Esc with bec and backup power
 

Hi
have been flying over a year With Jeti Mezon and a Jeti Sbec .
This has worked without any problems so fare have also landed without the battery conected at one flight , I think that is the motor work as a generator because a the time the plane slowed down on the runway the radio stopped working, this was With a Hacker Q80 , now I have change the motor to a OS belt drive and this one dont spinn so easy and I have started to think about some backup power to the RX.
I have looked at the Scorpion Backup guard , but this one you have to Power up and shut Down , is there any Device that can be Connected to the system that you can just forget?
What are the diffrent system that are avabile

Never mind. You have to turn it on and off.

Here is one possible solution:
1. Use a Jeti standalone BEC (several units to chose from), connected to your flight battery. Cut off the switch so it is always ON (or leave the switch and just hold it in the ON position). The standalone BEC will be connected to your flight battery (assume 10s)
2. Use a Jeti ESC with built in BEC (not the OPTO version). Cut off the switch so it is always ON (or lave the switch and just hold it in the ON position). The ESC will be connected to your flight battery (again, assuming 10s since this is F3A)
3. Decide which unit you want to be PRIMARY and which unit you want to be BACKUP. Set the PRIMARY to say 6.0VDC and the BACKUP to a lower voltage, say 5.8VDC.
4. Take the standalone BEC output AND the ESC/BEC output and connect them to the inputs of a Jeti DSM-ESC.
5. Connect the DSM-ESC output to your receiver.

The DSM will automatically connect the higher voltage to your receiver. In normal operation, this will be the PRIMARY. Should the PRIMARY fail, then the BACKUP automatically is connected. If you have telemetry on your radio, you can set an Rx voltage alert so you will know the switchover has taken place ; otherwise you would have no idea just flying the plane.

No switches; the system automatically powers up as soon as your 10s flight battery is connected. You will need a simple Y adapter to connect the flight battery to both the ESC and BEC.

There are many other configurations that would address your concern, but this one is pretty straightforward and simple.

ltc, that is a good suggestion but what if the flight battery fails?

Personally, I'd like to see a system that would consist of a high voltage BEC, say 5 A / 6 V (or adjustable from 5.5 V to 8 V), a connector for 2S backup battery and a charger circuit that would keep the 2S battery charged. Additionally there should be at least a power switch and a load switch with logic that would switch over to the backup immediately if the BEC output goes out of limits. Optionally over voltage protection and some monitoring functions could be included.

The idea behind this is to avoid dual RX batteries that you need to remember to charge every time and save weight too. I have heard the heli guys have something like this but so far I have not found one optimized for F3A use. If I don't find anything, I might just design this myself... ;) Rune, I think we will meet at the Nordic F3A championships in a few weeks. We could discuss this there and find out if others have same kind of needs.

Easy enough to design what you described.
BTW, how common is a total loss of 2 5s packs in a plane?

I haven’t used one of these yet, still using the Scorpion BUGs, but you might want to check out the Optipower Ultra-Guard. here is a link: http://www.optipower.co.uk/Catalogue...0COMBO&cat=132

It turns on by itself when power is connected, looks at the voltage and chooses a voltage just below the system voltage to activate. So if it sees 6V, it picks something like 5.8V to use as a trigger to activate. It is charged by the system and can have a light as an option to tell you it has activated. You do have to turn it off yourself, though I have read somewhere that some Jeti users have figured out how to turn it off remotely.

Personally, on a plane, I would prefer to turn on the system with the Scorpion BUG to check everything before I have armed the motor. But, that’s just personal preference.

Tom M

Hello Rune,
This is fascinating! Thank you for this story.
Regards,
Dean Pappas

In my opinion you want to be able to turn on the backup to be able to check to see if it's working. I have hundreds of flights using the Jeti BEC driving high voltage servos. My backup system is a Tech Aero PLR5 set at 6.2 volts with a 350 ma 2 cell lipo.

http://www.tech-aero.net/plr5

I check both sides every flight. I turn on the backup regulator first. When the servos kick in, I turn it off and plug in the main flight pack. When the BEC kicks in the servos, I turn the backup regulator back on.

I use a similar setup along with Jeti telemetry and alarms. Part of my preflight is to run thru the switch sequences you described (I use a Jaicco PerfectSwitch/2s Lipo backup regulator set slightly lower than my Jeti ESC BEC primary) and verify the Rx bus voltages on my Tx display for each along with alarms prior to heading out to the flight line.
You quickly get used to the '2 switch preflight', but if the OP wants a switchless solution, it is possible as to do as well.

I will not going to the Nordic F3a missed With one Place ....the Scorpion is a good solution but what if you forget to turn it on that flight the motor battery fail or you forget to turn it off.
The setup I have now With a Sbec from Jeti I just plug the battery in and fly...I want it to be idiot proof ...completely idiot proof

Maybe the optipower is the thing I look for??

