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Discussion Starter · #1 ·
Years ago I fitted my Sierra sound systems with supercaps replacing the gel packs. With no open houses last year, I've not run the trains in over 2 years now.


The other day I started to clean the wheels for the upcoming open house and as soon as I supplied power to the wheels, the sound systems came alive. The 6 volt gel packs would never do this, nor would they have lasted the 2 years unattended.
 

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There's a new member asking, trying to find the gel cell.... what values of supercaps did you use? I don't have a Sierra here to measure the "charging current" (i.e. max voltage) it puts out, nor do I know the capacity in Farads vs. how long they last when power is interrupted.

Thanks, Greg
 

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Discussion Starter · #3 · (Edited)
Use three 2.7V 6-10F wired in series. You can add a 1 ohm resistor, but I found it unnecessary and it takes just that much longer to charge before activation. With three 6F, I get over 30 seconds of idle using the lighting feature. The lighting lasts longer than the sound and the duration is very dependant on the volume.

If you want to get slick, what I also did was to put a "cut-out" relay on the cap so it would "disengage" at about 3 volts. It shortens the idle time on shut-down, and you may even loose something like the air pump because it shuts off before this feature would occur.

But, when the power comes back on, it doesn't not have to start the charge cycle from scratch, so it alleviates the motorboating both on start-up and shut-down for those periods where the cap doesn't have enough juice to sustain the board and motorboats.

I use a 5 volt relay and put a resistor in series to get it to shut off at a lower voltage. Don't worry about the amperage so much but instead look for the lowest current draw you can find. But then the relay needs a small cap across its terminal as a jump start it to get it to fire and hysteresis takes care of the rest.
 

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Discussion Starter · #7 ·
Lowest operating voltage is 7 volts and that's too much. Needs to be down around ~3 volts.
 

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Reading further down to Input voltage: 3V-15V so thought the cut off was at 3. I'll keep looking. thank you.
 

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Discussion Starter · #9 ·
Any sort of a "cut-out" is going to have a parasitic loss and you want to minimize this to maximize the available power for the idle time. I can't imagine that any sort of a cut-out is going to have less draw than the one little 80 mA relay I used, though you may be able to improve on this with a different relay (i.e., < amperage draw) slightly.

You don't need the cut-out if you just wire the three supercaps in series and replace the battery with that. If you don't idle the engine for more than about a minute at a time, you will not incur the motorboating except at the very first start-up and last idle of the day. One of my GP-9s is wired like this and it stops for ~30 seconds to "refuel" every lap and it is just not an issue. I just time the stop so it falls a short of the cap going into motorboating.
 

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toddling, I thought you mentioned that in an earlier post, thank you for clearing that up. Going to meet with a friend who runs a Batteries Plus location. He was an engineer for a battery company before striking out and he may help me finding a low draw low voltage cut out assembly. I ordered enough super caps to try on 2 locos. If I don't send them up in smoke will do the others as I don't run my electrics often enough to keep the batteries charged. I used to have a schedule to charge the batteries, but age and hard drive crash wiped that out also. Thank you for all your help.
 

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toddling: can do the basics of electronics, enough to be dangerous. Just a couple of ?? please. The potentiometer connections: looking at it's face, tabs on the bottom: the two to the right are the connections made in the circuit?? The designations of Sierra +, goes to where the positive side of the battery goes? and the two designated Sierra - go to where the negative side of the battery goes?? How will the on/off switch for the board effect this? Any help you can give will be appreciated.
 

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Discussion Starter · #12 ·
toddling: can do the basics of electronics, enough to be dangerous. Just a couple of ?? please. The potentiometer connections: looking at it's face, tabs on the bottom: the two to the right are the connections made in the circuit?? The designations of Sierra +, goes to where the positive side of the battery goes? and the two designated Sierra - go to where the negative side of the battery goes?? How will the on/off switch for the board effect this? Any help you can give will be appreciated.
We are using the potentiometer as a variable resistor. The "wiper" leg is attached to either of the two resistance legs with the difference being the direction you turn the pot to increase/decrease the resistance. I usually just use a fixed resistor here (more consistent over time) once I determine the "pert near" value from testing with the pot. The value, will actually change a bit with the volume you intend to run at.

Yes, and yes.

The on/off switch should work as it always did. The cap is now just a "replacement battery" with no other changes to the circuit except that you will never need the charger (though you can precharge the cap with it), and you never need to turn it off. It will just die away (motorboating) after about a minute of not receiving any power. And, next time it receives power, it will come to life, initially motorboating for a moment.
 

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Toddalin, had to capitalize first letter, spell check kept changing it. I sincerely appreciate you answering my questions. The board in one actually has the sound of the loco cranking up, and it doesn't catch right away, really like that added touch and hoping to keep it. Now to continue my parts search. Again thank you.
 

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Discussion Starter · #14 · (Edited)
Toddalin, had to capitalize first letter, spell check kept changing it. I sincerely appreciate you answering my questions. The board in one actually has the sound of the loco cranking up, and it doesn't catch right away, really like that added touch and hoping to keep it. Now to continue my parts search. Again thank you.
Do you mean like the Phoenix board where if you give it ~2.3 volts, the guy opens and closes the door then cranks the engine a few times before it starts? If so, that is not a Sierra board.


 

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toddling: I am aware of that one. Unless my memory is faulty (at my age a definite possibility) I was thinking of the one in my FA unit. That will be my first conversion. When I open it up will connect a 6V battery to make the sound. If it is the one, I'll let you know the board number, if you are interested. If I've erred, I'll let you know that also.
 

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Discussion Starter · #16 ·
Cool.

The reason I note this is because the Phoenix 2K2 board only uses a few volts from its NiMH battery. It is not the same as the Sierra battery and my Phoenix batteries have not failed on me to date, even after not being used for long periods (years).
 

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toddalin, agree. I occasionall the Hudson on an electrified track to charge. Haven't done in a while, you reminded me, will do it now, thank you.
 

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Video is only way I figured I could record the sound.
toddalin, I stand corrected. Neurons are still firing but the aim is off. Both have Sierra boards. The FA only has engine sounds. The Rail Bus doesn't have doors slamming, but has the brief sound of a starter motor which is trampled by the 'stuttering' at start of the board without battery. Want to build at least one, 'just because' . Thank You Again for all your help.
 

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Discussion Starter · #19 ·
I don't know if you will get the starter with the supercaps with the relay cut-out. It could be dependant on the actual cut-out voltage selected.

If the caps are starting from "dead" without the relay (e.g., first run of the session), I doubt that you will get the starter motor.

If the caps still have charge on them because you've only shut it down for a few moments, you may well get the starter.

I guess we'll find out.

I had never even heard the Sierra for the railbus before this, only the Phoenix systems.
 

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toddalin, I like the Phoenix for the Steam locomotives. Even got the programming disk and interface to 'massage' things like the rod clank etc. Not being that familiar with diesel's I went with the less expensive Sierra, but like them just as well. Last time I am going to impose on your generosity once more if I may. Hoping to order all parts from one site, Newark Electronics, found the closest relay they offer is RTE 24006, your thoughts on that one?? Supercaps I got elsewhere and they should arrive any day now.
 
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