SpinnerRow

I drew this up for a friend and thought I would share it with you guys.

All Day Dan

My Feedback: (5)

Spinner, you’re not going to have any friends left if they comingle their receiver and ignition electronics like that. That is completely contrary to all the radio manufacturer’s setup advice. Dan

pilotpete2

SpinnerRow,
I would only go the IBEC route with a 2.4Ghz system, never with an FM/PPM system. I fly all my gas engine models with either a single 2300mAh A123 pack to the receiver and ignition, or two 1100mAh A123 packs also to the receiver and ignition for pack redundancy, no issues. I would of course make sure to run a good range check.
Pete

SpinnerRow

LOL! Yea, yea, yea......

Been doing it this way for the last three years and have three planes flying with this setup now.

All Day Dan

My Feedback: (5)

Spinner, that's good news that the setup has worked so well for you. That's the problem with radio frequency interference. You never know when it is going to occurr. That is why you have to protect yourself against it at all times. Send that sketch to your radio's manufacturer and see what they say about it. Please post their comment. Here's what Futaba has to say on their website. Dan.
http://www.futaba-rc.com/faq/faq-gas.html

TimBle

Spinner, thats prettymuch the same set up I run.

dirtybird

My Feedback: (5)

That was written years ago. Outdated advice for 2.4ghz systems.

All Day Dan

My Feedback: (5)

Good point dirtybird. It is currently posted at their website. Send them an email with your comment and see if they agree with you. Please post their response. Here are two emails I got last year from JR and Hitec. They are in agreement with the the Futaba recommendation. Dan.

DaleD

Spinner, Iknow the diode is for reducing the voltage to what is acceptable for safely operating the ignition. This is the firt time Iam seeing a recommendation to include a capacitor. Would appreciate your help in understanding the reason for the capacitor.

Thanks

DaleD

SpinnerRow

The capacitor helps reduce RF noise. The bigger the better. From a discussion I had with a 42% engineer a couple of years ago, you would really need about 10,000uf for it to work near perfectly but anything over 2200 in the voltage range you need is just too big for a 20cc sized plane. A 16v, 10,000uf cap is about the size of a stack of 15 half dollar coins. The 2200 I'm using is about 1/2" and 3/4" long. On a 20cc bird I like to save the weight which is the reason I use this battery method. On larger planes, a 2000mah 4.8v battery doesn't add that much weight in relative to the size of the plane. I think I would still do this on a 30cc plane though.

dirtybird

My Feedback: (5)

As I said it makes sense to keep radios of any kind separate from a noise producing system if you can do it without pain or strain.
No manufacturer would advise you not to.
However, my tests indicate it is not necessary if you are using a 2.4ghz system radio.
The next time you contact a manufacturer ask them for the results of any tests they have made.

SpinnerRow

I'm sure this comment will cause a mass thread hijack but here goes.

I've read their comments before and if I had a Hitec,JR or Spektrum radio, I would be using a seperate battery. Personally, I can't stand their radios. Way over priced and I've seen and had (I used to fly Spectrum) too many problems with their products. Glitchs, lock outs were common when I was flying them with my glow planes.

By the way, all radio manufacturers feel or have said not to do this (if nothing more than to cover their asses) as 30,000votls popping within a couple of feet of an RF device isn't a good idea no matter how you slice it. Even if you could isolate the ignition power supply by placing it on the ground trailing a 600ft wire, it still isn't a good idea. I'm offering an alternative method to power a small gas plane on a single battery as a way to save weight. I wasn't the first to do this as I first read about JediJody doing it on his 20cc and 30cc planes. The single battery method I've presented here works and works well for me without a glitch or hiccup in three years. I'll go with what I know and you can do the same.

dirtybird

My Feedback: (5)

To bypass rf noise you don't need more than 0.001uf capacitor.( It must be a ceramic capacitor) The engineer apparently was trying to filter the voltage variations caused by the surge when the ignition system charges its coil.
BTW what is a 42% engineer? A half bright one? I have met a few of those come to think of it.

SpinnerRow

Cool, I'll add that to my next plane I build.

