Modifying an Estes PSII Launch Controller

[Dane Ronnow]

I'll be using a PSII controller to launch my yet-to-be-flown 2.6 inch 29mm rocket. The motors will be Aerotech F67, G74 and G80.

I've decided I want a little more distance to the pad, and am considering 50 feet of 18 gauge OFC black/red zip wire (https://powerwerx.com/red-black-bonded-zip-cord). My power source is an external 12 volt 7Ah SLA battery, connected through the PSII's JST connector.

Does that setup sound workable? Or am I looking at too much resistance from 50 ft of 18AWG copper?

I appreciate any input. (I apologize in advance for not knowing more about electronics.)

 

[Five]

I'll be using a PSII controller to launch my yet-to-be-flown 2.6 inch 29mm rocket. The motors will be Aerotech F67, G74 and G80.

I've decided I want a little more distance to the pad, and am considering 50 feet of 18 gauge OFC black/red zip wire (https://powerwerx.com/red-black-bonded-zip-cord). My power source is an external 12 volt 7Ah SLA battery, connected through the PSII's JST connector.

Does that setup sound workable? Or am I looking at too much resistance from 50 ft of 18AWG copper?

I appreciate any input. (I apologize in advance for not knowing more about electronics.)

I had the same idea and the answer to your question is yes it will work. I added 60’ of 14 gauge and 30’ of 16 gauge along with the 30’ of wire it came with giving me a total of 120’ and I use 6 c Duracell’s and it works great. Ive launched l’s and a cluster of 3 H’s.
I never could get that dang jst plug to work. It was probably my fault. I may have overcharged the lipo batteries.

 

[Dane Ronnow]

I never could get that dang jst plug to work.

My problem at first was finding the right JST connector. There are about nine different types. I finally found a chart, and from that I found this RCY type JST connector:
https://www.amazon.com/gp/product/B071XN7C43/I'm using spade connectors between it and the 12 volt battery. It works, at least as far as having continuity. I haven't actually ignited a motor yet.

I thing I don't like about this connector is the wire gauge -- probably 24 or smaller.

Back to the wiring on this PSII setup, I'm now considering using a pad relay, and RJ11 phone cable to connect the controller, since it's cheaper than 18AWG zip wire. My hurdle there is that I don't have the expertise to build a suitable relay. I was looking at the Pratt Hobbies relay, but it wants 12 volts at the controller and the relay, whereas my present setup allows 9 at the controller (back to the 6 C cells if I'm going the relay route) and 12 at the relay.

Or I may just forge ahead with the original plan—18AWG zip wire from the controller to the pad and no relay. At least I know it will work, from what you've told me. I appreciate the feedback. Thanks.

 

[teepot]

I have a wireless set up. I got it from Amazon for $50. It has a range of 1500'. I have only used it from 200' though. At one time I had 200' of lamp cord and a 12 volt battery and a switch. Now the battery sits at the pad. I have had other wireless switches. I got the least expensive ones. Some worked fine but didn't have the range I needed. Others didn't work for one reason or another. I don't remember if someone told me or I read it. But lamp cord is fine to use. But it's 3 cents a foot IIRC.

 

[Dane Ronnow]

But lamp cord is fine to use. But it's 3 cents a foot IIRC.

I found 18AWG black/red zip wire for 2 cents a foot. It's good stuff, OFC.

I think my biggest problem is overthinking this (and pretty much everything else I do with this rocket). The more time I spend looking at different possibilities—16AWG vs 18AWG, or 24AWG with a relay, etc., etc., etc.—the more time I spend just running around in circles.

I'm just going with 50 ft of 18 and calling it good. And, hopefully, I'll quit worrying about it.

 

[Five]

I found 18AWG black/red zip wire for 2 cents a foot. It's good stuff, OFC.

I think my biggest problem is overthinking this (and pretty much everything else I do with this rocket). The more time I spend looking at different possibilities—16AWG vs 18AWG, or 24AWG with a relay, etc., etc., etc.—the more time I spend just running around in circles.

I'm just going with 50 ft of 18 and calling it good. And, hopefully, I'll quit worrying about it.

That should work fine.

 

[rcktnut]

Get the cheapest 50ft 16AWG outdoor extension cord you can find and it will work well. If you can find a 2wire/prong one all the better. Just ditch the ground if you can't find a 2 prong cord. I have a 100ft. cord about 20 years old works great along with a 7ah 12v battery which is also 20 years old and still going strong. Extension cords are much tougher and easier to roll up than that zip wire.

