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Discussion Starter · #1 ·
Im curious about the power drain of digital systems. When multiple cars are running (they say) you can feel the other cars. This is true with any two lane home set power supply, but large amperage aftermarket supplies fix this problem.

So my question:

If a four lane club track has a 20amp supply, you generally cant feel the cars in other lanes, BUT, will the same thing be true with digital???

So I'm wondering if I want to run 6 cars on a digital system, will it suffice to get a 30Amp power supply, or are digital cars always going to "feel" bad because the cars are sharing the same rails?

I hope that they work well with big power supplies because nothing would be better than running 8 cars on a four lane club track!
 

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At present, only the Davic system can support more than 6 cars.
Enough amps should cure any 'dead' feel on any system.

SCX have let it be known that they plan to upgrade for the possibility of a total of three power supplies to their two lanes (6 cars max) in order to alleviate their particular problem. I don't yet know the total current that these will be able to supply.

Scalextric apparently have 24va and 30va PSUs available. Feedback from triallists of their system has been a little mixed about whether this is quite enough, some say yes, some say no. I would have thought 60 va would be minimum for 6 simultaneous cars, myself.

Carerra system is currently reported to only support 4 cars, so the current requirement is around a third lower.
 

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Discussion Starter · #3 ·
Thanks!

Its possible to run multiple power supplies in parallel, in which case the amperage is doubled (tripled, etc).

Thomas said the carrera system is limited by the power supply and that the digital mechanism is not limited to four cars. I was hopeful that you could add another power base and run 8 cars. Of course, they would never advertise this to the standard consumer because you need an aftermarket power supply to pull this off!

I am a software engineer by trade and I guarantee it would be no more difficult to engineer a digital system that could send signals to 16 cars as opposed to just four. The hardware imposes the limitations. In this case, the power base only has connections for four controllers and the power supply only has a certain amperage.

If a given power base can be coded to send four independent signals, then another power base could just as easily send a differnt four signals. The question is if the four "frequencies" are hard-wired at the power base?

Likewise, the lane-counter blade with four holes can be coded to represent 16 cars, but can the lane counter recognize patterns?

I highly doubt if any of these systems are hard-wired to accept a max of 4 or 6 cars. I bet a scaly system could take 12 cars if there was enough power and an additional base.
 

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I am inclined to agree with you on the theory at least.
I don't know enough about the technical detail but it could be that the huge requirement for sensitive speed control over quite a large range could be a limitation on the 'electronic traffic' as opposed to the physical traffic? Compared with say model trains, where it's pretty easy to assign around 100 or more unique addresses, slot cars travel immensely faster and we are REALLY pernickety in our requirements for 'feel' on the controller.

At present, it seems that neither of the 'big three' are even planning on more than 2 lanes, let alone more than six cars but this might well change IF a provable demand is there. I think they are wise to be ultra cautious!
 

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Just a reflection about manufacturers 'incentive'.

If it is true that the VAST majority of sets etc is sold to home users AND if it is true that the vast majority of home users do not become involved with clubs and clubtracks. If it also is true that most home set owners do not build a four lane track. Then it is possible that the market for the current digital sets is the home user. In that case it will hardly be of much importance to have a system developed for more than two lanes, more than four cars (six is almost a luxury here if it does not matter to the main market).

OK you say but the majority of set buyers loose interest in the slotcar hobby within a very short time and their home set is put away on the attic etc. Well suppose that this has been the case for the last ten or more years - it might not really matter (to the manufacturer) that it is a 'short-lived' hobby for most people (kids?) if this is a continually re-occuring phenomena year after year? As long as there are new 'kids on the block' every year... So for us the 'real' hobbyist and enthusiasts it stands it might be the case of pure politeness that the manufacturers ever care to listen (to us the 'hobbyists') if the majority of the market is a very different from the one we represent.

This might also mean that as long a system runs 'reasonably well' with four cars the power issues might be looked upon as 'good enough'.

..just a thought.



... on the other hand we are probably the main market for their cars... I would assume that we 'enthusiasts' buy a significant amount of cars, compared to the 'average' home set buyer / user (kids with their christmas presents?).


//peter
 

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Brian Ferguson
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Peter, good points! The output of set power supplies has always been minimal (we've all experienced the dreaded power surge at some time), but problems may become far more pronounced and obvious on digital sets unless the manufacturers seriously address this issue. They haven't in the past, so I wonder if they will now.

