Which LiPo pack for the Estes PSII launch controller?

mh9162013

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I have used Sanyo Eneloop AAs (and Sony CycleEnergy AAs) for a number of years in some applications, though not Electron Beam launch controllers. They are much better, yes, with respect to relatively low self discharge. But even Eneloops are — or were, I haven't purchased any for awhile — sold as AAs with sleeves to fit them in C-sized battery compartments.
For C-size applications, there are several actual C-sized LSD cells available that are about 4000mah. Or you can use 3 AAA LSD cells in a 3AAA-1C adapter if you happen to have a lot of AAA LSD cells for other applications (like me).

But using any nickel chemistry cell in the PSII controller probably wouldn't be ideal because of the lower nominal voltages. They'd still probably work for in applications where a stock Electron Beam launch controller would work, though. I assume the extra few volts isn't a problem for the typical Estes BP igniter.
 

BEC

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For C-size applications, there are several actual C-sized LSD cells available that are about 4000mah. Or you can use 3 AAA LSD cells in a 3AAA-1C adapter if you happen to have a lot of AAA LSD cells for other applications (like me).
I figured they had to be out there, I just haven't looked for awhile.

As for the 3xAAA adapters....that would mean needing 18 AAAs for the PSII controller. So that's what, five of the typical 4-slot chargers to charge all that at one time? Possible, but not all that practical. I see eight-slot chargers are easily had...so only three of those would be needed to charge up a bunch of AAA cells for the PSII controller.
But using any nickel chemistry cell in the PSII controller probably wouldn't be ideal because of the lower nominal voltages. They'd still probably work for in applications where a stock Electron Beam launch controller would work, though. I assume the extra few volts isn't a problem for the typical Estes BP igniter.
That thought occurred to me as well....though current delivery is really what is needed. I would be skeptical of firing something like a copperhead with 6x1.2V cells as the power source for sure. Aerotech FirstFire Jr/Micro and Estes Solar/Startech and Sonics would be fine. I did actually run an Electron Beam with Eneloops in it for awhile and it worked OK for the uses for which it was intended. But for an occasionally used controller like that, Duracells are really more likely to still be ready to go after sitting for months.

Added: I see full capacity C and D cells in low self-discharge NiMH are now easily available. I may actually have to look into some for recurring use around here.
 
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neil_w

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In my (somewhat limited) testing I haven't seen any performance improvement from using NiMH rechargeables vs. alkalines, which surprised me a bit. Of course it's nice not to be throwing batteries in the garbage, but I wouldn't expect any other sort of improvements.
 

mh9162013

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In my (somewhat limited) testing I haven't seen any performance improvement from using NiMH rechargeables vs. alkalines, which surprised me a bit. Of course it's nice not to be throwing batteries in the garbage, but I wouldn't expect any other sort of improvements.
Another benefit from LSD NiMHs is not worrying about cell leakage when storing the controller with the batteries inside for a long period of time (think 6+ months)
 

4regt4

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I get my Duracells at Costco. There's one toward Woodinville from Maltby. 14 of them for $19 or so.

Still, that combo that Hans (@4regt4) suggested looks like one that will work well. I was serious about checking out that $12 charger...I like to be able to recommend stuff from personal experience and I've done quite a bit of charger testing in the past — I even used to have a "column" on RC Groups years ago called "Recurring Charge" where I did that sort of thing and wrote it up....but rockets came back into my life about 12 years ago and I've not done much RC airplane-related equipment testing since. Instead I've been obsessing over testing altimeters....
I very much look forward to you testing this charger. To see if I screwed up......

Hans.
 

BEC

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I very much look forward to you testing this charger. To see if I screwed up......

Hans.
Well, I ordered it. It should be here Tuesday. I’m trying to think how to approach it since it seems to basically charge each cell separately through the balance connector. I probably should look at each of the three channels independently. Hmmmmmmmm….
 

4regt4

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Well, I ordered it. It should be here Tuesday. I’m trying to think how to approach it since it seems to basically charge each cell separately through the balance connector. I probably should look at each of the three channels independently. Hmmmmmmmm….
If it burns your house down, I'm changing my username and going into hiding...

Hans.
 

AcadiaRockets

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OK, I have a new observation.
I have the Turnigy 3s 1000mah lipo in my controller. Great voltage shows 12.3 on the multimeter and lights igniters fast.
BUT, when using the lipo the controller does not light up or give an audible signal.
Thinking I blew something by using the lipo I swaped to the C's and both audio and light works.
Swap back to lipo - no light or sound. I am sure there is a quick electronics answer but that is beyond my pay grade. Is it something simple? Technically, legally I don't think we are supposed to use a controller without an audible alarm.
Ideas?
 

