[Redeka]

Hi folks,

I have been working on an old 81" Lanier Cap 232 kit. This will be my first foray into the gas powered world. As this is new to me, I have done lots of research on the subject. As I continue with the build though, more and more things pop up to learn. The latest topic of research for me has been 50cc engines and how to power them.

I recieved my 55cc EME II yesterday (thanks Lorne, incredibly fast shipping), and while going through the contents and adoring my first gas engine, I realised that somehow during my reasearch I skipped over the electrical side of the engine. It goes without saying that things are a bit different than nitro...

Before I became confused, I was going to power my reciever with this. Then I came to realize I needed to power the ignition. It seems most people use a second battery to power the ignition. Is this required, or can I get away with a BEC? What size of battery is appropriate for the ignition? Is this typically charged as often as the rx battery (is the ignition contantly drawing power)? Do most people use a manual kill switch or a remote one?

To throw a wrench in things, I heard about people using A123 batteries for their electronics. Lightweight, consistent power output, and fast charging. Sounds great. However, maintaining these batteries seems difficult, lots of literature mentions adapter cables and manual balancing and such. On top that, A123 seems to be mentioned in threads dating back a few years, and not as of recent...why is that?

One more thing, are you guys adding a choke servo, or just going manual?

Thanks for taking the time to read my questions, I hope they make sense.

[cf100]

This is what I do, there are many choices, do you research and do what you feel works for you. I had that same CAP kit years ago, flew good, but like to tuck it's nose under in a high G turn.
cheers - ken

I use a dual rx pack set up for my big birds, see http://www.hangtimes.com/parallel_packs.html

Lots of other good battery and charging info at Hangtimes.

Last year I switched from nicads to LiFe batteries, a buddy recommend these HK Zippy packs at $8.99 each https://www.hobbyking.com/hobbyking/...iver_Pack.html

I used them in my Ziroli Harvard and three other warbirds all last season with no issues.

For ignition I use a 1400 - 2200 mah HK Life 2s pack but with a diode to drop the voltage down as the DLE igniton modules do not like 6.6 volts. I get the diode wire in a extenson lead from Bad Brad http://www.badbradgraphics.com/photo_23.html

Check to see what voltage your ignition specs are.

If you use Life batteries make sure your charger does LiFe batteries.

If using nicads I use 1400 mah - 5 cell for the rx packs and a 1400mah 4 cell for ignition.

Never had much luck with nihms performing reliably so I do not use them in rx packs, I have one in my TX but I can see the voltage on my TX screen.

cheers - ken
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[bhughes]

I recommend life packs as well or a123's. Lorne also stocks life packs. I use two for my receiver and steal power off one for my ign. I haven't played with bec or ibec's.
http://www.pro-rc.ca/life-a123-batteries/
Lorne has been using these lately for engine kills
http://www.pro-rc.ca/rcexl-opto-gas-...switch-ge3001/

[grizak]

A few comments:

First - you need to check your ignition to see what voltage it is rated for. The EME Ignitions are RCEXL ignitions with an EME sticker on them. Many Asian engines (and EME is one) with RCEXL Ignitions that were manufactured in 2013 or before had ignitions that were rated for only up to 6.0volts. This means that any 5 cell NiCad/NiMah battery or any Lithium based battery will need to be regulated to power this ignition. Anything over 6.0volts will eventually fry the ignition (It may happen in a few flights or it may happen in a year - but it will happen). Newer RCEXL ignitions are rated for up to 8.4volts.

In general - NiCads and NiMH have fallen out of favour with the giant scale crowd - mostly because of 2 factors: 1) Current Hungry Digital servos 2) Weight. NiCads and NiMH can't come close to the current produced by Lithium based batteries.

You should consider the requirements of the servos you are using before selecting your batteries - if you are using higher end, higher torque digitals then using one NiCad/NiMaH may result in torque loss as the voltage of the pack will drop as these servos draw current (The servos may draw more current than the NiCads/NiMah are capable of producing). If this is the case, then you may need to add a second battery or switch to a Lithium battery.