Even with just four cars on two lanes, typical supplies will need to be more than doubled in capacity. Why? Because the effects (surges) won't be felt by just one driver as now, but potentially by three - it will become much more obvious, more frequent, and more frustrating. And while the additional current draw of the on-board electronics is pretty minimal, the sorry state of home set supplies means this can't be ignored.

Hopefully, better power will be addressed as part of the digital scheme. Otherwise, I think many people will experience frustrations with it, and it may (as was pointed out elsewhere, by Beppe I believe) also limit digital car motors to rather low-powered units. I realize power supplies cost money, but it still amazes me that no common manufacturer has ever used a decent supply in their sets. Perhaps such a change in architecture as digital will soon force them to do so?


On the limit of number of cars in the various digital systems, there should, in theory, be no problem with 16 cars (given adequate power!) and I'd be surprised to find out that anyone intentionally designed for less. I suspect, and hope, that future releases will expand the apparent current limits, which may well be constraints more of a cautionary nature than of necessity. Companies could lose a great deal if their digital promises exceeded their initial product's capabilities - this is a big step and a big investment for these guys and they can't afford to screw it up.

What's that?... time's up?....I'm babbling?... okay...
 

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Discussion Starter · #8 ·
It all good!

Cant wait for the carrera pro-x digital! I'll be the guinea pig and hook up a 50amp power supply! And get an extra power base to see if I can run 8 cars! on 3 lanes! (with one lane for reslotting).

Im stoked about digital and i expect those crazy germans are going to get it right!
 

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Beppe Giannini
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(in no particular order)

- I'm tickled pink seeing how fast digital (or MCPL) has become mainstream, with little or no actual experience yet !!! - I remember the first threads on SCI, maybe 20% were (very cautiously) in favor, and it was just April last year...

- about power surges/number of cars - I repeat that Davic runs well (no surges, no delay) with up to 15 NC1/2 motored cars and a 10 A stabilized power source - this tells us that the real problem is the crappy wall warts that manufacturers inflict upon us for price reasons - we all know that a 12 V nominal wall wart will deliver 18 V on no load, but this drops precipitously as soon as you draw amps - to be fair, we also know the cost of a regulated supply

- max. amps per car - on one hand, the total current drawn by all cars must be coded (chopped) by the base unit - I don't know the practical limit, I believe trains use 10A units - on the other, the onboard decoder chip should withstand the stalled rotor current - I don't have the figures, but my feeling is that you don't get much further than say a 23k wind

- because of deslotting and mainly shunts (same-lane collisions) the practical limit on two lanes is IMO 6 cars. Another aspect that hasn't been really considered until now is ease of overtaking - again IMO the minimum requirement for that is a track length of at least 20 m - we are then talking of a permanent, club track - frankly, I doubt that home, under-the-bed MCPL tracks will be worth the additional complication.
But (the more I think about Scalex Digital the more I like the guys) you should be able to run your car at home on analog and then go to the club and race MCPL - I just hope that such a market is big enough for Scalex (and others) to justify their continuing interest

- more than 2lanes/6 cars : we are talking of the Davic scenario, 15 cars on 4 lanes, 60 m tracks, long distance events (that's the only way to have enough corner marshalls available) - it's such a small sector, that components will inevitably come from aftermarket

- other tracks than Scalex : I've already said that the (possibly unintentional) beauty of the Scalex system is that it opens the way to open source components - the way the LC is triggered makes it standalone/independent from the base unit, plus it cannot be patented
Since the Scalex track is really too narrow for MCPL, one should tell people at Carrera to drop their ridiculous contraption and concentrate on their wide track advantage

Beppe
 

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Discussion Starter · #10 ·
Actually, my plan is to build 75' 4-lane club track into a 3 lane digital setup, with one lane for reslots.

Carrera accepts offset construction so this should be no problem.

If you can run two head units with differnt addresses for every car, then that would be 8 cars on 3 lanes with one lane for reslots.

Obviously this is just conjecture, but I dont see the need to go to a Davic system for the average club. It looks like the carrera digital hardware may work fine to run 8 cars on 4(3) lanes.

Carrera Offset Construction +
2 head units +
Aftermarket Power supply =

8 cars on four lanes. Perfect for club racing IMHO.
 
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