# Current Keepers and capacitor additions..



## MatroxD (Jan 19, 2018)

Hello all, I am moving on along with my layout, but I have one little problem that is annoying.. My n scale F7, is the only engine, that it stops for a second, and the headlight goes out.. I am sure that I could take up all my flex track and redo all my hard work, but I really don't want to do that.. Just to get the headlight to stay on(basically smooth that out and I'm good).

I know for soundtraxx and other brand decoders, you can add capacitors(soundtraxx calls them current Keepers) to keep the engine rolling for a few seconds over bad areas, and that's all I need. But the problem is that this decoder does not have the built in port for the keeper. I'm wondering if anyone has made their own, or has added something like this to their own locos, and knows where I would solder in the capacitor(s) on the boards/connections? Or any suggestions whatsoever.. My plan is to add whatever system, to the boxcar that runs behind the engine, and run the wires to the Loco and the board..???

Thank you again in advance, you all are awesome!

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## Bwells (Mar 30, 2014)

Is the headlight the only problem and does the flywheels carry the loco over the dead spot? If just the headlight, a capacitor in parallel with the bulb (LED hopefully) will cure that but you would want to use the largest one that will fit. I assume the dead spots are the frogs at the turnouts. What make are they?


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## MatroxD (Jan 19, 2018)

Bwells said:


> Is the headlight the only problem and does the flywheels carry the loco over the dead spot? If just the headlight, a capacitor in parallel with the bulb (LED hopefully) will cure that but you would want to use the largest one that will fit. I assume the dead spots are the frogs at the turnouts. What make are they?


Thanks for the reply.. Yes, the healthy is really the only problem, as most of the time the Loco will keep going, and just jerk/pause a little. But the light(yes, they are all led) is really the main issue/annoyance.. And it's actually a place my flex track butts up to the next piece. I tried shaping with solder and a dremel, but I just can't get this single spot right. And I really don't want to tear up things.. This will also allow, I'm hoping, if the tank gets a little dirty, that it will let the Loco coast a bit (I'm going to mess with the acceleration and deceleration CV's also so try and find values to get the little guy to coast better).. 

And you have to beat with me, how would I wire it in parallel to the led? I'm new to this and have received much help but for some reason, parallel, even though I did my layout and the lighting, it hasn't fully sunk in.. So all, and any help or instruction you could give would be awesome! 



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## Bwells (Mar 30, 2014)

How about adding feeders to both sides of the track connection? Are the track joiners perfectly seated and one rail is not higher than the other? 
Parallel would be connect the positive lead of the cap to the positive lead to the LED and neg to neg.


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## MatroxD (Jan 19, 2018)

Bwells said:


> How about adding feeders to both sides of the track connection? Are the track joiners perfectly seated and one rail is not higher than the other?
> Parallel would be connect the positive lead of the cap to the positive lead to the LED and neg to neg.


Hmmnn.. The feeder is a good idea..

And cool I get it now with positive to positive and negative to negative.. What capacity or size would you suggest? I may have to run the wires out the back of the Loco, too a boxcar and place the cap in there...?? 

Sent from my Note 8


Oh.. And this connection, the parallel, on the positive side, should be after the resistor correct?


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## Bwells (Mar 30, 2014)

Rather than doing a work-a-round by adding a cap, take a close look at the rails and the joiner. When you mentioned a dremel, I suspect one rail is not in the joiner and sitting higher than the other. Use a magnifying glass if need be and see if this is the case. If so, fix that and your problem will be solved, not just for this engine but all the others that come along.


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## DonR (Oct 18, 2012)

Any time you have loco flickering lights or pausing
you have a loss of electrical contact. 
I agree with Bwells, look at the track as a possible
problem. In N a tiny fraction that is wrong can
look like inches to N wheels, even lifting them
off the rail top which would then open the circuit.

It is also very important that both track and
power pickup wheels be very clean. Make
sure that the wires and wipers on the loco
trucks are functioning correctly.

In short, you should not need a cap to keep
the loco running.

