Battery backup?

that's why many times capacitors filters are used so there is no interruption when going over a switch in case of roller missing center rail so sound stay on during momentary interruption!

In addition to my suggestion above, here is how I would like to see it done. I run MTH. They have a battery charging port on the tender. MTH, I'll buy the following item for all my locomotives: A tender that is pulled behind the engine-paired tender with an 18v rechargable battery from its pick up. There is a low profile cord that will plug into the tender bottom just ahead. What do you think fellow OGR members and MTH?

I would rather spend my efforts correcting the trackwork rather than installing of batteries in all my engines...

The batteries in O-gauge trains don't have anything to do with continuing with no power, they just power the electronics (DCS) or the sound system (Lionel).  If your wimpy flywheel gets you over the dead spot, you may be able to continue on.

There is a move afoot by some to create battery powered locomotives, do a search and you'll find some threads on it.

I understand the batteries now supply power for the electronics. However, does not the power to run the engine come from the track? The idea, is that this higher amperage and voltage battery would parallel with the track voltage. The engine would not know whence comes the power. But I now understand that the battery port would not work as I envisioned above, as it is the wrong voltage. I don't want dead rail, just help on switches and occasional dead spots at very low speeds. I am interested in your ideas.

Thinking about it more. one could use the battery port as an input from this 18v large battery, disconnect the route to the 9v battery, and connect it parallel to the input from the track rollers. Do you think this would work?

Well, one little problem is most of us are running AC, and all of the Lionel TMCC/Legacy stuff REQUIRES AC to function.  So, unless you're limiting yourself to DCS and maybe LionChief, the battery will have to be a bit more complex to deliver AC to the locomotive.

In this OGR post from earlier this year there's reference to increasing the weight of the flywheel.  Unfortunately the mentioned video link has never surfaced as I would be curious in seeing what was done and presumably a before-after of the engine smoothly gliding thru a switch.

The point being the flywheel is effectively a mechanical capacitor/battery storing energy to help carry thru brief losses of track power.  As I recall, when the idea of adding an electrical capacitor/battery to an existing engine comes up, one issue is whether the electronics would know what to do with this newfound reservoir of energy.  That is, the software in modern engines are constantly scanning the incoming track voltage and making split-second decisions on directing power (load management) to where its needed.  If the software detected the loss of track voltage, it's not clear to me that it would direct whatever remaining energy to driving the motor which would be a lost cause.  Instead it might even turn OFF the motor driver electronics and direct the residual electrical energy to running shutdown algorithms or whatever.  It would be the mechanical energy in the spinning flywheel that would have to carry the engine thru the switch if the loss of power was intermittent.

There was a discussion which I can't find from years ago about the coasting performance in MTH engines.  I believe the math showed that a heavier/larger flywheel is the best bang-for-the-buck.  The energy is stored in a form that is directly useable (mechanical).  If the energy is stored electrically, it must still be converted to mechanical energy.  This incurs losses due to electronic inefficiencies as well as in the motor conversion itself (Watts to Horsepower).  

Intermittent potential loss of track power due to a number of reasons (dirt, switches, etc.) is one major flaw of electric model trains that almost everyone has experienced. For DC track power setups, high value capacitors can help. For AC, non-polarized capacitors can also help. As a minimum, two sets of roller pickups need to be on each engine or car that requires power from the track. Deadrail has become popular because it avoids the issue, but is a major departure overall from track power.

I'm not an electrical genius, so I'm just asking, not trying to be smart.   Why does the engine need to make decision on track power vice capacitor?  What if all of the power ran through the capacitor to where it needed to go?   Then if there was a drop in power from the track, the engine would still be taking from the capacitor.

John, isn't that the way your gizmo works for your passenger car LED lighting?

Ron

BOB WALKER posted:

Intermittent potential loss of track power due to a number of reasons (dirt, switches, etc.) is one major flaw of electric model trains that almost everyone has experienced. For DC track power setups, high value capacitors can help. For AC, non-polarized capacitors can also help. As a minimum, two sets of roller pickups need to be on each engine or car that requires power from the track. Deadrail has become popular because it avoids the issue, but is a major departure overall from track power.

Explain to me how non-polarized capacitors do any good for AC power.  Although they will survive connected to track power, they won't charge, so they're not going to offer any benefits.

Ron045 posted:

I'm not an electrical genius, so I'm just asking, not trying to be smart.   Why does the engine need to make decision on track power vice capacitor?  What if all of the power ran through the capacitor to where it needed to go?   Then if there was a drop in power from the track, the engine would still be taking from the capacitor.

