I've ordered a 5v regulator to install with my A123 2S on-board battery to permit me to eliminate the ignition 4 cell pack. I know I need to carefully check range, etc.

I'm also using Spektrum 2.4, so anticipating no radio issues and plan to use existing ignition switch, cutoff, etc. just as is, just replacing the battery with the output lead of the regulator.

Anyone done this? Comments? Things to check?

(Ignitions that will be tested are the DL 50, and the CH on Brillelli engines)

May be fine
The reason I won't use a reg is that as well as limiting voltage - the instant current draw is limited
The closer the batt voltage is to the reg setting (output voltage) the less this will hapen
personally ---on a single cyl engine a 4.8 v - setup - I see nothing which beats a 4.8 v 1400/1500ma Intellect pack - which is tiny and weighs about 3+ounces.

Yep. You're right, Dick. One reason I want to try this is the "overall" weight loss per plane. Since going to A123, I lost 5.7 oz on the second Rx batt. Take out the ignition, and now up to over 9 ozs. Not a big deal, but good to have happen.

MAIN reason I hope this works is laziness.

If I don't have an ignition battery to fuss with, it's one less thing to remember to do, and one less charger to carry on those "long days". Plus, when 'peaking' after 4 flights or so, I know the ignition will be full, too.

Anyone DONE this yet???

Which battery are you using?

I just received a couple of the A123 racing packs and they are physically pretty large, it would be tough for me to find a place to mount that big of a battery that far forward.

I'd like to get something smaller to use on the Ign, the engine is a ZDZ which doesn't require a regulator on the supplied Ign.

Dick- (and Bob you may be interested in this too which is why I'm mentioning it here)

I had a difficult time locating a switch setup that I liked for the A123 on the RX side of the house.

I emailed Fromeco and they are building me one of their Badger switches with a Deans connector in and two JR type outputs to go directly into the RX.

I realize I loose redundancy by using a single battery and switch, but this is a nice clean simple setup.

The cost was $34

Nick - I'm only using ONE, two-cell A123 pack that I made from the DeWalt 36v pack. I installed TWO 22ga male connectors from + and -, and ONE "three wire" male with the orange wire on the center tap between cells. This male mounts to the fuse side in an Ernst housing, and I have the output connector from my Cell Pro wired so that the "node" wire is the orange wire. It works just dandy (thanks to Dick for working with me to come up with this solution). This configuration permits the on-board three wire switches to work normally. I just don't charge through the switch anymore.

To power the ignition regulator, I'll use a "y" off of one of the switch battery input leads.

Ahhh... I PM'd Dick a few times but didn't really "get it" we're doing basically the same thing, I was thinking he was saying to have two leads coming from the pack going to two separate switches each with a single lead to the RX.

This plane is for another person and he's using a "old" JR PCM RX, I don't think I should "Y" the ignition off the main pack without being on 2.4.

Question.
Are you using just one A123 pack for both the receiver and the ignition?

That's the intent.
One 2S, 2300mah, A123 pack.

Pic attached is concept drawing.

IF--- there is no problem with "crap" coming from the ignition to/thru the batt -to the rx - it should be fine .
Howsomenever - I am a bit spooked of any setup to the ignition which does not allow it to suck a quick deep shot of power.
It won't show on a meter - but a good scope setup will show it
The problem is in a ignition transistor not fully saturating - which means heat which means a shorter life for the transistor.
Both 3W and Jeri Vlach have issued warnings or recommendations on NOT using regs to ignitions and/or not using cells with high impedance -
-
I asked a knowledgeble model engine ignition designer and he 'splained it to me.
, step by step
maybe I am just an old worry wart

I would not use a regulator anywhere. The receiver front end has its own regulator built in. You might want to put a good rf filter between the ignition box and the battery or receiver.
Let me know how you make out.

The intent of the regulator is to get the voltage down within spec (voltage and current) for the ignition module. The receivers are working just dandy on the straight A123 juice.

Flew 7 flights today.... these were gentle "pattern-like" flights for the most part, and only used 395ma. Not bad. Not bad at all.

So would the regulator filter out any potential "crap" coming from the Ign? I don't know if I would be confident enough to use it on a PCM setup.

I've been running that Smart-fly "Ignition Regulator" on my DA and so far I haven't noticed any problems.

I see from your drawing my understanding of Dick's recommendation was correct.

What's up with these A123 Cells? Never heard of them.

THere's threads everywhere; Google it, LOTS of info out there. DeWalt "pro series" power tools utilize this battery technology.

Look umder Batteries and chargers-A123 support.

Why not use a singe A123 cell on the ignition ? Guys are using 3.7v Lipolys...

If you think you can keep it above 4.3 volts for a long period of time, go for it. 4.6 would be better but the CH style ignitions start dropping out of the loop at around 4.3v.

I have no idea!! LOL!! Im just thinking out loud..or should I say writing out loud!

basically do NOT run ignitions at lowest possible current levels - some are designed for 4.8 and ideally you use a four cell batt that stays above the 4.8 -such as a good Ni Cad or NiMh.
if you use flashlight batteries or other really low instant current types -you may weaken the ignition
It is amazing how many ignition mfgrs do not really specify type of cell for their stuff - some just say oh a 1000ma is enough -enough what ?
maybe they do have a bulletproof design which will run on 3.8 volts at an instant draw of .0000001 amps
too many of em on the market to make a generalization
-

Yea I will stick to my 1500 4.8 Intellect pack..only weighs about 3oz and lasts all day...

Whaddaya mean "how many manufacturers"? None of them do. You're generally darn lucky to find out what the average current use per cylinder per hour is.

Finished phase one ground tests (limited range use, but engine running, all settings) with the A123 feeding a MPI 5.4v, 10A regulator.
All worked fine.
As expected, total milliamp draw from the A123 was as much as anticipated, indicating the reported current draw of the RC-EXL ignition is about as stated.

There were no issues, nothing to report, really. Solid, reliable performance and nothing visible in radio-land because of it.

Way too hot/windy for me to do more, so I just continued breaking the engine in.

Phase two will be at the field, ground tests, bind button depressed to find engine on/off limits to range, all attitudes of airplane. If all's well there, then there is only the airborne test remaining.

Good to hear..

I have obtained a primitive 72Mhz PCM setup to test with... so I can find out if the A123 puts crap on the RX power buss or not, and whether it will work right with 72Mhz *and* DSM. More news at 10....

Did you try it in the air yet Bob with the 2.4 stuff?