Need information for outback instalation

Hello, we are new on this site, we are a Dutch couple living in Mexico and we just installed an solar panel installation and i found this site.
Our goal is lower the elec bill and have power when the grid is down.

So we build a grid interactive battery back up system.

15 ERDM 235 w panels ( 5 string of 3 panels )
Outback 3648 LA inverter ( special for Mexico )
Flexmax 80
Hub and mate 3
48 volt battery bank Rolls surrette AGM 3 x 12 V 127 A/H ( just for emergency,s )

We like to extend the live time of the battery,s

The system is performing very well, low sun angle now and still 10 KW a day ( panels facing due north at an angel of aprox 27 degrees ) [probably 10 kWH per day? -Bill]

Is there somebody to give us some answers, we will appreciated that very much.

Questions

1) did we build a good system ? do we make mistakes ?
2) Ho do i set the setting for long battery life time, no cycling or at les at possible at a low level ! battery voltage is at system sleeping in the early morning 51,4 V
at the moment i have 54,4 V float and 58 V absorb, but now the confusion if i adjust the flexmax at max charging rate for this battery,s 23 A, i lost a lot of power because the inverter scale down ( set it at 80 amps now but are afraid for over charing in bulk state when start up )
3) start up mode 0, 1 or 2 ( now at 2 )
4) time setting for float and absorb

I,am a bit confused whit the setting manuals of the inverter , mate an Flexmax.

Please advise.

Regards

Ps: sorry if I,am in the wrong topic

Comments

  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Need information for outback instalation

    Welcome to the forum.

    I'd say this is the right category since this is a grid interactive system.

    The inverter is an FX3648 LA not GFX right? No "sell back" to the grid?

    Fifteen 235 Watt panels is 3525 Watt array, probably capable of 55 Amps peak current on the FM80 in Mexico's climate.

    Your battery bank doesn't make sense as "3 x 12 Volt": to get 48 Volts there must be four 12 Volts. And 127 Amp hours is pretty small. Do you know the model of these batteries? To get the best charging parameters we'd need to know this. Surrettes, as a rule, like slightly higher than normal charging Voltage.

    The array you have would support 550 Amp hours @ 48 Volts, which is quite a lot of capacity. At 25% DOD it would be about 6.6 kW hours.

    Outback's programming is complicated indeed. With the FM80 and FX3648 connected via the HUB and MATE you can get them to agree on important things such as battery Voltage. A remote temperature sensor is a must have here.

    I would set the FM80 as the primary charge source. You can set limits for the maximum charge current as well as End Amps (again, we need to know the exact batteries) as well as the time limits (it will 'count up' during Bulk and adjust the Absorb time accordingly, but you need a maximum limit). Then the inverter can be programmed to follow the FM or set with slightly lower Voltage points so that it doesn't do much charging. The inverter also has settings for charge Amps (in AC - has to be converted to DC by a factor of about 2.5).

    So further info all hinges on exactly which batteries you have.
  • BB.BB. Super Moderators, Administrators Posts: 29,002 admin
    Re: Need information for outback instalation

    Do you have a Hydrometer to measure the battery bank's specific gravity? Depending on the specific battery type and your overall operating conditions, you may need to run the charging voltage a bit higher to get the batteries fully charged (some folks here have reported that they where undercharging their battery bank if they used standard charging voltage settings for their banks).

    My first suggest would be to get a good quality hydrometer (and thermometer) and measure/log the specific gravity for your battery bank and let us know what the the temperature corrected numbers are.

    I would also suggest that you get a DC Current Clamp meter (Sears US sells a "good enough" one, really a full Digital Multi Meter, for ~$60 USD). And start measuring the cell/battery voltages too. What you are looking for is "differences" between identical batteries. If you find differences, you need to figure out why there are differences and how to correct them.

    Also, you might find a battery monitor handy too... Makes it much easier to manage a battery bank day to day without having to use a hydrometer every time you want to know the estimated state of charge for the battery bank (Victron also has a good battery monitor, and Outback sells an integrated battery monitor system too). Note that battery monitors can drift if a battery bank is not fully recharged every few days/several times a month.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • SofiaSofia Registered Users Posts: 4
    Re: Need information for outback instalation
    Welcome to the forum.

    I'd say this is the right category since this is a grid interactive system.

    The inverter is an FX3648 LA not GFX right? No "sell back" to the grid?