A123/LiFe are used interchangeably now. A123 is brand name (Like Duracell) - LiFe is a battery chemistry. A123 has a patented manufacturing process which arguably produces the "best" LiFe batteries. There are thousands of LiFe batteries on the market - some are very good, some aren't - be very cautious in what you buy, as many don't perform near to what they advertise.
At one point A123s were really the only option for LiFe batteries in R/C airplanes, so that is why you only heard mention of A123 a few years ago - and now you mostly hear/see LiFe.

You shouldn't use a "normal" BEC to power your ignition from your receiver. The Ignition modules can generate a tremendous amount of RF interference - and if you use a BEC, you are basically providing an electrical path for this interference right to your receiver. Ignition modules fail (and more often then you would think) - and if yours failed while "electrically" connected to your receiver, your plane will likely crash - the RFI generated from a failing Ignition Module can swamp a 2.4Ghz protocol easily. If you want to power your ignition from your receiver, you should use a device called an IBEC (Ignition Battery Eliminator Circuit - click here) this has filtering built in to eliminate RFI to the receiver.
Also -keep in mind that using an IBEC will change your power requirements for the main battery - I can't recommend using an IBEC with a single NiCad/NiMH.

[FLYINCHASE]

I use a 2500 LiFe batt to run all my 50cc size planes with an Ibec from Jeff at T bolt. never had a prob......

Thanks
Mike

[Redeka]

Thanks for all the incredibly informative replies. You guys have made the wealth of information available on the internets much easier to digest. I believe I have come to a decision about the route I am going to take, but I have a couple more questions to clear up first.

First things first, my ignition is rated up to 6.o volts, so some power regulation will be required.

I am picturing my setup something like this:

-AR-6210 Reciever
-Savox SC-0251 Servos
-2500mAh A123 battery(batteries?)
-Ultra IBEC
-Charger
-And of course a few switches to go with it all

I am slightly confused about the modifications hangtimes.com mentions are required to avouid damage to your RX while charging.. The way I understand it is that I must disconnect the third wire from any standard HD switch in order to charge my A123 battery from that switch. Is it really this simple or did I miss something?

I am split between using 2 batteries in parallel for the extra flight time and redundancy, or going with a single battery and using my last RX port to operate a choke servo instead. The deciding factor for me is how many flights I can get out of a single pack (running the RX and Ignition) before needing a charge. Flyinchase, how many flights are you squeezing in before a charge?

Bhughes, you mention you have 2 batteries, both are plugged into the RX, but one is also run into the ignition. Is this simply done with a Y-type connector? Where can I find such a product?

And finally, how quick can I expect the charger I linked to charge a 2500mAh A123 battery?

Once again guys, thank you so much for you answers, I have learned a ton!

[cf100]

You are on the right track by reading up on this stuff. Everyone has a method and opinion and things work well.
A retired flying buddy uses only one 1700 nicad rx pack and has never had a power failure, go figure.

Another guy at the field lost a new 50cc Extra260 on the first flight because they figure the single battery became unplugged -
would a second battery helped. who can say,
you have to decide your level of risk.

I was fortunate to have buddy Lt. Dan at the flying field to explain all this to me in his 50cc Yak set up.


What is most interesting is that guys spend hundreds of dollars on fail safe systems / power systems yet everything is connected by the 10 cent r/c connectors made in china.

The simple dual back system was promoted by Red Scholefied an engineer with GE. Red's bio http://www.hangtimes.com/red_scholefield_.html
more good reading http://www.hangtimes.com/redsbatteryclinic.html

Hope this adds to your research and I'll try to answer your questions, I hope others add theirs too.

