KC8QPU

What systems are you guys using or have you made your own?

big_G

2 LiFe batteries, 2 switches into 2 receiver ports. Cheap and simple.

Anthony-RCU

My Feedback: (2)

Two Tech Aero regulators plugged into two receiver ports. One set at 6.9 volts and connected to the first two cells of the power battery. Important must be cells 1 and 2 if you use cells 5 and 6 things will break. The second regulator is set to 6.0 volts and connect to a 350 mah 2 cell lipo for back up. Power pack doesn't notice the extra load and I only use the back up for programming.
Search this and the pattern forum you will find dozens of ways to do this.

OhD

High voltage system:
Mezon ESC with BEC set to 8.0 volts to receiver
500 mah 2S LiPo through switch to receiver

Low voltage system:
Mezon ESC with BEC set to 6.2 volts to receiver
500 mAh 2S LiPo through Jaccio Perfect Switch Harness set to 5.7 volts to receiver

The 500 mAh pack is strictly for backup and the RC system is normally operating on the propulsion power pack in both cases. In the case of the HV system the 2S LiPo is being charged by the motor pack. In the LV system you will need to charge the 2S LiPo periodically depending how much time you use it to test and tune with it.

Jim

bem

My Feedback: (1)

Hi,
I use:
Jeti/Hacker Master Mezon ESC with BEC to supply servos+receiver with power and Scorpion Backup Guard (2 cell LiPo with curcuit that will let the Backup Guard kick in if voltage drop to 5 volt or below from BEC (or if BEC fail). Backup Guard weight is 38 grams.
I use this system on three F3A planes and have used this backup solution for total of 3 years without a single problem (that I have noticed).
It is a KISS solution for me, Keep It Simple Stupid.

/Bo

ltc

My Feedback: (3)

Jeti Mezon ESC as primary supply
2s LiPo as emergency backup
Jeti DSM-ESC for isolation/switching (magnetic switch for arming)
Jeti telemetry monitors voltage /current /capacity and switchover alarm

KC8QPU

Ok maybe I should have been a little more detailed. I want to use the speedo BEC but have read you can put in a diode circuit to also use a receiver pack in case something happens to the ESC. I believe that is the way it works.

ltc

My Feedback: (3)

Diode or MOSFET
depends on the design of the voltage switch you purchase

DagTheElder

Hi,
This gadget is all you want for redundancy.
http://www.optipower.co.uk/Home.aspx?pid=102&mid=202

bem

My Feedback: (1)

Hi KC8QPU,
What ESC with BEC (brand and model) do You use?

Have You checked this BEC Guard? (in combination with Ultra Guard if You want)
http://www.optipower.co.uk/Catalogue...&cat=135&cnode=

/Bo

bem

My Feedback: (1)

Do You know what the weight is on the Optipower Ulra Guard 430 Backup?
- The card only (weight?)
- The LED (4 grams according to homepage)

Card and their LiPo (430 mAh 2 cell Lipo) weight according to their homepage 35 grams, and with LED also it is total 39 grams.

An Ultra Guard card with maybe 250 mAh 2 cell Lipo could be lttle better for F3A usage, should maybe be possible to get weight of card+250 mAh 2 cell LiPo to be around 20 grams? For example a ThunderPower 250mAh 2 cell ProLite+ Lipo weight 15 grams. So how much weight for just the Ultra Guard card (without LiPo and without LED)?

/Bo

KC8QPU

Currently have a Gens Ace 100 amp ESC. I am sure that will be fine for now but just want to have a back up just in case.

DagTheElder

Hi,
The Leds will be wasted Money. Thats for E-
helicopter and not neccesary in a plane.
My advice, purchase the less costly one.

RuneG

Hi
what I have used the 2 year is wery simpel.
First I use a Futaba Fastesst reciver ,Jeti Mezon with bec( dont know if other ESC will work like this).
I use a simple 2S battery(no regulator) ca 200mah as backup Power this is just conneted directly to RX only a simpel swithc between, the idea is that the BEC in the Mezon hold the backup battery at 8V at all time , i know this is a bit lower than fully charge but will give me Power to land if the BEC or main battery fail.
Routine on the field is like this first Power up the TX then the RX from the backup battery then arm the main battery and fly when I land i turn off the main and then the backup.
I have newer charge the backup just Connected it after i bougth it and that is all.
I have newer had to use it so far but this simpel system has worked fine for about 200 flights.
If you Connect this to others ESC with Bec be sure that it will work with power from the backup battery

OhD

Yes, this is what I described above. For those worried about weight, you can't beat this. For redundancy you need two voltage supplies and two switches. This approach satisfies that requirement with no added components. For the low voltage case, the 5.7 volt regulator adds about 5 grams to the weight of a switch harness.

