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Powering ignition and chamber fan.

Posted: Tue Jul 20, 2010 11:33 am
by 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?

Posted: Tue Jul 20, 2010 11:38 am
by kjjohn
I would use a 12v battery (rechargeable NiMH or Lithium RC battery), but use a 9v voltage regulator for your HV supply circuit.

Posted: Tue Jul 20, 2010 11:41 am
by ramses
I believe 12V fans run fine off a 9V. A little slower, but good enough.

Posted: Tue Jul 20, 2010 3:37 pm
by bighead33
what is your HV supply?

Posted: Tue Jul 20, 2010 6:19 pm
by 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.

Posted: Wed Jul 21, 2010 1:20 am
by Moonbogg
8AA's for fan & a 9V for the stun gun. Last all day loooooong at full power with monster fan.

Posted: Wed Jul 21, 2010 2:52 am
by 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?

Posted: Wed Jul 21, 2010 8:46 am
by 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.

Image

Posted: Thu Jul 22, 2010 4:19 am
by 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!

Posted: Sat Jul 31, 2010 8:40 am
by 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.

Posted: Sat Jul 31, 2010 8:45 am
by 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.