Ep solar Tracer 3215 mppt charge controller discussion/owners thread

AeronbAeronb Registered Users Posts: 8 ✭✭
I put together my first little solar system with one of these in the pipe. I've had it up and running for a few weeks now and I must say, I'm pretty happy with it. So far the max input to the batteries that I have calculated was around 500 watts with an array which is rated at 535 watts. These are Solar World panels wired in series so the array voltage sits up around 68-75 volts.


http://epsolarpv.com/en/index.php/Product/pro_content/id/158/am_id/136


The only issue I can find so far is that the unit seems to take quite a while to get the tracking dialed in first thing in the morning. Voltage kicks off at around 35 and slowly comes up to Vmp over say an hour or more. At this point, for the price, I would recommend this unit. It is a basic unit with few amenities that mostly show with the optional remote "meter".

Regards,
Aeron

Comments

  • AeronbAeronb Registered Users Posts: 8 ✭✭
    Re: Ep solar Tracer 3215 mppt charge controller discussion/owners thread

    I've been playing around with the system for the past couple days and have a few more details. It turns out that the remote meter that is available for this unit doesn't report very accurate numbers for amps or volts. So needless to say, the 500 watts that I calculated previously is suspect. So what good is this accessory if the numbers are unreliable? It's useful for programming. It's nice for when the CC is mounted somewhere that isn't ideally suited for access. Finally, when the batteries are closer to full and there aren't any loads much over 3-4 amps, the reported numbers are pretty close to reality.

    So, what I did was to get my amp clamp around the incoming pv wires. Then I setup a volt meter at the pv terminals on the CC. I put a 50 amp load on the battery bank and started watching the numbers. As the battery bank had been close to full, the pv array started out at 72 volts. Voc is 76.2. Vmpp at 1000W/m^2 is 63.6. The amp meter went up to 6.5 in a couple seconds and the volt meter dropped to 40. In the next 30 seconds the amps climbed steadily to there peak of 6.8 and held steady. The volts climbed erratically to 45-48. Over the next 90-120 seconds the amps held and the volts continued to climb to a peak of ~56. The volts would jump around a bit and dip to 52 sometimes.

    So panel nominal watts is 535. Today at 12:45pm I'm gettin' 380 with panels mounted flat on top of a cargo trailer, cloudless day. I sure wish I had an irradiance meter. At 800W/m^2 Vmpp is 57. So what's the take away here? At this point I have to assume my panels are seeing slightly less than 800W irradiance. If so, the CC appears to be hitting the mark at 56V. I'm going to borrow the irradience meter from work and repeat the test. What I think is missing here is the speed at which the tracker is able to adjust to varying conditions. The claim of 95% efficiency seems subjectively optimistic.

    With that said, I'm still happy with this unit. I had been having some misgivings about it. Once I dove into the panel specs, took these readings, and did the calcs; everything seems to fall into line. If y'all have had any experience with this unit, then chime in with what you know. For those that might be looking for an economical alternative product, this seems to be it. I'll report back if I have any problems with the unit over time. Maybe a couple years down the road I can come back and report that it's still going strong.

    Regards,
    Aeron
  • westbranchwestbranch Solar Expert Posts: 4,873 ✭✭✭✭
    Re: Ep solar Tracer 3215 mppt charge controller discussion/owners thread

    Welcome.

    Question: As you seem to have a good handle on the PVs, I have to assume you are aware that you should only get in the neighborhood of 72% of the STC ratings for any panel. NOTC numbers should be more in line with reality...

    Also that that inexpensive CC may just not be any kind if a match to the name brand CC's out there. FYI I have a small PWM CC and it is satisfactory for its application, keeping an RV battery from sitting uncharged, does it adequatly ...

    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, Hughes1100 Sat Modem
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • AeronbAeronb Registered Users Posts: 8 ✭✭
    Re: Ep solar Tracer 3215 mppt charge controller discussion/owners thread
    westbranch wrote: »
    Welcome.

    Question: As you seem to have a good handle on the PVs, I have to assume you are aware that you should only get in the neighborhood of 72% of the STC ratings for any panel. NOTC numbers should be more in line with reality...

    Also that that inexpensive CC may just not be any kind if a match to the name brand CC's out there. FYI I have a small PWM CC and it is satisfactory for its application, keeping an RV battery from sitting uncharged, does it adequatly ...

    hth

    Thanks, glad to be here.

    I think that any panel should be capable of its STC rating. If the cell temp is at STC and the panel is oriented perpendicular to the sun at noon time on a cloudless day, the panel would receive about 1000W/m^2 and convert that into its rated capacity, or somewhere close. I might be missing something.

    My panels aren't perpendicular, and I was taking measurements down at the CC, so there would be some losses to account for. Of course the conversion through the CC to the batteries is going to be another source of loss. I think next time I test it I'll check the output too, just to get an idea of what it looses through there.

