estes igniters minimum voltage

Hello everyone,

I would like in my next rocket to use an ejection charge that would be controlled electronically from an arduino nano via an altimeter. For that, I will use the igniter of estes mounted on a load cylinder holder. Has anyone ever done research on the minimum volt/amp to activate estes igniters ?


Do a 1200mAh 9 volt battery will be sufficient ?

Typically it was about 6 volts. Quest used 9 volt batteries in their launch controllers and 14.4V was what Pro Series 2 controllers could output with two battery packs. When in doubt, do a ground test to make sure the igniter fires as igniters cost a lot less than replacing a rocket.

Good advice. Estes has also made two launch controllers that used a 9V battery. The most recent was the "Astron II" controller. The battery had to be a high quality unit (Duracell or Energizer) in order for it to be reasonably reliable.

Wiring inside a rocket would be much shorter than that used by a launch controller, which will help. But ground testing is certainly indicated.

How are you switching the circuit? Are you using an output from the Arduino to fire the charge directly, or using it to close a relay or switch a MOSFET or some such?

It's not voltage you need to consider, but current. Voltage measured at the ends of the starter's leads is tantamount to the same thing, but it's really the current that matters.

I couldn't find the technical details at Estes web site, but eRockets provides this:

• Minimum all-fire current: 2 A
• Maximum no-fire current: 0.5 A
• Nominal resistance: 0.6904 Ω

I'm disappointed that there is no tolerance given for the resistance, only the nominal value. I suspect the tolerance isn't more than 5%, but I could easily be all wet. Let's go with 10% to be on the safe side. Also, I'm skeptical that the resistance is actually known to four significant digits, but that's not important.

To be certain of firing you need at least 2 A with load resistance possibly as high as 1.1*0.69 Ω, so you need at least 1.52 V at the ends of the leads. But again, voltage is the wrong thing to focus on; just focus on the 2 A. What is the 9 V battery's internal resistance? What losses are there and is there a current limit in the switching method?

And if you are building in an on-board continuity test, be sure that the test current is under - well under - 0.5 A.

A question for you - why are you using Estes igniters to activate an ejection charge? The standard method to do that is using an electric match, which is substantially less delicate, more reliable, and easier to activate than an Estes igniter.

thank you for your answer
a moffet will be used as a relay for ignition
tests will be done on the electric match and the christmas lights.
I will share the results of my ground test