Cluster launching with Car Jump Starter Q's

[Marc_G]

Hi folks,

I've been successful with launching my LPR clusters with the Quest Q2G2 ignitors using an estes controler modified with a resistor and LED instead of the bulb, using the standard 4 AA alkaline batteries.

However, those Q2G2 ignitors cost a bit, and I've got about a million Estes ignitors, so I went out and bought a 500 peak Amp jump starter. $40 at Walmart:
https://www.walmart.com/catalog/product.do?product_id=15140203&adid=bzv_fb_revshr_001

This one has a convenient USB power port as well as the 12V cigarette lighter port.

I'll hook this up to another Estes controller (got several...) to use with Estes ignitors. Should give me nice solid firing of the standard Estes ignitors.

My questions are:

1. Let's say I start with a standard Estes controller, wired to this thing for power but no other mods other than better (& longer) wiring and a clip whip. Will the 12V power source blow out the bulb that is standard in the Estes controller? Let's assume up to 4 standard ignitors (in parallel) so resistance probably not so high in the circuit.

2. Let's say the bulb doesn't blow. Is there any chance the standard continuity circuitry will pre-fire the ignitors like the 6V + standard bulb would do to the Quest ignitors?

I should probably do the same math I did last fall when making my controller for Quest ignitors and choose an appropriate bulb/resistor combo. But I figured I would ask the assembled crowd-sourcing mind here.

I remember cutting through the plastic of the current edition Estes controllers to get to the bulb was annoying... the parts were all superglued together.

Marc

 

[scsager]

12v into a 6v bulb will burn out the bulb. I would replace the bulb with a 12v LED.

This is the one I used https://www.radioshack.com/product/index.jsp?productId=2062568

 

[luke strawwalker]

Hi folks,

I've been successful with launching my LPR clusters with the Quest Q2G2 ignitors using an estes controler modified with a resistor and LED instead of the bulb, using the standard 4 AA alkaline batteries.

However, those Q2G2 ignitors cost a bit, and I've got about a million Estes ignitors, so I went out and bought a 500 peak Amp jump starter. $40 at Walmart:
https://www.walmart.com/catalog/product.do?product_id=15140203&adid=bzv_fb_revshr_001

This one has a convenient USB power port as well as the 12V cigarette lighter port.

I'll hook this up to another Estes controller (got several...) to use with Estes ignitors. Should give me nice solid firing of the standard Estes ignitors.

My questions are:

1. Let's say I start with a standard Estes controller, wired to this thing for power but no other mods other than better (& longer) wiring and a clip whip. Will the 12V power source blow out the bulb that is standard in the Estes controller? Let's assume up to 4 standard ignitors (in parallel) so resistance probably not so high in the circuit.

2. Let's say the bulb doesn't blow. Is there any chance the standard continuity circuitry will pre-fire the ignitors like the 6V + standard bulb would do to the Quest ignitors?

I should probably do the same math I did last fall when making my controller for Quest ignitors and choose an appropriate bulb/resistor combo. But I figured I would ask the assembled crowd-sourcing mind here.

I remember cutting through the plastic of the current edition Estes controllers to get to the bulb was annoying... the parts were all superglued together.

Marc

The 6 volt flashlight bulb will last a little while, but it won't live a long time with 12 volts running through it. Replacing it with an LED indicator is a good idea.

The main thing is, you have to have PLENTY of current-carrying capacity (low resistance) between your battery pack and your ignitors. That means you need to use lamp cord for your launch leads and have GOOD connections... a bad connection (dirty clips) on any of your clip whips is going to cause a dead motor or late firing ignitor. Make sure you have plenty of slack in your leads as well, because sometimes the rocket will start lifting off before the last motor fires up, and if you have slack sometimes they'll light before the ignitor leads pull free of the ignitor.

