Lucky Escape !

[RaySky]

It was one of those days when the wind was from the right direction to fly  :) maybe a little breezy but well within the limits  :D
All it needs is to top off the charge on the packs and off to the flying field... in my case the local flying field is right outside the back gate, whilst I wait for my T1000FC autopilot/RTH I opted for a LOS flight as technically I am inside a class D airspace so flying FPV is a NO NO ! However ( ;)) I just couldn't resist knowing if the Vid link range was good, having decided to flying LOS I could see no reason not to power up the Vtx and leave the Vrx and goggle box with my missus and ask her to check it for a few mins in the back garden.
Off I went and enjoyed 20 mins swishing back and forth getting more familiar with my new aircraft  ;D
On returning back to base the first question was "what did the screen look like" Answer was total static when I checked it even though it was powered up when it was launched...

I couldn't believe I was out of range during the flight and checked the memory card and it was recorded perfectly so I know the camera gave a vid signal to the Vtx but the Vrx didn't receive a signal!
I was surprised to find the Vtx 2S pack had an output terminal voltage of ZERO
I had never seen that before so it became a quest to find out what went wrong, first I did the wire pull check...
The negative was rock solid but the positive came away...



Close inspection looked like it was what I call a tack solder joint... but I needed to go deeper to see the problem so off came the shrink wrap




This is a tiny 2S pack but size makes no difference... its job is to provide very important and needed power to the Vtx only at this point in time!
Once I stripped the pack down I checked how the wire came away so easily and found the wire could never have been soldered correctly in the first place!



Even though I have used this very pack for probably 20+ flights for a small fun glider motor pulling 2-4 amps I was staggered how it failed,

It was and is a lucky escape because I may have decided to power the T1000FC directly from this power source instead of via the ESC
I have since checked all the other packs and all are good to rock and roll

[Billy_boy_2010]

Blimey! Is there any way to inspect this without ripping the battery apart?

[Charliewalker]

Lucky to get away with that, I've had wires on the balance leads come away twice but not power leads, I suppose thats a + for powering everything from the same power source ie no video = no flight. 
but don't help if it happen in flight does it.

[Coyote]

Very lucky to get away with that.

Blimey! Is there any way to inspect this without ripping the battery apart?

You can, but with extreme caution ! Cut the end and expose the tabs, I then use reinforced tape to insulate the end again. I say extreme caution because you are going to be having  metal knife in very close proximity to live pads just waiting to be shorted out on high discharge battery :) 

[RaySky]

Blimey! Is there any way to inspect this without ripping the battery apart?

Billy, I gave the other packs a gentle but firm tug to see if they would also come away but they are fine and solid  :)

Charlie, I was so lucky to be on a LOS flight, I think using one battery for everything is putting all your eggs in one basket!
I have been soldering since I was 10 years old and I have never seen a soldering joint done so badly! I can only assume it was the first one on the line the day it was made and the welding gun wasn't up to temperature,
it could only have been the tape and shrink wrap holding it in place and making contact,
It makes me wonder how many unexplained RC crashes may have been caused by something like this  :+

I made the simple error of thinking because it was made in a factory with quality control IT Must be Good
I wouldn't mind if a balance wire came away as it just means charging cant be done until its back in place but to loose power whilst in flight OMG  :o

[Charliewalker]

Yes I thought "Zippy" had a good reputation & wouldn't put out anything that was below par,but I suppose you'll always get one that slips through.

[dogzilla]

In my opinion a single power source is the way forward, though ideally with parallel flight pack. Worst case one pack fails mid flight and you see your voltage drop. Now time to head home.

I've read sooo many threads where people have had accidents or near accidents because of multi battery setups. Also the thing about flight packs is that it's usually very obvious when there is a problem with them because they are stressed hard on take off. It's not like a receiver battery which is basically a ticking time bomb if it just decides to fail one day.

There are two ways to achieve better reliability:

1. adding redundancy
2. removing single points of failure.

Separating your video + flight pack does neither in my opinion, it actually adds another point of failure. Your main flight battery can still fail and so can your VTX. It's very easy to think that by splitting them you are increasing your resiliency but it does the opposite.

