Estes Pro series II launch controller question....
 

I have been looking at the Estes Pro series II launch controller as an upgrade.

By default it uses 4 C cell batteries but they also mention it accepts alternate power sources.

However it does not go into any detail about what power sources and how. I did see one mention of someone using a LiPo and that makes me curious as I have lots of those and know they can deliver tremendous amounts of current very quickly from a small package and would seemingly be ideal.

Anyhow I searched the web and came up empty.

Anyone know or have some linkage??

Thanks!

the only launch controller I found by that name uses 6(six) C cells (alkaline). it has a 'JST' socket in the battery compartment for external power(off hand I would suggest a 3s lipo pack if you want to go with that option). the 30' launch wire is IMO a tad short, 40 - 50' would be better. from what I could find via a google search(which led to the rocketry forum) it would appear to be a serviceable unit.
Rex

I have two of them. I like 'em.

One of them has an Electrifly 3s LiPoly inside. It works very nicely and has even managed to fire the infamous Copperhead ignters a couple times. As Rex noted there is a two-pin JST socket inside for the alternate power source. Space inside is kind of tight because this alternate power source has to fit between the springs for the C-cells.

Heck - I should just go grab it, take a couple of pics with my iPhone and post 'em here.

Back in a little while......

OK - here we go.

This particular unit was inadvertently left behind at a launch in eastern Washington and collected several days later after it had been rained on a bit - no issues.

An odd feature is that there are two clips on each of the two leads - essentially a built-in clip whip. The trick is to get one clip from each on the igniter :)

Pictures - exterior with a ruler and an Electron Beam for scale. Then back cover, open with the 3s 1200 mAh LiPoly in it, some details of how that's connected, and a view with the C-cells.

Only five per post, so here's the C-cell view - note it takes six, not four.

This controller is like a couple of its predecessors in that it takes two hands to fire it. The yellow button on the left is essentially a second arming (after the key is in) and a beeper sounds. You have to hold that one down and press the red one to fire the igniter(s).

Wow perfect!

I cant thank you enough. Answered every question I had.

Thanks!

You're welcome. I like when I can actually answer a question.

$28.39US at Hobbylinc this week. http://www.hobbylinc.com/estes-pro-...controller-2240

And Bernard is just being modest. He has (almost) all the answers ! :)

I know Bernard has a lot of answers Ive been cruising these forums for a while now. The photographs helped a ton and showed me pretty much exactly the setup I want to go with using a 3S 1200mah lipo of which I have about 6 of them and the proper chargers etc.

Thanks for the heads up on the sale but I have one on order already. Ran out and ordered it almost as soon as I saw the info. Only paid about 5 bucks more so....

Has anyone been inside of one of these controllers? Wonder how the continuity check is done. If there is transistors or relays for low current checks or if its basically a big "Electron Beam" type circuit with maybe a resistor and LED?

Oh by the way I notied on Bernard's lipo a date stamp of 06/06? If so you sure got your moneys worth out of that one!!

I am assuming the PSII launch controller just uses one of a variety of premade piezoelectric buzzers available. I installed in an Electro-Launch for school launches, since the buzzer gets everyone's attention, whereas a continuity light does little for a big group of school kids out on the playground. :)

The buzzer I bought was from Radio Shack (many years ago -- not sure they are still open ...). It is housed in a small round plastic enclosure, with leads protruding from the bottom -- suitable for panel mounting. I ground down the raised area on the controller around the bulb, and epoxied the buzzer in place over the bulb opening. It is wired into the launcher in place of the bulb, soldering each lead to one of the two contacts for the bulb. I do not recall the current draw, but it is pretty low (under 50mA), and is therefore safe for low-current igniters. A Google search shows many piezo buzzers that operate on voltages from about 3V to 15V, and from 10mA to 50mA or so), so there are a lot of buzzers available that are well suited to handling continuity checks safely.

Another mod I made was to ditch the 4 AA batteries inside the controller, and add leads for an external 12V gel cell battery. This controller will fire igniters all day, and was especially handy for group launches. We would typically launch around 100 rockets on the playground each outing. I never worried about the battery power running down.

If I were to make another launcher today, I'd substitute a 3S lipo battery (nominally 11.1VDC) due to their smaller size and lighter weight, but a gel cell battery is a great launch battery for dependable, long-lasting power.

I just like the convienence of not having to lug around a brick with me also no hookup wires to fuss with.

A hot lipo can probably out perform a gel cell in supplying large amounts of current in a very short time span. Probably live to do 'dozens' of launches too.

One thing did concern me was dropping in what amounts to a dead short (the first few microseconds) onto a Lipo. I have seen the results of shorting out a lipo albeit a lot longer than microseconds. They will go off like a road flare!