Now, some will say that lighting clusters with Estes controllers using Estes ignitors has been done since dirt was new and you don't HAVE to have this stuff, BUT your likelihood of success increases DRAMATICALLY if you have 1) a good 12 volt power source capable of delivering plenty of amperage (you do), 2) a low-resistance firing circuit (either a relay at the pad (best) or heavy lamp cord running from your controller to the clips, 3)individually tested and verified ignitors that have been checked for proper continuity and/or resistance before launch. The more you skimp, the worse your chances are. A relay system is best-- but it can be done with a regular controller if you make sure you have really good contact with everything and you have plenty of power to play with.

The Q2G2's are just MADE for clustering-- they're the Cadillac of ignitors for this purpose. Estes ignitors have been used for clusters since dirt was new, true enough, but they're REALLY outdated for this purpose beside the Q2G2's... Yeah, they're a bit expensive and I too have a ton of Estes ignitors, but I think I'll be using the Quest ignitors for clusters and the Estes ignitors for the single-engine birds...

Later and good luck! OL JR

 

[Marc_G]

Thanks, great confirmatory info here.

At this point I'm too lazy to build a relay system but definitely understand the need for good wiring. I will definitely invest in some good wiring and make sure my connections are solid.

I just wish those Q2G2's weren't so darned expensive!

Marc

 

[bobkrech]

Point 1. A 6 volt bulb draws twice the current of a 12 volt bulb of the same type because they are designed to have the same brightness and that's determined by the power it draws. It's accomplished by changing the wire gauge of the filament: a 6 volt bulb filament has twice the cross-section of a 12 volt bulb of the same family.

Power, P, is the current, I, multiplied by the voltage, V, so P=IV=RI^2=V^2/R so a 6 volt bulb operated at 12 volts draws twice the current than it does at 6 volts and 4 times the power. You'll fire the igniters on continuity check and probably blow the bulb as well. Not good. You need the LED/resistor combo to limit current. A 1,000 ohm resistor in series with a red LED will work with either 6 or 12 volts.

Point 2. You are building cluster rockets. They are more expensive anyway since you are using multiple smaller motors than one bigger one. There's a 50% premium for the Quest igniters, but they are still less than $1 each. In the scheme of things, not a major expense.

Bob

 

[luke strawwalker]

Point 1. A 6 volt bulb draws twice the current of a 12 volt bulb of the same type because they are designed to have the same brightness and that's determined by the power it draws. It's accomplished by changing the wire gauge of the filament: a 6 volt bulb filament has twice the cross-section of a 12 volt bulb of the same family.

Power, P, is the current, I, multiplied by the voltage, V, so P=IV=RI^2=V^2/R so a 6 volt bulb operated at 12 volts draws twice the current than it does at 6 volts and 4 times the power. You'll fire the igniters on continuity check and probably blow the bulb as well. Not good. You need the LED/resistor combo to limit current. A 1,000 ohm resistor in series with a red LED will work with either 6 or 12 volts.

Point 2. You are building cluster rockets. They are more expensive anyway since you are using multiple smaller motors than one bigger one. There's a 50% premium for the Quest igniters, but they are still less than $1 each. In the scheme of things, not a major expense.

Bob

Bob, I'm not arguing with your numbers, but I can tell you from practical experience, that I've converted Estes controllers to 12 volts and kept the 6 volt bulb in there for a long time and it worked just fine. The bulb shines quite a bit brighter than at 6 volts, and gets hotter of course, but it will work for awhile. Part of it is because usually our continuity bulbs only burn for a few seconds at a time, I suppose. I know converting tractors over from 6 volt systems to 12 volt, you have to replace the headlights/worklights pretty much at the same time, because they don't last hardly any time at all, but these are MUCH bigger bulbs and throw a lot more light, and the change is a lot harder on them (6v to 12v).

I didn't have ANY problems with the converted Estes controllers I used launching the rocket when inserting the key using Estes ignitors, even when pushing 12 volts through a 6 volt bulb, and this was with launching single engines/ignitors, which means the single ignitor has to carry ALL the current passed by the bulb... with a cluster connected in parallel, the current would be shared among ALL the ignitors and be even less likely to fire prematurely.

Like I said, the numbers look good, but practical experience sometimes trumps the numbers...

