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Adding a voltage meter to your Sur-Ron

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    Adding a voltage meter to your Sur-Ron

    IF you would like to replace your wonky % meter on your Sur-Ron but don't want to open the battery or would just like to rely on voltage to get a more accurate reading then we have a simple fix for you.

    Installs in no time, no need for any electrical tools, just need a plier, Allen key, blade and pick (or flat head screwdriver), if you break it you can replace it for a couple $ as they can be found online anywhere.

    Since my % meter is not super reliable in cold temp and when I ride hard I wanted to add a voltage reading. I initially wanted to have a watt-meter (for Wh, Ah and wattage) but I could not find a good watt-hour meter to suit the high powered Sur-Ron that would fit inside the frame and have a small display. So I went to basics with a since voltage meter, accurate enough for the Sur-Ron and visible at night & day.

    Click image for larger version  Name:	IMG_1834 2.JPG Views:	0 Size:	2.39 MB ID:	99485

    • No parasitic drain. When the ignition is off the display is off.
    • Turns on when you turn the ignition to ON and backlight stays ON
    • Shows voltage and all offers a bar type capacity meter (visual representation of the voltage)
    • Programmable for a 60V Sur-ron battery
    • Weather proof from the top but the bottom is not (unless you add silicone)
    • You will need: pliers, blade, Allen key and flat head screwdriver (or a pick, something pointy)
    Luna voltmeter kit:
    Click image for larger version  Name:	image.png Views:	1768 Size:	1.39 MB ID:	99515

    1) Remove the battery cover:

    Open the cover and locate the cir-clips holding the 2 pins in place, pry it off using your screwdriver or a needle nose plier (make sure to pry it off from the opposite side of the opening, like this following
    pic). Be careful as they can fly off if you use a screwdriver!

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    2) Finding the right place to install the display:

    I didn't mind covering the battery % as I don't need to take a look at it while riding but if you mind you can install it a little lower or anywhere you see fit.

    So I made sure that I could access the the connector from the bottom

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    Then I wanted the display to sit flush or recessed into the battery top so I cut down the side tabs with a blade.

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    Once done it should look like this:

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    Sugru time:

    I'm a big fan of moldable plastics so I went with the Sugru brand as it works great.
    So clean you battery top and display with alcohol to remove any trace oil and grease . Open one packet of Sugru at at time and work one of the 3 areas at a time; top right top left and bottom. I didnt put Sugru over the little programming button and not over the power connector incase I need to disconnect it.

    Note: You have about 20 min before it gets harder so please keep this in mind when you start your project. Sugru fully cures in 24 hours so do not touch it until then.

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    3) Electrical connection

    Turn the main breaker to OFF position
    Remove the 2 Allen head (hex) bolts holding down the ignition and USB plate.

    You have 2 wires out of the display (red and black) you will need to connect the red wire (from display) to the Red cable with a black stripe (coming out of the ignition).
    Then you will have to connect the black wire (from display) to the green wire of the USB module.

    Use the T-Tap connector to splices the wires together, if you dont know who to use it , just click to link or search on YouTube for T-Tap connector:

    Click image for larger version  Name:	IMG_1788 2.JPG Views:	0 Size:	1.85 MB ID:	99494

    Now you are done this is what it should do when you turn the ignition ON. Forget the voltage shown on the video it was connected to another battery.

    4) Voltage reading

    If you are new to voltage on Li-ion battery please take the time to check this out, a fully charged 60V battery is 67.2V (or close to) and about half full at 60V and empty at 48V.

    Voltage will fluctuate when you draw power out of the pack so don't be surprised when you see a couple volts lower as soon as you hit the gas and see the voltage rising when you let go of the gas . It's called voltage sag! It's always best to take a reading when the bike is either costing, not using power or resting (anyways you should be looking at the road not at your display).

    Click image for larger version  Name:	60v chart.png Views:	0 Size:	69.3 KB ID:	99495
    Want to program it?

