DCC Hybrid Drive FAQ

Surely "Hybrid drive" can't be something as simple as putting a cap or battery on the DC output of the bridge.

You are correct, it is not as simple as what you describe. The problem with any new technology or concept is that one tries to place it in context of what one is familiar with. Often that leads to difficulty as when several things change at one time you can miss the overall concept. Installing a cap or a battery on a normal decoder does not improve its ability to receive packets. An internal power source also does not work well in practice because the locomotive will continue to travel even when the track power is turned off, such as what happens when there is a short.
I was lead to believe the transistor turns the battery on when it looses track power. Does that only occur when there is a DCC speed command above zero?

Actually the battery is connected at all times during normal operations. The battery is disconnected only when the decoder detects the absence of a DCC signal, the decoder has shut down due to a short or overload or the decoder is in service mode.

What happens when you slow a loco to a stop and the loco happens to stop on a dirty spot? Will it still have a charge hours later if the smoke generator or lights are on?

The decoders micro and the functions it controls only stay on as long as the decoder has power. However there is an interesting side effect of DCC that helps. If you place a locomotive with a decoder on a powered track that has some dirt and leave it, in time it will power up. The combination of bi-polar nature of the DCC signal with the power has the tendency to have this effect.

When rail power is lost where do you get the power to energize the relay to close S1 and connect the battery?

The battery provides the energy to power the relay. Relays generally have one voltage needed to engage and a much lower voltage to disengage. The relay is turned on when the decoder powers up and notices a DCC signal. It remains on until either the DCC track signal is no longer there or the energy store is exhausted.
Will all functions achieve the benefits of the battery backup?

When you hook up a function you have two choices. If you use the decoder + function (the blue wire) then the decoders internal power is used. If you use one track rail as the common then track power is used. For example the default for the Bachmann locomotive boards is track common.

Will the battery make it more difficult to program the decoder?

No the decoder does not activate the battery in Service Mode.

Can I use a 1 amp decoder in large Scale to achieve Hybrid Drive?

Yes but I do not recommend it. The reason is that all current loads are additive. Running the motor, the sound system, the light functions and charging the internal power source all consume power. I have found that under large loads for extended period of times a 1 amp decoder will overheat. It is better to use a 2 or more amp decoder.

Can you use the Lenz Power 1 module for Large Scale instead of a battery?

You can use the Power 1 for Large Scale (I have one on one of my locomotives) but it does not work as well as one would like for three reasons.

1) Not enough energy - Large Scale needs more current for a longer time
2) to low a voltage - the difference between the voltage output and the track voltage used in large scale is to large. When the Power-1 Module takes over there is a noticeable drop in speed.
3) The ratio between charge/discharge is to long. Often you get several dirty spots in a row and the Power-1 does not have a chance to charge again before it is used again. This is also related to point 1 above.

Lenz is working on a Power 3 module but to date the battery solution works better.
How difficult is it to install?

You need to find room for some small batteries but the installation is not much more difficult than a normal decoder install. Some examples are included on the example install page.

This page was written by Stan Ames
Last Updated September, 2006
Copyright 2006 by Tried & True Trains