Keep Alive capacitor

[fender777]

I see where Scaletrains has this keep alive capacitor in them to prevent stalling' what other brands use this. Seems to me they should all use it. And can this be installed in any loco. Thanks

[Nevin]

I think that these capacitors are the greatest thing since sliced bread.  In my opinion they fulfill the promise of DCC and allow our locomotives to really function as they are meant to run.  Especially in smaller locomotives and steam with less wheels contacting the rail.  The biggest drawback is their size and getting them to fit.  I just put one into a plastic 0-6-0 and had to cut more and more plastic away to get it to fit.  Finally got it and a TCS decoder in but it was worth it.  

[BigDaddy]

Walthers Plymouth has one.  It's all about money and if the manufacturers don't want to use LED's or Kadee couplers they aren't going to want to add capacitors.

I was watching Ken Patterson's most recent Youtube video where he designed two different lift out sections.  Not sure why you would need 2 for the same place, one was scenicked and one was stained plywood.   Someone commented about switching track power off before the lift out in case it wasn't installed.  That wouldn't be much help with a capacitor. 

 

[mlehman]

Most decoder mfgs offer a keep alive option now and instructions on where and how to hook it up. You need to use DCC to permit keep alive use, as it's not a DC thing.

The sticking point for using a keep alive is usually the available space to install it. If engineered into the design, you can make them fit, but like many things this may require some planning.

[IRONROOSTER]

An oddity here is that the smaller the locomotive, the more useful it is, but the less space there is for it.

Paul

[7j43k]

IRONROOSTER

An oddity here is that the smaller the locomotive, the more useful it is, but the less space there is for it.

Paul

 

A small exception might be old stuff that only has 4 wheel pickup.

I've got a brass gas-electric that's essentially a big box with no passenger windows that's about 60 scale feet long.  It picks up using two wheels on each side.  On DC, it couldn't go more than a few inches without stalling.  There was lots of room inside for "keep alive", so I installed it during DCC conversion.  It runs beautifully now, and has yet to stall.

I've also got a Hobbytown switcher drive that picks up using two wheels per side.  It will also get "keep alive".

I realize I could add wipers to get 8 wheel pickup.  I've done it, back in DC days.  Now I don't have to.

 

On a different note, some or all DCC/"keep alives" have a user-set time limit for the "keep alive" effect.  You can choose how long the motor will run without getting a packet.  Setting that time for a second or so would go a long way towards keeping a unit from a floor dive through a lift out.  

I haven't researched this at all, just heard about it.

 

 

Ed

[G Paine]

As mentioned above these devices need space in the locomotive and add to the cost. Some examples (Walthers show the full list, availabe on-line at discount)

TCS Keep Alive KA2 $36.95 and KA3 $26.95

https://www.walthers.com/ka2-keep-alive-device-with-2-pin-quick-connect-harness-1-3-x-458-x-347-quot-or-32-92-x-11-63-x-8-81

https://www.walthers.com/ka3-keep-alive-w-wire-harness-1-02-x-45-x-347-quot-25-9-x-11-43-x-8-81mm

Soundtrax CurrentKeeper $26.95 (on sale $23.98)

https://www.walthers.com/currentkeeper-1-9-16-x-1-4-x-7-16-quot-4-x-6-x-1-1cm

IN the Walthers Plymouth, the CurrentKeeper has been disassembled and parts installeld to fit the space. Probably Soundtrax made a special run for Walthers just for this small locomotive.

 

[richg1998]

Keep alive info.

https://sites.google.com/site/markgurries/home/decoders/keep-alive-compatibility

http://www.members.optusnet.com.au/mainnorth/alive.htm

Rich

[rrinker]

 I am ever the contrarian, it seems - though I do need keep-alives in the locos I run on the club layout, as the older sections connect via fitter track sections and the joiners wear out so they become effectively unpowered track sections longer than even a #8 turnout frog. However, on two different home layouts now with DCC, I've never had an issue. Before, it was #6 turnouts with non-powered frogs. But the smallest locos I ran on it were 8 axle first gen diesels and all of them had 8 wheel pickup, even the old Atlas/Kato Alcos. The Stewart Baldwin switchers might be smaller - oh yeah, P2K S-1's. Even at creep speeds, no issues. Modern steam models, like Broadway/PCM, with pickup on both sides of the engine plus both sides of the tender, definitely no issues. Last layout, had #4 unpowered frogs (4 1/2, Atlas Custom Line), but now I had a smaller DCC loco, a Bachmann 44 tonner. Even it had no issues on the unpowered frogs. No sound cutouts on the sound locos. So I've yet to add keep alives to any of my DCC locos. New layout will use Peco Electrofrog turnouts and they will be powered, so there will be even less chance for dead spots. 

 Wish I could explain it - I don;t clean my track, either, only to make sure there is no paint on the railhead after paiting the sides. At least for Atlas turnouts, I have power feeds on all 3 legs of each and every one, there is no reliance on sliding contacts for power other than the point blades themselves, every other piece of rail in the turnout has a power feed to it somehow. I do burnish the rail with the side of hardened cutters, but I don't apply any sort of metal polish or any of the rest of the steps of the 'gleaning' process. There is no smoking allowed in my house - I don't smoke, and visitors who do need to step outside. 

