Xantrex mppt 60a Operating temp vs output

MichaelB
MichaelB Registered Users Posts: 16
Hello All.

I have a XW6048 and two MPPT 60A charge controllers mounted on the wall in the garage in FTWorth Tx. I noticed while reading specs on both units that Air Temp drops power efficiencies quickly 50-70' F temp. The Charge controllers show at 45F full power is available at 3.5kW and at 60F its down to 2.5kW and falling

My Garage air is at 95F and my laser temp reader shows the heat sinks at 119F on the controllers

XW in full sun is at 4.0 - 4.5kW production when selling to grid so the numbers seem right on with what the manual says.

In winter my garage is about 50F and even with a lower sun and tilt panels I am making 5.6kW to 6k in the dead of winter which is great.

So,,, Thats a lot of loss based on Air temp.

I have a 4" pvc pipe tapped into the home via the wall and a 4" PC fan blowing air at maybe 50cfm which does connect to the vent holes under my midnite solar e-panel perfectly. Air temp is at 80F at bottom of inverter and 105F at the top
Best I can do for now.

Im not able to put cool air on the chargers tho due to the low cfm

I can try to find a larger fan or try to contain all the solar units in an enclosed air space and push a a/c duct into the area from the home but would have to return the air back to the home.
Or

I can look into moving the solar inverter and chargers into the basement which would require about 12foot of 4-0000 battery cables. Be some work but the air temp on the other side of the wall is maintained at 75F.

Comments

  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,729 ✭✭✭✭✭✭
    Re: Xantrex mppt 60a Operating temp vs output

    95 F is also going to shorten your battery life! The heatsink temp is not that high in my opinion. Obviously lowering the air temp is your main problem! Many people in the south west just accept high summer temperature as the cost of doing this offgrid. But it does not make sense grid-tied! You need to move the system or cool the environment to 80F. Good Luck! Also the air temp is also dropping outside which may be a big part of your loss data!
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    Re: Xantrex mppt 60a Operating temp vs output

    Your reduced output isn't the charge controller doing, it works to 45C for 60 amps, its the heat is dropping the voltage on the solar panels and hence the watts being harvested.
  • MichaelB
    MichaelB Registered Users Posts: 16
    Re: Xantrex mppt 60a Operating temp vs output

    At noon I can take a reading on the panels at see what temp they are at.

    According to Kyocera 110F on the panel is taking about 1.5amps off per unit and
    best temp is below 75F . Guess spraying a 70F water hose on them at ground level wont help much.
  • MichaelB
    MichaelB Registered Users Posts: 16
    Re: Xantrex mppt 60a Operating temp vs output
    95 F is also going to shorten your battery life! The heatsink temp is not that high in my opinion. Obviously lowering the air temp is your main problem! Many people in the south west just accept high summer temperature as the cost of doing this offgrid. But it does not make sense grid-tied! You need to move the system or cool the environment to 80F. Good Luck! Also the air temp is also dropping outside which may be a big part of your loss data!


    Batteries I can pump AC into that box and let the air just vent outside.
    We are in the middle of a heatwave this week in N.Texas so my numbers are down about 1kW at any given time.
  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,729 ✭✭✭✭✭✭
    Re: Xantrex mppt 60a Operating temp vs output
    MichaelB wrote: »
    Batteries I can pump AC into that box and let the air just vent outside.
    We are in the middle of a heatwave this week in N.Texas so my numbers are down about 1kW at any given time.

    Most all solar panels have a negative temperature coefficient. The output will go down with increased temperature. Where I live it is about 20% less on very hot afternoons compared with winter temperatures. This is normal !
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    Re: Xantrex mppt 60a Operating temp vs output

    On my roof the panels get 65C+ range with 35F ambeint air, very typical in the summer., panels rated output is specified at 25C cell temperature.
  • GreenerPower
    GreenerPower Solar Expert Posts: 264 ✭✭✭✭✭✭
    Re: Xantrex mppt 60a Operating temp vs output

    Something changes in the LoneStar state this year, my array this summer generates close and slightly exceeding name plate wattage at high noon sun. It used to be 15% - 20% less last few summers.
    GP
  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    Re: Xantrex mppt 60a Operating temp vs output

    Probably the accuracy of how you measure it, not the actual power being harvested
  • MichaelB
    MichaelB Registered Users Posts: 16
    Re: Xantrex mppt 60a Operating temp vs output

    At 1pm my panels backside were 147F ( ground mount ) so I dont have any roof influence with heat load.

