Epever tracer 4210 MT50 inaccurate voltage

DaveDave Registered Users Posts: 59 ✭✭
I have the Epever Tracer 4210AN hooked up to a 400Ah lithium iron phosphate (LFP) battery and have been disappointed that the V readings on the MT50 are very inaccurate. If it were just a reading, I would use a separate readout or meter but those readings are what the MT50 and charge controller control the charge cutoffs on. I have had to adjust boost voltage up 0.4 V to try to get the charging to work correctly - i.e. I want the boost to happen at 13.8V but I've had to set it on the MT50 to 14.2V because its voltage reads about  a half volt too high. Anybody else having this issue and figured out some workaround? I saw that the MT50 is not supposed to be used with LFP batteries but voltage is voltage, isn't it? As long as I am using appropriate charge points for LFP, what is the difference?
12 * 300 W (10 fixed rooftop, 2 movable pole mount), Morningstar Tristar MPPT 60, Magnum 4448 PAE, 64 200Ah CALB in 4p16s arrangement with 16 LED Balancers and a Choice BMS300 (It is lousy and I don't recommend but it provides high and low voltage cutoff)

Comments

  • BB.BB. Super Moderators, Administrators Posts: 32,205 admin
    Only things that you could possibly address:
    • Lithium Battery Settings: There is a temperature offset used for Lead Acid Batteries (the colder the batteries, the higher the charging voltage). Some controllers will give a "temperature corrected to 25C/77F" voltage vs the actual measured voltage (don't know if true for this controller. If the temperature is very warm, the controller would drop the charging voltage. For Lithium Batteries, the temperature correction is normally set to zero volt temperature correction (instead of -3 to -5 mV per degree C per Cell). That may change the voltage reading (when not at 25C standard temperature).
    • Voltage drop: Either poor/loose/dirty connections can create voltage drop issues (high controller voltage, lower battery voltage).
    • Voltage drop: Wiring voltage drop... If you have relatively small AWG wiring and/or long wire runs from controller to battery bank. What is the AWG and wire run length of your wires, and the typical max charging current?
    Otherwise, you may have to contact the support folks for your controller... They may have some "hidden" voltage correction/calibration menu--Or you may need to return the controller for repair/replacement due to inaccurate voltage readings (use a known good DMM and measure voltages at the Vbatt terminals on the controller vs Battery Bus connections to ensure voltage drop is not an issue.

    -Bill

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • DaveDave Registered Users Posts: 59 ✭✭
    edited August 23 #3
    BB. said:
    Only things that you could possibly address:
    • Lithium Battery Settings: There is a temperature offset used for Lead Acid Batteries (the colder the batteries, the higher the charging voltage). Some controllers will give a "temperature corrected to 25C/77F" voltage vs the actual measured voltage (don't know if true for this controller. If the temperature is very warm, the controller would drop the charging voltage. For Lithium Batteries, the temperature correction is normally set to zero volt temperature correction (instead of -3 to -5 mV per degree C per Cell). That may change the voltage reading (when not at 25C standard temperature).
    • Voltage drop: Either poor/loose/dirty connections can create voltage drop issues (high controller voltage, lower battery voltage).
    • Voltage drop: Wiring voltage drop... If you have relatively small AWG wiring and/or long wire runs from controller to battery bank. What is the AWG and wire run length of your wires, and the typical max charging current?
    Otherwise, you may have to contact the support folks for your controller... They may have some "hidden" voltage correction/calibration menu--Or you may need to return the controller for repair/replacement due to inaccurate voltage readings (use a known good DMM and measure voltages at the Vbatt terminals on the controller vs Battery Bus connections to ensure voltage drop is not an issue.

