I am assembling an Aeroworks Cessna 195 that comes with a set of running lights and it will be powered by a DLE 30. I was thinking of simplifying things by using an A123 2S1P 2300 mah battery (in series with a IN4007 silicon diode) to power both the ignition and the lights. The lights would be turned on/off by a separate Rcexl remote switch. My concern is whether the switch end of the remote switch will prevent any ignition noise from being radiated through the lighting wire harness or does the remote switch only prevent ignition noise from reaching to the receiver connection? I think I said that correctly


Howard

The optic part of the switch protects the RX only

http://www.himodel.com/engines/Rcexl...itch_v1.2.html

The way I read the specs this is a optic kill switch which does nothing to prevent RFI ignition noise from reaching the receiver.
John

It is optical coupled to prevent RIF from the ignition getting to the RX.
To use it as Howard wants would place noise on the landing lights and the wires would act as antennas and possibly send the noise in to the servos. BUT his RX would be protected noise from the ignition battery, BUT not from noise sent back from the servos.
So probably all in all a bad idea. But with a separate landing light battery it would be OK.

TKG,
You have very accurately identified my concern that if the power sent to the lighting system is not filtered from the ignition noise then the lighting system becomes an antenna to radiate the noise. As you stated the solution is to use a separate battery for the lighting, which I had hoped I might be able to omit I think I will leave it in.

Howard

TKG,
Please correct me if I'm wrong. I thought the switch is opto coupled to the FET that passes the voltage to the receiver. This means the switch leads cannot pickup RFI but the FET can still transmit ignition noise. So if the ignition battery is the same as the receiver battery there is no RFI protection from the ignition feeding noise into the receiver. The unit is not designed to work as an ignition battery eliminator.
John

You have the potential of having your lighting wires act as antennas for your ignition's radio frequency interference. You will be radiating it throught the entire model. It's a very bad idea. Dan.

I have not done a good job of articulating my question: I wanted to use the same battery to power the ignition and the lighting system but not the receiver and flight controls. The plan was to have one opto isolator switch turn on/off the ignition system and a second opto isolator to switch the lights on and off and both would be powered by the same battery (ignition battery) and both switched remotely from the TX which means each opto isolator has one lead going to the receiver. The concern was that with the ignition on and the engine running, when you switch the lights on would the lighting system wiring begin radiating noise coming from the ignition system through the ignition battery leads because both the the ignition opto isolator and the lighting opto isolator would be in a parallel circuit with respect to the ignition battery. I think I said that correctly sorry for the confusion.

Howard

Howard, you're not saying it wrong, you're doing it wrong. The RFI from the ignition will be in the ignition battery pack. The wires from that battery pack to the lights will act as antennas for the RFI and radiate throughout the model all over your receiver system. Dan.

Exactly, that is why I asked the question and will not do that. I will use a separate battery for the lights which has no connection to the ignition battery - the ignition battery and system will not even know it is there.

Howard

Howard, Good. Make sure that the batteries are seperated as far apart as possible to avoid any pickup. Dan.

The batteries themselves actually act like a condensor and more or less tend to absorb the RF.

The problem is the wires going to the point of use from the batteries can pick up and emit RF

There is no DC pathway between the RX ground and power lead and the battery leads for the ign.
1/2 of the switch gets its power from the RX and the other half gets its power from the ignition battery. The optic coupler just passes frame rate info.

Got it.

I have been successfully using the Wike R/C battery eliminators for some time now, I power everything on the plane, including the EI modile with 1 single A-123 battery.

This is what I use -> http://www.troybuiltmodels.com/items/WRCIBEF.html