Speaking of lipo safety I might see if I cant get some of that foamy tape over the battery springs just so they wont puncture one by accident. Punctures... see above sentence :p

Oh one last thing I will probably look into the JST connector and its conductors as to their ampacity. A mod may be in order :)

The PSII controller has a bright LED that lights if there is continuity after the key is inserted. See the spot between the two rocker switches (yellow and red). Then, when the yellow one is pressed a piezo beeper of some kind sounds a continuous tone. The two of them together draw a low enough current (I don't recall what I measured exactly) that the controller is Q2G2 safe.

The time it takes to fire a standard Estes igniter with the LiPoly is very short. I know I kind of chided the folks at Estes about the choice of that little orange JST connector as I found them to be lousy in small electric airplanes when the current draw was any more than about 2A (say a GWS IPS drive). But again the time is so short that in practice it's OK. (that's why you can see that there is a mini-Deans plug on the battery and I made a small mini-Deans to JST adapter to put the battery in the controller. I use the mini-Deans plugs on my small electric planes up to about 12A or so.

Point taken about protecting the sides of the pack from the springs. Certainly a pack that doesn't have a good heat shrink tubing wrap around it would benefit from some other protection there.

When mine arrives I will most likely do some mods and check out the circuitry inside. Hrm maybe I should have ordered two :D

Anyhow I will report back in this thread on my findings.

If you never plan to use C cells, maybe just cut off the protruding ends of the battery springs? That way there is no potential for puncturing the LiPos.

I thought about that and thought that maybe the cut off springs would leave sharp pointy ends and may be worse than before.

Is the unit 'welded' shut? I wonder.

One option would be to coat the covered ends of clipped battery springs. Globs of silicon caulk or globs from a hot glue gun.

It looks from the pictures that there are 4 screws for holding the case together, but look like "tamper-proof" types. I tend to find those to be more "tamper-resistant", and can be backed out with the right tool.

Have fun tearing it apart to see what makes it tick.

Finally, I found no explanation on any of the pages about this controller -- why does it look to have two sets of igniter leads? Or maybe the picture was misleading, does it have 3 clips on the positive, and a single clip on the negative, for clusters?

Its just two sets of clips in parallel. Supposedly to ignite clusters of two I guess.

Dunno what you do if you have three let alone the 'extra' pair of clips dangling around. Probably cover that in the instructions but I don't have them yet... :chuckle:

ps; I poked around estes web site and they don't have the instructions online (yet) either.

I should think that a couple of rectangular pieces of 1/32" ply would suffice to protect your packs:).
Rex

The instructions (which do not download properly for me from the Estes website, but I have a printed copy at home that came with the controller) show you how to use the twin set of clips for one to 4 motor ignition.

Good idea -- and probably the simplest solution for protection. Would still allow for use of C cells with removal of the ply strips. I think I'd do a hybrid -- shorten the clips and epoxy the ply strips in, giving a little more room for the LiPos.

Have we sufficiently beat this almost-dead horse? :)

For now yes... please. Poor horsie.. :p

The ply is a good idea.

But I will revive this thread once mine arrives and I do a little peek and poke.

Till then !

So could one modify this unit to be able to use a 12v battery?
Such as a small motorcycle or garden tractor battery?

Yes quite easly Woody. There is the jst connector inside which could be connected to a jumper run out of the case through a hole of some sort. Or put a jack of some sort into the bottom of the battery case cover. Observe polarity of course.

On the one I just received the positive lead for the connector is on the pin closest t to the bottom of the battery tray opposite the lid.

For the record as I understand it the jst connector is rated for 10 amps continuous and is connected with what appears to be 24 gauge wire.

Now for the diagnosis. I got her open with little trouble and found the following:

There is not much in the way of circuitry. A printed circuit board populated as follows. A very large (6A10) diode to protect against reversed polarity to the LED and buzzer. That diode is a brute rated at 6 amps at up to 1,000 volts! Then the led itself and its 1/8 watt dropping resistor. The 'switches' are just leaf spring tabs that are pressed down with the buttons. The key 'switch' is a similar matter with two leaf springs that make continuity when the 'key' metal pin is inserted between them. All wiring inside the unit is 24 gauge. The NEC does not give ampacity for 24 ga wire but I believe in these short lengths it is capable of 10 amps.

I tested the current with a really cheap harbor freight multimeter but measured 40ma with the led on and 60ma with the buzzer activated. No way to measure the peak current but with a 3S 1800ma lipo at a 'storage' charge (3.8V/cell or 11.36v total) it incinerates estes starters and Quest Q2's go off with a resounding snap :D

That pretty much sums it up except for the JST connector is glue welded into the case. I was hoping to replace it with something a little more robust but when its all said and done it is probably adequate for the average task of low to mid power rockets.

Sounds like the controller should serve its intended use very well. Should you really feel the need to replace the JST connector, don't underestimate the capability of Mr. Dremel with his cutting wheels and grinding stones!