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Batteries in series vs parallel Launch controller

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Lunarxray1968

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Ok, ImageUploadedByRocketry Forum1475867595.218642.jpgImageUploadedByRocketry Forum1475867606.287189.jpgI built my second electronic launch controller. I have a question.
I have 4 9 volt battery's that I want to arrange in either a series or parallel arrangement. I am running a 25 foot igniter wire from the launch controller to the igniter. Which arrangement would give me the best power to ignite the fuse?
 

ttabbal

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Do they have to be 9V? There are much better options....

What type of ignitors do you want to be able to light? Just Estes style for BP motors? AP motors? EMatches?
 

hornet driver

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Two in series will double the voltage and so on and so on-- the amps will remain the same -- two in parallel will double the amperage and so on leaving the voltage the same- if your using a four battery configuration you can combine the two and double both so you would get 18V and double the amperage!
 

Bat-mite

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Did you mean "igniter," or are you really using fuses? If the latter, what kind of fuse and what kind of motor?
 

Lunarxray1968

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I mean igniter. Sorry
Does anyone what voltage I need to lite a Estes igniter?
I think maybe my wire is too long. Idk
I want to test the end of the wire to see if I'm getting enough volts to ignite
 

Woody's Workshop

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When small batteries are used, it is not uncommon to have to hold the "Fire" button down for several seconds until enough heat builds up at the end of the line to get the py-ro-jin to egg-nite. :wink:
 

Micromeister

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To answer your earlier question the general rule of thumb for Estes igniters and newer pyrogenless Starters is 2amps per igniter.

Over the years I've built many controllers with internal and/or external power sources. While just about any bare Nichrome 30ga igniter or starter wire will glow red hot on 6 volt batteries the use of Carbon or alkline batteries is regularly given the thumbs down as shorting these and 9v batteries severely damages the internal power creating chemistry of these batteries.
It is hightly recommended that a simple 12volt 7amp/hr or higher Gel-Cell or Sealed Lead Acid battery rechargable battery be used as these will deliver pleanty of power to single Starter/igniters or Clustered Igniters up to 6 with no trouble at all. I've used these small 12v - 7amp/hr gel-cells avaialble from just about any RC hobby store for decades. The first Hobbico lasted almost 24 years with nearly constant weekly used and recharging. I believe the currently sell for less then 20.00 bucks and can be recharged with any 500ma to 1amp 120/12 volt wall pack adaptor. Simply remove the plug and replace with a couple alligator clips. (see photo/tip below.)

A couple things you don't mention:
What gauge "Stranded" copper wire are you using for your 25ft controller leads? I strongly suggest 16ga stranded copper Lamp cord or Zip cord if you can find it locally with the white jacket rather then brown. Much less of a trip hazzard:)

What is the amprage rating of your 4.9v batteries? If I were building this controller instead of using 3 in series to give a 14.7v supply I'd go with an external drop cord (same 16/2 Lamp cord with alligator or 30amp battery clips) and get that 7amp/hr 12v gel-cell:)
Since we don't know what the Amp rating of your 4.9volt batteries, it really doesn't make much sense to parallel them, 3 or 4 times 0 is still 0.

12V Gel-Cell-b_ Batteries & Adaptor Charger(128dpi)_11-05.jpg
 
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