iliveonlytocrash

My Feedback: (1)

I've read bits and pieces of people using a single A123 battery pack for both the receiver & ignition. I wanted to know if there is any reason why a 6 volt nimh with a diode in the igniton circut, wouldn't work just as well as the A123's?

wind junkie

My Feedback: (1)

Not sure on that diode you're proposing is it just to knock the voltage down by .7V to further protect the ignition?

I'd imagine as long as your battery capacity is sufficent to provide the current needed, you could do this. However, the self discharge of NiMH cells compared to A123's make them inferior, and I believe the current capability is also not as good for the same capacity packs, but I'm not sure on that.

I think you'd come out ahead in all respects with A123s over NimH except maybe cost.

kenhiraihnl

fwiw, here's a coupla pics of my 2s a123 1100mah packs, and how they compare w/ a 2s lipo 900mah, and a std 4s nicd rx pack...ken

iliveonlytocrash

My Feedback: (1)

Where did you get the A123 packs from?

yarom

My Feedback: (82)

Fromeco has nice packs at two different power levels - one is real A123 and the other one, LiFe packs that are a bit less powerful, but still way overkill for what we are doing.

Sin City Jets used to have good packs but they seem to be out of stock all the time.

I heard Duralite is doing these packs now - YMMW....

yarom

My Feedback: (82)

I take it back about Duralite - just saw they charge twice what other people do.

For the marginal value-add of some 14G wiring and yellow shrink tubing, I don't see the merit of even considering them...

dirtybird

My Feedback: (5)

Wallmart has been selling VPX batteries for $11. That is two 1100 A123 batteries and make a nice receiver pack. I just leave them in the VPX case and plug into them with auto spade lugs. That way I can pull them out and charge them with the VPX charger

kenhiraihnl

i got my packs from battlepack.com...kinda pricey @ $13.60 per cell, but saves me the trouble of making them (heatshrink, deans, balancing plug)...ken

tkg

My Feedback: (1)

[:@]Very BAD Idea. using the one battery for ignition and rx

iliveonlytocrash

My Feedback: (1)

Even with a 2.4 Ghtz radio?

tkg

My Feedback: (1)

YES.....BAD BAD

rlmcnii

My Feedback: (3)

ilotcrash,

http://www.rcaerobats.net/A123_INFO/...on_battery.htm

There is a lot of information here about 123 cells used as you wish to do. This fellow has also posted a lot of information here in RCU about the single pack for all uses.

I have not used one pack for all uses. But do use an 1100 pack for ignition and a 2300 for the receiver/servos in a 50cc gasser. The cells are great.

Apparently the fellows using one 2300 pack for ignition and radio are doing so successfully.

Read and consider.

Bob Pastorello

My Feedback: (198)

There are a variety of opinions on this issue, and very few folks who have actually DONE the work, and used the configurations posted on my website. I do not configure my aircraft in an unsafe manner, nor would I recommend to anyone to do anything that I had not proven to be successful (and safe).

Without doing keyboard battle, which is much like trying to teach a pig to sing, the facts are these....

1. A123 discharge voltage is so flat, for so much of it's capacity, that the use of diodes to drop roughly .7 per diode is highly effective. Using two diodes ensures that source voltage to an igniton will never exceed nominal values of a typical NiCad or NiMh pack.
2. When using A123's, one must KNOW the current draw of their particular equipment configuration by measurement, using real world data, and reliable and accurate chargers to indicate power replaced when recharging packs. Then, one must be absolutely sure to NEVER attempt to fly beyond 75 or 80% of that capacity (this leaves a good safety margin).
3. I have several aircraft which have utilized a single 2SA123 pack for both rx/servos and ignition. All have performed flawlessly, and post flight data measurements of the AR9000 receivers with the data logger has not demonstrated any adverse results.

As always, I recommend that folks try what they personally KNOW to be workable, and when in doubt, use discretion and reason, and in the case of A123's, use a separate pack for your ignition. Just be sure to either regulate it down, or use diodes stacked in series to produce the safe output voltage that your equipment warrantor requires.

