AC Opportunity Load working, BUT there are questions

Options
pyintheye
pyintheye Registered Users Posts: 35 ✭✭
I have been playing with the FM80 AUX Diversion SSR values for 2 weeks or so and have settled on what seems to make sense to me, but I'm looking for comments on what I see happening.
My Battery specs settings are, ABS 59.2V, FL 52.8V, 8- 6V Trojans@ 435AH/48V, BAT TEMP- 53f, 13% CHARGE Rate- 56.5A
Diversion SSR settings- HOLD 15.0, DELAY 3, RELATIVE Volts 0.0, HYST 6.2
CC Current limit set to 80A
HYDRO constant @ 2A
These settings were actually set by ear. Meaning, the Nano Hydro audible pitch tracks the load hits from the SSR Pulses, so this is where it runs the smoothest and holds the voltage with a minimum of fluctuation as the CC AUX DIV adjusts the percentage of current directed to the 3000W/ 240V Hot water tank.
When the sun hits, the BULK Stage starts and will put all the current to the batteries, as it should.
As the Voltage hits 59.2 and activates the AUX, the batteries are at 98% on the BMK SOC.
The Div load hits and the initial voltage drop is around 4-5 volts, settling in at 54-55volts and slowly moving up or down depending on how many Amps of solar is coming in.
If the Voltage climbs back to the 59.2V set point the CC AUX increases the % of current Amps by 11-12Amp increments, to the DIV load.
All the while the BMK shows the batteries getting a charge of +0- 4-6 Amps and briefly falling into minus as the sun fails and the CC AUX re-adjusts the DIV Load current %.
When the Voltage falls to the 52.8 set point (cloud bank) the BULK stage is triggered, so then the sun hits the panels hard(cloud passes) and the Amperage "IN", sometimes spikes to 65-70A, before the 59.2V Upper set point is reached and the AUX DIV takes most of the current from the CC.
BUT
The 65-70A CC spikes, exceed the Battery Manufacturers charge Rate Specs. Although, never for very long and always never constant as the MPP adjusts, BUT, happens frequently on sunny days.
So, as the current is sent from the CC, the Magnum 4448 picks it up first and tries to satisfy the DIV Load set by the AUX %, adjusting. I see this in the flickering lights and I also hear it in the various appliance engines(W/D, DW) as they run in concert with the DIV Load.
So should I be "Happy" it's all working or am I slowly going to fry my batteries and my appliances trying to get " Every last AMP"?

Thanks to all TT
Midnite Panel Box for MS4448PAE, FM60- 720w, FM80- 2340w, 8 Trojan L16H AC- 48V, NH600 Turbine, DHW 2000w opp/div load.

Comments

  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,753 ✭✭✭✭✭✭
    Options
    I would not be happy with any noticeable/measurable effect on the AC produced in an offgrid home. I would use an air source heat pump for diversion or opportunity.
    I think you might be confused though on the current going into your battery. I believe you need to subtract the AC wattage being used from the battery DC current to get the actual amount going into your battery. Once the battery is charged, it should be limiting the amount of current and not "frying" the battery as you say.
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

  • pyintheye
    pyintheye Registered Users Posts: 35 ✭✭
    Options
    I think you might be confused though on the current going into your battery.

    When on BULK charge stage doesn't all the current that the CC's produce go to the batteries?
    TT
    Midnite Panel Box for MS4448PAE, FM60- 720w, FM80- 2340w, 8 Trojan L16H AC- 48V, NH600 Turbine, DHW 2000w opp/div load.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,448 admin
    Options
    Charge controller current - Loads = Battery Current

    You can have the charge controller in Bulk, but the loads consume 10% / 100% / 200% of the available current from the battery bank.

    10% to loads / 90% to battery bank.
    100% to loads / 0% to battery bank
    200% to loads / 1/2 the load current comes from battery bank.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • pyintheye
    pyintheye Registered Users Posts: 35 ✭✭
    Options
    BB. wrote: »
    You can have the charge controller in Bulk, but the loads consume 10% / 100% / 200% of the available current from the battery bank.

    What is happening when there is no load, before, the DIV Load kicks in?
    TT
    Midnite Panel Box for MS4448PAE, FM60- 720w, FM80- 2340w, 8 Trojan L16H AC- 48V, NH600 Turbine, DHW 2000w opp/div load.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,448 admin
    Options
    Charge controller limits current and voltage to battery bank / dc bus.

    Solar panels can be turned off when power is not needed.

    With wind and water turbines, they need constant loads to keep spinning at the correct rpm. If you turn off their electrical loads, they will over speed and self destruct. The diversion load drains extra electricity from the turbine so the battery does not over charge.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,753 ✭✭✭✭✭✭
    Options
    pyintheye wrote: »

    What is happening when there is no load, before, the DIV Load kicks in?
    TT


    If you turned off the DC input to your Inverter, and you had no other DC loads, all of the energy would go into your battery. There is loss in charging batteries and that will be part of the charging 3 step process.

    I am not saying give up on an oil pipe line, but how about a water pipe line down to California?
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net