Login    Register
User Information
Username:
Password:
We are a free and open
community, all are welcome.
Click here to Register
Sponsored
Who is online

In total there are 67 users online :: 6 registered, 0 hidden and 61 guests


Most users ever online was 218 on Wed Dec 07, 2016 6:58 pm

Registered users: Bing [Bot], Google [Bot], Google Adsense [Bot], jackreacher, MSNbot Media, Yahoo [Bot] based on users active over the past 5 minutes

The Team
Administrators
Global Moderators
global_moderators.png CS

Some Electronics Help

A place to ask general spud cannon related questions.
Sponsored 
  • Author
    Message

Some Electronics Help

Unread postAuthor: mark.f » Sun Oct 14, 2007 9:48 am

I finally got my plans for an ignition-coil-based igniter for spudcannons. Now, there are more immediate problems like powering the coil and switching it.

The main problem I've come up against is powering the coil. It takes some pretty heavy current to provide the same spark as on the ATV the coil came off of. The battery for the ATV is rated at 12 ampere*hours. Most standard consumable batteries are listed in terms of milliamp*hours. So this could be a problem. Switching the coil will be by way of a standard automotive relay.

My power solution is going to be simple 1.2 volt "Sub C" NiCd batteries. Lowes always has a recycle bin with old batteries like this in them. My friend says there's a way to test the batteries with a multi-meter, so I'll ask him about that unless anybody else can tell me how.

Each of these batteries provides 1.2 volts at around 1500 mAh, (milliampere*hours). So for a 12 volt power source, that would be 10 batteries, 12 volts at 15,000 mAh, or 15 ampere*hours, right?

That is my main question. My next question would be charging. How would I charge these batteries? Most of what I've read has suggested, to me at least, some sort of adjustable current charger with a timer. For the life of me, though, I can't find any of these. I would like to do the slowest charge possible, because the batteries are used and probably won't take many quick charges.

Any help here would be hot. Most of you know I'm not a terribly good electrician, although I can get by on simple circuits such as this. Thanks in advance for any advice.
  • 0

User avatar
mark.f
Donating Member
Donating Member
 
Posts: 3464
Joined: Sat May 06, 2006 11:18 am
Country: United States (us)
Reputation: 21

Unread postAuthor: jrrdw » Sun Oct 14, 2007 10:41 am

Go with a garden tractor battery, cheep, easy to charge and carry and will be enough to power your ignition. The way your talking about doing it is going to be problem-matic. To test batteries, you need a load tester, much different then a multi tester. Useing old batteries is also going to be a pain in the ass. You can get a mower battery for 24 bucks, around 230 cca.
  • 0

When life gives you lemons...throw them back they suck!
User avatar
jrrdw
Donating Moderator
Donating Moderator
 
Posts: 6538
Joined: Wed Nov 16, 2005 5:11 pm
Location: Maryland
Country: United States (us)
Reputation: 25

Unread postAuthor: dewey-1 » Sun Oct 14, 2007 10:54 am

--
  • 0

Last edited by dewey-1 on Sun Apr 20, 2008 3:44 pm, edited 1 time in total.
User avatar
dewey-1
Major General
Major General
 
Posts: 1298
Joined: Wed Mar 28, 2007 10:24 am
Location: NE Wisconsin USA
Reputation: 0

Unread postAuthor: Fnord » Sun Oct 14, 2007 12:06 pm

I believe Batteries like NiMH (the ones you're supposed to use for cameras and stuff) can put out far more amps than the standard NiCd ones.
They have lower internal resistance also, so they don't run out quicker than normal when under high load.

Or, you could just use a camera flash :)
  • 0

Image
User avatar
Fnord
Major General
Major General
 
Posts: 2244
Joined: Tue Feb 13, 2007 9:20 pm
Location: Pripyat
Reputation: 7

Unread postAuthor: mark.f » Mon Oct 15, 2007 5:42 am

Jrrdw, if I get a lead-acid battery like that, it would make the thing as portable as a refrigerator, but I think that may be what I end up doing.

