RCKen

My Feedback: (9)

Rob,
As Isaid above, I've used the Go Pro camera, but it's not my prefered camera. If you want to know what Iprefer it's the Contour HD. Full 1080P resolution with a much smaller mounting footprint. It's easier to mount as it's a bit smaller and more sleek than the Go Pro.

http://www.amazon.com/ContourHD-1080...5986898&sr=8-1

Ken

c_makhija

With battery chemistry changing so rapidly its getting difficult to check what is the stop fly voltage for different batteries. In most of my jets i now install 2- 2300 Mah A123 packs. On an average most of my jets consume around 150Mah per flight, if i have 5 flights without charging i would have consumed 750 Mah, which i think is safe even if one battery fails.

Chatty.

mikedenilin

My Feedback: (67)

A123 BATTERY Has a very constant voltage of 6.6V. Do you think it's safe for digital servos? Li-Po voltage seems too high for servo if we don't put regulators in between the batteries and receiver. Any suggestions?

Mike

c_makhija

I personally use powerbox products in all my jets, but i see a lot of people using A123 packs directly plugged into the Rx using digital servos on them with success.

Chatty.

Nhalyn

5 elements NiMh at full charge can deliver up to 7.5V just out of the charger and go down to 6V after. All brand Rx and high powerservos are designed to work with that sort of voltage. So plug an 6.6V accu is not a problem, like A123 battery.

That's also why an 2S lipo battery can't bu pluged directly on a receiver (8.4V full, 7.4 nominal), which is over most of product for something else that burst. You need a voltage regulator.

But when you plug two accus on a receiver, you need a meaning to ensure accu #1 can't directly discharge himself in the accu #2, thus comming to a total power of 0 volt quickly. This meaning can be a simple diode. I'm amazed to read here that lot of people seem to plug twoseparate accus directly on a receiver ! Doing that, you don't have a redundant system, you only have like a single accu with twice capacity.

I'm flying nearly all my model (all my recent ones) with 2S lipo with regulator of different brands, from cheap to powerbox champion. Doing that, I ensure having a regulated 5.5V or 6V (different brands) whatever the current isin my plane, i.e. whatever the effort on servos, sothat they always perform the same. Twice accus installation with all those regulator ensure a totaly redundant installation. This had save a giantglider some times ago...

JohnMac

What you really need Rob, is more power. Then you would not have to worry about the weight

GR7Racer

A couple of points that I think are relative to this discussion...

The JR 1222 RX has dual inputs for batteries. It also has circuitry that helps match the voltage between the batteries so they are drained fairly evenly. It also isolates a battery if it fails. This receiver also uses a soft switch that isn't part of the circuit powering the RX and the servos.

A123 batteries, and really all of the LiFe batteries have a very low voltage drop under load. Even a single 1200mah pack would be enough to power a Jet like this for a flight if it was charged above 3/4 capacity. These batteries will easily stay above RX voltage cutoff, or minimum servo voltage when fully charged... even under a heavy load .

A123/LiFe batteries don't need a regulator when used with modern radio equipment. Some folks insist on using regulators though, which is one more component that can fail and cause trouble.

On this installation, were regulators being used? Or were the LiFe batteries plugged directly into the RX and the soft switch used?

KMac

AndyAndrews

I would say 100% not the go pro. Ive been using mine for a couple of years now on multiple jets and never had even the slightest problem.

I would look to your batteries. There is no way in hell I would use 1200 mah batteries when there are so many better alternatives out there.

c_makhija

c_makhija

No regulators, 2 A123s directly into the Rx using 2 heavy duty JR switches.

