Low current

ameenameen Registered Users Posts: 6
Hello

i have problem with my new solar system

now i already bay new 10 solar flex panels

each panel produce 100 w

after i run my system ... i get normal voltage but low amps i dont know why ..

my system run in 24 v array and 24 v battery with tristar 45

i hock every 2 panel together in series , total 5 gruops

i hock the 5 groups in parallel

so after i run the system i get low wattage between ( 150 to 300 ) and amps between ( 6 to 10 )

i parallel the solar panels direct to the sun , i checked the wiring many times ... but i still have the same problem

this is my panel info

- maximum power (pmax) 100w

- open circut voltage ( voc) 21.12v

- short circuit current ( isc ) 6.36 A

- maximum power voltage (vpm) 17.6V

- maximum power current (imp ) 5.68

- maximum system voltage 700 vdc

size 1050*540*3 mm

the total panels give 1 kw power

is there any thing i can do to fix it up

Ameen

Comments

  • CALLDCALLD Solar Expert Posts: 230 ✭✭
    Re: Low current

    Hi,

    I assume you are hoping to see approximately 28Amps under direct perpendicular sun conditions (AM 1.5, 1000w/m2).

    Many things affect current:

    Battery SoC (a fully charged battery will only take what it needs to maintain the set voltage.

    Charge controller - a PWM or MPPT? There is a difference!

    Wiring - Amps = Volts over Ohms. There is an inevitable voltage drop from the panels to the charge controller. Use ohms law to figure out if the wiring can carry the current while still maintaining the required voltage at the charge controller/battery/load.

    Sun intensity plays a big role, it drops off dramatically when the sun is lower than 30° from the horizon. At low altitudes things like clouds, mist, haze, pollution etc. have a huge effect.

    Shading, with your setup if any of the PVs are shaded the diodes will not be enough to compensate, you just don't have enough "reserve voltage"

    As I pointed out in the last point, your PV voltage is very close to your battery voltage, meaning that under certain conditions it will struggle to overcome resistive losses. Unless you have very heavy gauge wiring or very short distances you could find that ohms law is "stealing your amps"...

    D
  • ameenameen Registered Users Posts: 6
    Re: Low current
    CALLD wrote: »
    Hi,

    I assume you are hoping to see approximately 28Amps under direct perpendicular sun conditions (AM 1.5, 1000w/m2).

    Many things affect current:

    Battery SoC (a fully charged battery will only take what it needs to maintain the set voltage.

    Charge controller - a PWM or MPPT? There is a difference!

    Wiring - Amps = Volts over Ohms. There is an inevitable voltage drop from the panels to the charge controller. Use ohms law to figure out if the wiring can carry the current while still maintaining the required voltage at the charge controller/battery/load.

    Sun intensity plays a big role, it drops off dramatically when the sun is lower than 30° from the horizon. At low altitudes things like clouds, mist, haze, pollution etc. have a huge effect.

    Shading, with your setup if any of the PVs are shaded the diodes will not be enough to compensate, you just don't have enough "reserve voltage"

    As I pointed out in the last point, your PV voltage is very close to your battery voltage, meaning that under certain conditions it will struggle to overcome resistive losses. Unless you have very heavy gauge wiring or very short distances you could find that ohms law is "stealing your amps"...

    D

    yes , i appreciate your response

    right , i was espect to have 25 to 20 amps

    i'm using tristar 45 amp mppt charge controller , also i'm using 2 free maintenance car battery both new with same date

    i have run mini Air condition 5000 btu " 445 Watt" after my battery get Full 28.5

    the problem is the battery voltage keep getting low to 24.7 v and stile the charge contrller dose not give much current to make the battery voltage stable ...

    i see many video of people running devices on 12v system and there battery is stable at 13.6 v in 500w load

    i live in desert area with full sun high intensity no cloud , and my solar cable are fully copper 10 gauge i musur my current for full day the maximam current i get when sun in the meddle of sky is 12 amp

    so my Q is ... is it possible case i'm using free maintenance car battery this problem happen to me or maybe the charge controller setting is wrong ..or maybe my solar panels arepoor ?!

    this is the setting for my charge conntoller i try all battery type with same result

    off-off-off1 - Gel 14.00
    off-off-on2 - Sealed*14.15
    off-on-off3 - Sealed*14.30
    off-on-on 4 - AGM/Flooded 14.40
    on-off-off5 - Flooded14.60
    on-off-on6 - Flooded14.70
    on-on-off7 - L-16 15.40
    on-on-on 8 - Custom
  • CALLDCALLD Solar Expert Posts: 230 ✭✭
    Re: Low current

    I think you need a pro to come and look at your system for you. There are at least several problems with your set-up.

