How to know my controller is a MPPT or PWM controller

sabahansabahan Posts: 2Registered Users
I am switching my estate labour quarters from fossil fuel electricity to solar,I wish to use MPPT solar controller for the setup,local supplier supply the controller mostly are from china,although it stated that it is MPPT controller,but the pricing let me suspect it is not,I know those branded controller are good,but I'm buying 120 unit,well beyond my budget,can anyone help?

Comments

  • mcgivormcgivor Posts: 2,203Solar Expert ✭✭✭✭✭
    There are some Chinese controllers that are fake MPPT whilst others are genuine, can you provide links or make and model numbers, this would be helpful.  
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery bank 

  • littleharbor2littleharbor2 Posts: 1,027Solar Expert ✭✭✭✭
    edited September 3 #3
    Here's one of the fake units. These are typically about $45.00 or so. Anything less guaranteed fake. The real ones online pricing start about $120.00 for the basic imported models.

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric, 700 ah @24 volt AGM battery bank. Plenty of Baja Sea of Cortez sunshine.

  • EstragonEstragon Posts: 2,838Registered Users ✭✭✭✭✭
    Not definitive, but maximum recommended pv string voltage for the controller can be suggestive.

    Mppt CCs are used to take higher string voltages (eg ~100-150v) down to battery (12-48v nominal) voltage. PWM just pass pv voltage, so strings would be a bit above charging voltage (eg 60v pv for a nominal 48v bank). An mppt would want more like 90+v to work reliably.

    Self-consumption (idle) is also suggestive. Pwm should be lower (typically milliwatts) vs mppt which could be low single digit watts.
    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
  • sabahansabahan Posts: 2Registered Users
    Thank you,found the above solar controller in Aliexpress.com,it cost only 46 dollar ,will it be a fake product?
  • mcgivormcgivor Posts: 2,203Solar Expert ✭✭✭✭✭
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery bank 

  • jonrjonr Posts: 1,074Solar Expert ✭✭✭✭
    edited September 4 #7
    MPPT (holding the panel at Vmp) is only part of what's important.  When people say MPPT, they typically also mean a buck DC-DC converter.  This requires a  somewhat heavy, more expensive coil and heat sink.

    I always found this inaccurate use of "MPPT controller" odd. 

  • MichaelKMichaelK Posts: 79Registered Users ✭✭
    Honestly, one strategy I use is the unit's weight.  If it's shipping weight is 8oz, it's fake.  If it's 8lbs, it likely to be a legitimate MPPT controller. 
    15 Renogy 300w panels,  Midnight 200 CC, 8 Trojan L16 batteries, Schneider XW6848 NA inverter, AC-Delco 6000w gen.
  • NANOcontrolNANOcontrol Posts: 78Registered Users ✭✭
    A bigger question is how do you know it actually works. I bought one that is on a 60V PV array into a 12V battery. Every once in a while I see it drop to 16- 25V. Not just for a little while, but 5 to 10 minutes. Disconnect the panels for 3 seconds and reconnect. Voltage goes up to 60ish volts and power increases over 40%.  I don't think you call that tracking. Of course, anything with a digital display just has to be believed.  I think a lot of MPPT algorithms suck and people don't know it.
  • oil pan 4oil pan 4 Posts: 751Solar Expert ✭✭✭✭
    If you got the same amps going through it it's pwm, of its got more amps going to the battery than being made by the solar panels it's mppt.
    You are paying for the ability step up or step down DC power like AC systems can.
    You know get about 130% the output of a pwm unit.
    I only keep pwm units around for backup, because they are cheap and can handle a lot of amps but aren't nearly as efficient.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • EstragonEstragon Posts: 2,838Registered Users ✭✭✭✭✭
    With properly matched panels in a moderate climate, PWM can be at least as efficient as mppt, and possibly more so. I use both - trying to use the right tool for the job.
    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
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