Dewey, I'm gonna research into your gel-cell batteries. I haven't heard of them before, so that might be an idea. I've already checked RC battery packs and couldn't find one with enough amperage.

Thanks for the ideas from all of you. Maybe when I'm forced to learn electronics as a prerequisite for fluid mechanics, I'll stop bugging you. :wink:

_Fnord, that'll be my last choice. I'm actually researching induction coils, (which you can pull out of a gag "shock lighter"), for driving an ignition coil to produce the spark voltage you need. Looks promising and cheap, as you can get them from the dollar store. :P
  • 0

User avatar
mark.f
Donating Member
Donating Member
 
Posts: 3464
Joined: Sat May 06, 2006 11:18 am
Country: United States (us)
Reputation: 21

Unread postAuthor: jrrdw » Mon Oct 15, 2007 6:28 am

markfh11q wrote:Jrrdw, if I get a lead-acid battery like that, it would make the thing as portable as a refrigerator, but I think that may be what I end up doing.

Dewey, I'm gonna research into your gel-cell batteries. I haven't heard of them before, so that might be an idea. I've already checked RC battery packs and couldn't find one with enough amperage.

Thanks for the ideas from all of you. Maybe when I'm forced to learn electronics as a prerequisite for fluid mechanics, I'll stop bugging you. :wink:

_Fnord, that'll be my last choice. I'm actually researching induction coils, (which you can pull out of a gag "shock lighter"), for driving an ignition coil to produce the spark voltage you need. Looks promising and cheap, as you can get them from the dollar store. :P


Not at all, the measure approx. 8"W X 6"H X 5"D. Only weight about 12lbs. Very portable.

Gel batteries are the size of car batteries and weight approx. 45/50lbs, they are normanly used in electric wheelchairs, or in very cold climents.
  • 0

When life gives you lemons...throw them back they suck!
User avatar
jrrdw
Donating Moderator
Donating Moderator
 
Posts: 6538
Joined: Wed Nov 16, 2005 5:11 pm
Location: Maryland
Country: United States (us)
Reputation: 25

Unread postAuthor: ShowNoMercy » Mon Oct 15, 2007 7:09 am

The smallest lead acid or AGM battery you are gonna find is a size 24 which is similar to like a shoebox maybe. But look into lead acid batteries from jet skis, ski mobiles or atvs.
  • 0

Jesus saves, no need to pray
The gates of pearl have turned to gold
It seems you've lost your way
User avatar
ShowNoMercy
Brigadier General
Brigadier General
 
Posts: 1094
Joined: Mon Mar 19, 2007 8:08 am
Location: Jersey Bitches!
Reputation: 0

Sponsored

Sponsor
 


Unread postAuthor: jrrdw » Mon Oct 15, 2007 7:58 am

ShowNoMercy wrote:The smallest lead acid or AGM battery you are gonna find is a size 24 which is similar to like a shoebox maybe. But look into lead acid batteries from jet skis, ski mobiles or atvs.


Those type batteries cost twice as much as a garden tractor battery.
  • 0

When life gives you lemons...throw them back they suck!
User avatar
jrrdw
Donating Moderator
Donating Moderator
 
Posts: 6538
Joined: Wed Nov 16, 2005 5:11 pm
Location: Maryland
Country: United States (us)
Reputation: 25

Unread postAuthor: ShowNoMercy » Mon Oct 15, 2007 8:05 am

  • 0

Jesus saves, no need to pray
The gates of pearl have turned to gold
It seems you've lost your way
User avatar
ShowNoMercy
Brigadier General
Brigadier General
 
Posts: 1094
Joined: Mon Mar 19, 2007 8:08 am
Location: Jersey Bitches!
Reputation: 0

Unread postAuthor: jrrdw » Mon Oct 15, 2007 9:01 am



Good find, but low amp hours. Heres what i was thinking of -- more shots.