    Charge controller was at 135F each with air temp in garage at 98F

    Inverter was 109F on the top with 4.0kW production.

    Im going to build an air tight box to hang on the wall over the electronics and push 78F or less air into the box and chill the hardware to see what diff that might make..or not.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Xantrex mppt 60a Operating temp vs output

    Temperature should not have much effect on the efficiency of the charge controller--although, reducing the temperature can certainly increase life...

    The typical engineering rule of thumb is for every 10C (18F) reduction in temperature, you will get a 2x increase in life. 20C reduction, 2*2=4x increase in life.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    Re: Xantrex mppt 60a Operating temp vs output

    57C is no where near the maximum the charger can safely operate at. Its simple math, the voltage goes down with heat, your panels at 64C or 39C over what the panel listed specifications.

    In general terms , you lose about 0.5% for every degrees C over standard ( 25C ) on Silicon Solar Panels , so you looking at close to a 20% reduction which is very typical

    At most it might be 0.25 to 0.5% less efficient at elevated temperatures ( charger and inverter ), but it depends on the step down ration of Vin to Vout on the charger

    You will just be wasting energy trying to force cool the electronics, they are designed to run just fine at the temperatures you have listed
  • GreenerPower
    GreenerPower Solar Expert Posts: 264 ✭✭✭✭✭✭
    Re: Xantrex mppt 60a Operating temp vs output
    Probably the accuracy of how you measure it, not the actual power being harvested
    Well! same HW, same SW. So, this is the same set HW/SW reports this summer relative to past summers (from the I/V input side reported by the MX).
    Hmm! maybe it's time to get a Volt meter and an amp clamp to check the accuracy of what being reported.
    GP
  • blackswan555
    blackswan555 Solar Expert Posts: 246 ✭✭
    Re: Xantrex mppt 60a Operating temp vs output
    Xantrex mppt 60a Operating temp vs output
    Not speaking from experience, cause I do not look after any of them, but from general electronics and a question I asked Outback once,
    Firstly electronics do not like hot and lose efficiency the hotter they get.
    My question to OB,
    What is the difference between the MX an the FM series charge controllers, ( I had found some old stock MX 60`s :D)
    Their reply was the MX series CC was rated @ 25 deg c and drops off quite sharply, they recommend to de-rate 1 amp per deg C as a rule of thumb, & for altitude PG 65 http://outbackpower.com/pdf/manuals/mx60_pv_mppt.pdf , The later model FM series is rated at 40c so does not suffer from heat so much,
    As I said , I do not have any "hands on" with Xantrex, But noting the other similarities with OB, may be a point ?

    Have a good one
    Tim

    As mentioned, don`t forget to factor in the panel temp vs efficiency, about 1/2 % a "C" above 25c check plate for exact %
  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    Re: Xantrex mppt 60a Operating temp vs output
    Well! same HW, same SW. So, this is the same set HW/SW reports this summer relative to past summers (from the I/V input side reported by the MX).
    Hmm! maybe it's time to get a Volt meter and an amp clamp to check the accuracy of what being reported.
    GP

    The OB MX-60 reported watts accuracy is very poor, I have seen anywhere from -10% to +30% and I have over the years tested 6 different units. You can be certain, your array isn't putting out STC watts in the summer heat
  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    Re: Xantrex mppt 60a Operating temp vs output
    What is the difference between the MX an the FM series charge controllers,
    Tim

    There is no difference in the hardware, they are identical, the attempt at dynamic mppt tracking firmware is what makes the MX unit a FM unit ( this is for the 60 amp version ). The FM-80, has a fan stuck on the top to make the 60 amp hardware become a 80 amp unit magically :roll:

    As for the XW, it was designed from day one to be convection cooled and run to full specifications in an ambient air of 45C. The differences in efficiency running the unit in a hot environment is minimal, about 0.5% ( so 97 vs 97.5% was an example ) , and all of the above is from lab testing, no guessing here
  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,729 ✭✭✭✭✭✭
    Re: Xantrex mppt 60a Operating temp vs output
    There is no difference in the hardware, they are identical, the attempt at dynamic mppt tracking firmware is what makes the MX unit a FM unit ( this is for the 60 amp version ). The FM-80, has a fan stuck on the top to make the 60 amp hardware become a 80 amp unit magically :roll:

    As for the XW, it was designed from day one to be convection cooled and run to full specifications in an ambient air of 45C. The differences in efficiency running the unit in a hot environment is minimal, about 0.5% ( so 97 vs 97.5% was an example ) , and all of the above is from lab testing, no guessing here

    I had an MX 60 when it came out and an fm at a clients house. I have never done any open the box testing on either of these products SG. It just blows my mind that people can't see the improvements of the xwcc, the morningstar cc and even the apollo cc @ 200vdc. The major anomalies of the outbacks do not exist!