I have ONLY utilized the single pack configuration with JR and Spektrum 2.4 Ghz equipment using Hitec servos. I don't know about ANY other equipment configurations, brands, or choices, so will not comment on the viability of those setups.

tkg

My Feedback: (1)

2.4 GHz is NOT bullet proof, I can lock up any 2.4 GHz system with a badly installed ignition setup.
What are we talking about is trying to save less than 3oz on a plane that weighs 10lbs or more.
Remember that doing an ignition/radio install is NOT about what is the minimum I can do before I fly, but the MAXIMUM I can do to ensure a solid radio link.
A solid link MOST of the time ain't going to cut it for very long.
The soap box is now available for opposing views.

Tired Old Man

My Feedback: (1)

With you all the way Terry.

Providing a directly plumbed, potential source of strong RFI to a receiver is just not my idea of a smart thing to do. Even the people flying the ultra sophisticated, extremely expensive, military hardware separate their ignition systems from the operating systems. Some of them are even CH type systems. There's a reason, and it all came from some tremendoulsy pricey experience. They use just about every frequency useful for operations and telemetry, including 2.4 and more, and have learned. At a few hundred grand a crash you learn not to mess around over a few grams or ounces.

Most of us recognize the safety limitations involved in radio controlled flight. To minimize those very small safety margins to eliminate a switch, save 10 or 20 bucks, or shave 3 or 4 ounces off of a 10 to 50 pound model is ludicrous. It's not just the model that is at risk, but all those around you and those that may lie under the path of a "fly away" plane. Yea, that's an extreme but even those of that flew gliders with no engines or ignitions at all have seen such events happen. Who gets the blame when something eventually does happen because of a common receiver/ignition battery connection? Will it be the radio manufacturer, the manufacturer of the assorted switches and wiring? The battery manufacturer, the ignition manufacturer, the engine manufacturer? Or will it be the true cause of the event? That of course is you, the person that elected, for whatever reason, to bypass well proven safety precautions established by the people that make ignitions, and carried on by anyone that keeps safety and reliability in front of everything else.

Keep in mind that all that participate in this hobby do so willingly. That outlook extends to the manner that aircraft are set up. To do something you know to be risky, or where commonly available information accessible by anybody suggests that it might be risky, could easily be considered negligent. Wilfull negligence.

flatspinjim

My Feedback: (3)

Well put!

kenhiraihnl

i'm a 50/50 heli/plank flyer...all of my stuff fly on one battery pack...my gasser cdi module is rated at 6.8v max and 6.0v optimum (good for 2s a123)...my radios are futaba so my 2.4 receivers are 2s a123 capable...as you know, some servos, like the fut s9254 heli tail servo are not 6v capable so a step-down regulator is required...all that being said, i'll probably use separate ignition and radio 2s a123 packs on my next 50cc plank...i've had enough electronic glitches and lockouts to make me cautious on my setups...ken

iliveonlytocrash

My Feedback: (1)

Is there any such thing as a filter that would "clean up" any noise being generated by the ignition module?

kenhiraihnl

fwiw, i use this http://www.aircraft-world.com/prod_d...L-BEC-INST.pdf in an 81"ws gpss to drop the 3s2200 lipo rx pack to 5v...that regulator incorporates noise elimination technology and comes with a ferrite ring...btw, regarding the gpss, i'm swapping a smooth-running nitro os1.60fx, 17x10apc with a gas xyz50, 20x10apc...i'll be using the same rx pack/regulator setup, but will use a separate 2s a123 1100mah pack for the ignition...ken

sdstick06

Sure go ahead and use a common battery... and one wing bolt is all you really need... why waiste the time putting in 2... not to mention the weight of an extra wing bolt

2.4 is NOT bullet proof it is still best to keep all the set up rules on aircraft with ignition systems.

rctom

In spite of what everybody else says, to be cautious, I have had the same experience as Bob Pastorello. So I stole some of his language.