    -Bill


    thanks bill, i just verified i have the temp correction set to zero. the voltage reads too high on the MT50 or i would think it was a voltage drop issue as well. it is also not a constant difference, the MT50 reads 0.0-0.1 high when the battery voltage is around 13.3 but is 0.5-0.6 high when the battery gets to 13.6 or 13.7. weird huh?
    btw, the controller is right next to the battery and is connected with 10AWG but it's in a well and hard to view the V on the monitor there. i'm going to to compare the V shown on the controller with the mt50 today. the MT50 is 10 feet away but connected by their supplied comm cable so i would hope V drop wouldn't be an issue there.
    i am checking V right at battery terminals and using a fluke 117 but also three other meters to verify. the meters all agree withing 0.03V. i've written Epever, we'll see. thanks for your reply.
    12 * 300 W (10 fixed rooftop, 2 movable pole mount), Morningstar Tristar MPPT 60, Magnum 4448 PAE, 64 200Ah CALB in 4p16s arrangement with 16 LED Balancers and a Choice BMS300 (It is lousy and I don't recommend but it provides high and low voltage cutoff)
  • BB.BB. Super Moderators, Administrators Posts: 32,205 admin
    edited November 24 #4
    I don't think this is the issue--But there are two other remote possibilities...

    Rebooting the controller... Disconnect solar array first, then battery connection to solar charge controller. Wait a minute, then first connect the battery bank to controller and let it boot. Then connect solar array. Solar charge controllers need to connect to the battery first to boot correctly and measure battery bank voltage (to select if 12 or 24 volt bank). Connecting to solar array first can confuse the controller and even possibly damage it.

    Second--Reset the configuration to factory default. Reboot, then reconfigure the controller. On occasion, it is possible for the configuration to get corrupted and confuse the software.

    I don't think either of these are giving your problem... But it could happen(?).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • DaveDave Registered Users Posts: 59 ✭✭
    thanks, i had rebooted it a couple times earlier but i will give it another shot when i get done my current experiment. i need to pull it out anyway to retrieve the serial number. fwiw, my compensation method of just inputting higher boost V than i want seems to be working although i am right now at the end of the charge curve and wathcing closely. luckily, i set my boost well below the battery's listed max (or recommended boost V, but my charge rates are way slower than the battery was designed for) so i definitely have some headroom before i cause any problems. thanks and take care.
    12 * 300 W (10 fixed rooftop, 2 movable pole mount), Morningstar Tristar MPPT 60, Magnum 4448 PAE, 64 200Ah CALB in 4p16s arrangement with 16 LED Balancers and a Choice BMS300 (It is lousy and I don't recommend but it provides high and low voltage cutoff)
  • andreshs1andreshs1 Registered Users Posts: 1
    Hi there

    I have the same setup and in my case the MT50 reads 0.4 lower than the battery charge, I have compared with a manual reading and also with the voltage meter on the main panel of the boat. in both cases shows 0.4v lower than reality
  • DaveDave Registered Users Posts: 59 ✭✭
    Follow up after a few months use. Voltage is definitely off at the charge controller, which is right next to the battery. I verified that the remote shows same v as controller.

    I adjusted absorb v to compensate and that's worked ok. However, I've found that when absorb v is reached, controller is quite slow to react. Current reduction is too slow and the v of the battery continues to climb past set point. So, I've adjusted v and absorb time to ensure battery doesn't get too high.

    I assume this is because this controller is intended for lead acid which are not nearly so sensitive and still require lots of charge when they hit absorb. Lfp is virtually full when voltage is reached and current needs to be reduced quickly to avoid continued v rise. My morningstar controller on home system does this perfectly.

    I'm regretting buying the epever. I'm making it work ok but it certainly doesn't seem to be a good match for lfp batteries.
    12 * 300 W (10 fixed rooftop, 2 movable pole mount), Morningstar Tristar MPPT 60, Magnum 4448 PAE, 64 200Ah CALB in 4p16s arrangement with 16 LED Balancers and a Choice BMS300 (It is lousy and I don't recommend but it provides high and low voltage cutoff)
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