XW+6048 dropping AC2 qualification and using Generator support

RileyRiley Registered Users Posts: 4

Hi Guys –

 First time caller here, just found your website and I’m glad to add another web-forum to my off-grid resource knowledge base

I have been on other solar web-sites and also stumbled across the writing of ChrisOlson previously. His thinking tended to steer me towards my system sizing when I first built my system 2 years ago.  

Anyway, here’s my problem: when under fairly heavy load on my generator (Bulk charging at over 50% of generator capacity), my XW will disqualify the AC2 input when larger loads switch in and out. I think I can solve this with some adjustments on my XW but I wanted to ensure I didn’t damage anything before tweaking.

 First off, here’s my system components:

  • XW+6048
  • 48V FLA battery bank with 428 A/H capacity at C/20 (Rolls S-550 batteries)
  • Conext MPPT 60 150 charge controller
  • SCP
  • Combox
  • 12 260 solar panels
  • Onan 5KW CCK propane generator (old school but in good shape. I like it as it’s a classic workhorse). That decision and technical support has been from Smokstak.com (another great site). 

So I assume that part of my problem is the response time of the generator when reacting to changes in the load. There’s a brief duration where the Onan needs to adjust to the demands of the load and when that happens, the XW disqualifies AC2. I see there are settings for qualification of voltage and freq. If the load is fairly constant, everything works pretty well. 

Here’s what I would like to do:

  • During Bulk charge (max load), I would like to load the generator at 4KW (don’t want to push it too hard).
    • According to my calculations for charging rates, my bank should be charged at minimum of 42 Amps (10% of C/20 rate) = 2KW plus loads (which are generally low)
  • Use Generator support feature to reduce the battery charge rate for short durations like water pump being switched on.
  • Not have AC2 disqualified when loads switch in/out as it interrupts the Bulk charge process.

My questions: 

  • I read that there are qualification settings for voltage and freq of AC2. I haven’t changed anything settings for fear of damaging the XW due to poor quality AC. Question: if I start to adjust the volt and freq limits (say +/- 5% or  so), do I need to worry about damaging the electronics in the XW with out of spec AC or just the other loads (TV, fridge, water pump ect)?

  • Should I first focus on adjusting Volt or Freq or both?

  •  I had tried to get the Gen Support feature working (enabling and adjusting the ‘GenSupport’ Amps) but it never seemed to do anything. I didn’t adjust the AC2 breaker setting so perhaps that was part of the problem? Anyway it’s time to try again as that was early days when I first installed the system. I assume that the calculations are done at 240VAC and not 120VAC? For example, if I want to limit the load on the genset to 4KW then the GenSupport Amps setting should be: 4000/240=16 Amps (perhaps my problem was that I used 120VAC as the voltage for this calculation).

I realize that I may have to do some work with the governor on my Onan genset but before getting into that, I thought I would loosen up the qualification settings on the XW.

I look forward to learning more from this site as I find this all very interesting for my off-grid mainly seasonal cabin.

Thanks, 

Riley

Off-grid: XW+6048 / 48V FLA battery bank (428 A/H (Rolls S-550 batteries)) / Conext MPPT 60 150 charge controller / SCP / Combox / 12 - 260 solar panels / Onan 5KW CCK propane genset

Comments

  • EstragonEstragon Registered Users Posts: 3,721 ✭✭✭✭✭
    I set max charge rate at ~35adc (10%C/20 on my ~350ah bank) charging with early 1980s vintage 4kw Onan diesel. Could go to more like 50a, but if doing so, I'd turn off loads like pumps.

    My Outbacks cut back charging, but sudden loads at higher output makes it lug a bit until the charging gets dialled back.

    IMHO, voltage and frequency at +/- 10% should be ok.

    I don't have gen support, but my understanding is it's used to supplement generator output with inverter output, so I don't think it would work in charge mode.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • mike95490mike95490 Solar Expert Posts: 8,288 ✭✭✭✭✭
    One issue that comes up with generators, is load balancing.   Problem is one leg of the generator is loaded, the other is not. This can cause voltage fluctuation issues.

    I'll share my 3Kw genset settings with you. (followed by settings for 2Kw eu2000)
     I've set my voltage and freq limits quite widely, so the gen does not get needlessly disqualified if it lags on a surge.