Cost a little more, close to size, 1lbs less, that surprized me.
  • 0

When life gives you lemons...throw them back they suck!
User avatar
jrrdw
Donating Moderator
Donating Moderator
 
Posts: 6538
Joined: Wed Nov 16, 2005 5:11 pm
Location: Maryland
Country: United States (us)
Reputation: 25

Unread postAuthor: dewey-1 » Mon Oct 15, 2007 10:12 am

--
  • 0

Last edited by dewey-1 on Sun Apr 20, 2008 3:45 pm, edited 1 time in total.
User avatar
dewey-1
Major General
Major General
 
Posts: 1298
Joined: Wed Mar 28, 2007 10:24 am
Location: NE Wisconsin USA
Reputation: 0

Unread postAuthor: jimmy101 » Mon Oct 15, 2007 12:11 pm

The amp hour rating is really not relevant in this useage.

The "1200mAH" metal hydride batteries will put out ~10 amps for a short time. Since you won't be running your ignition circuit for more than a second or so for each firing, the amp/hour rating really isn't all that important. The important thing is the peak current for a short duration pulse.

10 amps might be enough, it is worth trying.

Most wall warts won't put out anywhere near 10 amps (usually more like 1 or 2 amps), so they probably won't work very well.

I would think your best bet would be a surplus sealed lead acid (gel cel) 12V battery. All Electronics has several types. This one should work well and will probably supply at least tens of amps in a pulse;
12 VOLT 5 AH GEL CEL BATTERY
Maintenance-free, rechargeable sealed lead-acid battery. Can be used in any position and trickle charged for long periods of time. Will not leak. 2.75" x 3.53" x 4" high. 0.1875" quick-connect connectors.
CAT# GC-125 $16.00 each

You can use a standard car battery charger to recharge the 12V gel cel batteries.

I've got a couple different batteries of this type, mostly salvaged from dead uninteruptable power supplies and home alarm systems. They'll put out a heck of a lot of current, not as much as a car battery but they are much smaller and cheaper than even the smallest car battery.

Another possibility is the "emergency batteries" you can usually pick up for $40 or so at car parts places, Kmart, Sears, etc. These'll supply at least a couple hundred amps for a short time. They are pretty small and usually come with their own wall wart for recharging. And, you can use it to start your car when the battery is dead.

Here is a $40 one from Sears that claims 750 peak amps. You can probably find simpler/cheaper ones elsewhere.
  • 0

Image

jimmy101
Lieutenant General
Lieutenant General
 
Posts: 3129
Joined: Wed Mar 28, 2007 9:48 am
Location: Greenwood, Indiana
Country: United States (us)
Reputation: 7

Unread postAuthor: dewey-1 » Mon Oct 15, 2007 1:20 pm

--
  • 0

Last edited by dewey-1 on Sun Apr 20, 2008 3:46 pm, edited 2 times in total.
User avatar
dewey-1
Major General
Major General
 
Posts: 1298
Joined: Wed Mar 28, 2007 10:24 am
Location: NE Wisconsin USA
Reputation: 0

Unread postAuthor: jrrdw » Mon Oct 15, 2007 4:00 pm

How long the battery is going to last depends on the resistance load the coil and switch/s puts on the circuite???
  • 0

When life gives you lemons...throw them back they suck!
User avatar
jrrdw
Donating Moderator
Donating Moderator
 
Posts: 6538
Joined: Wed Nov 16, 2005 5:11 pm
Location: Maryland
Country: United States (us)
Reputation: 25

Unread postAuthor: dewey-1 » Mon Oct 15, 2007 4:41 pm

--
  • 0

Last edited by dewey-1 on Sun Apr 20, 2008 3:47 pm, edited 2 times in total.
User avatar
dewey-1
Major General
Major General
 
Posts: 1298
Joined: Wed Mar 28, 2007 10:24 am
Location: NE Wisconsin USA
Reputation: 0

Next

Return to General Spud Cannon Related

Who is online

Registered users: Bing [Bot], Google [Bot], Google Adsense [Bot], jackreacher, MSNbot Media, Yahoo [Bot]

Reputation System ©'