That said, ditch the bulb and put in an LED indicator from Radio Shack-- they're rediculously easy to install and TOTALLY ELIMINATE any possibility of premature launching when the key is inserted, ESPECIALLY with Quest ignitors (Q2G2 is too hard to type!) You gotta crack open the controller to install lamp cord anyway (and make it compatible with external power sources) so go ahead and ditch the bulb while you're at it...

Here's some pics and an internal diagram to help you with the wiring...

Good luck! OL JR

 

[Marc_G]

Thanks guys. I've opened up one yellow Estes controller last fall so doing another isn't threatening. Im just lazy is all. Ok, next stop rat shack.

 

[sandman]

Thanks guys. I've opened up one yellow Estes controller last fall so doing another isn't threatening. Im just lazy is all. Ok, next stop rat shack.

Better yet if you're going to Rat Shack anyway, get a 12v pievo buzzer instead of a new bulb.

They are nice and loud.

 

[bobkrech]

JR

I was replying to Marc's post, not yours, primarily because he was wondering about whether it might be ok with the Quest ignitors.

You are 100% correct that when used sporadically, a 6 volt bulb will not likely burn out immediately on 12 volt. I was more concerned that Marc asked if the bulb didn't burn out, would the current would be significantly less at 12 volts than 6 volts and not set off the ignitors. (It still would set of the igniters.)

Bob

 

[Marc_G]

I've got my parts. I'll try to assemble this weekend but other projects, as well as the prospect of a launch at the local park (unless the wind picks up) in a couple hours, may push this a bit.

While at WalMart to buy other stuff I found a 12 V cig lighter plug (with leads coming out of it) for two bucks; I bought it to plug into the jumpstart pack.

It comes with a 5 A fuse built-in. As I recall, solar ignitors require ~2A each to fire (I forget whether this is at 6 or 12 V) but I think the 5A fuse would blow (given say 4 ignitors) unless the ignitors pop before the fuse can. What do other folks using such parts do? Put in a high-amp fuse (like a 30 A) or just hardwire the thing fuse-less?

I'm leaning towards getting some fuses and trying it out...

Marc

 

[MKP]

I just stuck a chunk of lead in there the same size as the fuse, works great.

 

[plano-doug]

I've got my parts. I'll try to assemble this weekend but other projects, as well as the prospect of a launch at the local park (unless the wind picks up) in a couple hours, may push this a bit.

While at WalMart to buy other stuff I found a 12 V cig lighter plug (with leads coming out of it) for two bucks; I bought it to plug into the jumpstart pack.

It comes with a 5 A fuse built-in. As I recall, solar ignitors require ~2A each to fire (I forget whether this is at 6 or 12 V) but I think the 5A fuse would blow (given say 4 ignitors) unless the ignitors pop before the fuse can. What do other folks using such parts do? Put in a high-amp fuse (like a 30 A) or just hardwire the thing fuse-less?

I'm leaning towards getting some fuses and trying it out...

Marc

I agree with MKP. You don't really want a fuse, so I'd bypass it. With a simple 3-motor cluster, you could be dumping 30+ amps. The last thing you want is the fuse to blow before you get them all lit.

Fuses are needed in continuous supply applications. For momentary load situations, they're not so important. Also, it takes two failure modes for the fuse's absence to result in a problem - you would need the ignitor(s) to not burn thru or for the clips to be in contact after launch, and for the launch button to be stuck in the on position. So the likelihood of a problem arising where the fuse would be helpful is pretty low.

As for the solar ignitors only needing 2 amps, that may be true. But they're usually on the order of 1 ohm, so, in a 12V system, they can draw ~12+ amps each. A 3-motor cluster could draw (assuming minimal path resistance) as much as 36A or more. Both your 5A and 30A fuses stand to get blown. You could end up having to bypass your fuse at the field using your pocket knife and masking tape So, better to do that properly ahead of time.

One other thought - the cigarette lighter circuit in the car will probably be fused for 30 or 40A. You could easily pop that launching. So you don't want that connected to your jumpstart pack during launching.

Doug

.

 

[Marc_G]

Ok. No fuses. And the thing wont be hooked to the car so no worries there. Thanks.