xantrex xw60 mppt as diversion load controller

System
System Posts: 2,511 admin
in Solar Beginners Corner #1
hi guys. i am after some advice on my system that consists of:
1) 8x6 volt trojan t-105's in series for 48v
2) 1.6kw 48v inverter
3) xantrex xw60 mppt
4)3X125 watt conergy panels and 1x125 watt chinese panel in series
5) newly installed hydro turbine currently making 8 amps.
6) 600 watt water heater dump load

i'm still pretty wet behind the ears so please excuse if i'm missing something here.

i hooked the turbine up today and have set the xantrex aux on to switch the dump load on and off.
the trojans have a float voltage of 52.8, so i'm wondering what i should set the cut in and out voltage for the dump load. i currently have it set to activate the dump at 56v and to disengage at 51v. the specific gravity is between 1225 and 1250 indicating they are not yet fully charged. does this then mean i should raise the activation voltage? the charge voltage for the trojans is 59.2 but that seems to be too high if the batteries are near full?

the other thing that's confusing me is that if the batteries do have a large load applied and they discharge to where they need a bulk or absorption phase,won't this aux setting need to be de-activated to allow the controller to do a bulk charge or alternativley raise the activation voltage further so this can happen.
looking forward to any light that can be shed and to knowing more than i do today.
cheers,
ben.
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Comments

  • n3qik
    n3qik Solar Expert Posts: 741 ✭✭
    #2
    Re: xantrex xw60 mppt as diversion load controller

    Guess first question is, can the hydro over speed, if so, will there be any damage or pose a safety problem. If no to both, then a dump load may not be needed.

    I have a wind mill without a dump load. It is homemade with homemade blades. The blades oscillate in high wind, this keeps the RPMs down. The plus side of poor quality hand made parts.
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  • System2
    System2 Posts: 6,290 admin
    #3
    Re: xantrex xw60 mppt as diversion load controller

    the turbine can and will overspeed if it is disconnected from the battery bank,just as i understand most wind turbines will.i do indeed need a dump load as my household load will not always use the available output from the turbine.

    ben.
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