regulator that that has 3 stage charging instead of pouring money into relays.

    13.8 is too high for a float charge and could overcharge a full battery
     
  13. Wildman

    Wildman Read Only Funster

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    160W solar into 2 x 120 amp/hr batteries, I had problems charging when both were connected so disconnected the alt as we spend more time static. Rather than put 2 switches in a relay would do the job cheaply enough
    We do have a second identical bank without any Alt connection that also has 160W solar, just for the TV.
     
  14. Wildman

    Wildman Read Only Funster

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    a 3 stage regulator is silly money compared to a relay at £13.95. The batteries in one bank are 6 years old and still doing the business. 13.7v today after heavy use the past 4 days. So perhaps it does not float charge rathe it switches off the solar once the battery is fully charged. Besides only need alt charging in the winter when sun is low in the sky. So still need both
     
    Last edited: Dec 1, 2014
  15. Techno

    Techno Funster Life Member

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    What regulator is it you have? even cheap ones should have a float charge certainly not just 13.8 full time
     
  16. Don Quixote

    Don Quixote Funster

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    Perhaps something like this:
    http://www.amazon.co.uk/SunWorks-In...otorhomes-Black/dp/B005HH2O7I#customerReviews
     
  17. Wildman

    Wildman Read Only Funster

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    I never said it was 13.8 full time the charge depends on the state of the battery and load at any given time plus of course sun available. The regulator was an expencive one and not the problem. A £200 regulator will not increase the charge when there is no sun. The solar setup is fine, problems only arise when the alternator is charging at the same time.
     
  18. Techno

    Techno Funster Life Member

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    There you go then
    As I said , when your regulator sees 14.4 volts from the alternator it will go into float mode and thus not interfere
     
  19. Techno

    Techno Funster Life Member

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    As I said in post above

    and as I said in my first reply
    The alternator works at 14.4 volts this will put any solar regulator into float mode 13.2/13.4volts
    Usually the alternators target voltage is a minimum of 13.8 and thus it will keep up output (current) to achieve that.
     
  20. Techno

    Techno Funster Life Member

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    The float mode voltage (solar regulator) as I stated is well below an alternators target battery voltage so the alternator will continue to ouput whatever current is needed at 14.4 volts to achieve the target voltage.
     
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