Elect. Ignition question
11-29-2006, 10:41 PM
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Elect. Ignition question
Some help needed from people experienced with elect. ignitions:
So what is likely to happen when an electronic ignition fails? Does it send bad things to whatever is connected to it?
My proposed scenario: A Double Vision with DA-50. All 8 servos, Rx AND ignition running from ONE battery thru the Rx.
Current draw is no problem, battery is capable of 60Amps+ continuous and over 100A in 10 second bursts. Capacity is 2300 mah
I'm thinking of using the 2 cell A123 Racing battery pack without a regulator for the above setup. Max voltage will be 7.2v, but quickly drop to somewhere around 6.8 to 6.6v, the discharge curve is very flat until it drops off the cliff (that's the other scary part). I'll use a no fly voltage of 6.4 under a 1A load until I get more info collected.
Oh, and this will be with the Spektrum DX7 which is suppose to be unaffected by any electrical ignition noise.
Any comments? Or just run another battery for the ignition JUST BECAUSE?
So what is likely to happen when an electronic ignition fails? Does it send bad things to whatever is connected to it?
My proposed scenario: A Double Vision with DA-50. All 8 servos, Rx AND ignition running from ONE battery thru the Rx.
Current draw is no problem, battery is capable of 60Amps+ continuous and over 100A in 10 second bursts. Capacity is 2300 mah
I'm thinking of using the 2 cell A123 Racing battery pack without a regulator for the above setup. Max voltage will be 7.2v, but quickly drop to somewhere around 6.8 to 6.6v, the discharge curve is very flat until it drops off the cliff (that's the other scary part). I'll use a no fly voltage of 6.4 under a 1A load until I get more info collected.
Oh, and this will be with the Spektrum DX7 which is suppose to be unaffected by any electrical ignition noise.
Any comments? Or just run another battery for the ignition JUST BECAUSE?
11-30-2006, 02:17 AM
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RE: Elect. Ignition question
Unless you are an electrical engineer and can do a filter system, run a second battery. Most ignitions impress on their battery a noise pulse equal to engine RPM. This pulse will drive the rx nuts.
11-30-2006, 06:49 AM
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RE: Elect. Ignition question
We had a member that was insistent he could run the ignition and Rx of his plane off one battery. We watched with delight every time he came out and stated he had solved the problem with filters, boxes, wires, regulators, and would fire it up, and watch the surfaces dance.
Never did get to fly it. Finally went to two batteries.
Never did get to fly it. Finally went to two batteries.
11-30-2006, 08:06 AM
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RE: Elect. Ignition question
Airbike
The Specktrum is not immune to interferance it just has a very efficient filtering system if you are using one battery for the ignition, rx and servos the system will be working overtime filtering the ignition pulses possible leaving no capacity to filter rouge signals, IMO don't do it have a seperate battery for the ignition.
Mike
The Specktrum is not immune to interferance it just has a very efficient filtering system if you are using one battery for the ignition, rx and servos the system will be working overtime filtering the ignition pulses possible leaving no capacity to filter rouge signals, IMO don't do it have a seperate battery for the ignition.
Mike
11-30-2006, 10:38 AM
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RE: Elect. Ignition question
If you really want to do this here is how I would try it.
1) Run a second set of wires to the battery for the ignition. Run these wires all the way to the battery connection with a separate switch .
2) From Radio Shack get two ferrite chokes. Put one each in both the positive and negative lines to the receiver.
3) At the receiver install the largest electrolytic capacitor you can find in parallel with a 0.01 uf ceramic capacitor directly across the input power.
4) let us know how you make out.
1) Run a second set of wires to the battery for the ignition. Run these wires all the way to the battery connection with a separate switch .
2) From Radio Shack get two ferrite chokes. Put one each in both the positive and negative lines to the receiver.
3) At the receiver install the largest electrolytic capacitor you can find in parallel with a 0.01 uf ceramic capacitor directly across the input power.
4) let us know how you make out.
12-01-2006, 03:28 AM
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RE: Elect. Ignition question
Thanks for the replies guys.
It looks like this may be not worth it. Man, I thought I could save 1/2 pound just by swapping out the batteries for this single pack.
I guess I would have to approach it very carefully if I try this. I'll see if I can get some input from the Spektrum guys regarding their receiver.
It looks like this may be not worth it. Man, I thought I could save 1/2 pound just by swapping out the batteries for this single pack.
I guess I would have to approach it very carefully if I try this. I'll see if I can get some input from the Spektrum guys regarding their receiver.
