I heard that the continuicy tests from other launch controlers could set these babies off. So I was inside and I layed everything down on a concrete floor so I had my trusty 6v electron beam with me (I figured my interlock would deffinetly set it ofF on the test) so I inserted the safety key in (I didn't press the launch button) and the Q2G2 went off..... Explosively not like the estes solar igniter where it would light up the Q2G2 went off with I big bang Is this supposed to happen? The quest controler was a 9v and the estes was a 6v so how did it set it off?
Rocketry is an exact science...... But not exactly!
It's more about amps than volts...
The Estes controllers use a light bulb, which is low-impedance (low resistance). Plug in Ohm's Law (amps= volts/resistance) and you'll see how the three factors work together. What it boils down to is, the light bulb in the Estes controller allows more current to flow to the Q2G2 than it needs to ignite. The Quest ignitors only need about 100 MILLIAMPS to fire-- and that's not much!
Now, the Quest controller uses an LED continuity indicator. LED's have resistors wired in series with the LED to protect the LED's semiconductor bridge so that it doesn't burn out. Therefore, the LED only passes a few milliamps, FAR less than is needed to set off the Quest ignitors. That is why Quest ONLY recommends using THEIR controller for the Q2G2's... because of it's high impedance design.
When you press the launch button, the LED is essentially 'short circuited' (more like bypassed, actually) and the power is then allowed to flow unimpeded to the ignitor, which is what happens in EVERY controller-- the unrestricted power heats the ignitor and it burst into flames, igniting the motor.
Now, it's a simple fix to get around the 'continuity light" problem... there have been a number of threads in the last month or so about rebuilding Estes controllers, and IMHO ANYTHING you do to an Estes controller is a distinct improvement!
The simplest "fix" is to install an LED bulb in place of the regular old flashlight bulb the Estes controllers are equipped with. These are available online from various sources, or from local big box/camping stores. The LED bulb 'chokes back' the current going to the ignitor and reduces it to a safe level that can show the continuity without heating the ignitor up. Use the "Search" box above and look for the "launch controllers" threads-- there's a LOT of good information in there. (some from yours truly
)
It's actually a VERY good thing that the Quest ignitors are low-current and a bit more energetic when they fire-- the lower current requirement means they are MUCH MUCH easier to ignite, even with low batteries, small wire, etc... and they are ESPECIALLY useful for clustering where you DEFINITELY WANT EVERY IGNITOR TO FIRE VIRTUALLY INSTANTLY. Estes ignitors with their high current requirements are WAY INFERIOR in this regard. They take a LOT more wattage (volts times amps= watts) to heat up and ignite, which means they need larger wire, more current, and higher voltage definitely helps as well) and getting several of them to all ignite simultaneously can be a daunting task...
Hope this helps! OL JR