 

[Five]

Get the cheapest 50ft 16AWG outdoor extension cord you can find and it will work well. If you can find a 2wire/prong one all the better. Just ditch the ground if you can't find a 2 prong cord. I have a 100ft. cord about 20 years old works great along with a 7ah 12v battery which is also 20 years old and still going strong. Extension cords are much tougher and easier to roll up than that zip wire.

View attachment 496817View attachment 496817

You ain’t kidding about it being easier to roll up. Its a pain in the butt for me to roll up zip wire.

 

[Dane Ronnow]

Get the cheapest 50ft 16AWG outdoor extension cord you can find and it will work well.

Actually, I'm kicking that idea around. I know long lengths of zip wire can be a mess to coil.

The trouble with cheap ($15) cords from the box stores is they're often copper clad aluminum. I haven't found anything that's pure copper—or at least states somewhere on the packaging or online description that it is—for less than $25. And I can get a lot of zip wire for that.

On the other hand, I guess that's like saying I can get a lot of tangles for the price of a good indoor/outdoor 16/2 cord.

 

[rcktnut]

I think if you shop around at your local lumber/hardware stores or Walmart etc, you should be able to find a cheap cord. Most cords use stranded copper wire. Husky 50 ft. 16/2 Green Extension Cord-HW16250HLG - The Home Depot

 

[Dane Ronnow]

Husky 50 ft. 16/2 Green Extension Cord-HW16250HLG

I was looking at that one the other day. (I kind of like the neon green color.) Nobody at Home Depot could tell me if it was copper or not, and the packaging doesn't say.

Do you know if this particular cord is copper? My guess is they won't take it back once I lop off both ends.

 

[rcktnut]

I was looking at that one the other day. (I kind of like the neon green color.) Nobody at Home Depot could tell me if it was copper or not, and the packaging doesn't say.

Do you know if this particular cord is copper? My guess is they won't take it back once I lop off both ends.

I have no idea whether if is cca or not. I realize that cca wire does not conduct as good as copper but if it works use it. You could buy one and just attach the wires from your controller to the prongs and plug your igniter leads in and see if the igniter fires. If it doesn't work return it. No need to hack it up to test it. I would bet that a cord with cca or copper wires will work just the same for the intended use.

 

[Dane Ronnow]

You could buy one and just attach the wires from your controller to the prongs and plug your igniter leads in and see if the igniter fires.

That's what I was thinking too. But rather than waste an igniter, I use an 1157 tail light bulb that has short wire leads soldered to it. When you hit the launch button, the bulb lights up. My understanding is the light bulb takes about the same amount of amps to light as the igniter does.

As far as CCA vs copper, I think you're right—both would do the job. The CCA might be a half-second slower getting current to the pad, but it'll still launch the rocket.

Anyway, I appreciate all your input. It's been helpful. Thanks.

 

[Dane Ronnow]

Home Depot was out of the 50 ft. green extension cable (referenced above by @rcktnut), so I bought the 100 ft. cable instead, reasoning that I can always stand closer to the launch pad, but still have the extra distance if I need it.

Before cutting the ends off, I wanted to make sure that a cord that long would work. If it didn't, I could return it. I rigged a couple of short pigtails using 18AWG zip wire, then connected one end to the launch controller, and the other to an 1157 tail light bulb.



If the cord could deliver at least 3 amps through 100 ft. of length when the firing button was pushed, the bulb would light up. It did, with no delay, and burned brightly.

Then I cut off both ends and stripped the 16AWG wires, and found that this cord does in fact have copper cores.



Next, I attached spade connectors to the controller end, and alligator clips to the igniter end.



Here's the PSII controller with my modifications:



The wiring on the left is the stock 30 ft. wire cut short, with spade connectors attached. This is where the 100 ft. cord will connect. The wiring on the right was connected to the JST plug inside. I clipped it at the JST, attached spade connectors, then ran it out the same side of the controller as the other wiring. This wiring connects to the 12 volt external battery with 10 ft. of 18AWG zip wire.

Both sets of wires are reinforced with heat shrink tubing where they pass through the wall of the controller.

Finally, I connected the battery and the 100 ft. cord, then attached the alligator clips to the light bulb. With the launch key inserted I got a continuity light, pressing the arming button gave me tone, and the firing button lit the bulb, again with no delay and burning brightly.



The biggest benefit to this extension cord from Home Depot—or any comparable indoor/outdoor extension cord—apart from price per foot compared to 16AWG zip wire with copper cores, is its durability. I'm guessing this will outlast me.

For those who are interested, here's a link to the cord:

https://www.homedepot.com/p/Husky-100-ft-16-2-Indoor-Outdoor-Extension-Cord-Green-53100HY/206460258

 

[Five]

Excellent. Im glad you got it to work.