John, isn't that the way your gizmo works for your passenger car LED lighting?

Ron

Nobody says it's not possible to build electronics that will use high capacity capacitors to handle brief power interruptions.  Truthfully, it would be much more compact to use rechargeable batteries, a rechargeable battery has a much better energy density than any capacitor.

Thanks for all the thoughts. I don't have major dead spot problems, my line of thought was that if they are talking dead rail to replace three rail because battery technology has advanced, how about just helping is over a few inches?  I do like the idea of adding extra pickups. I note that some pickups are double set up. Where could you get these twins, and how hard to add extra pickups? 

You have to look at the specific locomotive to know if double pickups will work.  For steam I do it the easier way, I just add a single wire tether between the locomotive and tender.  For older steam like 3rd Rail, I add a roller to the tender as well.

In theory you could have the equivalent of a UPS unit (uninterruptible power supply) , which is basically nothing  more than a battery and an inverter to change the DC of the battery to AC. Some UPS units have the 110v coming directly off the battery/inverter which continually charges, others have a system where if power dies a relay shunts power to the battery/inverter, which otherwise  sits and keeps charged. In theory you could have something like a LIPO battery with an inverter to put out 18v between the rollers and  the reversing unit/control board, the engine would run off the battery/inverter which in turn  would be charged. This would only work, obviously, with command control, since the engine would get a constant 18v from the battery. You also could theoretically have the battery in parallel with some sort of relay that would feed the 18v from the battery to the motor if the track voltage were interrupted.  This isn't dead rail, so the battery wouldn't have to run long if isolated from power, so might not need to be all that  big. 

Is this practical? The hard part would be where to put the battery and inverter, in a steam engine it could go in the tender (maybe), but if the battery required was too big then space might prevent this. Usually the engines  that have the biggest problems going over switches are smaller engines with rollers close together, and they unfortunately also would not be able to have room for such a getup. 

Trying to build a UPS to fit in the tender is way over the top.  It's probably time to consider just redesigning the electronics so they could support a "keep alive" like DCC stuff does.

gunrunnerjohn posted:

Trying to build a UPS to fit in the tender is way over the top.  It's probably time to consider just redesigning the electronics so they could support a "keep alive" like DCC stuff does.

Agreed, you really only need something to provide power for a short time. Kind of surprised no one has come up with that kind of thing, shouldn't be that big an engineering challenge these days. 

Interesting note: Word is out that some manufacturers of after-market RC systems that are compatible with battery power are running at full capacity and can't keep up with orders.

Atlas O dad posted:

However, has anyone thought about adding a hefty battery (18 V I guess) that would provide parallel energy to track power, and eliminate trains stopping on switches at low speed and other problem spots? 

As the Atlas O dad, you should know that "dead spots" are a known issue with Atlas switches in particular. There are past threads on how to get power to these dead spots if you do a forum search.

There really shouldn't be any "other problem spots" unless the track is dirty or there aren't enough power feeders going to the layout.

BOB WALKER posted:

Interesting note: Word is out that some manufacturers of after-market RC systems that are compatible with battery power are running at full capacity and can't keep up with orders.

The one's I've talked to, however, are pretty small outfits and "full capacity" is likely to be not that big a number.

Thanks for the well thought out responses. (Note, I switched (ha ha) to Ross to complete my layout, and I am definitely not an Atlas O fan, The connectors are vastly better in Ross and z-stuff switch machines are very reliable. My track climbs from train board level to overhead, and I have never had a dead spot or faulty switch machine with the Ross track or switches. This is important, as an error at 7 feet high could be disastrous.)

Back to the topic at hand. I agree with "gunrunner john" above that this temporary power should not be hard to engineer and it is surprising no one is on this. I think I will go with your-all ideas of extra pickups.Where do you get yours? I run MTH command exclusively.

Thanks, Robert

I buy my pickups direct from MTH.  For many of my mods, I use the BD-0000042 pickups.  Occasionally, you get lucky with MTH stuff and there's a hole in the truck for the pickup.  More often than not, I just make my mount out of Styrene or fiberglass.

Here's a couple of samples that I've done in the past. 

From an electrical standpoint, the center rail roller pickups are a fundamental weak spot and an engineering challenge. I am constantly running into pickups that stop working at some point. The idea of a short term battery backup for on-board electronics has merit, but is not as simple as it may seem.