[NSRCA-discussion] Mezon 90 Lite investigation

Fri Aug 23 14:10:22 AKDT 2019

Is there a place where I can read this whole story from experiencing the problem to defining the cause and proposed  solution?  

Jim O

> On Aug 23, 2019, at 4:11 AM, tim pritchett via NSRCA-discussion <nsrca-discussion at lists.nsrca.org> wrote:
> 
> Building on Matt's comments, the Graupner HV 100 is a nice piece; lighter (after putting them both on the scale), cheaper, and higher ampacity than the Mezon 90, .  The only issue is that the firmware has to be the latest version to use BEC + backup battery combo., according to Graupner, and mine came with an older version.  
> Knowing this ahead, I pulled the power lead out of the receiver connector, and use just the receiver battery for the time being (opto-style).  If someone elects to go this route, just be sure the firmware is up to date before plugging both power sources into the receiver.
> 
> 
> -----Original Message-----
> From: Xavier Mouraux via NSRCA-discussion <nsrca-discussion at lists.nsrca.org>
> To: General pattern discussion <nsrca-discussion at lists.nsrca.org>
> Sent: Thu, Aug 22, 2019 8:29 pm
> Subject: Re: [NSRCA-discussion] Mezon 90 Lite investigation
> 
> Thank you all for the information and confirmation that it's most likely my fault ... :-(
> 
> Xavier
> 
> 
> On Thursday, August 22, 2019, 10:51:44 p.m. UTC, Derek Emmett via NSRCA-discussion <nsrca-discussion at lists.nsrca.org> wrote:
> 
> 
> FYI:  There's a nice article in the July K-Factor that covers redundant power systems.  It discusses isolating power sources, etc... 
> 
> 
> 
> On Tuesday, August 20, 2019, 02:33:56 PM PDT, Peter Vogel via NSRCA-discussion <nsrca-discussion at lists.nsrca.org> wrote:
> 
> 
> 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 <mailto: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 <mailto: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 <mailto: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 <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 <http://adgaero.com/>
>> 334.380.8228
>> 
>> On Mon, Aug 19, 2019, 10:52 PM Xavier Mouraux via NSRCA-discussion <nsrca-discussion at lists.nsrca.org <mailto: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 <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
>> 
>> 
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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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