I see it like this, you have two sockets at home, lets say they both have 10% chance of failing at any time. You can either plug both your computer + your screen into one socket via a gang lead. OR you can plug your computer + screen separately into each socket.

You say, but it's better to split them up, at least then if my screen goes off my computer stays on. But it's still unusable? And what if your computer goes off but your screen goes on? You are equally stuffed. Better to plug them both into the one socket and take the 10% chance than plug them in both and double your odds to 20%.

[Ynot6]

 :yeahthat: my set up is separate only to the point of my FPV kit runs off the balance plug, and my FC and motors run off the XT60.

[marcin]

This is another Zippy lipo !!

I change my mind about zippy lipos long time ago ,and recommend to everyone stick with turnigy  ;)

[RaySky]

In my opinion a single power source is the way forward, though ideally with parallel flight pack. Worst case one pack fails mid flight and you see your voltage drop. Now time to head home.

I've read sooo many threads where people have had accidents or near accidents because of multi battery setups. Also the thing about flight packs is that it's usually very obvious when there is a problem with them because they are stressed hard on take off. It's not like a receiver battery which is basically a ticking time bomb if it just decides to fail one day.

There are two ways to achieve better reliability:

1. adding redundancy
2. removing single points of failure.

Separating your video + flight pack does neither in my opinion, it actually adds another point of failure. Your main flight battery can still fail and so can your VTX. It's very easy to think that by splitting them you are increasing your resiliency but it does the opposite.

I see it like this, you have two sockets at home, lets say they both have 10% chance of failing at any time. You can either plug both your computer + your screen into one socket via a gang lead. OR you can plug your computer + screen separately into each socket.

You say, but it's better to split them up, at least then if my screen goes off my computer stays on. But it's still unusable? And what if your computer goes off but your screen goes on? You are equally stuffed. Better to plug them both into the one socket and take the 10% chance than plug them in both and double your odds to 20%.

i am a new kid on the block when it comes to fpv and still on a massive learning curve, i understand the idea of reducing points of problems to as few or one but still see it as all the eggs in one basket... all or nothing!
At present i have 3 batteries, ESC,Vtx and camera battery built in, if any pack fails i am still left with something  ;) and something is always better than nothing in my book.
If i loose the camera and vtx i can still fly los, if i loose the esc i loose motor and control but maybe can see where it lands/crashes.
What i have learned is... IF it can go wrong it Will go wrong lol but being an optimist i still like the idea of having something to work with than to panic like crazy when the screen goes to static fearing its a total loss of everything.
i Imagine everyone has different points of view on this one and for different reasons.

R.

[Brucey]

I'm with dog on this, one battery for everything.
You say that if the vtx battery fails you can fly los. Have you ever tried taking the goggles off and try and find the plane in the sky. If the brightness of the sky doesn't blind you the sheer panic will!
The other problems are, remembering to charge all those batteries, human nature dictates that we will forget stuff.
And how do you monitor the second battery in flight? Most osd's will only monitor 1 voltage. If that voltage starts dropping fast you won't know till it goes dark... cue the panic!
In this video, I was monitoring the voltage and current, all of a sudden the current drops to 0, I had to assume the motor had stopped, which it did. Immediately turned for home and saved the plane. Without that info I would of wasted time and altitude trying to work out what was going on
http://youtu.be/zgvQRvi11_c

[Gundummy]

Grrreeeeaaat stuff Brucey!! I like those sort of clips.

(So what was it in the end?)

[Brucey]

Thanks. It was a tricky fault to find. When I got home it was working fine. So I ran the motor for a while and it stopped again. Using a temperature probe (my finger) I was checking the esc and motor temps, nothing wildly hot, then I touched one of the bullet connections, wow it was hot! Turns out a badly soldered bullet connector was creating a lot of resistance, so it got hot enough to unsolder itself.
I don't have the bullets on that plane anymore.
But it did prove how well the venturi can glide!

[Xup]

Same, Only use 1 bat for everything, less to go wrong/fail!.

A 2-3 flight ZippyCompact (one of the early batch 8awg wire)

[Lola]

Nice flying mate, well done!


If it looks right, it'll fly right.