Powering ignition and chamber fan.

[Biopyro]

What's the best way to power a 12v fan and a 9v HV supply on a cannon. I'm thinking a 9v battery and 2(maybe 4) AAs, but will they give me enough power to run the fan properly?

[kjjohn]

I would use a 12v battery (rechargeable NiMH or Lithium RC battery), but use a 9v voltage regulator for your HV supply circuit.

[ramses]

I believe 12V fans run fine off a 9V. A little slower, but good enough.

[bighead33]

what is your HV supply?

[jimmy101]

A single 9V should be enough if the fan doesn't draw too much current. Figure the 9V can source about an amp so. If the fan draws less than a couple hundred milliamps you should be OK.

Use a pair of 9V in parallel (not series) if the fan is a power pig.

[Moonbogg]

8AA's for fan & a 9V for the stun gun. Last all day loooooong at full power with monster fan.

[Biopyro]

I've decided to go for a piezo igniter, it's a great salvaged one, has at least 1cm spark!
As for the fan, it's 100mA, I'll have to test it with a 9v, but if it's pathetic, I will likely need 8AAs, or perhaps a 12v camera battery, maybe 2?

[Hubb]

You could always do what I did and use a rechargeable battery pack. The one pictured is just hooked up to the fan, but I did manage to hook it up to the stun gun as well and had no power down. It made things a lot easier (and cheaper since it was salvaged), and more compact than using AAs or 9v batteries.

[Biopyro]

I might well do that, although I now have 14 AA batteries, so I'll likely use them.
If it's too bulky or doesn't deliver enough power i might well have to splash out for a rechargeable 12v.

In other news, lots of parts for the fuel meter arrived today. Pretty excited!

[mark.f]

Sorry for the late reply.

I would use a 12V source wired in parallel with the fan, and then in parallel with a 9V voltage regulator and the ignition source.

[Biopyro]

I wound up going for the piezo BBQ igniter separately, then 8AA batteries in a purpose built enclosure for the 12v supply. It gives plenty of power and isn't too bulky.

Attaching the gas to the metering system is still a bitch, have caved and bought a blowtorch and will be attaching it with some hose.