BEC

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I have no idea how that could be.

I just opened up the one I normally use and traced where the wires go. The leads from both the C-cell holder and the JST go to the same points on the little board inside, save for what I take to be a polarity protection diode on one side of the JST socket's wiring.

There's no "legal" requirement for an audible alarm. The NAR Safety Code requires a removable arming key.

Actually, having looked at the wiring inside mine, I suppose it is possible for the JST's wiring to have been installed backward, so no LED and no beeper.....but I'm not going to open mine up again to see if the power would get through the switches and the arming key socket to the clip leads anyway. I should have taken pictures while I had it apart. My controller, made in 2013, has pretty lousy quality workmanship on the wiring/soldering inside. But it's been working for me for nine years, so I'm not going to complain.


In related news, I have the little AC charger from Amazon in hand. I'm still trying to figure out how to get some useful measurements of it in use. At the minimum I would want to see current and voltage over time, preferably on each of the three "channels". But how to rig that up has not yet jumped out at me. I've made a four-lead JST XH extension, into which I'm going to have to break to make the measurements. Maybe I'll just start with current/voltage across the whole thing and worry about how to do individual cells later.
 

AcadiaRockets

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I have no idea how that could be.

I just opened up the one I normally use and traced where the wires go. The leads from both the C-cell holder and the JST go to the same points on the little board inside, save for what I take to be a polarity protection diode on one side of the JST socket's wiring.

There's no "legal" requirement for an audible alarm. The NAR Safety Code requires a removable arming key.

Actually, having looked at the wiring inside mine, I suppose it is possible for the JST's wiring to have been installed backward, so no LED and no beeper.....but I'm not going to open mine up again to see if the power would get through the switches and the arming key socket to the clip leads anyway. I should have taken pictures while I had it apart. My controller, made in 2013, has pretty lousy quality workmanship on the wiring/soldering inside. But it's been working for me for nine years, so I'm not going to complain.
the multimeter and actually setting off igniters agree that the c cells and Turnigy 3s 1000mah lipo both work. Just the lipos don't activate the alarm and light.
The only different is 3 volts of juice.
I don't have a way to draw down the lipo to see if its the extra lipo voltage or something else? Could the controller electronics not like the 12 vt configuration?
 

BEC

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Check the polarity at the igniter clips with one power source vs. the other. That's the only way I can think that the LED/beeper wouldn't work in one case and not the other. And of course when both switches are down, both the LED and the beeper are shorted across....so yeah, it should still fire igniters either way.

It's not extra voltage. I've been running 3s in this particular PSII controller for literally years and it works the same as with C-cells with respect to LED/beeper.

added: or the polarity into the JST connector on your battery is reversed relative to the PSII controller.
 

AcadiaRockets

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Check the polarity at the igniter clips with one power source vs. the other. That's the only way I can think that the LED/beeper wouldn't work in one case and not the other. And of course when both switches are down, both the LED and the beeper are shorted across....so yeah, it should still fire igniters either way.

It's not extra voltage. I've been running 3s in this particular PSII controller for literally years and it works the same as with C-cells with respect to LED/beeper.

added: or the polarity into the JST connector on your battery is reversed relative to the PSII controller.
huzaah!!
That was it. I didn't notice before that the multimeter was negative with one and not the other! Thanks BEC!
With great trepidation I fashioned a JST pigtail with two jst plugs I had and plugged them in.
In my experience reversing polarity results in smoking, bangs, pops, and generally bad things.
But this was the solution.
So now just out of curiosity, Do the planes and drones these batteries are for have different polarities? Does the controller? I mean if the controller designers knew this why build it like that. Which one is not normal? Not playing nice.
I should be able to get all the wire to nest in the cavity. And I may just pop the case and reverse it inside too.
 

BEC

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huzaah!!
That was it. I didn't notice before that the multimeter was negative with one and not the other! Thanks BEC!
You're welcome. I have to admit when I first saw your post I was thinking "that's not possible"....and it was only after looking inside mine (it takes a 2mm triangle bit to take out the inside screws, by the way, not a regular Phillips) and seeing just how — well, sloppy — the workmanship was that it occurred to me that things could be messed up.
With great trepidation I fashioned a JST pigtail with two jst plugs I had and plugged them in.
In my experience reversing polarity results in smoking, bangs, pops, and generally bad things.
But this was the solution.
So now just out of curiosity, Do the planes and drones these batteries are for have different polarities? Does the controller? I mean if the controller designers knew this why build it like that. Which one is not normal? Not playing nice.
Then I remembered that in other places (say cells for Arduino projects vs. cells for small quadcopters and other RC vehicles) there was a disagreement on polarity from one application to another and it occurred to me it could be at the battery itself. Since my controller works fine with an RC airplane battery and I'm pretty sure that's what John Boren and the folks at Estes had in mind for the auxiliary power input, I'm really more suspicious it's a wiring error with the pigtail from the JST socket to the circuit board inside the controller.
I should be able to get all the wire to nest in the cavity. And I may just pop the case and reverse it inside too.
As I said, you'll need a triangle bit to be able to do that. I forget when/why I ordered the set I have, but it came in handy when I was looking at this earlier today.