    Fifteen 235 Watt panels is 3525 Watt array, probably capable of 55 Amps peak current on the FM80 in Mexico's climate.

    Your battery bank doesn't make sense as "3 x 12 Volt": to get 48 Volts there must be four 12 Volts. And 127 Amp hours is pretty small. Do you know the model of these batteries? To get the best charging parameters we'd need to know this. Surrettes, as a rule, like slightly higher than normal charging Voltage.

    The array you have would support 550 Amp hours @ 48 Volts, which is quite a lot of capacity. At 25% DOD it would be about 6.6 kW hours.

    Outback's programming is complicated indeed. With the FM80 and FX3648 connected via the HUB and MATE you can get them to agree on important things such as battery Voltage. A remote temperature sensor is a must have here.

    I would set the FM80 as the primary charge source. You can set limits for the maximum charge current as well as End Amps (again, we need to know the exact batteries) as well as the time limits (it will 'count up' during Bulk and adjust the Absorb time accordingly, but you need a maximum limit). Then the inverter can be programmed to follow the FM or set with slightly lower Voltage points so that it doesn't do much charging. The inverter also has settings for charge Amps (in AC - has to be converted to DC by a factor of about 2.5).

    So further info all hinges on exactly which batteries you have.

    Thanks for quick reaction.

    Sorry it is 4 x 12 V battery , type AGM S12 128
    Float 13,6 13,8
    Cycle 14,5 14,9

    Inverter is a sell back type GVFX 3648

    Battery's are only for short grid down situations , are common in Mexico , something between a couple of minute a 2 a 3 hours , for longer of grid we have to shut down parts of the house ., just a bit LED light and the fridge some teli , i calculated that i have 2 KW a night for 50% discharge in case of emergency.

    I have 2 sensors one in the inverter and one in the FM 80
  • SofiaSofia Registered Users Posts: 4
    Re: Need information for outback instalation
    BB. wrote: »
    Do you have a Hydrometer to measure the battery bank's specific gravity? Depending on the specific battery type and your overall operating conditions, you may need to run the charging voltage a bit higher to get the batteries fully charged (some folks here have reported that they where undercharging their battery bank if they used standard charging voltage settings for their banks).

    My first suggest would be to get a good quality hydrometer (and thermometer) and measure/log the specific gravity for your battery bank and let us know what the the temperature corrected numbers are.

    I would also suggest that you get a DC Current Clamp meter (Sears US sells a "good enough" one, really a full Digital Multi Meter, for ~$60 USD). And start measuring the cell/battery voltages too. What you are looking for is "differences" between identical batteries. If you find differences, you need to figure out why there are differences and how to correct them.

    Also, you might find a battery monitor handy too... Makes it much easier to manage a battery bank day to day without having to use a hydrometer every time you want to know the estimated state of charge for the battery bank (Victron also has a good battery monitor, and Outback sells an integrated battery monitor system too). Note that battery monitors can drift if a battery bank is not fully recharged every few days/several times a month.

    -Bill

    Battery's are brand new and are AGM type no hole to stick a hydro meter in.

    I have a multimeter and al are the same, i corected the FM80 voltage reading .
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Need information for outback instalation

    If you are selling back to the grid 128 Amp hours of battery isn't going to work. It will allow too much AC ripple on the input of the inverter causing it to switch in and out of sell too rapidly. If you leave this function off there is no point in having that 3.5 kW array as those small batteries sure don't need it.

    I'd recommend upping the battery bank capacity to over 350 Amp hours. I don't think you'll ever be happy with the function using a smaller bank.
  • BB.BB. Super Moderators, Administrators Posts: 29,002 admin
    Re: Need information for outback instalation

    Oops--Sorry, AGM. :blush:

    Anyway--I would highly suggest the Battery Monitor. It is one of the few ways to really know what is going on with an AGM battery bank (from the battery's point of view).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • SofiaSofia Registered Users Posts: 4
    Re: Need information for outback instalation
    If you are selling back to the grid 128 Amp hours of battery isn't going to work. It will allow too much AC ripple on the input of the inverter causing it to switch in and out of sell too rapidly. If you leave this function off there is no point in having that 3.5 kW array as those small batteries sure don't need it.

    I'd recommend upping the battery bank capacity to over 350 Amp hours. I don't think you'll ever be happy with the function using a smaller bank.

    Sorry i do not understand your commend, i observed the inverter the whole day and he is selling continue .