Don


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## Shdwdrgn (Dec 23, 2014)

Regarding the size/capacity of the capacitor... You want to get an electrolytic but they vary greatly in size vs capacity. You also want to check the voltage at the point where you plan to add the capacitor. For example if you connect it directly to the LED then you are probably only looking at 2-3 volts, however every LED has a matched resistor and if you measure behind the resistor then you are probably looking at 12V. The capacitor you get MUST be rated for the voltage you will apply to it! Common ratings are 6v and 16v, and a larger voltage capacitor will have a smaller capacity within the same physical size, so you are better off if you can tap in at the lower voltage level. As for the capacity (value), anything will work however a larger capacity means it holds more electricity and will power your LED for a longer period.

Search online and try to check a number of different sources. There is a huge variation in available capacitors so you might find one with a given voltage and capacity in one size, and then find another vendor sells one with the same values which is only 1/4 the size. Your best bet is to find a location for the capacitor and measure how much space you have, then use those dimensions to find the largest value capacitor that will fit.


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## MatroxD (Jan 19, 2018)

DonR said:


> Any time you have loco flickering lights or pausing
> you have a loss of electrical contact.
> I agree with Bwells, look at the track as a possible
> problem. In N a tiny fraction that is wrong can
> ...


Nope it is(was the track).. Lol, I put the dremel to it very carefully, and I can for the most part, keep the lights running continously at 4(out of 28 steps) on the controller(not as slow as I would like), but it's for sure an improvement, because I couldn't keep it running at all earlier.. 

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## MatroxD (Jan 19, 2018)

Bwells said:


> Rather than doing a work-a-round by adding a cap, take a close look at the rails and the joiner. When you mentioned a dremel, I suspect one rail is not in the joiner and sitting higher than the other. Use a magnifying glass if need be and see if this is the case. If so, fix that and your problem will be solved, not just for this engine but all the others that come along.


It was the rails, and I simply didn't and don't want to pull all of my ballast, but I got it going for the most part. That section is mostly a non issue now(thanks to the dremel).. Lol but it's showing other dirty posts of the track.. But as I mentioned to Don, I can cruise it at 4(fairly slow) confidently without the lights cutting out most of the time.. At 2 and 3,it runs constantly without fail now, but my headlight cuts off every now and then.. That's the annoying part to me.. I don't want to dremel to much, so I may just leave it as is.. Not sure... 

Sent from my Note 8


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## MatroxD (Jan 19, 2018)

Shdwdrgn said:


> Regarding the size/capacity of the capacitor... You want to get an electrolytic but they vary greatly in size vs capacity. You also want to check the voltage at the point where you plan to add the capacitor. For example if you connect it directly to the LED then you are probably only looking at 2-3 volts, however every LED has a matched resistor and if you measure behind the resistor then you are probably looking at 12V. The capacitor you get MUST be rated for the voltage you will apply to it! Common ratings are 6v and 16v, and a larger voltage capacitor will have a smaller capacity within the same physical size, so you are better off if you can tap in at the lower voltage level. As for the capacity (value), anything will work however a larger capacity means it holds more electricity and will power your LED for a longer period.
> 
> Search online and try to check a number of different sources. There is a huge variation in available capacitors so you might find one with a given voltage and capacity in one size, and then find another vendor sells one with the same values which is only 1/4 the size. Your best bet is to find a location for the capacitor and measure how much space you have, then use those dimensions to find the largest value capacitor that will fit.


Actually, soundtraxx sent me a picture of a connected current keeper to my decoder(this takes all the guess work out of it for me) . I will probably buy one and outfit it next week at some point.. Just to have the little extra. I will eventually do my HO engines as well... "Now", they all run fine, but never hurts to have that little extra insurance.. 

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## MatroxD (Jan 19, 2018)

Ha ha! It works awesome! It will run 1/4 around the track with no power at all on it.. No flickers, can run it at 1, no complaints.. I will have to buy some micro connectors, so I don't have to remove both the loco and the car, but besides that, I'm happy! And in awe at the same time with how much technology has advanced..

I'm actually sold on them honestly.. For 20.00, it makes it fun to watch. If nothing else, I can run it as soon or as far as I want...

You will see in the pictures, the little wires that you can see..









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