one for the double E's

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Well-Known Member
Sep 20, 2003
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Hello All,

Well, I have endeavored to build my own launch controller. My plan is to use a hand-held-controller-and-battery-at-the-pad-configuration with a dual circuit. The first circuit will power the bells and whistles, and relay coil. I figure a 12V-12Ah gel cell will be more than adequate for this application. For the second circuit, I plan on a 12V-high amp source, such as a lawnmower battery from Wally Martinez, to fire the igniters. (I'm looking forward to cluster applications or simultaneous single ignitions.) Of course the common point is the relay. I already have a P&B "general purpose" relay with contacts rated at 10 amps and a 12V coil. The lawnmower battery advertisement boasts something to the effect of "140 (or some such number) cranking amps".

So my question is, will the lawnmover battery fry my little 10 amp rated relay. Will high inrush fuse the contacts or worse yet, perhaps the current will simply arc across the contacts, thus defeating the whole purpose. Comments and constructive cirticism welcome.

Thanks for your input.

An old Ford type starter solenoid is also a good choice. You can get them cheap at any auto parts store.