New to MPR. Want to launch with some Aerotech F and G size. What are the absolute minimal requirment for power in volts/amps? Is a 12 volt car battery necessary? Would two 6 volt batteries wired together be enough? Thank you.
F7 G Ignition requirements
- Thread starter gary7
- Start date
Help Support The Rocketry Forum:
I've used 6v lantern batteries, but now I'm using a 12v "Jump Start" device which is rechargable. You can pick them up at Home Depot or similar stores and sometimes at reasonable prices. It also runs the starter box for an RC car when needed.
If you have a car battery charger already, you might want to consider a motorcycle/garden tractor/ATV battery. They are much smaller and lighter then car batteries but have plenty of juice to last all day.
blackjack2564
Crazy Jim's Gone Banana's
Got any rechargable power tools?
I have used my battery out of my rechargeable power tools...... drills, screwdrivers....saws.....lights. Mikita, Ryobi, Black and Decker. Some are 18 volt some 12. They all work equally well and hit hard! just a couple of small alligator clips on a wire and attach them to the removed battery. When done back in the tool!
I have used my battery out of my rechargeable power tools...... drills, screwdrivers....saws.....lights. Mikita, Ryobi, Black and Decker. Some are 18 volt some 12. They all work equally well and hit hard! just a couple of small alligator clips on a wire and attach them to the removed battery. When done back in the tool!
dpower
Well-Known Member
- Joined
- Jan 18, 2009
- Messages
- 1,961
- Reaction score
- 633
The copperhead and FirstFire instructions on aerotech's site both state:
"Make sure that your launch controller power supply is capable of delivering 12 volts at a minimum of 3 amps to the igniter. A fully-charged car battery or 12 volt gel-cell is recommended."
I use a Werker brand, 12V, 5 Amp-Hour sealed lead-acid battery, and it works great for copperheads, and is quite compact (about 2" x 3" x 4"). It fits in a small toolbox with my launch controller and cables. A car battery is not necessary, though will certainly work fine.
bobkrech
Well-Known Member
- Joined
- Jan 20, 2009
- Messages
- 8,352
- Reaction score
- 65
APCP motors are not as easy to ignite as PB motors and require heftier igniters. The peak current draw of a copperhead on a 12 volt launch system is ~20 amps. Lantern batteries and other high impedance batteries will not source that level of current.
You really need a low impedance 12 volts system that can deliver 10s of amps to light a copperhead promptly. Any 12 volt gell cell battery of 2 Ah or more or a gell cell powered auto jump starter or air compressor can be used and is a good option since the battery recharger is included with them. 12 volt gell cells for emergency lighting systems can be purchased at any electrical supply house for $15-$25, and 12 volt self-contained air compressors and jump starters can be purchase at any auto supply store starting at $40.
High capacity 12 volt NiCad or NiMH packs capable of delivering 10s of amps will also work. The R/C car supply houses and power tool power packs typically are good sources for these type of power units.
Added Comment: This is not to say that you can't do it with other types of batteries. The issue is the the copperheads are not characterized for their all-fire current, so you don't know how much current is need to guarantee activation, nor do you know how long the igniter will take to activate. If you supply 3 times the all-fire current to most characterized e-matches, they usually activate in less than a millisecond.
If an igniter is not well characterized, you simply don't know how hard you need to hit it to activate it promptly. For marginal current near the all-fire current, it might take most of a second or so to activate an igniter. Yes the motor will eventual ignite, but if you're trying to light a cluster or have a drag race, the results will be unpredictable.
Bob
You really need a low impedance 12 volts system that can deliver 10s of amps to light a copperhead promptly. Any 12 volt gell cell battery of 2 Ah or more or a gell cell powered auto jump starter or air compressor can be used and is a good option since the battery recharger is included with them. 12 volt gell cells for emergency lighting systems can be purchased at any electrical supply house for $15-$25, and 12 volt self-contained air compressors and jump starters can be purchase at any auto supply store starting at $40.
High capacity 12 volt NiCad or NiMH packs capable of delivering 10s of amps will also work. The R/C car supply houses and power tool power packs typically are good sources for these type of power units.
Added Comment: This is not to say that you can't do it with other types of batteries. The issue is the the copperheads are not characterized for their all-fire current, so you don't know how much current is need to guarantee activation, nor do you know how long the igniter will take to activate. If you supply 3 times the all-fire current to most characterized e-matches, they usually activate in less than a millisecond.
If an igniter is not well characterized, you simply don't know how hard you need to hit it to activate it promptly. For marginal current near the all-fire current, it might take most of a second or so to activate an igniter. Yes the motor will eventual ignite, but if you're trying to light a cluster or have a drag race, the results will be unpredictable.
Bob
Last edited:
Similar threads
