PV Batt charger amperage question

Discussion in 'The Projects Forum' started by Dominick, Feb 13, 2009.

  1. Dominick

    Thread Starter Member

    Dec 6, 2008
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    0
    I'm looking into building this circuit
    http://www.solorb.com/elect/solarcirc/scc3/index.html

    Can I add a few more Q2s to up the charging amps hmmm
    now that i look at it a few Q2 and D1s in parallel?

    Also what is TZ1 hes calling for a V470 or a V747 I cant seem to
    find any data sheets on these.
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    The TZ is a transient surge absorber. Adding more current passers will increase the output current capacity if:

    1. you have the added photovoltaic cells to source it.

    2. you change connectors to accommodate the extra current.

    3. your batteries can handle the extra charging current without damage.
     
  3. Dominick

    Thread Starter Member

    Dec 6, 2008
    28
    0
    Is there a suitable replacement for the V470 and V747 I cant seem
    to fined these two.

    Current passers would I be adding more of Q2 and D1 or is it Q2, D1, R14, R18, and Q1?
     
  4. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
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    The transzorb is to eliminate voltage spikes. Anything with a breakover of 50 volts and capable of handling the PC output will do as a sub.

    Do you satisfy my 3 conditions above? Simply adding more FET's won't magically cause greater current flow - you have to be able to source it.

    If you look at the data sheet for the IRF4905 you will see that it is rated for 74 amps - I doubt if you will need extras if the charger operates the circuit with clean transitions between on and off states in the FET.
     
  5. Dominick

    Thread Starter Member

    Dec 6, 2008
    28
    0
    Ok here is the system:

    each row is 17volt 3.5 amp
    116 rows should give me 406 amp 17volt or 6.9 KWh is my math on this right?

    Now I just have to figure out what batt bank i need if the batts are
    6V 225AH I know ill need a series/parallel batt bank.
     
  6. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    Why do you want to power an entire city from batteries charged by a few million dollars worth of solar panels?
    What will the circuit do when it is cloudy? Nada?
     
  7. Dominick

    Thread Starter Member

    Dec 6, 2008
    28
    0
    lol ok that just sounds funny the way you put that.
    and by your reaction whats o normal KWH of panels for an average sized home?
     
  8. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    What size entry panel do you have? 200 amps has become pretty standard, or 24 KW.

    Remember that the conductors are sized for 120 VAC feed, and will burn up trying to deliver comparable power at only 6 VDC. Plus the AC motors in appliances won't run on DC

    If you want to keep going, check E-Bay for surplus submarine batteries.
     
  9. Dominick

    Thread Starter Member

    Dec 6, 2008
    28
    0
    The system will be 12 volt 6volt batts series/parallel for my AC needs
    I will be going with inverters.
    Will keep the inverters as close to the batts as possible and will put in
    a DC sub panel for those DC needs.

    I do not have the panels yet.
     
  10. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    There are any number of people who have done such things. You might look on the web for special interest groups and alternate energy sites.
     
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