Can I use A123s with this G-62 ignition?
 

I'd like to use a 2 cell A123, (LiFe) pack with this ignition. Can it handle 6.6V?

Thanks in advance,

Martin
http://www.rcuniverse.com/forum/atta...mentid=2117225

Probably not. Who made it? To be safe just go to what used to be Radio Shack and get a diode and put it in one line.

It looks like Ralph Cunninghams ignition and last I knew he did not recommend using over 6.0 volts . A freshly charged a123 will have over 7.2 volts and a nominal voltage of 6.6 . A Nimh 6.0 pack will peak slightly higher when freshly charged but the nominal voltage will be a lower 6.0 v. I would recommend using a dropping resistor or a 5.0v voltage regulator if using more than a 4.8 pack .

+1 CK1 nailed it.

Thanks guys.
I was under the impression that it was one of Ralph's so to limit it to 6V max. does make sense. I guess a set of Eneloops is best and simplest.

Martin

I have one of Ralphs G62s. The case back does not look like one of his.
A simple diode is a lot easier and more reliable than a regulator. A123's are not at 7.2 once they are connected to a load. They quickly drop to 6.6V . A silicon diode drops 0.6 V in the forward conductive direction. That puts you right at 6.0V.
A regulator has many active parts than can fail. Plus it ads to the internal resistance of the battery.

Ralph converted two G62's for me in the last 6 mos. His new ignitions can handle 12 v. I have one RC Ignitions G62 converted 7 years ago. I have been running a life 6.6 on it for the last 4 years. 100's of flights on issues. I do not use a regulator.

To the best of my knowledge Ralph is the only one who used an RCA type jack for input power. Most guys will go regulator as it is a plug and play solution. If you want to continue to suggest your diode setup you may want to publish a schematic. Giving guys a supplier, part number and informing them that a diode is polarized may help your suggestion along.

Exactly how do you install a diode...where to buy...part number...etc?

We need your expertise...schematic?

I believe everything i read on the web....not! Lol:):):)

If you don't want to make a diode step down, you can buy them already made. Wrong Way RC sells them along with Align Helicopters. Wrong Way sells them as a voltage step down for ignitions where Align sells them as a voltage step down for tail rotor servos that are not rated for higher voltages. Even JR use to sell these but I'm not sure whether they are still available or not. Much simpler than a regulator for this sort of application and almost foolproof reliable. Couldn't agree more with Dirtybird this is the way to go and this is a plug and play solution.

Also, with all the speculation regarding voltage, why doesn't the OP just call Ralph and see what that older ignition is rated at. Why rely on keyboard experts when the original source of the ignition is still available to answer any questions? That is clearly one of his early conversions with mechanical advance.

A diode will look like a little black cylinder with a band printed on one end. Install the diode in series on the positive lead from the battery with the band towards the ignition module. For the A123 you have the option of installing TWO in series if you're worried. This will result in about 6.1 V at full charge. Cover the whole thing with shrink tubing. I just cut those big 1/4" dia diodes from old circuit boards. radio shack was good, but they're sadly gone. Try Digikey.com. Make sure they're rated for at least twice your voltage, both forward and reverse. Also they must handle the current and wattage. Don't try to cut it close, over-rate the crap out of it. It won't hurt anything. Even a 125V diode will work.

As Truckracer suggests Wrongway sells plug and play diode system.
There are still some Radio Shacks around. They just dont call them that anymore
Almost any rectifier diode will work. Just dont get one of those tiny ones made for RF.
Voltage ratings are meaningless because you are using it in the forward direction.
As for a schematic, do you want me to draw a line with a diode on it? ok
+-------------->l--------- -

great reply guys. This should help a lot of people that just do not know...i am one of them.

I HAVE BEEN FLYING GAS AIRPLANES SINCE 1946...TOO OLD TO CARE ABOUT DOING THE MATH.

JUST STARTED USING A-123 LIFE BATTERIES...MY IGNITION SYSTEMS ARE ALL GOOD FOR AT LEAST 7 VOLTS. HOWEVER, IT WAS NOT THAT WAY IN THE PAST.

GOOD JOB TO TRUCKRACER AND PULL UP FAST.

UNCLE GENE

Cool...dirtybird. You made me laugh...a good laugh...i like that... My kids all went to college in tucson

Dirty, like you I have a background in electronics only for me it's on the production side and not design. The reason for my comments about particulars is that you would be surprised how many guys have never had a diode in hand. Seems simple to us as that is what we are accustomed to but others that don't have the knowledge may need a breakdown that they can better understand.

My kids went to college in Seattle. I just paid off the last loan.I am lucky, the last one graduated 10 years ago.If it were now I would have to work for another 100 years.

I would not be surprised. I just hope some one would try to figure it out for himself. Its simple enough.

I agree 100%. Unfortunately it seems as if people want fast and easy these days. As a country that manufactures very little it is a shame that we have lost so much hands on skill.

TopGun - If you want to do it yourself, I used 1N4007 to do this. Can be sourced all over the place, just watch what you are being charged for it (should be just a few cents). Never had one cause an issue or failure of any kind. After installing, if it doesn't work, swap it end for end. Think of it as a check valve. It only lets power go through it in one direction. If you manage to install it backwards, the circuit will act like it's open.

So simple even I can do it..... (with no electronics background). -Al

I tried to make a schematic but the drawing did not post correct

Where's a good place to buy a123 cells to make your own packs at a good price? The ready made packs have gotten pretty expensive. I've got a good size fleet of planes and I'm tired of messing with NiCads and the fragile LiPoly batteries. I would like to change the whole fleet to A123's, but man, the cost!!
AV8TOR

I generally do OK poking around on Ebay. You just need assurance that you are talking about NEW A123's (not recycled drill pack batteries) and that they are actually genuine A123's. Obviously lots of fakes and "equivalent" batteries available.

Still not cheap, but they're wired my way. Careful of the 26650's. Outside of the case is positive - opposite of what you would expect.

I know some guys prefer actual A123 batteries over LiFe and depending on the application the additional performance will be seen. That being said, I have had great success running the BP hobbies LiFe RX batteries. They are quite inexpensive and work as advertised.

here $10/cell
https://www.buya123products.com/goodsdetail.php?i=6