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750c Display Documentation

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    750c Display Documentation

    This covers the basics of the 750C display.
    • 3.2 inch High-contrast IPS colorful dot screen.
    • UART Communication Protocol.
    • Password control
    • Speed display: RT SPEED,MAX SPEED,AVG SPEED
    • KM / Mile: Setting up adjustable
    • Mileage : ODO,Trip,Time.Range.
    • Clock. (note: internal battery needs a long charge before keeping time, see below)
    • Power indicator.
    • Error codes and built in diagnostics
    • Software Update capability
    • 48V/52V Bafang mid drive motor compatible
    • Rain proof, but not fully waterproof

    Common questions:
    Password for advanced settings: 1199
    Throttle is tied to selected PAS level no more full throttle in lower PAS modes
    How do I access the display settings, basic settings and advanced settings?
    2 quick pushes of the M button
    Walk mode for going up stairs?
    Hold down “-”
    Night mode?
    Hold down “+”
    Reset Odometer?
    Hold down both “+/ -”
    Error codes
    Error Code Error description Error display 750c
    0x01 Normal No error
    0x03 Brake signal No error
    0x04 Throttle on high position show 04H
    0x05 Throttle error show 05H
    0x06 Low voltage protection show 06H
    0x07 High voltage protection show 07H
    0x08 Motor’s hall sensor error show 08H
    0x09 Phase line of motor error show 09H
    0x10 Controller over temperature show 10H
    0x11 Motor over temperature show 11H
    0x12 Current sensor error show 12H
    0x13 Battery’s temperature sensor error show 13H
    0x14 Motor‘s temperature sensor error show 14H
    0x15 Speedo sensor issue show 15H
    0x21 unknown show 21H
    0x22 BMS communication error show 22H
    0x23 Head light error show 23H
    0x24 Head light sensor error show 24H
    0x25 Torque sensor error-Torque show 25H
    0x26 Torque sensor error-speed show 26H
    0x30 Communication error show 30H

    Display Settings
    • System - Metric or Imperial (imperial changes to MPH on main display screen but not on the speed limit setting in advanced setting, it stays on kmph)
    • Brightness - 1 thru 5
    • Auto Off - 1 thru 9 minutes or OFF
    • Scenes - Analog or Digital (doesn't seem to change anything)
    • Battery Indication - Percent, Voltage or OFF
    • Clock - Date and Time Settings

    Basic Settings
    • Wheel Size - 16, 18, 20, 22, 24, 26, 27, 27.5, 28, 29, 30, 31
    • Battery - 24v, 36v, 48v, 52v

    Advanced Settings (access with password 1199)
    • Speed Limit - Has no effect on throttle or PAS
    • Current Limit - Has no effect on throttle or PAS
    • Poles In Motor - Has no effect on throttle or PAS
    • Start After Poles - Has no effect on throttle or PAS
    • Clockwise Start - No effect on throttle or PAS
    • Throttle 6km - No effect on throttle or PAS
    • Throttle - Ties throttle to level of PAS (variable throttle)
    • Start Mode - Has no effect on throttle or PAS
    • Assist Levels - Levels of assist 5, 9 or (UBE?)
    • Key Anti jam- Seems to have no effect

    Clock keeping time when off:
    Thanks to forum members in this thread for figuring out solution to this. Battery needs a long charge before it will have enough charge to keep time when off, so turn off auto shutoff and leave it on long enough for internal batt to get a good charge. See this part of the thread below for details

    Manufacturer manual (generic version, some menus can differ)

    Basic video walkthrough
    Last edited by Sebz; 01-05-2021, 08:05 PM.

    Thank you for posting this, very very helpful. What symbol shows on the display to indicate the brakes are being applied? I am having issues with mine and I have read through all the documentation but can't seem to find a documented picture of the symbol the brake motor inhibitors will display on the screen when applied.


    • thedadude
      thedadude commented
      Editing a comment
      I get a red "brake warning" Icon at the middle top of the screen when I apply brakes or shift gears (purchased the shift sensor also). It is a red, "drum brake" style symbol on black background and only stays on momentarily, so may be easy to miss.

