[NSRCA-discussion] Mezon 90 Lite investigation

[Peter Vogel]

I misread the issue on my phone.  Indeed, it is very bad (even during
flight) for the BEC to get back-fed power from a backup battery, that's
what diodes are for and the DSM ESC has such a diode in place.

On Tue, Aug 20, 2019 at 6:07 AM Andrew Jesky via NSRCA-discussion <
nsrca-discussion at lists.nsrca.org> wrote:

> The issue I’ve found is if you leave the battery backup on it keeps power
> to the capacitors in the mezon so the second you plug in your 42v source
> there is no buffer in the esc and this will happen.
> You’ll see by disconnecting your main flight pack, leave the backup on and
> move the throttle stick. The motor will turn over just a little until all
> the energy is gone.
>
> What I’ve found is that always disconnect the backup when you unplug the
> main pack or have the esc arm and need to re plug in.This is critical if
> your doing any amperage checks.
>
>
> Andrew
> Sent from my iPhone
>
> On Aug 20, 2019, at 6:56 AM, Daniel Underkofler via NSRCA-discussion <
> nsrca-discussion at lists.nsrca.org> wrote:
>
> Matt, I'm of the opinion that his regulator in line with the backup rx
> battery would protect him (essentially acting like a diode).
> Admittedly, I've only used smart-fly regulators in this application.
> Dan
>
> On Tue, Aug 20, 2019 at 4:38 AM Matt Griffitt via NSRCA-discussion <
> nsrca-discussion at lists.nsrca.org> wrote:
>
>> All of the ESC from jetti will have the same issue. You need to put a
>> diode in line with the bec power supply and the RX. You can get away the
>> diode if you always plug your flight pack in and arm the esc and then turn
>> you 2s lipo pack on. As of right now the only esc that can take power in
>> both directions is the Graupner HV line of ESC. They work great and are
>> less money than the mezon.
>>
>> https://www.graupnerusa.com.
>> like I said , I am not aware of any other ESC with BEC that can take
>> voltage both directions . I hope this helps.
>>
>> Matt Griffitt
>> ADGaero.com
>> 334.380.8228
>>
>> On Mon, Aug 19, 2019, 10:52 PM Xavier Mouraux via NSRCA-discussion <
>> nsrca-discussion at lists.nsrca.org> wrote:
>>
>>> Hi,
>>>
>>> I have 2 planes with that ECS. The primary has 300 flights, the backup
>>> had 100 flights since the installation of that ESC.
>>> Both planes use the BEC at 6.2V and a backup 2S lipo with a radio south
>>> regulator at 5.7V.
>>>
>>> Getting ready for a 3rd flight on the backup yesterday, the ECS made
>>> sparks and smoke when I connected the battery. I took the ECS apart and
>>> found what I think is a FET busted.
>>>
>>> 2 observations: I accidentally left the backup battery and BEC switches
>>> ON after the 2nd flight about 10 minutes before and only noticed it after I
>>> connected the main battery. I may have touch the connectors twice in quick
>>> successions when connecting the battery.
>>>
>>> I usually turn the backup battery ON first to check the voltage to the
>>> receiver and then the BEC.
>>>
>>> See pictures in that album:
>>> <https://photos.app.goo.gl/gaN4bqG9BCgDyUzt8>
>>> https://photos.app.goo.gl/gaN4bqG9BCgDyUzt8
>>>
>>> Since I have the same ECS on the other plane, I want to understand what
>>> caused it and if I did something wrong.
>>>
>>> Abt idea what happened ?
>>>
>>> Could it be repaired or is it done ?
>>>
>>> Thanks you
>>>
>>> Xavier
>>>
>>>
>>> _______________________________________________
>>> NSRCA-discussion mailing list
>>> NSRCA-discussion at lists.nsrca.org
>>> http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
>>
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-- 
Director, Fixed Wing Flight Training
Santa Clara County Model Aircraft Skypark
Associate Vice President, Academy of Model Aeronautics District X
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