JohnMac

Hi KMac,
That is important information. I had not realised that JR made dual input Rx's too now. This totally changes the scenario is this Rx was used then we can discount a single Rx battery pulling down the second battery. This being the case, if the battery was charged and in good condition it is very unlikely that the power supply was to blame.
I have started using Emcotec BIC soft switches. It is more than a switch as it is a regulator too. With A123 it can be set to give a steady 6V output, but one of the main benefits is that it logs average and maximum current. I set each servo up using it. Also i then check the overall current the model will pull and I checkit at the end of a days flying. And sudden increase in current logged tells me of a problem, hopwfully befor it gets too far.

olnico

Andy, for information all my SuperPhoenix use dual A123 1100 mAh 2s1p packs. Direct input into Weatronic micro12 receivers.
The first Superphoenix is now 5 years old, has done 300 flights and 900 landings with this configuration. It is still flying on a regular basis.
Overall I have accumulated 600 flights with the 3 airframes on this exact same setup.

All the planes are equipped with 8 JR 3421 and Merlin 90/110 and are regularly flying up to 450 km/h ( 280+ mph ). I do a maximum of 4 flights from a freshly charged set of batteries.

So it really comes down to the quality of the install/components and quality of the battery monitoring ( internal resistance check and logging during each charging cycle ).

olnico

Hi Jack, John, Mike and others. I see an amazing amount of useful information here not related to the GoPro.
I am opening a new thread related to sizing the power source for jets...

http://www.rcuniverse.com/forum/m_10292301/tm.htm

c_makhija

While most of my 120 size and above jets use 2 2300mah LIFEs, my small savex l39 and Avonds Rafale use 2 1100mah packs. Like Oli mentioned hundreds of flight on these jets and never a problem so far.

Chatty.

gruntled

He stated earier that the reciever used was not of this type that offers redundancy / isolation.

GR7Racer

I think he mentioned that he was using a JR 1222 RX....that one has built in dual battery inputs that employ large gauge wires with heavy duty connectors and circuitry that balances the batteries and offers some isolation.

He mentions that he was using two heavy duty switches between the battery and the RX, and not the soft switch that comes with the RX. Not sure why you would do this as this puts components into the power circuit which might fail. These heavy duty switches typically still use fairly small gauge wire that limits their current capacity and somewhat defeats the benefit of having the powersafe RX with its larger wires and connectors. The JR/Spektrum RXs with the powersafe features are really well designed and very applicable to larger models and Jets where current drain is high, and battery redundancy is valuable. Used with the included softswitch, there is very little that can go wrong with the power supply side of the RX.

Using the two heavy duty switches between the battery and the RX also presents the possibility that only one switch was turned on before the flight, an accidental or unintended occurence that can lower/eliminate your redundancy and put more load on your single/smaller battery. Still, with only one switch on, and only one battery supplying current...even a smaller 1200mah A123...the RX and servos should still function even under a load of 3+ amps. Assuming the battery was charged 75% or greater.

KMac

GR7Racer

Ok, I've gone back through the thread and mistakenly read Mike Denlin's post referencing the 1222 RX and thought that was the equipment being used in the airplane that had the trouble. Realize now that it was a 9ch RX, and probably not a powersafe RX.

My info above still applies to anybody else putting equipment in a Jet....strongly recommend JR/Spektrum powersafe receivers with the use of the included soft switch. A123/LiFe batteries with no regulators is the way to go too. These batteries and their higher voltages are perfectly fine with digital servos and most analog ones as well. Avoid regualtors if at all possible. They are one more point of failure.

Sorry for the hijack.

While a dead short in a battery is a possibility, it is very remote. A dead short in a switch or its related wiring is more possible. Damaged wiring to a servo, switch, or battery due to heat, chafing, etc is also a possibility. Unfortunately, there's a buch of possibilities... Interference from a GoPro is pretty unlikely, as is a "lockout". A failure in a connector or wire to a remote RX could cause a problem. Was more than one remote RX being used? This would improve your chances of surviving the loss of one remote RX.

Sometimes it's just not possible to diagnose these things after a crash and a fire. All you can do is look at all of the possible things that could have gone wrong and try to minimize the possibility of them occuring in your next install.