    • dales2ale
      dales2ale commented
      Editing a comment
      Appreciate the above Documentation and video for the 750C Display, Recient (08/17) purchase the advanced settings menu has been stripped everthing except wheel size and error codes.


    On the 750c the "brake applied" symbol is a red "exclamation mark" surrounded by a circle and then enclosed in a pair of round brackets. It appears on the top line of the display, between the clock and the battery indicator.

    Sorta like this: (!) only with a circle around the !

    See this thread for a photo of the same symbol on the DPC-14:

    Hope that helps!
    Last edited by cajk; 05-01-2017, 04:34 AM. Reason: Corrected spelling


      How do I reset the trip to 0 miles.


      • cajk
        cajk commented
        Editing a comment
        To reset trip miles and trip time hold down the + (plus) and - (minus) buttons at the same time.

        The total mileage (odometer) cannot be reset (or at least I haven't figured out how to do it).

      • ykick
        ykick commented
        Editing a comment
        Once it resets to 0 you must rotate the wheel at least one pass of the magnet or else the previous value won't be overwritten. If you reset trip ODO and just turn the system off the next time you power it ON it will appear to ignore the reset and show the previous value.

      Common Question #2: "Throttle is tied to selected PAS level no more full throttle in lower PAS modes"

      Sorry to be kinda slow here but...

      Does that mean that the "Variable Throttle Option" (that the Luna Cycle page refers to) is not really an option but rather a permanent function?


        Hi somebody knows how you can do Software Updates or can Change the Logo ??


          Sorry not possible to do that.


            Anyone have any issues with their unit not keeping the correct time? I'll set it to the correct time and once the unit is powered off it "forgets" the time.


            • Stagehandman
              Stagehandman commented
              Editing a comment
              I have also noticed that even when the 52V mode is selected the battery graphic and percentage options are still scaled to 48V so are not accurate.

            • MichaelT
              MichaelT commented
              Editing a comment
              If the dash is independant and all that is needed is a larger battery, then its worth a try to open it up and stick a bigger one in.
              If the time is dependent on the reserve held by the capacitors in the motors controller, then a circuit will have to be made and a battery squeezed into the the dash with it.
              This is worth investigating further.
              I see further down that there is a teardown and the CB is exposed, the internal battery can be upgraded to a larger one, I will try a CMOS battery leads hard soldered in.
              Last edited by MichaelT; 07-04-2017, 10:09 AM. Reason: info edit

            • thedadude
              thedadude commented
              Editing a comment
              FWIW this is a silly, silly, most annoying and by the way...did I mention...a really silly problem to have for a computer in this day and age. How could they not have designed the clock to retain time at least off a small capacitor, or small replaceable internal battery for the controller....that is at best clumsy design FAILURE. If it can't keep time why have a clock with date settings? Is there an update coming for this or is it a hardwired design failure?

            From what I can tell they all do that if there's no power.


            • cajk
              cajk commented
              Editing a comment
              And yet my DPC-14 (which is a older display) has no problem remembering the time, even if the battery and display are turned off for several days.
              Last edited by cajk; 06-20-2017, 08:00 PM.

            • jaymz77
              jaymz77 commented
              Editing a comment
              I have tested leaving the power on and it will keep time but even being plugged to the battery the whole time and the display turned off, the time changed once turned back on.

            So now that I've had this display for a while, I can say that the drawbacks, (and disappointments) are significant:

            1) "Variable Throttle Option" is not optional (not through the display settings anyway)
            2) Clock loses memory when battery is removed (a la shark pack) or possibly even when turned off
            3) When using a 52V battery, the "battery life remaining" indicator is so optimistic as to be useless. (Though the digital battery voltage reading is correct.)
            4) The Daytime/Nighttime settings are virtually identical (black and white background cannot be toggled)
            5) PAS level adjustment is extremely "laggy". (i.e. can't repeatedly press - or + buttons quickly)
            6) If trip odometer is to be reset, it must be performed at the beginning of a trip. (reading will return to previous value if power is turned off before new mileage is recorded)
            7) PAS level indication is one of the smallest, least readable datum displayed (granted my eyes are old)
            8) Costs more

            That's just what I've noticed so far...

