How many amps?

I will be building a launch controller and does any one know how many amp does it pull to launch mid power rocket engines? I do not want to get anything like key switch that has too small of wire.
Thanks
Jeff

I have heard that lamp cord is adequate. As a starting point, your system might use between 2 to 9 amps, depending on the resistance.

Greg

GregGleason said:

I have heard that lamp cord is adequate. As a starting point, your system might use between 2 to 9 amps, depending on the resistance.

Greg

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I saw where someone was sell fuses and they where 5 amps. So to be on the safe side if I set up for 10 amps I will be fine.
Thanks
Jeff

The better question is how many joules... aka amp-seconds.

The current requirement for igniters varies greatly. Those that come with CTI products will fire with quickly with 0.2 amps at 3 volts, an old but functional copperhead will absorb that amount of energy until your battery is depleted. The higher the DC operating voltage of your launch control system, the less impact impact to your launch leads will have when it comes to delivering enough current to the igniters, assuming of course the battery is capable.

John

46u said:

I saw where someone was sell fuses and they where 5 amps. So to be on the safe side if I set up for 10 amps I will be fine.
Thanks
Jeff

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The self-resetting circuit breakers designed for trailer brake applications will keep you flying as compared to searching for a replacement fuse.

John

Being my only transportation is my motorcycle with a side car and I have plug going straight to the batter I will be using the battery on my motorcycle.
Thanks
Jeff

I use 2 6 volt 4.5 amp SLA batteries in series for 12 volts at 9 amps. I started using the SLA batteries due to my infrequency of launching. 8 AA batteries would go dead after sitting in the launch box. I'm not happy with 8 AA rechargeables, 9.6 V just doesn't have the same "pop" you get from the slightly overcharged 14 volts of an SLA setup. I'm getting 4 more 6 volt batteries to replace the AA in the relay boxes...I'll have a ton of rechargable batteries left when I'm done.

Being I have limited space to carry my stuff I am using my motorcycle battery. I found some cheap 10amp key switches that should work fine.
Thanks all for the input.