 

[Dane Ronnow]

Excellent. Im glad you got it to work.

Thanks for your help.

 

[rcktnut]

Good to see you got the 100ft. cord, I was going to suggest it just in case in the future you want to get into some high power stuff, where you need the extra distance. That cord and battery will ignite any igniter you will be using at that 100ft. distance.

 

[Dane Ronnow]

Good to see you got the 100ft. cord, I was going to suggest it just in case in the future you want to get into some high power stuff, where you need the extra distance.

It just made sense. I can stand 50 feet away with a 100 ft cord, but it's kinda hard to stand 100 feet away with a 50 footer. And the difference in the 50 and 100 was only 5 bucks.

 

[neil_w]

but it's kinda hard to stand 100 feet away with a 50 footer

I think you're just not trying hard enough.

 

[Dane Ronnow]

I think you're just not trying hard enough.

You're right! I should break out my arm stretcher!

 

[Philip Tiberius D.]

Home Depot was out of the 50 ft. green extension cable (referenced above by @rcktnut), so I bought the 100 ft. cable instead, reasoning that I can always stand closer to the launch pad, but still have the extra distance if I need it.

Before cutting the ends off, I wanted to make sure that a cord that long would work. If it didn't, I could return it. I rigged a couple of short pigtails using 18AWG zip wire, then connected one end to the launch controller, and the other to an 1157 tail light bulb.

View attachment 498354

If the cord could deliver at least 3 amps through 100 ft. of length when the firing button was pushed, the bulb would light up. It did, with no delay, and burned brightly.

Then I cut off both ends and stripped the 16AWG wires, and found that this cord does in fact have copper cores.

View attachment 498355

Next, I attached spade connectors to the controller end, and alligator clips to the igniter end.

View attachment 498356

Here's the PSII controller with my modifications:

View attachment 498357

The wiring on the left is the stock 30 ft. wire cut short, with spade connectors attached. This is where the 100 ft. cord will connect. The wiring on the right was connected to the JST plug inside. I clipped it at the JST, attached spade connectors, then ran it out the same side of the controller as the other wiring. This wiring connects to the 12 volt external battery with 10 ft. of 18AWG zip wire.

Both sets of wires are reinforced with heat shrink tubing where they pass through the wall of the controller.

Finally, I connected the battery and the 100 ft. cord, then attached the alligator clips to the light bulb. With the launch key inserted I got a continuity light, pressing the arming button gave me tone, and the firing button lit the bulb, again with no delay and burning brightly.

View attachment 498358

The biggest benefit to this extension cord from Home Depot—or any comparable indoor/outdoor extension cord—apart from price per foot compared to 16AWG zip wire with copper cores, is its durability. I'm guessing this will outlast me.

For those who are interested, here's a link to the cord:

https://www.homedepot.com/p/Husky-100-ft-16-2-Indoor-Outdoor-Extension-Cord-Green-53100HY/206460258

How is the Controller modified ? LiPo batteries ? I've got a set up that uses my car battery but I almost got stuck in the field I fly at and I'd like to fly H and above since I've got the space (and L2).

 

[Dane Ronnow]

How is the Controller modified ?

Using a torx-head screwdriver (works in place of a triangular bit), I opened the controller and cut the 24 gauge wire coming off the backside of the JST connector, then spliced 8" of 18 gauge zip wire to it and ran it out the back of the controller. This serves as a pigtail to connect an external 12 volt 7 Ah SLA battery.

Next, I removed all but 8" of the 30-foot ignition wire. That 8" wire serves as a pigtail for the 16/2 ignition wire.

Originally, both pigtail sets were terminated with spade connectors. But these were difficult to unplug without pulling the wire loose from the crimp. So I replaced the spade connectors with soldered banana jacks.

Here's the controller as it stands now:



Below is the wire between the 12 volt external battery and the controller (10 feet of 18AWG zip). It has a 10 amp circuit breaker on the positive battery wire, and connects to the controller with soldered banana plugs, and to the battery with .187" F1 spade connectors, crimped.



Below is the ignition wire (100 feet of 16/2 medium duty extension cord, on a spool). It has soldered banana plugs on one end for connection to the controller, and soldered alligator clips on the other end for the igniter.



Although the spool is wired for plugging other extension cords into it, I only use it to transport, unwind and wind the ignition wire.

 

[Dane Ronnow]

I had a chance to use this launch control system for the first time about 10 days ago. Two flights on a G74, one on a G80. All three were instant on—press the button and the rocket's gone. That's a 12v SLA battery through a 100-foot run of 16/2 wire.