    Battery Bank Capacity 1000 A (1,000A makes for easy, direct conversion to charging amps,
    mistakes are limited to AC2 & Generator Support amps limits)
    Maximum Charge Rate 5-35 A (for Mikes 800ah battery bank

    AC2 Breaker Size 18.5 A (each breaker is only @ 120V so both will add, this setting = a limit of 4680w, internally derated to 3744w)

    Generator Support Enable    Enabled
    Generator Support amps 13.5 A (each breaker is only @ 120V so both will add, this setting = a limit internally  derated to 2515w)
    Generator Support PLUS    Enabled  (this helps greatly with load balancing)

    ST5 on lister 6/1
    AC2 Breaker Size 18.5
    Generator Support amps 13.5

     Honda EU2000i spec  13A   1600w cont, 2kw 30 min
    AC2 Breaker Size 9.0
    Generator Support amps 5.0


    Another 3kw generator I have, has power factor issues, when running my 1/2 hp pump, it's .6 PF pretty much maxes out the generator, and strange things happen if I allow PF to overload the generator.


    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • RileyRiley Registered Users Posts: 4
    edited August 2018 #4
    Thanks guys, I will start by widening out my settings. Then worry about Gen Support. All my big loads are 240VAC (2 water pumps) so each leg should be pretty well balanced I think. Just a fridge and UV filter in the day time. 

    Given the Breaker numbers above and the math examples, I understand that the Amps value should be calculated in terms of 240VAC (not 120VAC). just like you did because you doubled the breaker size (one for each leg). So if I want 4000 watts max, then breaker size should be 4000/240 = 16.6 A
    Off-grid: XW+6048 / 48V FLA battery bank (428 A/H (Rolls S-550 batteries)) / Conext MPPT 60 150 charge controller / SCP / Combox / 12 - 260 solar panels / Onan 5KW CCK propane genset
  • EstragonEstragon Registered Users Posts: 3,721 ✭✭✭✭✭
    Amps are amps (more or less) regardless of voltage. Breakers are there to protect wire, so the size of the wire is what governs maximum breaker size. For example, a 14ga wire should be protected by a 15a breaker.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • mike95490mike95490 Solar Expert Posts: 8,288 ✭✭✭✭✭
    Estragon said:
    Amps are amps (more or less) regardless of voltage. Breakers are there to protect wire, so the size of the wire is what governs maximum breaker size. For example, a 14ga wire should be protected by a 15a breaker.
    Actually, not in this case.   The inverter breaker settings  are for configuring the setpoints that the inverter will use to support the generator, WITHOUT tripping the breakers.   The breakers on the generator and your electrical panel are what protect the wires, these settings are to prevent the generator from being disqualified, and to properly assist it.    Failure to comprehend these setting fully is what causes grief when folks say generator support does not work.  The manual, BTW, is not clear on the internal 20% derating of the settings.    As I use it, the generator can be charging batteries, and running the house, be hit with the blowdryer and will throttle back on battery charge.  When the microwave is on, the inverter kicks in and assists the generator and nothing gets overloaded and computers do not reboot, the inverter syncs to the generator - just as if it were grid tied.  When loads scale back, battery charging resumes seamlessly.

    In my situation, the AC cables are 8 ga, way oversize for this generator, but leaving room for growth.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • Dave AngeliniDave Angelini Solar Expert Posts: 4,486 ✭✭✭✭✭
    I install 6 Gage to protect against future generators. The XW is a 60 Aac  passthru inverter/charger.
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • RileyRiley Registered Users Posts: 4
    Thanks guys. Here's an update. just for the record, my breakers are  sized for my wiring but I want to reduce this because the wiring can handle more than my generator can output.... but anyway.... 

    I am now able to get the generator support feature working properly. The problem was that I never changed the breaker setting from the default. I also think when calculating the generator support limit (in Amps), I used 110V to do the math and not 220V. 

    It seems to be working perfectly now in that it will dial back the battery charging to limit the load on the generator (even under heavy loads). Then the loads are removed, the charge current jumps back up. 

    Perfect.... now to tweak my generator. 

     
    Off-grid: XW+6048 / 48V FLA battery bank (428 A/H (Rolls S-550 batteries)) / Conext MPPT 60 150 charge controller / SCP / Combox / 12 - 260 solar panels / Onan 5KW CCK propane genset
  • BB.BB. Super Moderators, Administrators Posts: 29,229 admin
    Famous last words, Riley.
    It seems to be working perfectly now in that it will dial back the battery charging to limit the load on the generator (even under heavy loads). Then the loads are removed, the charge current jumps back up. 

    Perfect.... now to tweak my generator. 
    Best wishes, and have fun,

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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