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12v Drill rechargable batteries for launchers?

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rabidsheeep

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Anyone tried this? Does it work? I know i need a 12v for a few 2x and 3x 18mm clusters i have, but i dont wanna spend 20-30 bucks on one that will run out quick. These I can recharge fast. Im just wondering if anyone has experience with them.

I cant find an amp reading anywhere on the things.
 

rocketsonly

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Why not just use a standard 12v rechargable lead-acid battery? It's also probably easier to hook up, just use some sort of aligator clip. The drill battery may require special adapters.
 

DynaSoar

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Originally posted by rabidsheeep
Anyone tried this? Does it work? I know i need a 12v for a few 2x and 3x 18mm clusters i have, but i dont wanna spend 20-30 bucks on one that will run out quick. These I can recharge fast. Im just wondering if anyone has experience with them.

I cant find an amp reading anywhere on the things.
I haven't. Yet. But someone else here did and wrote about it.

My wife's drill actually uses 17v NiCad batteries about the size of 6 C cells. I've been planning on building a contact cap for them to connect to my automated countdown controller. They'll only run at high torque for 5 minutes before starting to wear down, but even at maximum draw and giving a full 5 seconds per launch, that's at least 60 launches on a charge. I can't chase down that many landings in one day.
 

rabidsheeep

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ill give it a shot on some scratch built beauties

i already modified an old estes launcher to have two alligator clips taking in charges, one + one -, and its worked ok.

btw, do 2 6 volt batteries=1 12v? or does combining batteries increase the charge? cause if so i could connect about 5 or 6 6 volts together with some 20 gauge wire leading into two wires, almost like a clipwhip...
 

Elapid

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in series, the voltage is doubled, in parallel, the amperage is doubled...you'd be better off with higher current capability, imo.

i have used my Black & Decker 18v cordless drill battery to launch bp clusters of 3 motors successfully.

good luck!
 

Micromeister

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Rabid:
The problem with Drill batteries is we do not know the amp/hr rating. A quick recharge is no consulation if they won't dump the amps necessary for your particular cluster. I've tried a Robi 12V battery in some ignitor bench tests with mixed success, 3 igniters no prob. 4 igniters some yes some only 3. For 3 & $ motor clusters the Hobbico 7amp/hr 12V gel is fine... you can launch all day and not worry about it. Recharges overnight on a 500ma radioshack adaptor. I just purchased a new Hobbico in February for 17.95 at a local hobby shop.. Can't bet that with a stick! I don't understand not investing a few bucks in a good piece of equipment. Crash a couple models and you've spent the money you could have on a decent battery.
 

limd21

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Not being able to know the details about the particular battery pack you're considering, the following is *generally* true.

Most cordless drill battery packs are made from NiCd (nickel cadmium) cells strung in series to make 12v, 14.4v, 18v, etc... Even the cheaper brands use cells that are in the 1000-1500 milliamp-hour range. NiCd cells have lower internal resistance than do lead-acid batteries, which means they are able to deliver more instantaneous current for packs of similar capacity. In short (no pun intended!), they are great for launching rockets.

Go to harborfreight.com andyou'll find all sorts of launch batteries in the 12-18v range, for not too much money, that have a drill and charger tossed in for free! Just do a search for "cordless drill" ;-). Since clustering is your concern, I'd step up to a 14.4 or 18v pack - as voltage goes up, current requirements for similar load go down.

I use my cordless drill batteries for launching rockets all the time. The work great with both nichrome bridge wire and conductive primer "dipped" ignitors, which can be quite a bit more demanding of current.
 