Rune, I think the Optipower could be the solution. It is very similar to what I have been planning with the exception of built in BEC circuit and it seems to run under software control. I'm planning something that would not have a processor at all. No software code, no bugs... :)

Sorry to hear that you did not make it to the Nordic Championships.

Hi Rune,

Scorpion Backup Guard (BG) works fine as such but has the drawbacks You have mentioned. I have used the BG for two years now, in MythoS 125E (two seasons) and in MythoS Pro (1,5 seasons). I use Master Mezon ESC with BEC in both (and Hacker A60-7XS, Q80 14-XS).

I was thinking about Emcotec DPS Micro SingleBat (F3A Edition) or the DPS Micro DualBat (F3A Edition):

SingleBat (for single battery):
http://shop.rc-electronic.com/DPSI-S...=A11064&p=3664

DualBat (for two batteries):
http://shop.rc-electronic.com/DPSI-S...r=A11057&p=541

It has electronic on/off switch controlled by an external magnet from outside. Drill a 5 mm hole in the fuselage for the LED and the DPSI Micro can be glued to the fuselage’s inner sidewall, then You will easily see when it is turned ON.

The DualBat can be used with one battery also, I asked Emcotec, but then You must use Y-Cable they said so You feed both connectors on the DualBat.

/Bo

You could also consider using the new Jeti DSM-ESC, designed just for this application

http://www.espritmodel.com/jeti-elec...y-dsm-esc.aspx

It is based off the successful DSM-10 design

If I understnd correclty the optipower has to be turned off? mayb its not possible to find exactly what I'm looking for?

I've considered removing the regulator as well, but still don't feel comfortable non balance charging a Lipo pack, even if it's just 2s. It just seems like a bad idea.
I purchased a RadioLink CB86 charger for all my smaller Rx packs and it has made charge/discharge very easy for all the planes.

Another option, although heavier, would be to install Rx packs with built in balancer electronics (Booma and Duraflite sell these IIRC)...then it's simple and safe to charge in the plane.

I've been running the mezon bec with the 2s lipo without regulator through a switch to the rx. Haven't had any problems with this setup over 50 flights now.

One big advantage of this setup if you have the telemetry, is you know if the 2s LiPo is charged. With the regulator in the circuit you don't know the state of charge of the 2s unless you go out of your way to measure it. Unfortunately a 2s has too high a voltage for 6 volt servos.

Jim O

Yeah, I'm using HV servos with the setup. Been running the jeti telemetry with the profi box through the mezon esc with futaba tx, rx. Works really well with access to a lot of info and alarms.

so you have a separate 2 s lipo With a simpel switch Connected to the RX besides the bec from the Mezon?? and no regulator on the 2s pack?
as you read in my first post my consern is if I lost the Power from the motor battery in flight, With the Q80 we have "tryed" this several times and as long as the motor spinns you have Control when it stops ... radio is out but the OS gir motor I use now do not spinn by it self in the air at idle ..maybe if the ESC is out and brake is disabel ..havent tested that but its pretty hard to turn by hand

That's it. Runs in parallel with the bec. bec keeps the batt at the same voltage as the bec output. Never worry about charging it, I use 7.9V and its 250mah. You do have to turn the switch on and off and I try to get the batt to the same voltage prior to hooking it up. ie, I don't attach a fully charged 8.4V batt to the system, its at 7.8 or 7.9V prior to hookup.

Never heard of a spinning motor powering up an esc's bec, that's a new one.

I have been using the Opti-Power Back Up for about nine months. I used to run two 2s 450mah packs run through Tech-Aero Regulators operating in parallel for redundancy. I reconfigured to incorporate the Opti-Power Back Up. I now run the Tech Aero Regulators in Parallel off a single main pack's balance lead. (Must be the first pack in the series) To that I added the Opti-power Back up. The Back Up battery trickle charges off of the main pack so it remains charged and ready to take over if needed. An optional 3 LED strobe indicates when it's armed and continuously flashes if main power is lost. I flew half a sequence with the main pack supplying power, landed - turned off both regulator switches and flew the second half of the sequence on the Opto-Power Back Up. The Flashing LED was clearly visible from the ground and gave me confidence that I'd know if I lost main power. I also looked at the Scorpion Back Up. It essentially works the same except it beeps so there no indication in the air of a problem. I have switched all of my electrics, planes and helicopters, to this configuration and haven't had a single issue.

The one lesson learned is to disconnect the battery from the circuit board as it will slowly discharge the battery if left connect for extended periods. If I flew every day I'd just leave it connected.

James

I have been using the Optipower Ultraguard all this season and it have been prefect. I am running a Power box digiswitch with a 850mah 2s as the main supply. I have the Ultraguard setup with the Fasstest telemetry through the Futaba 14sg. I have set a warning for low voltage on the rx. The digiswitch runs at 5.9volts. Anything lower the 5.7 will activate the alarm. See video.

https://www.youtube.com/watch?v=75Hoih2X72g