    1) the batteries. Even with two "Big" car batteries you have far to little storage for your PV! I'm also assuming you live somewhere where you can't get proper deep cycle batteries and that's why you ended up using car batteries? Sad thing is they are probably going to fail long before you figure out what is wrong with your system:(

    2) if you have an MPPT charge controller why did you not opt for the highest possible voltage from your array? Most MPPT controllers can accept up to 150volts?

    3) I could go on about your loads, inverter etc but I'd rather let the boffins jump in from here.
    My advice would be to get someone who knows what they are doing to come and help you before you ruin your equipment...

    D
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Low current

    Welcome to the forum.

    You need to check the panels individually to make sure each is actually producing power (current).

    To do this you will need to disconnect everything, and check each panel individually in full sun by putting a Digital Multi Meter (and nothing else) set for DC Amps across the leads of the panel. You should get a reading near the Isc rating of 6.36 Amps. If one (or more) doesn't, then that panel is defective.

    Once it has been established that all panels are working you can move on to the next step.

    With the batteries in a low State Of Charge and/or additional load applied you should indeed see current around 25 Amps in full sun. With the current reading less than half that I suspect some panels are wired backwards, as that is the most likely cause.
  • PhotowhitPhotowhit Solar Expert Posts: 5,653 ✭✭✭✭✭
    Re: Low current

    Several things,

    The Tristar comes in 2 types of controllers that look pretty much the same, are you sure you purchased the MPPT type? It tends to run 3x and much as the PWM type.

    The panels I assume of these grape flex panels? I'm not a huge fan of flexible panels, they don't tend to last as long and tend to discolor over time, but initially they should be fine.

    I would expect amps at 24 volts on a sunny day to be around 90-95% of the panel rating for PWM, or 5.68 x 5(strings for 24v) x .9 = @26 amps for a PWM and about 1000 / 24 x .77 = about 32 Max for a 24 volt system.

    Many things can limit your charging current. First would be do your batteries need the current, as others have pointed out, car type batteries do not have a lot of capacity, their goal in life is to produce a lot of current over a short period of time for starting a car. Deep cycle batteries produce a small amount of current over a long period of time. Your charge controllers will see the rise in voltage and limit the voltage so the batteries don't over heat. The batteries will begin not needing the current/amps rapidly and you will see a reduction.

    Did you check to see how much current the charge controllers were passing through when you were running the air conditioner? When a heavy load is applied, the maximum amps should be passing through the charge controller. If you were only seeing a voltage drop to 24.7 you should be seeing more amperage than 12 amps or you should see additional voltage drop somewhat quickly.

    If you do indeed have a MPPT type charge controller the input voltage should be around 2x the output voltage to be most efficient. How far is your array/panel from your charge controller? Long runs over the wrong gauge wire can drop your voltage, and you will loose some power there.

    Trouble shooting, do these with a heavy load so you know you have the demand for maximum current;

    Do you have breakers for each string? If you turn off each breaker, one at a time you may find that some strings have problems, perhaps even wired backwards. Do NOT do this is you have fuses!

    You could use a clamp meter to measure the current while in use, this would tell you if you have other issues, bad wiring past the breaker or fuse or perhaps even a bad fuse or breaker.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
  • ameenameen Registered Users Posts: 6
    Re: Low current
    CALLD wrote: »
    I think you need a pro to come and look at your system for you. There are at least several problems with your set-up.

    1) the batteries. Even with two "Big" car batteries you have far to little storage for your PV! I'm also assuming you live somewhere where you can't get proper deep cycle batteries and that's why you ended up using car batteries? Sad thing is they are probably going to fail long before you figure out what is wrong with your system:(

    2) if you have an MPPT charge controller why did you not opt for the highest possible voltage from your array? Most MPPT controllers can accept up to 150volts?

    3) I could go on about your loads, inverter etc but I'd rather let the boffins jump in from here.
    My advice would be to get someone who knows what they are doing to come and help you before you ruin your equipment...

    D

    1- right now i want to use car battery cause it is cheep ...if the system work good with me ill bay the deep cycle

    2- i have changed the connections , i tray to connect the panels in 2 groups, Each group have 5 panels in series and i connect the 2 group in parallel i masseur the voltage in the system array was "90 volt" with 3.7 Amps, then i run the charge controller and i run the Air conditioner the result was same " low amps " 6.6 amps in 25 volt battery voltage ..



    picx.jpg
    pic11.jpg
    cyrd.jpg
    pic6.jpg
    pic5.jpg
  • ameenameen Registered Users Posts: 6
    Re: Low current
    Welcome to the forum.

    You need to check the panels individually to make sure each is actually producing power (current).

    To do this you will need to disconnect everything, and check each panel individually in full sun by putting a Digital Multi Meter (and nothing else) set for DC Amps across the leads of the panel. You should get a reading near the Isc rating of 6.36 Amps. If one (or more) doesn't, then that panel is defective.