GL-P

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We used to have a system where we used a Dewalt 12V battery pack to fire off some rockets. Not much but it worked. Look in the phone book to see if there is a rebuild shop for drills in your area. They sell cheap batteries. Just use alligator clips to hold on to the contacts.
 

rabidsheeep

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ahh crud

i tried it on my B&D 12v and the alligator clips connecting to the battery touched so it shorted out

i have another drill but im not gonna test my luck on it, or else i have no drill, jigsaw, or sander...

ill look into the suggestions...

in series, the voltage is doubled, in parallel, the amperage is doubled...you'd be better off with higher current capability, imo
uhh, by this do you mean which in the attached image, or something else?

edit: micro, do you have a link from a place online you could pick one of those up, i googled and found nothing

edit again:

radioshack-ed and came up with this

http://www.radioshack.com/product.asp?catalog_name=CTLG&product_id=23-275

cant find anywhere they say a charger reccomended for it
 

aksarben10

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I have had found cordless drill batteries work very well for rockets and use mine for that purpose all the time. Last time I used mine for this was this July 4th I got off about 10 launches, all H and I motors, with no problems. I like how small they are as it fits right in my range box.

I have not tried it with a cluster yet, but I have no doubts that they would do fine on 2 and 3 motor clusters. If you are skeptical wire up a couple of ignitors add test.

Scott
 

rabidsheeep

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so a series would work best. ok, now how do you use a series for lets say 6 volt batteries that have prongs ontop, like #2 in the image i attached above?
 

solrules

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As far as I understand it, all you would have to do would be connect the two positive terminals to a single wire (using a clip whip type cable) and the same for the negative terminals.
 

sandman

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rabid,

Maybe this can explain it better.

Your drawings 1 and 2 actually show the same, thing two parallel circuits.

I kinda used your drawing.

See how in series the bateries are wired pos. to neg. Then the voltages add up to 18.

In parallel like yours they stay at the 6v but woul last a lot longer with say a light bulb.

The series circuit would burn out the bulb.
 

DynaSoar

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Originally posted by rabidsheeep
ill give it a shot on some scratch built beauties

i already modified an old estes launcher to have two alligator clips taking in charges, one + one -, and its worked ok.

btw, do 2 6 volt batteries=1 12v? or does combining batteries increase the charge? cause if so i could connect about 5 or 6 6 volts together with some 20 gauge wire leading into two wires, almost like a clipwhip...
Hooking up pos-neg/pos-neg/pos-neg lined up like cells in a flashlight is series. You add together the volts.

Hooking up all the pos's together to one line, and all the negs together to one line, that's parallel. You get the same volts as the single battery (or average of them) but you add together the amperage.

According to Ohm's Law, you should get the same amount of heat out of a given resistance (igniter) from the same combination of volts and amps, no matter whether the amps are added or the volts are added while the other remains constant. In reality, batteries have to "come up to speed" and will do so in a line if in series. They'll do it faster, giving you a faster dump of current and so a faster heating of the igniter, if done in parallel. Either way, you do get the same amount of heat and Mr. Ohm stays happy, it's just a question of when.

Ohm's Law (equivalent forms):
E = I x R
R = E / I
I = R / E
where E = Electromotive force in volts
I = induced current im Amps
R = resistance in Ohms

If you've got two, toss them on one side, do the math, and get the third.

Actually, power (E x I) is involved here in getting the heat, and for 3 batteries of X amps and X volts, you can wire them for X amps and 3X volts, or 3X amps and X volts, and either way Power = 3.


If you ever find yourself in a situation where the calculation doesn't balance, the place where the extra numbers end up is where the smoke comes out. Then you have to call a smoke technician, and he'll replace the parts the smoke escaped from with parts that are completely filled with smoke. An igniter is a piece of high resistance wire coated with stuff that accumulates these numbers. The current slows down in the high resistance and the numbers jump from the wire to the coating. When it gets enough of them, they jump to the engine, and smoke comes out of it. Then you have to replace the engine with another that's still full of smoke. Trust me. I am both a scientist and a smoke technician. And a known and convicted comedian. Incriminating evidence is in http://www.sciencesbookreview.com/The_Best_of_Annals_of_Improbable_Research_0716730944.html
 
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