Q. First things first, my ignition is rated up to 6.0 volts, so some power regulation will be required.

A. Yes, depending on your ignition modules as others have stated. On my and Lt. Dan's DLE 55 ignition modules we uses a diode, we get ours wired up in a lead from http://www.badbradgraphics.com/photo_23.html

"6" extension with single diode. Drop your voltage to ignition or throttle servos when using A123 packs. 3A 400V Diode - Drops Voltage by .7v- No more worries of a shorted regulator. Price $5.00 each"

I've also used this on a silver box CH ignition on my Brison 3.2

Q. I am slightly confused about the modifications hangtimes.com mentions are required to avouid damage to your RX while charging.. The way I understand it is that I must disconnect the third wire from any standard HD switch in order to charge my A123 battery from that switch. Is it really this simple or did I miss something?

A. Yes, on JR Spektrum I disconnect the orange wire on the battery lead that plugs into the receiver. Normally this wire is unused (red is +, brown is -) however since we have wired the battery lead off the pack so that we can charge off the three wire battery lead this orange wire is now live.

" from Hangtime ........In any case, most HD switches are equipped with that 'third' wire.. it's a 'signal' lead and we need to remove it from the plug that goes into the Rx so we don't put power to the Rx on that lead. To remove it you need a razor knife and a bit of electrical tape. With this mod, we're going to turn your switches 3 wire Rx power feed into a 2 wire power feed. Check the photos below.. http://hangtimes.com/a123rxsetup.html

Q. I am split between using 2 batteries in parallel for the extra flight time and redundancy, or going with a single battery and using my last RX port to operate a choke servo instead. The deciding factor for me is how many flights I can get out of a single pack (running the RX and Ignition) before needing a charge. Flyinchase, how many flights are you squeezing in before a charge?

A. We are not looking at extra flight time with the dual packs, only redundancy. I normally fly 4 - 12 minute max flights on the 50cc Top Flite P-51 and put back in 500 to 700 mah back into each pack, running 9 servoes. I think the ignition takes 300 to 500 mah. I charge at 2 amps.
I'm not a 3D flyers so my numbers may be less.

Flyinchase will have diffferent numbers as he is single pack.

Note: "using my last RX port to operate a choke servo instead"

If you are using dual batteries, one of the batteries can be plugged into a y harness - say put a Y harness on the throttle servoe, I do this on the AR7000rx, while the AR9000 has two battery ports.

Q. And finally, how quick can I expect the charger I linked to charge a 2500mAh A123 battery.

A. I BALANCE charge at 2 amps, so if I need 500mah back in, that would take 15 minutes.


I am using two of these 2S packs from HK at $8.95 per pack for my rx on four 50cc warbirds and one 50cc extra, so far so good.

http://www.hobbyking.com/hobbyking/s...iver_Pack.html

i'm using a 2S 1600 mah Life for the ignition because it fits better on the firewall under the cowl.

cheers - ken

[FLYINCHASE]

Yeah your on the right route for sure. I agree on the redundant batt for the rec but I took mine out a few years ago and never looked back (Wight savings on batt and switch and wires) but peace of mind for your first big bird is also a good thing. I get 4-5 flights (3d-ish ones lol) then put 800-900mamp back in my 2500 pack. Changing a LiFe pack is fast and easy. As far as voltage for your ign the ibec from Jeff have a built in adjustable regulator. Like I say its just the way I do mine and ive learned it from the great guys here on Rcc that are always will to help.

Thanks
Mike

[bhughes]

I use life packs that have three leads off them one is deans for my powersafe receiver one is the balance lead the other is a jr lead. I just plug the jr lead into my smartfly reg ign opti kill. So each day I go flying I just plug the ign in and good to go. At the end of the day I unplug the battery from the ign. And if you do leave it plugged in it will only pull about 80 mah's in a couple weeks. One of our flyers found that out lol. For me I run two packs cause the plane will still hover with the added weight. And a plane that costs over 2k I want it to be human error not my setup that fails.