all wet, going full sun

sam c
sam c Registered Users Posts: 16
new to forum, been off grid for a couple of years, running hydro, 12vdc system, current system--- 10 golf cart batt--c60 charge controler--- xantrex dr 1512 inverter, system been working great, but now the creek is going dry, northen ca.
just bought 8 215watt pv,( $ 1,65 a watt) the problem is the panels are 48v,
question-- is there an easy fix
thanks for any help Sam

Comments

  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: all wet, going full sun

    Use a MPPT controller, like the MX 60.

    Tony
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: all wet, going full sun

    With modern MPPT (Maximum Power Point Tracking) solar charge controllers, the 48 VDC is not a problem any more--in fact, it is actually an advantage.

    Take a look at the Outback and Xantrex MPPT controllers. Morning Star also has a very nice, new model, MPPT controller--but it is for smaller installations.

    Basically, as long as your Vmp of the solar panel is between Vbat+2v<Vmp<145 volts (150 Vmax or Voc), the controller will convert (switch mode power supply) from the higher panel voltage (and lower currents) to lower voltage and higher current.

    In general, the output current is what limits the "size" of a MPPT solar charge controller... For example, a very popular one is 60 amp limited.

    For a 12 volt battery:

    15v*60a=~800 watt maximum power output

    For higher voltage systems:

    30v*60a=1,800 watt (24 volt system)
    60v*60a=3,600 watt (48 volt system)

    The nice thing about the MPPT controllers--it is a simple programming change to support different battery bus voltages.

    I guess you are at 12 volts right now--but if you plan on using more than ~100 amps (1,000 watts), you should think about changing to a higher voltage battery bank... Of course, the downside is new inverters and hydro pump/controller (if not programmable)...

    The MPPT controllers are fairly complex--so you will probably have more questions than answers after reading this post--but I suggest that you visit the vendors' websites and read about the controllers, how they work, and the various options. And download the manuals too...

    Also, make sure that you buy the optional Battery Temperature Sensor option too... Will be much better charging control for your batteries.

    Lastly, if you have issues with knowing the state of charge of your battery bank--take a look at a Battery Monitor (Xantrex XBM has a good set of functions--I like the functions of the new LinkLite and LinkPros). Besides not adding distilled water and keeping the bank clean--under and overcharging are the two most "popular" methods for killing batteries.

    Have fun (sounds like nice place!)
    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset