Having looked at controllers, we'll now take a look at what they control; the power. Here we'll cast our eyes over the power supplies available, how they work, and what's best.
Power Supplies - Analogue
A slot car motor normally runs on 12/14 volts DC but the power coming out of your sockets at home is 230 volts AC (110v AC in USA), so it would be positively dangerous to plug your track straight into the mains supply! Therefore all manufacturers provide a transformer/rectifier to drop the voltage and convert it to DC in a safe manner.
Below is a standard Scalextric set up but other manufacturers are similar:
It consists of a plug in transformer and a powerbase to connect it to the track and hand controllers. As usual the transformer is primarily designed to be as cheap to produce as possible and, although safe enough, is only suitable for the smallest of home tracks.
- Most transformers supplied in analogue race sets deliver from 1 to 1.6 amps. That’s only just about enough to run two set cars around a small layout. Box standard cars are perfectly capable of pulling more than 1amp each at start up and, as soon as you modify the cars for greater performance or use higher specification cars, transformer output rapidly becomes marginal. That’s because every time you install a hotter motor or a stronger traction magnet you increase the amount of amperage the car needs.
- With longer layouts the amount of current available from standard supplies is only just adequate to begin with and the cumulative small losses at each track joint will be enough to make the power insufficient at the far end of the layout. If there are a few not-so-good connections the loss will really be felt.
- Manufacturers’ power supplies are usually ‘unregulated’ which, without going into technicalities, means that if one car deslots then the other one will often suffer a power surge and fly off the track as well.
For the average home user a quick and easy way to make a useful improvement is to add an extra power supply so each car is getting the full output of one transformer. Each lane then has its own circuit, the cars are not fighting each other for the available power and what one car does can’t affect the power to the other. Even if there still isn’t quite enough power for each car this makes them easier and more consistent to drive.
Not all bases will accept a dual power supply. Ninco made a twin port version and the new Policar system has it as standard. Scalextric used to make a suitable power base part # C8217 which although discontinued can still be found and often pops up on eBay.
If you can’t find a suitable twin port power base then just add another single port one to take the second transformer.
Important - When using two power bases they need to be connected the same way around with the boxes that the throttle controllers plug into on the SAME side of the track. Take care to ensure you never connect the powerbases in opposite directions or you could end up short circuiting both power supplies.
Also make sure you are powering each lane from only one source. To do this you need to plug the throttle controllers into lane 1 for one power base and lane 2 for the other.
This is only suitable for standard analogue systems, not the Scalextric ARC product or any type of digital layout.
Fitting power taps (booster cables) to the far side of larger circuits will also help distribute the available power more evenly.
If you have a permanent track then it is worthwhile ditching the standard product altogether and investing in a decent quality ‘regulated’ variable voltage power supply like this:
They are primarily meant for industrial/laboratory use but are ideal for slot car purposes and have three advantages over the cheap set versions:
- ‘Regulated’ power is completely stable so deslots on one lane will never cause power surges in another.
- Variable voltage. Although slot car motors are rated at about 12v DC they will happily run on a wide range of voltage. If you have racers of mixed abilities and/or small children using your circuit this gives you the option to reduce the power supplied to the circuit making it more driveable for young or inexperienced users. You can even set the voltage low enough that a very young child can simply pull the controller trigger all the way back and the car will drive itself around the circuit.
You can also increase the voltage to make your cars go faster if you want but don’t overdo it to the point where the motor self-destructs. A moderate increase of four or five volts won’t cause a major shortening of motor life, but beyond that you are running an increasing chance of letting the smoke out.
- Increased amperage. They are much more powerful so you will have more than adequate current for your cars no matter how large the circuit.
Suitable items are sold by some of the major slot car suppliers such as Pendle but eBay and Amazon list a large selection as well. Cost is entirely dependent on the power output, the more amps the higher the price. Don’t be tempted to purchase one with more amps than necessary, the electric motors in your slot cars will only draw as much current as they can use. If they are not getting enough power you can increase their performance by increasing the available amperage but only until the cars are getting all they need. After that all the amperage in the national grid won’t make the cars go any faster. As a general rule of thumb 5 amps per lane will be more than adequate for most purposes so a four lane track would need a 20 amp supply.
If the budget will stretch to it separate power supplies for each lane can be useful as you can then vary the voltage individually so different racing capabilities can be catered for. It is also worthwhile buying one with auxiliary 12v outputs which you can use to power accessories like track lights.
As you will not be using a standard power base to connect things you will need a wiring harness to complete the job. Pendle can supply ready-made items for proprietary plastic track but you will have to make your own for wooden tracks. This is not difficult and only requires very basic electrical knowledge. The BSCRA website contains a comprehensive guide to wiring in its track building section and you can always ask for help on the forum if you get stuck.
Power Supplies – Digital
Most manufacturers have produced digital power bases that integrate constant voltage track power and complex digital command circuitry. The exceptions are the Slot.it oXigen and Scorpius systems that use 2.4Ghz radio to control the cars – for these a constant DC voltage to the track is all that is required.
For the digital systems that have an integrated power base, power supply alternatives are limited by the power the digital command circuitry requires (minimum voltage) or can handle without damage (maximum voltage and amps).
The original C7030 6-car powerbase was powered by the C7004 12-volt, 2.5-amp supply. This wasn’t enough power for satisfactory digital racing but upgrading the power without modifying the powerbase could cause damage to the components. Enthusiasts produced the PB-Pro update to overcome this.
Subsequent digital powerbases – the ubiquitous 4-car digital powerbase, C7042 Advanced 6-car powerbase (APB) and ARC Pro – have all used the 15-volt, 4 amp supply shared with Hornby digital railway systems – currently the P9300 / C7024 in the UK. Both the APB and ARC Pro have twin power sockets, so can use two power supplies – essential for running four or more cars at the same time. This power supply also acts as an excellent semi-official upgrade for the analogue ARC Air powerbase.
Enthusiasts have also used the Toshiba PA3469U1ACA 15-volt, 5-amp laptop power supply as a direct plug-in alternative. The main benefit is that non-branded clones of this power supply are much cheaper than the Scalextric P9300. It is strongly recommended not to mix types of power supply – either two Scalextric units or two Toshiba clones. And, of course, using any non-standard units does void your warranty.
Using two power supplies with the APB or ARC Pro is enough to run six standard Scalextric cars with magnets or six performance brands (e.g. Slot.it) using a standard short-can motor rated at up to around 23k rpm and without traction magnets. If you plan to use six cars with more powerful motors that have a higher amp-draw (including most long can or flat-6 motors), then Riko Rocket’s high-power mod is something to consider. This modification powers the track separately to the digital command circuitry. Contact Riko via his website for more details. More power will damage the older Scalextric digital decoders, including the C7005 Retro-fit chip.
The Worthing Digital club use an unmodified APB and two P9300 Scalextric supplies for their club racing. Two or three power taps (plus a pit lane power tap) are used in their 100/150 foot temporary tracks. Good track connection maintenance helps provide reliable power, as does the use of INOX MX3 on the cars’ braids. WHO Digital race standard Scalextric, Slot.it Group C and Pioneer Trans-Am cars – all without traction magnets.
The Carrera Digital Control Centre is designed to take both the Digital132 14.8 volt, 3.5 amp and the Digital124 18 volt, 3 amp power supplies. These are just about sufficient to run six standard Carrera cars in Digital132 and four cars in Digital124. But only just.
Many Carrera Digital enthusiasts upgrade to a variable DC bench-top power supply. The Control Unit can handle an absolute maximum of 25 volts (although it is arguable why that would ever be necessary) and a maximum current of 8 amps – with a momentary peak of 10 amps possible. Most recommendations are for between 13 and 15 volts, 6 amps for Digital132 and 18.5 volts and 6-8 amps for Digital124. These recommendations should allow six standard cars to run, with or without traction magnets. Running up to 8 amps should also allow more powerful motors to be used, on a par with the unmodified Scalextric APB or ARC Pro mentioned above. It is, of course, worth mentioning that using a non-standard power supply will void your warranty should anything go wrong. The Carrera decoders are quite robust but should be run within the recommended power ranges above.
Although no longer produced, the eight-car Ninco N-Digital system still has its fans. Power is provided by a 14 volt, 3 amp supply – two of which can be plugged into the Digital Console for running more than four cars.
SCX (Scalextric Espana) Digital systems
There have been three different SCX Digital systems – SCXD, WOS and the current version SCX Advance. Both SCX WOS and Advance use the standard SCX U10294 14 volt, 1.5 amp power supply. The original SCXD system used a unique 18 volt, 2 amp power supply.