mho2
New Pyro Member
Posts: 15 
|
Post by mho2 on Jul 27, 2017 7:41:09 GMT -5
Hey Guys,
Brand new to this forum. I've got a question, but will be doing some experimental testing to supplement.
My background is electrical engineering but generally batteries are wildly variable.
I've got a custom cueing system and want to be able to fire off 4 e matches at the same time.
I'm reading that most of the time the recommended current for all fire is around 1A, but this has been tested at 1.5V.
Questions:
1) if I divide down to 4 different parallel power banks, is 2x AA batteries enough to fire off single fireworks consecutively?
2) if I keep my system at 2 power banks, can I draw enough current from the 4x AA batteries to light two fireworks at the same time with 100% success rate? I'm reading the internal resistance of AA's is around 30mOhm
|
|
dsj
New Pyro Member
Posts: 12
|
Post by dsj on Jul 28, 2017 9:16:41 GMT -5
Are you planning to wire your ematches in series or parallel?
This is a pretty basic application of ohm's law, series, and parallel circuits.
Is there any reason why you want to use as few batteries as possible?
AA's are so cheap that I would double or triple the quantity just to be sure.
Another option would be to use a couple of 9volt batteries in an 18 volt supply.
|
|
|
|
Post by Aussie on Jul 28, 2017 19:04:10 GMT -5
COBRA!!!!!!!!!
|
|
mho2
New Pyro Member
Posts: 15
|
Post by mho2 on Jul 28, 2017 19:15:29 GMT -5
Are you planning to wire your ematches in series or parallel? This is a pretty basic application of ohm's law, series, and parallel circuits. Is there any reason why you want to use as few batteries as possible? AA's are so cheap that I would double or triple the quantity just to be sure. Another option would be to use a couple of 9volt batteries in an 18 volt supply. Hi Dsj, Aware of the ohms law rules and Im finding the approx current requirements to be 1A over 100ms per e match. That said it probably does vary wildly in application. I guess my question was finding out in practice what you normally use. My e matches will be in parallel. I've got 4 power banks each with 4 AA's so I can source probably up to 6A at 6V until the internal resistance of the batteries kick in. I've also got a relay set to only turn on the ancillary power when firing more than one in parallel. |
|
mho2
New Pyro Member
Posts: 15
|
Post by mho2 on Jul 28, 2017 19:16:33 GMT -5
Aussie, Where's the fun in using a premade solution? Plus I've got mine hooked up in a multiplexed grid array so I only need 24 control pins to sequence 128 fireworks  |
|
|
|
Post by Aussie on Jul 29, 2017 8:30:10 GMT -5
Built many a nail board in my day,
It was fun, enjoyed the journey, came to the conclusion that I sucked at electronics.
Cobra rocks
Makes me look good with electrical shooting lol
|
|
dsj
New Pyro Member
Posts: 12
|
Post by dsj on Jul 29, 2017 18:41:21 GMT -5
Why don't you just wire in series?
In a series circuit, every ematch gets full current.
In a parallel setup ,the amperage is divided so that each match only gets a fraction of the current.
It would simplify your design quite a bit.
|
|
mho2
New Pyro Member
Posts: 15
|
Post by mho2 on Jul 30, 2017 17:28:15 GMT -5
Why don't you just wire in series? In a series circuit, every ematch gets full current. In a parallel setup ,the amperage is divided so that each match only gets a fraction of the current. It would simplify your design quite a bit. Hi Dsj, Thats a great point, unfortunately in a multiplexed array the only way to fire off multiple is in parallel as seen here:  As for the current division, you're right but the actual equivalent resistance cuts in half, so the current going to each load is still the same. The problem comes with saturating the battery max current. I've taken a look at AA characteristics and it looks like I can safely hit 1A of current, and possibly 2A of current over quick periods of time. To solve this i've actually switched my setup to be 2x 8-AA battery banks. The secondary battery bank will only turn on in parallel when multiple fireworks need to be set off at the same time. Looks like it should be ok  I'll post my tests. |
|
dsj
New Pyro Member
Posts: 12
|
Post by dsj on Jul 30, 2017 21:26:26 GMT -5
Heres some reading from cobra regarding series and parallel. wrtiii.net/wordpress/?page_id=122There are several ways to fire multiple ematches on factory built systems. The simplest is to connect the ematches in either series or parallel and then conect that to a single cue. A second way is to program multiple modules to the same channel a So the cues on each fire at the same time. Third is to use separate cues on a dedicated module or modules and use a "fire all" function if the system has one. I completely understand why your making this. I've built lots of things for $100 that i should have bought for $50. |
|
I'll post my tests.