If you don't have an ESC with a BEC, I have flown a high voltage setup with a Jaccio regulator set to 8.2 volts fed by a tap at the three cell level on the propulsion pack and a 2s LiPo connected directly to the receiver through a plain switch. Again the backup pack is continuously charged to 8.2 volts during flight.

Jim

FinnSpeed

Jim and Rune, I agree that yours are the lightest and simplest systems with fairly reliable backup. But there are some weaknesses:
- What happens if the BEC fails in such a way that the output is shorted? Likely the backup tries to power the system but depending on the short circuit resistance, may deplete too fast.
- What if the BEC puts the full input voltage through when it fails? In this case the backup battery may go up in smoke and flames as well.

Of course these failure scenarios must be extremely rare and in most cases the backup works well enough to land the plane.

I have a similar system, switching BEC that outputs 8 V and a 2S 500 mAh backup battery but additionally I use a dual channel switch that has voltage regulators set to 7,1 V inside. This totally eliminates problems with the first scenario I listed and limits damage in most cases should the BEC put a too high voltage out. The weakness is that I have to charge the backup battery now and then, typically after 9 or so flights. I could fine tune the switch regulators so that the battery channel would output a bit lower voltage which would eliminate the need to charge almost totally. Now the load is shared almost 50/50 between the two sources.

RuneG

I can live With those possibilities Finnspeed, what I was looking for was a system than could be like "put in and forget" , that was active when I armed the main battery and was off when I put the plane in the car .
Could not that time find what I was looking for so this has done its job so fare .
One intersting thing i that on the Jeti Mezon if the prop spinns you have Power to you RX if the main battery is out.....we have tried this a few time... in real life
But when I start to use the OS gir motor it a bit harder to spin than a Hacker Q80 so thats why I wanted a backup

ltc

My Feedback: (3)

If you want 'set and forget' use something like this
http://www.boomarc.com/en/dualbat-2-...lating-circuit
Just 2 diodes in a common cathode configuration
No switching, just plug in 10s motor pack, 2s Rx backup pack(s) and go

ltc

My Feedback: (3)

BTW, when you spin the motor with no battery attached, it acts as a generator
When the voltage produced exceeds the BEC regulator output voltage requirement, it starts up and you get BEC output voltage
It is not harmful to anything

RuneG

I know that it will act as a generator , working With motors and generators i over 30 years but if any others ESC will let the Power og the"wrong" way I dont know.
And if any other ESC With BEC will tolerate a back up battery as I have I dont know either , but for sure I know With Jeti it Works.
I will look into Your solution but does that eliminate my RX swithc? and what about charging the backup battery , in my system the bec does that

ltc

My Feedback: (3)

No the diode will prevent the Rx battery from being charged
I don't like the idea of non balance charging a 2s LiPo in a plane (via a BEC) ; it is simple enough to remove it at home and properly cycle/balance charge it

A switch is optional ...

OhD

Yes. and not only does it charge the battery, but it allows you to read the 2S receiver battery voltage at your transmitter (if you have a system like Jeti's). I turn on the 2S pack switch first and read the voltage and then turn on the BEC. I just turned on the 2S switch on a plane I haven't flown since September and it is still reading 7.9 volts. Hard to beat that.

Jim O

RuneG

Well this weekend I had the first use off the backup system .
I was flying in the Swedish Nats/Grensecup in Karlstad and in the takeoff off my second flight I lost engine power and the model landed about 30 meter after takeoff with some smal damage(UC Mount was slighly damage).
I really dont know what exactly happend but the Mezon is completely dead both ESC and BEC , if it is my bacup battery that killed the Mezon or what happend I dont know, but at least the backup kicked in.
So I think I try the Optipower

kdunlap

My Feedback: (12)

PowerBox system. Perfect.

http://www.chiefaircraft.com/pbs-6310.html say no more..

RuneG

WHat can I say when I took the system out off my model I found the fault it was a bad connector , so when I change that everything was ok .
I order a New backup system yesterday so when it arrives I will give that a try.