And this makes me vaguely curious to see if my other PSII controller (which is sort of held in reserve and normally lives with C cells in it) has the same problem as yours or if it works properly. Hmmmmmmm......
 

BEC

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Well, can't guarantee that it's being done correctly. But it seems to. Has the multi wire charge connector to supposedly balance the cells. The 3 LEDs - one for each cell - went red to green roughly about 10 minutes apart after about an hour of starting. So I assume it's working correctly. But, yes, I get a bit skeptical over cheap, too good to be true products.

Hans.
Still, that combo that Hans (@4regt4) suggested looks like one that will work well. I was serious about checking out that $12 charger...I like to be able to recommend stuff from personal experience and I've done quite a bit of charger testing in the past — I even used to have a "column" on RC Groups years ago called "Recurring Charge" where I did that sort of thing and wrote it up....but rockets came back into my life about 12 years ago and I've not done much RC airplane-related equipment testing since. Instead I've been obsessing over testing altimeters....
I very much look forward to you testing this charger. To see if I screwed up......

Hans.
If it burns your house down, I'm changing my username and going into hiding...

Hans.
Well, it didn't burn down my house on the first instrumented charge.

I charged a 3s Zippy 1300 mAh pack that I'd been using to drive a charger that can charge up to 5 1s cells....cells I use in my night flyers (flown at Sod Blaster a couple of weeks ago) and some other auxiliary cells, specifically the ones I'm using with Eggtimer ION altimeters. The battery was down to 3.67v per cell (slightly imbalanced) when I started. I put the sensing unit for a Hyperion eMeter II (a neat gadget developed to test electric power systems for model airplanes and such) in line with the two outer leads, then let it go until the little charger gave me three green lights. The center one lit first then a small number of minutes later the other two went green simultaneously.

In the end it charged at a maximum of 700 mA, but spent most of the time charging at around 500 mA. It very slightly overcharged all three cells, taking them to 4.21V each, ending up with all three of them with 0.02V of one another. As you can see on the graph below, this is not quite the typical constant current then constant voltage charge regime normally used for LiPoly batteries.

So....I'm still not worried it will burn the house down, based on this first result. I may discharge that same pack a ways, and maybe run the same test again while monitoring just one cell, to see if anything is markedly different. That will have to wait until at least tomorrow....and tomorrow I get a new iPhone (for the first time in a along time — my current one is a 7+) and I'll probably be spending a good chunk of time moving data and such.

The eMeter II is intended for testing electric power systems for models, so its current resolution is lousy (apparently 0.1A or 100 mA). That's obvious on the graph. That small a current delta is negligible when you're talking about power systems pulling hundreds of Watts.

I was recording at the eMeter II's maximum data rate, which is 8 Hz, and the test took over 100 minutes (so over an hour and a half). Consequently there are over 62,000 data points.

I clearly need to learn more about curve smoothing or some kind of approximations in Magic Plot...

AC_charger_test_1.png

Oh - the charger put a little less than 400 mAh into the pack over this time.
 
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4regt4

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Hmm...

So a bit of an overcharge....

I usually put some small load for a short period on any lithium batteries after charging, to draw down the "surface charge". Probably a good idea here.

Hans.
 

BEC

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Hmm...

So a bit of an overcharge....

I usually put some small load for a short period on any lithium batteries after charging, to draw down the "surface charge". Probably a good idea here.

Hans.
Yeah, just barely overcharging....so what you're doing makes some sense here.

Bear in mind that's only one test.
 

BEC

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I've done some more testing of that charger, and found a way to get better resolution on the current readings with my eMeter II (use the Micro Data Unit rather than the Remote Data Unit). The question is, should I create a new thread, post more here, or does anyone care?

TL;DR of what I would post with pictures of the test setup and graphs of the data: It does overcharge 2-3mV per cell, but otherwise seems to work more or less as advertised. At $12 it's quite the deal.

Here's the one additional graph I've created. I have pictures of the test setup and can write the approach....if there's enough interest to bother doing that.AC_charger_test_3.png

....and I have to switch browsers to post images again. Grrrrrrrr......
 
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