 

[Grog6]

A water hose roll-up,roll around hose holder is perfect for a 100 ft 18-12 awg extention cord; it carries all the weight, and has a handle to roll it up easily.

 

[SolarYellow]

I'm liking this extension cord idea, but not liking the bulk of the over sheath. Mechanical durability is great, but it adds up to a lot of bulk and weight, especially if one is traveling with it. Along with the positive idea that it will last until you're long dead, consider that you'll be lugging around the bulk and weight of it for the rest of your life. Also, it's highly probable that any repairs/failures will involve the connections you add to the ends rather than the wire itself.

One option I thought of is to use a 50 foot cord. Cut it close to the female end. Wire the female end directly into the controller, and put alligator clips on the long tail of the male end. Then you connect the cord to the controller using the original plugs of the extension cord. You have the 50 foot minimum safe distance under the Tripoli safety code and you can get another 50 foot cord and just plug it in in the middle using everybody's original extension cord plugs if you're going to do H-J motors.

Another option is to use smaller wire. Lots of comments about the tangling tendency and high cost of zip wire by-the-foot in this thread. However, I found 100 ft lengths of 16/2 landscape wire on Amazon for <$25.
https://www.amazon.com/Woods-55213143-Voltage-Lighting-100-Feet/dp/B06XKTBM1B
It's bigger, more durable and more resistant to tangling than 18/2 zip wire, but a lot more compact and lighter than the sheathed extension cord. Made for outdoor use where it will not be treated nicely. Could do something similar to the extension cord deal I suggest, with two 50-foot lengths and connectors.

Anyone have experience positive or negative with landscape wire in the 100' length?

 

[Dane Ronnow]

I'm liking this extension cord idea, but not liking the bulk of the over sheath. Mechanical durability is great, but it adds up to a lot of bulk and weight, especially if one is traveling with it. Along with the positive idea that it will last until you're long dead, consider that you'll be lugging around the bulk and weight of it for the rest of your life.

You make a good point about the weight of 100' of 16/2 extension cord. I chose it because I launch from a dry lake bed, which can be especially hard on launch wiring. The weight never really bothered me. I consider it just another piece of hardware I have to load and unload at a launch site—quite a bit lighter and easy to deal with than my Jawstand/rail setup.

One option I thought of is to use a 50 foot cord. Cut it close to the female end. Wire the female end directly into the controller, and put alligator clips on the long tail of the male end. Then you connect the cord to the controller using the original plugs of the extension cord. You have the 50 foot minimum safe distance under the Tripoli safety code and you can get another 50 foot cord and just plug it in in the middle using everybody's original extension cord plugs if you're going to do H-J motors.

I think this is a good idea. But be forwarned, the wiring inside the PSII that you'll be splicing into is 24 gauge, with what appears to be aluminum strands that are stiff, and difficult to twist together prior to soldering. I cut those off at the circuit board, and soldered 18 gauge zip wire as a replacment. Then I ran that out of the controller box about 6", and terminated the ends with banana clips. (Similar to what you propose above.)

Another option is to use smaller wire. Lots of comments about the tangling tendency and high cost of zip wire by-the-foot in this thread. However, I found 100 ft lengths of 16/2 landscape wire on Amazon for <$25.
https://www.amazon.com/Woods-55213143-Voltage-Lighting-100-Feet/dp/B06XKTBM1B

I don't have any experience with landscape wire. Make sure it has copper cores, not aluminum. Before I moved to the 16/2 extension cord, I used 50' of 18 gauge zip cord from Powerwerx:

https://powerwerx.com/red-black-bonded-zip-cord
Their stuff is extremely flexible, and was very easy to coil and uncoil. Copper cores and PVC sheath. The best red-and-black zip wire I've ever used, just not durable enough for my use.

 

[SolarYellow]

Automotive grade "GPT" PVC insulation

That's going to be a lot lighter duty and less durable than the landscape wire. I think more prone to tangling as well.

 

[Dane Ronnow]

That's going to be a lot lighter duty and less durable than the landscape wire. I think more prone to tangling as well.

I can't speak to the durability of the landscape wire, but I think you'll find very little practical difference between vinyl and PVC insulation. As far as tangling, I never had a problem with it. I flip the loose end of the wire with each loop so it lays flat.

I see little difference in the two, other than the landscaping wire having both legs black. I'm pretty sure it would work as well for launch service as the red and black zip. Or green or orange extension cord. Fact is, it's all wire. What matters to me is the gauge of the wire, is it copper, and can it stand up to repeated use on rocky ground. YMMV.