    This meter will read voltage accurately right out the box but if you want to program it, that is possible.
    • S1:%/V Rotate display in 2s
      Power percentage and voltage are displayed in turn recurrently and automaticall
    • S2:Inactivity sleep in 10s
      Automatically sleep after battery capacity display for 10 s, save power, press the function key to wake up power display for 10 seconds;
    • S3:Turn on backlight
      Power display turns on or off power backlight;
    • S4:Show logo(Applicable to small battery icon)
      Logo icon is located in the underface of battery symbol on the left side of LCD, turn on and show the logo;
    • S5:Discharge mode selection
      Power displays two kinds of battery discharge curve, different environments convert to select appropriate battery discharge modes;
    Setting procedure
    1. Disconnect the module power supply, press and hold the setting button until powering the power module. Display shows the current power setting parameters;
    2. Press the setting button to select P / L / F ,(P = 12V lead acid, L = 3.7V lithium battery, F = 3.2V lithium iron phosphate battery);
    3 press the function key to set the number of the battery string, according to the function keys and set the key up or down to choose the number of batteries in series;
    4. Press the function key for a long time to enter the advanced setting interface, use setting key to select S1-S5, enter key to select or cancel the current mode;
    5. Reenergize the power after setting. The power automatically saves setting data.
    E.g. 10 lithium battery power, turn on power percentage and voltage automatic rotation display (S1 mode)
    Operation: Disconnect display module power, press and hold the setting button, power the power module, press the setting button for a short time to select L, press the function key to select 10, press the function key for a long time to select S1 and re-power.
    Last edited by paxtana; 11-19-2021, 04:39 PM.

    Can I buy this kit from you?


      If you bought the xx bike from Luna just let me know your order# and we will ship you one free of charge! (let me know if your address changed since you placed the order)

      For stock bike, or if you did not buy it from Luna, or got it second-hand, private message to set up a special order, or email
      Last edited by paxtana; 04-15-2021, 09:13 PM.


      • BUD WHITE
        BUD WHITE commented
        Editing a comment
        I received the kit just as you pictured here. Neatly packaged too. Thank you very much.

      • Niterider
        Niterider commented
        Editing a comment
        Hello, my order # is 146468. I'm due to receive the bike 12/16. I would also like to install one of these on so I don't get stranded by accident. Address is still the same.

      • kvngreg
        kvngreg commented
        Editing a comment
        I got the Ludicrous XX and found out that the display doesn't read the battery % correctly. Left me stranded out in the desert at 40% battery. I want to install this meter so I can have a way to monitor. Thank you.

        Order # 145717

      Thank you. This is going to be very helpful and looks great the way you did the complete install


        Hi, My XX order is #146125, may I get a kit?


          Sure but just a heads up I need to get some more sugru to make enough to fill these requests. Might take a few days.


          • mxsitement
            mxsitement commented
            Editing a comment
            Not a problem, thank you!

          Hello, can I get a voltmeter shipped to me as well? Order #145683


            I also could really use one of these.

            Order # 146022


              I’d also like to hop on this train for my XX. Could I request one too? Order number #146470 Thanks


                Hey guys we only have like one of these left so it is worth bearing in mind about the XX bikes that the gauge will work properly after a few charge cycles. This replacement is really meant more for folks that have an actual defect. That said, if you bought XX we would be happy to send you one when we get more as a courtesy, but it may be weeks before it can be shipped.

                If you are leaving a comment here about XX gauge, what you want to do is take it from 100% charge down to like 10-15%, then charge it back to 100%, do this a few times, after that should work fine. This needs done anytime you unplug the BMS, it basically learns what is the percentage.
                Last edited by paxtana; 12-15-2020, 06:35 PM.



                  I purchased two XX (order # 145874). I would be more comfortable installing this voltmeter on both bikes. Please contact me using my email address if your offer to supply is still available. Thanks!


                    I would like to request one for my XX as well. Really don't want to be stranded due to incorrect battery % reading. (Order #146107).


                      What are the white connectors called is use for the ignition switch and use for the plug on the headlight


                        I may be late for the offer, but if sill stands I’d be very grateful order # 146063


                        • paxtana
                          paxtana commented
                          Editing a comment
                          Check your private messages, sent you tracking

                        • Blazeman
                          Blazeman commented
                          Editing a comment
                          Got kit, works like a charm, Thanks John

                        • paxtana
                          paxtana commented
                          Editing a comment
                          Glad to hear it!

                        Hi. We just rec'd Sur Ron black X. Would love to install the kit! Order 159080. - John and son, Spencer


                        • paxtana
                          paxtana commented
                          Editing a comment
                          Okay, pm me