            That's a pretty big price to pay for the much cooler (imho) mounting and appearance of the 750c over the DPC-14.

            Seems like it wasn't quite ready for prime time.


            • paxtana
              paxtana commented
              Editing a comment
              Probably a fair assessment, though it is important to consider each version has its upsides and downsides. For example the DPC14 will not mount on everything depending on the stem, which is a definite dealbreaker for some bikes.

            • ykick
              ykick commented
              Editing a comment
              I personally like the font size of the 750C much better. On the DPC-14 the PAS is same size as the Speedometer digits. But the power/Watt meter readout is small font. I prefer the 750C displaying Speed/Watts in largest size numbers. The Watt meter seems to be faster on the 750C too.

              They all have pros/cons and nothing is really ever gonna be "perfect" in the industry yet. It's come a long way but there's still a long way to go, IMO....

            • skymon
              skymon commented
              Editing a comment
              For the record, I still use the 750c even though its buggy. I prefer its mounting and low profile enough to put up with the bugs.

            Hello from NZ. 750 C posting an error message 0CH which is not on the list of error codes above. Any ideas?

            Display fogged up after a light shower yesterday. I totally agree with Skymon above. Spot on.



              Here's how to open the screen if moisture develops. You need a spudger (electronics pry tool set) and just work it along the edges of the outer plastic until the clips come off (it's easy)
              Then you have a few screws, remove those.
              Now you are down to the screen itself.
              You can remove a couple more screws on side if you want a peek at the circuitboard on the bottom.
              In any case if you leave it for a day or so it'll dry out and fogging will go away.

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              • ykick
                ykick commented
                Editing a comment
                Sweet, thanks! Also no doubt it uses a button battery. I suppose for volatile stored settings?

              • MichaelT
                MichaelT commented
                Editing a comment
                I'm going to try to upgrade the battery to a CMOS cell. I will hard solder the leads on and hopefully this will solve the time resetting after pulling the power.
                Cross my fingers the voltage is the same.

              • mtrain13
                mtrain13 commented
                Editing a comment
                Did you happen to note the voltage on the battery? Thinking of adding a replaceable CMOS battery and disconnecting the original battery.

              The battery is a Japanese cell that is spot welded on those metal contacts at the battery factory. It is sold that way before installation at the display factory. Those contacts are then held into place on the circuit board with what appears to be some sort of clear resin. It is unclear to me how we could retrofit this with another battery, there is nothing to desolder. Only way I see to remove it would be to cut it out, maybe with wire cutters.


              • ykick
                ykick commented
                Editing a comment
                My 1st job out of college was working for GI (General Instruments) Jerrold division cable box depot which opened a new production rework line for replacing defective button batteries on PCBs. Large number of new cable boxes were found to have defective Sanyo button batteries and the “settlement” reached was that Sanyo financed the creation of the rework line and 2 shifts working to fix the engineering recall.

                It was not a bad gig and they kept me on as a bench tech once the project was completed.

                Oddly there's no soldering to PCB here? That sounds like a problem waiting to happen....

              I do not think the 750c "forgetting time of day" problem is caused by insufficient internal button battery capacity. I can set the time and ride my bike (with 750c) in the morning, then turn off the display and the battery pack. That same evening, if I turn on the 750c display and check the time, it has already "lost time" and is incorrect. Surely ANY button battery would last longer than that!

              In contrast, my DPC-14 display will retain the correct time over many days of inactivity. Anybody know what type button battery it has?

              There must be a difference in the way the two displays are wired, either to the button battery or to the main battery pack. If the 750c was not designed to retain the correct time setting, then that is just plain dumb engineering.

              Of course, if the button battery in all these 750c displays is defective (non-functional), then that is a different problem entirely.
              Last edited by cajk; 07-05-2017, 07:21 AM.


                When the unit was opened, did anyone check the battery voltage? I wonder if the battery is actually dead or a design flaw.