Problem getting miniTimer 4 to ignite using 9V battery

[Julian]

We got our first miniTimer 4 in the mail this week and have been trying to get it to ignite a powder barrel for parachute deployment.

With a 9V battery it would ignite a standard Estes igniter outside the barrel, but no luck inside the barrel. The moment we hooked up 4 AA batteries, WHAM, it went off like a beauty.

The timer is supposed to work on 6V to 15V, so why is it that a 9V battery by itself can't do what 4 1.5V AA batteries can do together?

Any recommendations would be helpful -- we can't fly 4 AA batteries, too big and heavy.

 

[CarVac]

We got our first miniTimer 4 in the mail this week and have been trying to get it to ignite a powder barrel for parachute deployment.

With a 9V battery it would ignite a standard Estes igniter outside the barrel, but no luck inside the barrel. The moment we hooked up 4 AA batteries, WHAM, it went off like a beauty.

The timer is supposed to work on 6V to 15V, so why is it that a 9V battery by itself can't do what 4 1.5V AA batteries can do together?

Any recommendations would be helpful -- we can't fly 4 AA batteries, too big and heavy.

Try using a different igniter. Quest Q2G2's are excellent, and use very little current.

 

[fyrwrxz]

Estes ignitors for anything other than firing BP motors are useless. Go with quest or any other e-match (Daveyfire, Rocketflite, Quickburst, etc.) designed for low current. Your choice of 9 volts batteries may be suspect as some won't 'dump' enough over a short period to do you any good. There are a few threads on this site with more specific info. The minitimer is a great product-congrats on your choice!

 

[bobkrech]

We got our first miniTimer 4 in the mail this week and have been trying to get it to ignite a powder barrel for parachute deployment.

With a 9V battery it would ignite a standard Estes igniter outside the barrel, but no luck inside the barrel. The moment we hooked up 4 AA batteries, WHAM, it went off like a beauty.

The timer is supposed to work on 6V to 15V, so why is it that a 9V battery by itself can't do what 4 1.5V AA batteries can do together?

Any recommendations would be helpful -- we can't fly 4 AA batteries, too big and heavy.

You are using the wrong battery and e-match. There's nothing wrong with the timer. Estes igniters should never be used to ignite ejection charges. The all-fire current is 2-3 amps and they are fragile. The initial resistance of the Estes igniter is ~0.6 amps so if you use a 9 volt battery the current draw will be I = V/R = 9/0.8 = 15 amps! The problem is that a 9 volts alkaline transistor battery can only supply 5 amp when it is new..... so you need a lower current e-match. As stated previously, the Quest Q2G2 has an all-fire current of 0.35 amps with an initial resistance of 1.7-3 ohms. At 9 volts, I = V/R = 9/1.7 = 5.29 amps. You could also use small LiPo battery packs. Close enough. Checkout https://www.apogeerockets.com/education/downloads/Q2G2_Igniter_Report.pdf https://www.rocketshoppe.com/info/Igniter_Continuity_Tests.pdf https://www.rocketryforum.com/showthread.php?52490-Quest-Q2G2-Concerns https://www.rocketryforum.com/showthread.php?31545-Quest-Q2G2-Igniters https://www.rocketryforum.com/showthread.php?28103-9v-launch-controller

 

[Julian]

Bob, awesome links -- thank you so much for the help. This answers the question, it seems to me!

Julian

NAR 95955