I was referring to a 42% products engineer: http://www.42-percent-products.com/

All Day Dan

My Feedback: (5)

Spinner, I sent you a PM. Dan.

fly24-7

Glad it works for you. I wouldn't be comfortable with using only one battery to power everything. I assume that you have some sort of space or weight concern to be doing this?

ec121

My Feedback: (2)

On a 20-30cc plane I think I would gamble on a single battery. However, on that size plane the ignition battery is occasionally used for balance weight. Depends on the situation. On a larger plane the weight isn't so much a factor in either way. There I would use two batteries. I have a Seagull 1.20 Decathlon that has a CRRC 26 on it. I had to put the flight battery on the dashboard to balance it along with the ign. battery right behind the firewall. Really tail heavy. Two batteries helped there.

GerKonig

Thank you, now you make sense:-) I thought you asked a midget engineer...

Now in gas models, particularly the bigger ones weight of the battery is not an issue, s a matter of fact it can help while balancing. Are you doing this just for simplicity, or you do not have enough room, or is it a CG thing? I mean why using one battery for both systems. Just curious, that is all.

Gerry

airraptor

My Feedback: (66)

spinner i run my DLE like you have in the picture except the diode and the cap. I use about 200-250 MAH per each 10 min flight.

Sessholvlaru

I run a single A123 pack in my Sukhoi with a few diodes on the ignition lead to bump down the voltage. Many flights, zero issues. Tons of capacity left after four flights. I did this mostly for weight reasons, plane weighs 12.8 pounds with a DLE 55. [>:]

earlwb

I think it depends on how good the ignition system is and how it is installed. It may or may not work all the time using a single battery pack like that. But if it is working for you OK, then who am I to argue about it. But I think I'll err on the side of caution and keep them separate. there could be some low cost ignition units that are very noisy for one reason or another. Or even a good unit with a defect inside that causes it to generate extra RFI too. But there is a special BEC device that uses a single battery pack and uses voltage regulators for both sides and RF Filters. That device looks promising where space is at a premium. I forget who makes or sells it at the moment.

FenderBean

I found this out today on flying giants, the IBEC is the only way I would do this and I am going to use it on my 46% ultimate. I will 5200 ion on receiver/ignition and the servos will have there own 5200 as well. Its a great design and gets rid of any possible rf problems I guess.

OliverJacob

My Feedback: (12)

This setup might actually be working fine. The capacitor helps to get a constant current flow from the battery.
Only thing what could cause a problem is the moment you turn on the switch - the discharged capacitor will have a very low resistance and draw a high current until charged. This may not be a problem at all, just something to think about and the bigger the capacity the bigger the draw. This happens only for a split second and could fry your diode in the worst case.
Another thing - your power switch will not instantly kill your engine anymore. It dies after the capacitor is discharged, which can take some time.
This setup works if you have an optical kill switch. People who don't use them and kill the engine via throttle should be aware of the fact that the ignition stays 'hot' for some time after they turned the power switch off.
With the double pole switch and the optical kill switch you would not have that problem. Just be aware of the capacitor acting as a small battery.

CRFan1

I have over 50 flights on my 3DHS 71" Slick with a Single, 2300mah A123 set up to power everything. Quite honestly I wouldn't do it any other way on this size plane.

Rich from Wrong Way RC supplied all the parts (the guy is awesome btw). The battery has 3 leads...One with a deans for the smart switch, one for the iginition and a seperate charge lead. The smart switch has two power out leads which both go into the Rx (I use Spektrum stuff). The ignition goes to an optical kill switch (which goes into the gear slot on the Rx) and than into a simple in line diode to bring the ignition voltage down to around 5 volts. Very light weight and powerful set up that can be fully charged in about 7 Minutes

No RFI/EFI or any other issues have been experienced and it is a very simple set up that works.

SpinnerRow

A 2200uf cap will take about 22 milliseconds (or 0.022 seconds) to fully charge if the resistance on the battery is about 10 ohms (and LiFe batteries are very low resistance). Consequently, the engine may fire one more time after the switch is turned off and will not be something that I will notice (and don't notice as I have three planes with this circuit).

Also I have a P-51 with a DLE 20 that runs wide open from the time it leaves the ground until I'm ready to land it. On a 10 minute flight, it draws 180mah for the ignition and plane. I have a 2300mah battery in it and I could fly it 7-8 times with no worries. Plus a fully charged battery is only 10 minutes away.