KMac

David Gladwin

1. But when you plug two accus on a receiver, you need a meaning to ensure accu #1 can't directly discharge himself in the accu #2, thus comming to a total power of 0 volt quickly. This meaning can be a simple diode. I'm amazed to read here that lot of people seem to plug two separate accus directly on a receiver ! Doing that, you don't have a redundant system, you only have like a single accu with twice capacity. (Nahlyn)


2. Even if you get this fairley gentle mode of failure in a twin battery system, without diodes to separate the two batteries, the one that goes bad will always drain the good one. (JohnMac)



Battery specialist :

Q: Ok, that’s pretty kewl.. but my instructor sez I need diode protection or the packs will cross-talk or try to charge each other.



A: Sorry.. your instructor has been gaffed by Under-Informed Magazine Columists or the Battery Mis-Information Committee of your local fields Wives Tale Tag Team. There is NO need for diodes or a 'backup' circuit board (something else that adds weight, complexity and another possible failure point) and in fact there's no flight-safety significant energy transfer between packs at different charge levels.



You can test this yourself.. just plug a discharged pack and a fully charged pack together in a Y-Harness and check the two packs the next day.. You’ll find the system will pass a load test if checked through the ‘Y’, and you’ll also find that less than 20% of the charged packs energy has been ‘used’ by the discharged pack when you separately cycle-test the two of them. Next, consider that your average flight is 10-12 minutes, not 24 hours! The mythical "Energy Transfer Between Packs" scenario is simply NOT a flight safety issue and checking both packs before flight with a loaded ESV will certainly 'pick up' a weak pack before you fly it anyway!


It seems opinions vary !

Regards,

DG.

Nhalyn

Maybe with Nimh battery, but have you done this test with low internal resistance battery like 30C lipo pack or A123 ?

Not sure it will work the same... And would like to verify that !

HarryC

My Feedback: (1)

That's true David, but it doesn't account for the other failure which can be a short inside the mechanical switches that are often still used. Shorts in switches do happen and when they do, both batteries will be flattened very quickly, but if diode protection is fitted then at least the battery on the other side is protected.
H

AndyAndrews

Thats a very good record of success. I guess I'm not comparing apples to apples because I don't use A123s yet, I use lipos for the most part. I wouldn't use 1100 lipos when you can double that just as easy. I'm still a late adapter to A123s. Still can't get over the B1 Bomber dude losing his F4 a few years back after installing the A123s using all of the recomended components and chargers.

bearcatt1

My Feedback: (1)

If this thread is still thriving, here's an update. YES the GoPro 3 wifi DOES interfere with 2.4. When streaming from the camera to your phone or tablet. I've had that experience just last week. I make 3 flights, then landed and placed the GoPro onboard my Cessna 182. I headed for take off, as the plane ascended it dipped and all of a sudden when into a full loop about 30' above the runway( I believe it went into Failsafe mode) Then crashed onto the runway. GoPro recorded the whole thing. Will post a video soon on YouTube. (mrfallenasleep)

Im still trying to reproduce the crash on my bench testing. NTSB at home with video. OUCH!

wojtek

My Feedback: (73)

Guys, the new GoPro DOES have WiFi on 2.4 !! This is to work with the GoPro wifi connected smartphone app, or the key-chain remote. The camera acts as a hotspot for client apps to connect to..


Voy
www.all-scale.com

invertmast

My Feedback: (23)

Now it does, but two years ago when this thread was started it didnt.

wojtek

My Feedback: (73)

good point ... i should have read looked at post date ...

but it is an important point however for anyone using these currently. The GoPro with WiFi turned on will potentially cause interference to the receiver. I know my DJI phantom quadcopter went into return home mode ( basically failsafe) because of this after getting not too far away from the TX ... Granted this is a low quality stock TX set up, but still shows there is potential for trouble ..


Voy
www.all-scale.com