Keep Alive units

[Barnaby]

Can anybody give me a steer on these KEEP_ALIVE units.

Are they a one size fits all or is there some calculations to be done?

 

I have looked on here and found some how to's but I'm not too clear where or how to install these KA units.

My set-up on the Class 20 is a Loksound V 4 Sound Decoder with a Mashima 1833 motor.

 

I have two dcc + sound models a JLTRT class 20 and a Ixion Fowler in 0 gauge.

The Fowler is magnificent in that no section of my track causes it grief, I will even run faultlessly after a week of standing idle with no track cleaning being necessary.

 

I put this down to the wonderful KA units that got fitted to the Fowler by NG Trains / EDM when I purchased the Fowler so hence me wanting to fit a unit to my CL20.

 

The CL 20 is more critical of Track joins and point work giving little pauses and random stops.

 

I'm going to add some weight as cleaning the wheels and track does help the situation but the Fowler sails over the same track without any cleaning so KA is king.

I'll also check all the pick-ups as with a double bogie it should work ok over the point work as one set of bogies will always be in electrical contact.

 

Thanks Gents

Edited February 27, 2018 by Barnaby

[John K]

Hi Barnaby

There are several people here with more knowledge that me but I'll start it off. All of this is practical not theoretical - I have done it.

 

I have been using this device from DCC concepts and supplied by Kevin at Coastal DCC. Part DCD-ZNSSA-1. They are priced at £15 from Coastal.

These, like the TCS KAs (I have used these too), have the necessary charge and discharge circuitry built in.

They do need to be wired to the decoder - blue wire to decoder common positive and black/gray wire to decoder ground (GND).

I have a lot fitted to Zimo decoders, but the GND on the ESU V4 is easy to find (see full decoder manual).

You need to be fairly adept with the small soldering iron. Please do not blame me if you incinerate a decoder.

 

The other thing to note is that with these devices in place you will have locos capable of 'off-roading' for some distance, which looks very clever until one runs off the layout and onto the deck.

All decoders will have a CV that can limit the time that the motor will run without receiving a digital signal. In Zimo world it is CV153 and the number set in that CV is the time in 100 millisecond aliquots, so a setting of 20 will let the motor run for 2 seconds.

 

Can talk more if you are coming to Kettering on Saturday.

 

Best,

John K

Edited February 27, 2018 by John K

[Nigelcliffe]

Only two significant thing to add to John K's post:

 

 

1 - be aware of voltage ratings.  

 

Quite a few KA devices are built without much margin for error on track voltages, so if the maker says "good to 16v", they probably mean it.  There's usually a volt lost from the track through the decoder, but nothing else.      So, be sure you know what your track voltage from the DCC system is.     Some of the worst-offenders for high track voltages are systems with fairly crude transformers - older Roco systems for example.    Newer switched-mode DC power supplies are normally very accurate in delivering what it says on the label. 

 

It is possible to design KA devices with a zener diode to shunt away the excess volts coming in via the charging resistor.  I haven't met an off-the-shelf commercial unit which does this.

 

 

2 - technology.

high capacity KA's, such as the ones John mentions, use "supercaps" and are totally different in run times to cheaper "electrolytic" capacitors.  

 

 

- Nigel

[Barnaby]

Thanks John & Nigel both.

 

Since I posted the above I tried a little more weight [3 oz], just a guess to the Cl 20 and that made a hell of a difference to its running.

Because the fowler runs so well with its KA fitted I may well look to add to the '20 but as I am about to lay new track on my new baseboards I'll just gather the KA info at this time.

 

Can't make Kettering John as my wife has booked us into a Ludlow hotel for a foody treat that weekend, thanks though.

 

Best

Edited February 27, 2018 by Barnaby

[John K]

Enjoy Ludlow, loads of good food.

I had an excellent meal at Elliots Brasserie in the Dinham Hotel there last year

John

[Barnaby]

Yes John It's the Dinham Hotel we are eating and staying in, it's one of our favourites.

 

Regards

[mikeg]

I have a KA in my O gauge class 60 which together with the large flywheels will enable the loco to run about 100ft if the power is turned from full to zero in one turn of the knob, my class 20's run about 15ft but have much smaller KA I think they are a third of the class 60 as have two capacitors and the 60 has 6. my fowler has not had the KA unit fitted and runs on about 2ft so is a very slow and positive runner I think due to the chip that came with it but not fitted.

 

regards mikeg