    Once it has been established that all panels are working you can move on to the next step.

    With the batteries in a low State Of Charge and/or additional load applied you should indeed see current around 25 Amps in full sun. With the current reading less than half that I suspect some panels are wired backwards, as that is the most likely cause.

    i appreciate We have the Honor :D

    i have cheeked and masseur each panel alone

    all reading was near 18 volts and 1.8 amps

    all measurement got in full sun

    volt.jpg
    amps2.jpg
    sun.jpg
  • ameenameen Registered Users Posts: 6
    Re: Low current
    Photowhit wrote: »
    Several things,

    The Tristar comes in 2 types of controllers that look pretty much the same, are you sure you purchased the MPPT type? It tends to run 3x and much as the PWM type.

    The panels I assume of these grape flex panels? I'm not a huge fan of flexible panels, they don't tend to last as long and tend to discolor over time, but initially they should be fine.

    I would expect amps at 24 volts on a sunny day to be around 90-95% of the panel rating for PWM, or 5.68 x 5(strings for 24v) x .9 = @26 amps for a PWM and about 1000 / 24 x .77 = about 32 Max for a 24 volt system.

    Many things can limit your charging current. First would be do your batteries need the current, as others have pointed out, car type batteries do not have a lot of capacity, their goal in life is to produce a lot of current over a short period of time for starting a car. Deep cycle batteries produce a small amount of current over a long period of time. Your charge controllers will see the rise in voltage and limit the voltage so the batteries don't over heat. The batteries will begin not needing the current/amps rapidly and you will see a reduction.

    Did you check to see how much current the charge controllers were passing through when you were running the air conditioner? When a heavy load is applied, the maximum amps should be passing through the charge controller. If you were only seeing a voltage drop to 24.7 you should be seeing more amperage than 12 amps or you should see additional voltage drop somewhat quickly.

    If you do indeed have a MPPT type charge controller the input voltage should be around 2x the output voltage to be most efficient. How far is your array/panel from your charge controller? Long runs over the wrong gauge wire can drop your voltage, and you will loose some power there.

    Trouble shooting, do these with a heavy load so you know you have the demand for maximum current;

    Do you have breakers for each string? If you turn off each breaker, one at a time you may find that some strings have problems, perhaps even wired backwards. Do NOT do this is you have fuses!

    You could use a clamp meter to measure the current while in use, this would tell you if you have other issues, bad wiring past the breaker or fuse or perhaps even a bad fuse or breaker.

    yes the charge controller is mppt type

    the panels type i got is from Chinese company who claim that there solar cells are from U.s "sunpower cells " with high efficiency .. i tried to bay the panels directly from sun power but the say i need to have house in USA ..

    the panels are not far from the electric encloser it is on the roof o the Trailer

    top2.jpg
  • CALLDCALLD Solar Expert Posts: 230 ✭✭
    Re: Low current

    Hi Ameen,

    Thanks for the pics, they help explain a lot. First thing I notice is your panel frame potentially casts shadows on your module, which can cut power significantly as it shuts down a whole string of cells between the diodes in the junction box.
    Other than that it could just be a bad charge controller or a set of panels.
    Second thing is taking measurements while casting shadows on the panels is not going to yield meaningful results. PV modules need to be completely lit to give full output.

    D
  • PhotowhitPhotowhit Solar Expert Posts: 5,653 ✭✭✭✭✭
    Re: Low current
    ameen wrote: »
    all reading was near 18 volts and 1.8 amps

    all measurement got in full sun

    Well if the angle of the sun is 90 degrees \* rather than /* then I would say you don't have 100 watt panels! 18 x 1.8 = 32 watts and that is at short circuit! Likely more like 25 watt panels. ...of course the wires, ladder racks, anything that shades the panels will reduce you output significantly.(as CALLD has said)

    If your goal is to run the A/C, it is likely you will only be able to do this when the sun is shining, or for a short period on stored electric with only 1000 watts of array? I've done this in a well insulated building, in the shade, with panels correctly oriented toward the sun, and I only run the A/C 4-5 hours a night on thermostat... Much harder in a trailer with poor orientation and much less insulation, living in the sun...
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
  • Mountain DonMountain Don Solar Expert Posts: 494 ✭✭✭
    Re: Low current

    The panels on the roof like that are going to get very hot. It appears there is no ventilation space under them. That is not good either.
    Northern NM, 624 watts PV, The Kid CC, GC-2 batteries @ 24 VDC, Outback VFX3524M
  • ameenameen Registered Users Posts: 6
    Re: Low current

    Morning of the flowers

    Thanks for all people who hellp me , Id like to say "you have covered me with your generous"

    So the conclosion is all my dreams disappear after solar project fail.. but I m happy to win your frindship ..
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