Z21 Track Voltage

[RFS]

I recently upgraded my DCC system, replacing Lenz command station for the Roco Z21. The Lenz had a track voltage of 15v whereas the Z21 is 20v. I therefore set the Z21 booster voltage to 15.5v as this seemed to be the best match taking into account occupancy detectors etc.  But a few of my locos now seem a bit slow.

 

So what track voltage do people use as 20v seems a bit high? My layout is OO gauge.

[Andymsa]

A question first, do you set max speed of a loco by Cv 5 or do you use max voltage, Zimo and ESU have different cvs for this. Off hand can’t remember the specific cvs used for this. The effect would be as you have seen if you use cv5 to set max speed it can be different for different dcc systems. I not explained very well, but hope you get the idea.

[RFS]

I use CV 5 as most of my decoders are Lenz (75 out of 85) and I've only recently become aware of the max voltage option on Zimo (CV 57).

 

My concern was that increasing the track voltage might mean having to reprofile all my locos. 

[WIMorrison]

I use 18v on the Z21 and have the booster automatically reflect the Z21 settings.

 

I find that this works brilliantly for me and I only need to use CV57 on a couple of locos that I remotored with brushless motors that have a max voltage of 11v. Everything is par is controlled by CV5

[mikeg]

I have my Z21 set at 14v and am running O gauge locos with no problem, I have installed a booster set at 12v for points and accessories due to some of the points not working using the track power which I think was due to the power of having several sound equipped locos, upto 6/8 at anytime plus 4/5 non sound as well.

 I originally set my Z21 at 18v and used resisters on the point feeds which was recommended by Richard at DCC concepts  but changed to the system above following recommendations on this forum about two years ago. I now have reliable running and point controls.

 

regards mike 

[RFS]

Thanks for all of your replies.  I have a Z21 plus a dual booster: the Z21 itself just manages the accessories, more importantly 60+ Tortoise point motors controlled by NCE Switch 8s and I've set its voltage to 12v which keeps the point motors quiet and trouble free. For the two track power districts, I have now set the dual boosters to 18v and that seems to be working fine.

[melmerby]

I think mine is set to about 15v, as I get about 13.8v at the track via the occupancy detectors

I tried to set it to the same ouput as the Lenz LZV100 which previously supplied the track.

I'm still using the Lenz to power the RS-8s

[RFS]

Having changed the track voltage from 15.5v to 18v, I reprofiled a couple of locos which had been causing a problem. With the locos now OK, I now decided to run the system in automation following the timetable only to discover that any Zimo-fitted loco that had been profiled at 15.5v was now seriously overrunning stop markers. I have 10 Zimo-fitted locos and 75 Lenz-fitted and none of the Lenz locos were affected. They all stop in the same place regardless of track voltage.

 

So I've once again had to re-profile the 4-5 Zimo locos to correct this.  Seems the way Zimo decoders work internally is a lot different from Lenz!

[melmerby]

On 17/09/2021 at 13:43, WIMorrison said:

 

 

I find that this works brilliantly for me and I only need to use CV57 on a couple of locos that I remotored with brushless motors that have a max voltage of 11v. Everything is par is controlled by CV5

Brushless?

How? They need a 3 phase drive signal, nothing like  the output from a DCC decoder.

[melmerby]

5 hours ago, RFS said:

Having changed the track voltage from 15.5v to 18v, I reprofiled a couple of locos which had been causing a problem. With the locos now OK, I now decided to run the system in automation following the timetable only to discover that any Zimo-fitted loco that had been profiled at 15.5v was now seriously overrunning stop markers. I have 10 Zimo-fitted locos and 75 Lenz-fitted and none of the Lenz locos were affected. They all stop in the same place regardless of track voltage.

 

So I've once again had to re-profile the 4-5 Zimo locos to correct this.  Seems the way Zimo decoders work internally is a lot different from Lenz!

Although, once profiled I find the Zimo decoders produce nice smooth running and low speed control, I find them more difficult to profile than Lenz, where I rarely have to anything other than set the top and midrange speed CVs.

The Zimo MX618N18 in my Dapol GWR Mogul was particularly difficult, needing much tweaking with the speed table to get anything like a straight profile.

Edited September 18, 2021 by melmerby

[WIMorrison]

10 hours ago, melmerby said:

Brushless?

How? They need a 3 phase drive signal, nothing like  the output from a DCC decoder.

 

apologies, I meant to say coreless - but you knew that anyway

 

[melmerby]

Just now, WIMorrison said:

 

apologies, I meant to say coreless - but you knew that anyway

 

I suspected you meant coreless, but wondered whether there was some sort of brushless motor with inbuilt driver circuitry. (you never know these days)

 

Something to bear in mind with DCC decoders is that you don't normally vary the voltage going to the motor, just the duty cycle of the PWM signal.

However I haven't investigated exactly what the CV57 setting in Zimo decoders does.