    With regard to a comparison between this and those, I don't have any experience with those. I could only guess that maybe they have a faster processor capable of calculating and adjusting mpp more rapidly. That would justify some extra expense along with the bells and whistles. I love bells and whistles.

    Regards,
    Aeron
  • BB.BB. Super Moderators Posts: 26,872 admin
    Re: Ep solar Tracer 3215 mppt charge controller discussion/owners thread

    "It depends" is always the answer... :roll:

    For MPPT charge controllers, the STC temperature is 25C... Whereas the nominal operating temperature on a ~20-25C day is around 45C (20-25C rise due to solar radiation heating of panel and ~1 m/s air flow).

    The typical derating for a solar panel on a MPPT type charge controller:

    535 watts * (1+(-0.0043 per C)(20C ambient + 25C rise - 25C STC))= 489 watts

    If you assume 95% controller efficiency:

    489 W * 0.95 = 465 watts to battery

    If you are only 800 watts vs 1,000 w/sqm:

    465 W * 0.8 = 372 watts to battery

    Our 77% rule of thumb derating for "typical off grid system":

    535 Watts * 0.77 panel+controller derating = 412 watts nominal maximum (a few times a year at sea level with panels within ~10 degrees of sun).

    So, your numbers are certainly believable.

    If you had a PWM controller--It only lets "current" through (as long as the voltage is high enough). And Imp rises very slightly with increasing temperature. So, we would usually forget the Imp / PWM temperature correction factor.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • AeronbAeronb Registered Users Posts: 8 ✭✭
    Re: Ep solar Tracer 3215 mppt charge controller discussion/owners thread

    When you say the numbers are believable, do you mean that those are the numbers you would expect to see under these conditions?

    Regards,
    Aeron
  • BB.BB. Super Moderators Posts: 26,872 admin
    Re: Ep solar Tracer 3215 mppt charge controller discussion/owners thread

    Pretty much... You can look at the current, assuming the controller is operating in full MPPT mode (at Vmp/Imp for those conditions)--And the array current should be proportional with the amount of sunlight hitting the array (within ~+/-5%). I.e.,

    Irradiance on panel = Imeasured-array * 1/Imp-array * 1,000 Watts/sqmtr (STC)

    You can get any old crystalline solar cell and connect it to a current meter (i.e., measure short circuit current) and use Imeasured-shorted/Isc times 1,000 w/sqmtr too and use it to confirm your irradiance as perpendicular to the sun and lay it parallel with your array to see how much you are losing with a fixed/flat mount (should be the Cosine of the degrees from perpendicular to sun).

    You can also play with PV Watts to estimate the various mounting options vs seasons (and even time of day with hour by hour spread sheet output).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • ChrisChris Solar Expert Posts: 135 ✭✭
    Re: Ep solar Tracer 3215 mppt charge controller discussion/owners thread

    Just wondering how this controller is functioning for you.......I'm currently considering it as well as a few others come spring.....I'm running a EPSolar 20 amp PWM controller that I'm very happy with and well the fact that it's the cheapest the category that I'm looking for, it is a high contender.
  • AeronbAeronb Registered Users Posts: 8 ✭✭
    Hi all,
    Just checking back in.  I've been doing some research for a system I'd like to install on a travel trailer and of course this is the place to get all of the best information.  My Tracer CC has been working just fine for the past 3 years.  Still on my original 4, six volt batteries in a 24v configuration.  Only had to top them off a couple times and they are still going strong.  For my modest system and my modest needs, this is serving very well.
    Regards,
    Aeron
  • zero_coolzero_cool Registered Users Posts: 1
    Hello all! fun to find a thread dedicated to the exact MPPT SCC I bought. so my question is: does anyone know if there is a setting on the 3215BN that allows you to adjust the load output voltage coming out of the MPPT? Just got my system up and running yesterday, and the load output only seems to mirror whatever the voltage is going to the battery. I was hoping I would be able to set the load output from the charge controller to specifically 12 volts. Is there a setting I am missing, or am I going to have to resort to putting in a DC->DC converter circuit between my load output on my charge controller and the load itself?
  • BB.BB. Super Moderators Posts: 26,872 admin
    My guess is no--Load outputs are usually just a switch to the battery connection (and some sort of fuse/breaker/current sense for some units).

    Those are pretty common and easy to use these days (EBay usually has a bunch). Do you have more details on what your loads are?

    If you need 12.0 VDC -- You would need a "buck/boost" DC to DC converter (switching power supply). A "buck" can drop voltage (from 14.x to 12.0). A "boost converter" can raise voltage from 10.0 to 12.0 volts. Notice there is a "dead zone" where they do not usually work well (i.e., 11.5 to 12 volt, 13 volts to 12 volts)--A Buck/Boost has both circuits and will provide continuous regulated voltage over the entire input voltage range.

    -Bill

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
Sign In or Register to comment.