I have several aircraft which have utilized a single 2SA123 pack for both rx/servos and ignition. All have performed flawlessly, and post flight data measurements of the AR7000/AR9100/JR921 receivers with the data logger has not demonstrated any adverse results.

As always, I recommend that folks try what they personally KNOW to be workable, and when in doubt, use discretion and reason. I don't use any regulator or diodes, I usually am using the RCEXL ignitions that come with many Chinese engines. BTW if the RCEXL ignition has a date code of 10-2007 or before then you will want to reduce the voltage supplied to teh ignition, A123s are too much.

I have ONLY utilized the single pack configuration with JR and Spektrum 2.4 Ghz equipment using Hitec servos. I don't know about ANY other equipment configurations, brands, or choices, so will not comment on the viability of those setups.

I agree there's no need to do it this way to save an ounce or two, but for simplicity's sake I have done it and it works. I recently took advantage of this when my ignition battery was too low voltage to run right, I just switched over to the rx pack and used it as a backup.

TF

iliveonlytocrash

My Feedback: (1)

My reason for wanting to use a single battery is this: I own & manage several small businesses and my flying time is limited and usually a spur of the moment type schedule. I often do not get to fly because I have to charge 3 batteries first (transmitter and 2 airborn) and by then my free time is up. This year I only averaged 1, 10min flight/week. My charger is an accu-cycle so it only charges 2 batteries at a time, so I have to charge the plane batteries and then the transmitter.

After hearing everyone's comments, I think my best solution is to use 2 A123 batteries (1 for receiver, 1 for ignition) with a diode or 2 on the igniton to drop the voltage. Then I can charge each plane AFTER I fly, and hopefully, with the slow self discharge rate of the A123's (compared to nimh) I will be able to just grab a plane and go at any moment. Does this sound reasonable? Is there such a thing as using A123's for the transmitter?

Zeeb

My Feedback: (41)

Hmmm.....

While Bob and Tom have both successfully run the common pack as well as others I've seen post on "other" forums, I'm not quite there yet. So I run a 2300 for the flight pack and an 1100 for the ignition on my 50cc Bunny.

When I get it out of the Jeep to put together and fly, I start with the 2300 and switch to the 1100 when it's done. I'm using a CellPro 4S charger and the batteries are usually charged before I get the model put together. You could do as you suggested about charging them before you put 'em away and that will shorten the preflight charge time to practically nothing, but I would never fly an A123 equipted model without charging the batteries first as there is no practical way to volt check 'em and that's why we go on number of flights per charge. While the self discharge rate is extremely low, you never know when a problem might crop up somewhere and just assuming the batteries will be okay is not a good idea IMHO. Always start from a known condition with these batteries.

Just a thought...[8D]

On, tx batteries... No A123 setups that I'm aware of are currently available from vendors. Due to the differences in cell voltages, that use will present some difficulties in implementing it, but I keep hoping the A123's will find their way into our tx's someday...

kenhiraihnl

100% agreement w/ zeeb...i use 3s lipo in my xmtrs...haven't had a problem w/ low xmtr voltage since making the change...however, a safer and equally effective method would be eneloop nimh batts...ken

Tired Old Man

My Feedback: (1)

Most of the better transmitters have high capacity nimh battery packs available for them. Some available at the OEM distributors, some after market. One OEM vendor has a wall wart charger that will handle the increased charging amperage needed for the larger Tx packs. A Tx with the nimh battery packs last for an entire days flying and more.

Although it's not as considerate as it could be for a radio manufacturer to sead out computer transmitters with 600 to 800 mAh transmitter batteries that's what they do. We're the ones that buy them so we're the ones that need to squawk loud enough for them to pay attention. Sales volume makes the decisions for the manufacturers so if we buy the ones with the larger battery packs and ignore the rest they'll get the message eventually.