    For anyone experiencing large power delta's I would suggest torquing all your dc breakers or replacing if needed.
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

  • MichaelB
    MichaelB Registered Users Posts: 16
    Re: Xantrex mppt 60a Operating temp vs output

    I can recheck the breakers but I did find them loose this spring and corrected. They are only 1yr old and clean.

    Im sure its heat. Power production is down 20% like the other post mentioned.

    Im not planning on wasting power to only gain it back but I will try to keep the electronics cooler to help extend life which I have tapped of the air plenum in the basement for that.

    Maybe Ill put a 12vdc fan on top of the controllers just to move some air..
  • boB
    boB Solar Expert Posts: 1,030 ✭✭✭✭
    Re: Xantrex mppt 60a Operating temp vs output

    Kind of related... SG, what does this mean, on the XW60 spec sheet ? The part that says "full power" ?
    Does it mean that it will put out 60 Amps at all nominal battery and PV input voltages. even up to 45 C ? just curious... I figure you would likely know.

    "Operating temperature range (full power) -4 to 113 °F (-20 to +45 °C)"

    boB
  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,729 ✭✭✭✭✭✭
    Re: Xantrex mppt 60a Operating temp vs output
    MichaelB wrote: »
    I can recheck the breakers but I did find them loose this spring and corrected. They are only 1yr old and clean.

    Im sure its heat. Power production is down 20% like the other post mentioned.

    Im not planning on wasting power to only gain it back but I will try to keep the electronics cooler to help extend life which I have tapped of the air plenum in the basement for that.

    Maybe Ill put a 12vdc fan on top of the controllers just to move some air..

    If the breakers were loose, and I mean loose, you should shut down the source and inspect the cable end and the connector in the breaker for arch damage. It may be easier to replace it for test purposes and inspect it later.

    I pull 63 amps @ 24v on a regular basis thru the xwcc and it does not care what the temperature is so I go back to what I and others first posted! You panel output is lower in the summer heat. This is a no brainer!
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,729 ✭✭✭✭✭✭
    Re: Xantrex mppt 60a Operating temp vs output
    MichaelB wrote: »
    Hello All.

    I have a XW6048 and two MPPT 60A charge controllers mounted on the wall in the garage in FTWorth Tx. I noticed while reading specs on both units that Air Temp drops power efficiencies quickly 50-70' F temp. The Charge controllers show at 45F full power is available at 3.5kW and at 60F its down to 2.5kW and falling

    My Garage air is at 95F and my laser temp reader shows the heat sinks at 119F on the controllers

    XW in full sun is at 4.0 - 4.5kW production when selling to grid so the numbers seem right on with what the manual says.

    In winter my garage is about 50F and even with a lower sun and tilt panels I am making 5.6kW to 6k in the dead of winter which is great.

    So,,, Thats a lot of loss based on Air temp.

    I have a 4" pvc pipe tapped into the home via the wall and a 4" PC fan blowing air at maybe 50cfm which does connect to the vent holes under my midnite solar e-panel perfectly. Air temp is at 80F at bottom of inverter and 105F at the top
    Best I can do for now.

    Im not able to put cool air on the chargers tho due to the low cfm

    I can try to find a larger fan or try to contain all the solar units in an enclosed air space and push a a/c duct into the area from the home but would have to return the air back to the home.
    Or

    I can look into moving the solar inverter and chargers into the basement which would require about 12foot of 4-0000 battery cables. Be some work but the air temp on the other side of the wall is maintained at 75F.

    You do now realize that you are mixing the temperature data up. The xwcc is rated in Centigrade and you are stating fahrenheit. For Instance 40 degrees C = 104 degrees fahrenheit. That is a long way from your garage temp as far as electronics are concerned! Batteries are different and like temperatures that you and I do!

    What make solar panel and do you have the cc's linked thru the xanbus. Are you sure that the programmed values are the same?
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net