Mag+ (updated Feb. 1-st, 2016)

Starting this weekend I’m flying new Mag+ device. There are already on the market some magnetic switches available, but no one suits my requests. Here are parameters of my Mag+:

  • Max current 20A (peak)
  • Max voltage 13V
  • Min voltage about 2V. AutoReset function implemented (if your on board battery is so bad that it drops bellow 2V from any reason, when voltage exceeds again this limit, Mag+ resets and sets ON status)
  • Plus wire is switched. No collision with ESC BEC
  • Implemented Voltspy function. When voltage drops to (or bellow) 4,5V, LED will start to flash.
  • OFF status consumption is 0,3mAh/day i.e. your 1000mAh on board battery will be completely depleted within 9 years. Self discharging of any today usual voltage on board source (NiXxx, LiXxx) is far bigger than OFF Mag+ consumption
  • Optional one-segment display. Visible on direct sunshine. Same display is used on LOLO5 my altitude logger, you can use it with Mag+
  • On display you can read minimum on board voltage drop (100x samples/second). Maybe you will wonder how bad is your receiver pack.
  • On display you can read maximum current (100x samples/second, max 19,9A)
  • LiPo, LiFePo on board batteries are today more and more popular. Problem is that you have more or less no control of Voltage limit when batteries are depleted. Hardly you can rely on Voltage level, while cut-off limit is so sharp. Using some stabilizers is situation even more complicated and perfidious. Mag+ logs used capacity of your on board battery 100x/sec and you can always check after landing used capacity. Sure, used capacity is memorized even after switch OFF until you reset Mag+
  • High beam signaling LED (visible through many fuse layers)
  • Dimensions 26x9x3mm
  • Weight 3g (w/o LED display)

Operating instructions

  • Attached one-segment display shows Voltage, Current and Capacity. All values have fixed digit number. Voltage 2 digits (e.g. 5.3V), Current 3 digits (e.g. 06.3A) and Capacity 4 digits (e.g. 0570mAh). All are permanently rotating on display. You don’t have to fly with display, you can connect it after landing, but don’t switch off, otherwise Voltage and Current is cleared. Capacity is not cleared, you have to reset Capacity counter manualy.
  • Voltage display format “u_X.X” Example “u_5.3”. Value is in Volts and equals to minimum voltage drop during Mag+ on status. After switch-off this value is cleared.
  • Current display format “i_X.XX” Example “i_06.3”. Value is in Ampere and equals to maximum current peak during Mag+ on status. After switch-off this value is cleared.
  • Capacity display format “c_XXXX” Example “u_0570”. Value is in mAh and equals to accumulated capacity used until you reset capacity counter. After switch-off this value is not-cleared. To reset capacity counter hold magnet to Mag+ longer than 5seconds. After successful reset LED starts flashing.

Some hints

  • Glue Mag+ to fuselage using double sided foam tape
  • Mag+ wires are 1qmm cross-section. Cut Mag+ wires asymmetrical to save space and increase security (no short-cut). Don’t disassemble heat shrink tubing of Mag+.
  • Solder battery charging plug direct to receiver batteries and always charge with Mag+ switched-off. You can’t damage switch but you could damage your receiver if charging with Mag+ switched-on.
  • We tested Mag+ in heavy conditions. Measurement was done in 24°C (75.2°F). After this torture test, Mag+ is working without any flaw.
    • 4A/50°C (122°F)/more than 8 hours
    • 5A/65°C (149°F)/more than 8 hours
    • 7A/100°C (212°F)/more than 8 hours
    • 10A/180°C (356°F)/more than 2 hours
  • Peak current (several ms) at average F3X six servo model is about 7A maximum. Steady consumption is about 200-300mA maximum.
  • Fix magnet on transmitter belt using provided knot.

Updated February 1-st., 2016.

New firmware for Jeti Telemetry available.

Stinger installation

8 comments to Mag+ (updated Feb. 1-st, 2016)

  • Bob

    Hello Roman,

    the Mag+ sounds promissing! Hope to see it on the market soon. The size and voltage/ current range is enormous!
    Is the LED blinking in flight?

  • Hi Bob,
    as regards LED blinking. Above 4,5V steady light, bellow flashing. Any better idea? Firmware is USB flashable no problem to implement any request.

    • Bob

      Hi Roman,
      well… a variable Voltage would of course be luxury, because it would give you the option to use it as well as a capacity check. Although very roughly of course unless you can combine the Ah usage as well.
      A binairy code (steady/flashing) is good and keeps it simple, though you’d have to define voltage levels or Ah values for different setups 🙁
      Or make it programmable, or better selectable with the PC and a USB connection!?

      • Hi Bob,
        I’m not sure if I got you. Mag+ measures capacity of receiver battery as is written in specification. As you measure it in Ah, you don’t need Voltage.

        • Bob

          Hi Roman,
          Ok, you measure in (m)Ah, but the LED starts blinking at a certain voltage. Why did you choose to let it start blinking at 4.5V? I thought it might help if you let it start blinking at a certain capacity, maybe programmed in advance for this battery?
          This way you can easily see if the battery is towards ’empty’..

  • Hi Bob,
    Voltage drop you can see at small segment LED display. Programming, USB interface, PC SW etc. This device would become quite complex, nobody will pay for that.

    4,5V I selected just under my experience as really last limit. Usually I don’t fly bellow 4,8V.

  • Miky

    Hello Roman,

    It’s disponible? what price please.


  • Hi Miky,
    yes Mag+ is available right now. Price is 38EUR+2EUR shipment. Orders at