A Query For The Knowledgeable 12 Volt Charging Experts.

Discussion in 'Tech/Mech General' started by JJ, Jun 13, 2013.

  1. JJ

    JJ Funster

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    Ok.

    Here goes.

    I have solar panels wired up through a posh regulator thingy to my leisure battery bank.

    I have the engine battery wired up to the alternator.

    And I have a clever Sterling battery to battery charger. This is connected to the leisure battery(s) and the engine battery.


    As I understand that the B2B charger detects the voltage in the leisure battery and the engine battery.

    When you start up, the B2B can tell if the leisure battery needs any charging and proceeds to let the alternator do so once the engine battery has been fully charged.

    If the leisure battery is full it just "floats"... letting a small current keep it topped up.

    Ok... here is the query...

    If the sun is shining the panels put a voltage around 14 volts across the leisure battery terminals. This is the voltage of the panels and is there even if the leisure battery is flat. So surely the B2B charger will read this voltage and "think" that the leisure battery is full and therefore not allow the alternator to pump in loads of amps and charge it up quickly.

    Does my B2B only work to the maximum when it is dark?

    JJ :Cool:
     
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  2. vwalan

    vwalan Funster

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    yes . i find it works abit like that.
     
  3. haganap

    haganap Funster Life Member

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    Yes JJ it does.

    To get over this, you need to install a relay so that when you start the engine, the solar panels no longer charge the Leisure Batteries.

    Otherwise, when driving along the road, the B2B will never read properly because the Batteries are being charged by the Solars.

    However, it will not mean it doesn't work and doesn't charge the batteries, it just won't do it how it should.

    The above makes me sound real clever,,, but, When I fitted mine Jonandchell explained it and fitted the relay, also dropping out of the Fridge to stop that creating a circuit within a circuit. :thumb:
     
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  4. Snowbird

    Snowbird Funster Life Member

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    Has your trusty Kipor broken down :Rofl1:
     
  5. JJ

    JJ Funster

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    Haggers my friend... I have to confess I did not have you down as the Funster most likely to come up with the answer and solution...

    I apologise...:Rofl1:

    JJ :Cool:
     
    Last edited: Jun 13, 2013
  6. JJ

    JJ Funster

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    Which Kipor do you mean Dave... I have so many...

    Anyway... some people are "Belt and Braces" folk but I am a "Belt and Braces AND Bailing Twine" man. :Wink:
     
    Last edited: Jun 13, 2013
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  7. GJH

    GJH Funster Life Member

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    What, no WD40? :Laughing:
     
  8. icantremember

    icantremember Funster

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    I was given the same info' by the chap who carried out my last habitation check .....
    ... his simple solution (not yet done) was to fit a switch between the solar panel and regulator which should be off whilst traveling.
     
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  9. TheBig1

    TheBig1 Funster Life Member

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    a relay is only an electrically operated switch. so you dont forget to switch off when driving then back on when stopped. just make sure you fit a good quality relay with the right rating.

    very simple job to do realy as you just need to run the ignition feed to the point where you mount the relay and cut the solar feed to install. many vans have this feed already powering a relay to cut 12v power to the hab area when driving. saves running from the cab
     
  10. haganap

    haganap Funster Life Member

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    trust me, its not :Wink:
     
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  11. JJ

    JJ Funster

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    I am aware you can get a relay to switch on when the ignition is switched on and the engine is started but in our case being discussed here we need the relay to switch a circuit off.

    Am I right to suppose there are two types of relay or is it just a matter of the way it is connected?

    JJ :Cool:
     
  12. TheBig1

    TheBig1 Funster Life Member

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    there are various relays, normally open (off till powered) or normally closed (on till powered) and a version with both options, a normally closed and a normally open terminal

    [​IMG]
     
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  13. jonandshell

    jonandshell Funster

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    The Force is indeed with you, young electical jedis!:thumb:
     
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  14. Jim

    Jim Ringleader

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    Ok I with it so far. (just)

    What about the regular fitted charger. When the engines running, this charger comes into play and the battery reads just like it does with the panels, it appears to be charged. Does this have to be knocked out as well for the B2B to kick in?
     
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  15. haganap

    haganap Funster Life Member

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    Yes, on mine it is.

    Others have chose not too. Mine is knocked out, it is the "appropriate" thing to do. :thumb:
     
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