    If the battery are full the FM80 delivered power on demand of the inverter and/or ac load if i understand it well .

    As i understand it is this the GT mode in the mate and HBX mode.

    Please have patient
  • westbranchwestbranch Solar Expert Posts: 5,136 ✭✭✭✭
    Re: Need information for outback instalation

    If you can read German here are some links to the manuals, sorry could not find a Dutch version.

    http://www.outbackpower.com/pdf/manuals/FLEXmax_Overview,_German.pdf

    http://www.outbackpower.com/pdf/manuals/900-0131-04-00_Rev_A.pdf

    and the international Installation manual ,in English http://www.outbackpower.com/pdf/manuals/GTFX_installation_international.pdf

    hth
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • BB.BB. Super Moderators, Administrators Posts: 29,002 admin
    Re: Need information for outback instalation

    I guess the two points are:

    First, is it legal in Mexico to Grid Tie a solar power system... And does their power meters/billing support GT solar (some power meters will run backwards, others will not run backwards, and newer ones may run forward when backfeeding energy to the grid--charging you for putting energy onto the grid).

    The second point is if the battery bank is too small--It is possible to have secondary problems. First, the batteries may tend to wear out faster with a large solar array and GT inverter (the batteries sort of act a bit like a capacitor storing energy for 120th of second (part of a 60 Hz wave form). Also, with large surge currents (either from the array/MPPT charge controller, or from the GT Inverter/or going off grid during a power failure), the smaller battery bank may go over voltage (too much charging current) or under voltage (too much surge current) given the size of the rest of your system.

    The 100 AH battery capacity (at 48 volts) for every ~1kW of Hybrid inverter output or for every ~1kW of solar array seems to be conservative enough to support the overall system requirements for the life of the battery bank.

    For your 3.5 kW of solar panels and 3.6 kW of hybrid AC Inverter would suggest a minimum battery bank of around 350 to 360 AH @ 48 volt for long battery life and best operation.

    If your system is working OK for you now (your battery bank voltage is stable during the day, and your night time/emergency loads are relatively light), then see what happens.

    AGM Batteries are very good for surge power (supporting a large AC Inverter load), but appear to have less "charge surge" tolerance (they are just like flooded cell batteries, when the bank is 100% full, there is no where that the extra power can go--so it can over voltage the battery bank/Hybrid inverter in some cases--A lot of variables here--So not saying your system will not work with a smaller AH battery bank, just keep an eye on the system and make sure everything is going OK).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Need information for outback instalation

    The Absorb set point may be a bit high for the AGM batteries. Generic settings would be Absorb @ 56.8 and Float at 54.4. Be sure you get the right info from the manufacturer as you don't want the batteries to vent and lose electrolyte.

    With 128 Amp hours you have about 4kW hours back-up power taken to 50% state of charge.
  • westbranchwestbranch Solar Expert Posts: 5,136 ✭✭✭✭
    Re: Need information for outback instalation

    some data from Rolls:

    Deep cycle' refers to applications that typically discharge 60-80% of the battery capacity and the Rolls AGM Deep Cycle Battery Range feature thick plates with a high-density active material.

    This design allows for reserve energy to be stored deep within the battery plates and released during slow discharge.

    Leak-proof and safe transportation
    Glass mat and plates totally absorbed for high efficiency
    Design includes 99% recombination
    Better performance and service life
    At 50% discharge - 600 cycles
    Recover capacity even after repeated deep discharge
    Fast acceptance to recharge from alternator or boost charge


    Rolls S12-128AGM 13V Deep Cycle Battery

    Capacity in Ah @ C20: 115
    CCA @ 32°F: 1200
    CCA @ 0°F: 1000
    Terminal type: M8-TP08
    Dimensions (L x W x H): 330 x 172 x 215 mm (to battery lid)
    Weight: 33.0 kg

    Cycle charging 14.5 -14.9 V
    Float charge 13.6 - 13.8V


    http://rollsbattery.com/public/specsheets/spec_77.pdf
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • gww1gww1 Solar Expert Posts: 963 ✭✭
    Re: Need information for outback instalation

    you mentioned that you have two sensers hooked up. One to the inverter and one to the charge controllers. Are you talking about battery heat sensers? If you are and you have your system hooked up through a hub, I believe you are only supposed to have one senser hooked to the inverter not two. If I am wrong would someone please correct me.
    Thanks
    gww
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