Silly Question 2 - Control Panel Battery State

Discussion in 'Solar Power' started by EssexBoy, May 26, 2015.

  1. EssexBoy

    EssexBoy Funster

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    Hi All
    As a follow on from my first question about planning my solar install, my question is about how my van's control panel will work if I "bypass" it by having a solar panel->solar controller->batteries setup.

    Currently, the van's control panel shows hab & cab battery voltages when in use off-EHU & charging voltages when on-EHU. This is straightforward for me to know how much power I left have when off-EHU by the voltage/discharge chart, but it just struck me that after I have installed the solar panel, the van's control panel will effectively be showing a charging voltage constantly (well, during the day, anyway)
    So, in my situation, how will I be able to tell the state of my batteries charge?

    Thanks in advance, again

    Steve
     
  2. andy63

    andy63 Funster

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    the simplest way to know what is going on with your batteries is to fit a good power management panel..
    that will show the current draw or charge current from or to the battery bank, and record the amp hour usage from the batteries..
    during the day I can see what the solar is replacing after a nights usage and whether it totally recharges the batteries... takes the guess work out of what is going on..
    not sure if they all work in the same way, but installing mine involved fitting a large shunt on the positive feed from the batteries..
    I find it really handy... you can monitor the current draw of any device you switch on, and often reminds me that ive got something on that should be off just at a glance..
    that was my solution, rather than just rely on looking at voltages..
    ta andy
     
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  3. Tom A

    Tom A Funster

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    Hi Andy.
    I'm going to have same set up and sorry to appear thick but what's a "large shunt" and where do I buy one from ?
    Cheers Tom.
     
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  4. andy63

    andy63 Funster

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    Sorry ..The shunt is just a large metal bar of a known resistance.. as current flows through it you get a volt drop.. that volt drop relates directly to the current flow..
    Ohms law and all that lol.. .. The panel displays this and gives the amp hr usage.. In my case 1 mv equates to 1 amp..
    If you get a power management panel I'm sure you will get a shunt with it...I'm not sure if there are other more sophisticated / electronic means of doing the same thing..
    Hope that makes sense. ..
    Ta andy
     
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  5. EssexBoy

    EssexBoy Funster

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    Thanks for the suggestion Andy...

    I don't think I want to go to all the effort & cost of a power management system just to see the "real" battery voltage, so perhaps I'll just alter my routine to check voltage after the sun goes down..

    I already know that I can go 3 days off-EHU and no driving, so with the solar boosting input I don't see us having any issues...

    Thanks again...
     
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  6. andy63

    andy63 Funster

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    I put mine in at the build stage (self build) so was easy enough...
    It doesn't just show voltage.. It shows current flow and amp hours used and replaced ...but yes can understand that it may be too much expense and effort
    Ta Andy. .
     
  7. jockaneezer

    jockaneezer Funster

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    Could you not wire the solar in through your on board panel and utilise it's display ? I think Sargent's and Electroblok's have this facility ?
    I'm trying to do just this with a Schaudt solar controller through my E-Box but haven't worked out the best way yet.
     
  8. EssexBoy

    EssexBoy Funster

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    I stand to be corrected as usual :) but I think the Laika control panel is quite a simple thing and doesn't support a solar input
     
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