                        --Randy

 

[NYBW-John]

Many (most?) steamers have pick up in both the loco and the tender. Could the keep-alive capacitor be installed in the tender or does it need to go in a specific place?

[trainnut1250]

Yes they can be installed anywhere there is room.  Our local group has installed a bunch - personally I have installed around 8 of them so far.  They work great.

Specific points raised in this thread:

I haven't come across a user time limit setting...where is that info? Mine are hardwired to the decoder with no options for any kind of adjustment.

My local buddy has installed them in HON3 locos - it is possible to shoe horn them pretty tight. Most steam installs are in the tender. The device is easiest to install when it is next to the decoder.

IMHO - Small brass is the main beneficiary when it comes to keep alives. Most of mine are in small brass... I use very aggressive scenery techniques and have lots of hidden track. Keep alives have definitely helped on my layout...

 

Guy

[Geared Steam]

TCS has added the KA4 to their product line, its square in shape instead of long and rectangular. I'm not sure why, but I have the best performance using TCS Keep Alives over the others. 

[hornblower]

Anyone know how to connect a TCS Keep Alive or Soundtraxx Current Keeper to older decoders like the NCE D13SRJ or even an MRC 1627?

[peahrens]

I guess I've added capacitors to about 15% of my locos for my modest DCC layout.  I've powered the frogs and gleamed the track, which I think is directionally helpful.  So I've been able to be selective.  I have decided to keep several capacitors available so I can consider the relative oomph (a technical term) and the dimensions for optimizing a specific install.  

My first loco with the need was a Genesis GP9 that was the most likely to have a sound hiccup at my somewhat shaky triple crossing.  On that one I just experimented with a typical Radio Shack capacitor (of the right rating, quite important) and the max size that fit just barely solved the issue.  I now have the TCS Keep Alives 1, 2 and 4 handy to use as well as a Soundtraxx Current Keeper.  I used a KA4 in a IHC Mother Hubbard 2-6-0 that I recently converted, deciding it might need it.  I put a capacitor (as well as sound) in an Athearn motorized snowplow/tender combo and added one to a Bachmann doodlebug when I changed out the power to a NWSL Stanton drive.  So far, I've had the room on locos where I need the help.  My only small diesel, a BLI NW2 switcher, fortunately does not need one.  I do not find that the 4 Soundtraxx SoundCar installs I've done require one. 

I imagine my BLI trackmobile needs one, but I'm not planning to tackle that unless someone provides a "how to" demonstration.  And I find it's mainly a shelf sitter for me anyway.

I'm happy to spend the $ when needed, especially when all the locos do not need one.  DCC is fun when the items work as desired.  

[richg1998]

hornblower

Anyone know how to connect a TCS Keep Alive or Soundtraxx Current Keeper to older decoders like the NCE D13SRJ or even an MRC 1627?

 

Look at one of the links I posted before.

Two wires from the keep alive connect to the common and negative on the decoder. Essentially the plus and minus from the full wave bridge. Again, right in the link. All decoders have four diodes to form a full wave brdige rectifier. The diodes are labeled.

Some decoders come with a keep alive for only the sound. Right in the decoder specs. Do not put the keep alive in parallel with that cap.

I have some Tsunami that came with a sound keep alive cap.

It does help a lot if you understand basic components used in decoders.

Rich

[hon30critter]

Hey fender777:

I use ESU LokSound decoders in almost all installations, and I have added their 'Power Pack' keep alives in a few situations. They work great!

http://www.esu.eu/en/products/former-products/powerpack/

One of the biggest advantages of the ESU Power Packs is that they are quite small so they will fit into lots of places where the multi-capacitor keeps alives won't. Their small size does limit the length of time that they can supply power, but if you are using them to overcome momentary interruptions in power that is not an issue. (If you are installing keep alives to compensate for dead track or poor track maintenance then please disregard this whole post).

Here is an example of an ESU Power Pack at work (apologies to those who have seen these videos before). This is a two axle locomotive so any interruption in power without a keep alive would cause it to stall:

Here is a more finished shot of the box cab. It is at speed step one with no changes to the CVs from the factory settings. If you count, it takes seven seconds for the box cab to go from one tie to the next:

A few notes:

- The box cab was fitted with code 88 wheels which is why it drops into the frog gap. The wheels have been replaced with code 110, but the fact that the critter is lifting one wheel well clear of the track without stalling shows how well the Power Pack works. Before the Power Pack it stalled every time.

- The flywheel has been removed to create space for the keep alive. The manufacturer was scheptical that the drive would work properly without a flywheel but it runs just fine. I have run the box cab's twin, a 23 tonner with the same set up, for five hours straight without problems.

For comparison, here is the 23 tonner before the keep alive was installed and with the flywheel still in place:

- The drive systems are Hollywood Foundaries BullAnts with a 60:1 drive gear assembly. Next time I will use a 30:1. The 60:1 is just too slow.

Cheers!!

Dave

[fender777]

Thanks guys for all this great info and time to explain how and what keep alives are out their. Most of my Locos work well expect my BWL ' they have hiccups now and then. My Katos and Atlas allways run perfect ' for some reason I have more problems with my sounds locos stalling than non sound.