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SRXL2 SPM4651T Telemtry with Hobbywing V4 and BEC Voltage
Posted: Mon 27. Apr 2020 16:12:53
by Yabba
Hi,
just installed my first SRXL2 receiver SPM4551T. As far as I've found out, the receiver itself doesn't seem to provide any BEC voltage, just like the Hobbywing ESC.
Can it be realized by software (in the feature) that the Spirit supplies the own supply voltage to the telemetry if an ESC is connected that does not supply a BEC voltage to the telemetry?
Best regards,
Michael
Re: SRXL2 SPM4651T Telemtry with Hobbywing V4 and BEC Voltag
Posted: Mon 27. Apr 2020 21:35:34
by ZeXx86
Hi,
no, it can't be realized.
Spektrum telemetry receivers can sense BEC voltage through analog input pin.
But input voltage can't be exceeded.
Re: SRXL2 SPM4651T Telemtry with Hobbywing V4 and BEC Voltag
Posted: Wed 29. Apr 2020 5:37:08
by chris_0815
As far as I understand the question, Yabba is asking whether the BEC voltage can be sent from Spirit, if the receiver itself doesn't do it.
The answer is: yes, it is possible (in principle). The SRXL2 protocol does allow the Spirit unit to feed in this information. E.g. MSH brain does that in case of the 4649t (AFAIR).
Would just need a small Spirit firmware update ...
chris
Re: SRXL2 SPM4651T Telemtry with Hobbywing V4 and BEC Voltag
Posted: Wed 29. Apr 2020 6:12:47
by Yabba
Chris, that is exactly what I mean

Thanks!
Re: SRXL2 SPM4651T Telemtry with Hobbywing V4 and BEC Voltag
Posted: Wed 29. Apr 2020 6:24:26
by HeliMLM
chris_0815 wrote:As far as I understand the question, Yabba is asking whether the BEC voltage can be sent from Spirit, if the receiver itself doesn't do it.
The answer is: yes, it is possible (in principle). The SRXL2 protocol does allow the Spirit unit to feed in this information. E.g. MSH brain does that in case of the 4649t (AFAIR).
Would just need a small Spirit firmware update ...
chris
... another example is j-log (s32): j-log's own voltage is sent via (in my case) Spektrum telemetry as "Esc - BEC Voltage". should not be a big deal i guess too...
Re: SRXL2 SPM4651T Telemtry with Hobbywing V4 and BEC Voltag
Posted: Sun 17. May 2020 6:53:07
by Bladecrasher
Michael, I was hoping you might share your experience binding the 4651T in your set-up and any tricks you may have learned in that process. I have been unable to get my 4651T to remain "bound" after power-cycling the Spirit. Extremely frustrating and wondering if the 2.8.2 FW I have installed is the issue or what...
Initially, I pressed the "bind button" when powering up the unit. Then bound to my DX9. All seems good and I get ESC telemetry , but when I power down and restart, the 4651 is flashing again waiting to be bound.
Did you have any issues getting your setup working?
Any thoughts are appreciated.
Re: SRXL2 SPM4651T Telemtry with Hobbywing V4 and BEC Voltag
Posted: Sun 17. May 2020 8:51:54
by Yabba
The only issue was failsafe not working, so I switched to a Spm4649t.
Re: SRXL2 SPM4651T Telemtry with Hobbywing V4 and BEC Voltag
Posted: Sun 17. May 2020 9:12:53
by fassla
May I ask if you updated the SPM4651T - or at least which version you are using.
There have been 3 updates I did so far on the SRXL2 Receivers, last one is dated April 17
looks like this updates can solve both your problems.
attached the readme - i found on spektrumrc
Version 2.39.0 (April 17, 2020)
-------------------------------
- Fix bug in RF reception in EU mode that caused invalid RSSI reporting and increased fades in some radios (thanks chris_0815)
Version 2.38.2 (March 9, 2020)
------------------------------
- Fix SRXL2 telemetry behavior when used with AR6610T or AR637T as a remote receiver
(NOTE: AR637T/AR6610T must be v2.34.1 or higher to realize the full benefits of this improvement).
- Set default SRXL2 channel data to failsafe values during init instead of at RF connect.
- Improve bind reliability.
Version 2.37 (December 17, 2019)
--------------------------------
Re: SRXL2 SPM4651T Telemtry with Hobbywing V4 and BEC Voltag
Posted: Sun 17. May 2020 9:27:35
by Yabba
Are you asking me or Bladecrasher? I updated the Spm4651t to version 2.39.0 and my Spirit2 is on version 2.8.0
Re: SRXL2 SPM4651T Telemtry with Hobbywing V4 and BEC Voltag
Posted: Sun 17. May 2020 10:53:15
by HeliMLM
Bladecrasher wrote:Michael, I was hoping you might share your experience binding the 4651T in your set-up and any tricks you may have learned in that process....
Hi, no tricks at all...
i updated the 4651T to newest firmware (2.39), connected it &bound without any problems. the reason mine too is temporarily downgraded to 4649T is the non-working failsafe (to be solved on Spirit side) and problems in displaying correct RSSI in telemetry screens for some EU Tx models (in work by Spektrum dev team). during my tests on failsafe and RSSI i've used all available firmware versions on 4651T and 2.8 as well as 3.0 on Spirit... never any topics with binding or loosing bind.
just check if your bind button is jammed... the whole plastic case is only snap-on so it can be easily opened with a sharp flat screwdriver or similar (mine popped off once when playing around)
nb: one thing maybe... when swapping 4649T / 4651T - some of the higher channels (AX2/AX3) where reversed between the 2 of them iirc.