Getting ready to do an onboard battery install on a powered/dummy Lionel large scale GP20 diesel pair. The dummy will carry the battery and Revo TE reciever and PWM to Linear boards. MU cables will connect the two units. I will compare the current Revo TE diesels sounds vs the original Railsounds. The only reason I might consider using the TE diesel sounds is the abilty to run the horn. Not completely sure how Lionel was triggering the horn with the track side button as thier G scale were DC powered. The actual diesel rumble of the old Railsound is pretty good but lacks the turbo whine. I ran the powered engine tonight, forgot just how much of a power hog these are with 4 motors(1 per axle just like the real thing!!) Robbie over at RLD is recommending a 6000mah 18.5vt battery. It took two 1 amp transfomers to run the diesel with the sound off, turn the sound on and one of the transformers starts to cut out after a lap or two of my indoor layout. Considering I do not pull long trains that would tax the engine pulling wise, what battery life going to be. Without a way to measure amp draw, I am guessing around 2.5 amps with the sound turned on. Greg says that removing two of the 4 motors with not change the amp draw or run duration, I disagree. I can see it if I ran the engine near max load all the time, but that would also overload the two remaining motors. If battery duration will be decent on 4 motors, I will leave it alone. Darn thing will pull the house down. But if making her 2 axle powered, either 1 axle in each truck or just making the lead truck unpowered will help battery duration, I will do that. Wonder what Lionel suggested for a transformer when these came out in the early 1990’s??? A ZW with some bridge rectifiers from Radio Shack? My friend is bringing me his 10amp MRC g scale transformer to borrow till he makes his next payment to me for the train he is buying. At that time, I can order all the battery/Revo stuff and get rid of the track pickups. Mike
Mike, under load you will find no or very little difference. Unloaded, locos running alone will be different. This is a fact that has been proven over and over.
Another similar situation is when people worry about locos running exactly the same speed, so they test the 2 locos running a few feet apart and agonize about the difference in speeds even if slight.
Again, under load, things even out, the “faster” loco will take more of the load and slow down to more effectively match the slower loco.
(again minor speed differences here).
The bottom line is that the laws of physics hold true in our hobby, and the energy to move the train will require a certain amount of horsepower, and the difference in total current between one motor pulling the whole load and 2 motors sharing the load is minor. Your lights and sound board will be the major differences.
Again, this has been debated over and over, and then when put into place, and objectively tested, all the laws of conservation of energy, the formulas for work, power, energy, etc. all hold.
I’m trying to save you some unnecessary effort.
Greg
so the unanswered question, since you can figure the math out, if the unit draws say, 3 amps, with a 6000mah battery, whats the run time going to be? Rough guess, I know it wont be exact since it will vary on load being pulled. So lets figure it for running light engine.
answered on MLS, but amp hours divided by amps equals amps…
1000 milliamperes = 1 amp.
6 amp hours divided by 3 amps equals 2 hours…
Greg
Thank you Greg, I posted on both forums as some guys/gals are only members of one of the two. That should be good enough, I am usually ready to run something else after an hour or so.
No problem Mike, I monitor both sites every day.
That’s probably worst case, so basically most batteries will give you all they have if you discharge at 1/2 rate of their capacity or less.
Meaning: a 6 amp hour battery will give you an amp for 6 hours… and usually 3 amps for 2 hours (notice the product of amps times hours is always 6).
Now, can you get 6 amps for one hour? Usually no on most batteries UNLESS they are specifically designed for high discharge rates, like model aircraft batteries, BUT like the rest of life, you never get something for nothing, so discharging at these rates, the batteries won’t last you 10 years of use, they will “wear out” much more quickly.
Hope this helps
Greg
Greg, isn’t that figure at full load?
I have a 5.X amp battery in my USAT GP 9, and never run it at full load. I routinely get 6-7 hrs of run time with 8 cars. I can easily get 4 hrs out of a 2.8 amp battery in my Lionel Atlantic, pulling 6-7 cars.
I run at my walking speed, not warp speed. Terrain varies.
I think in another post Mike said the loco running light was 3 amps. I found that a bit hard to believe, but you gotta take a person at his word. I think this also prompted him to consider removing both motors.
My belief it the load is a lot less than 3 amps, thus my comment about “worst case”.
My experience is beating the living crap out of my USAT locos I can get about 2.5 amps per loco that has 2 motors. This is heavily loaded up a steep grade. I removed traction tires to keep from breaking axles and drivetrains. (I know Dirk can load his locos more heavily).
My experience is more closely parallel to yours Steve.
Greg
I think that I’d take a look at the drivetrain of that GP 20. 2 amps running light is quite a lot. There might be something impeding smooth operation.
Steve huh? Greg said 2.5 amps, heavily loaded going up a steep grade…
My experience with those 4 x motor Lionel diesel locos is that it is a combination of the sound system and really crappy power pick ups that is drawing the current.
My suggestion would be to disconnect the sound and then try a current test on track voltage. Then try a test with the motors being powered directly by batteries instead of the track pick ups.
Then pitch the Lionel sound and put in something decent that is smaller. Then you can probably fit the batteries in the powered loco as well.
I need to hear the Revo diesel sound in person, on the youtube videos it does sound more like a turbo charged EMD. And yes I agree about voltage drop issues thru the pickups as 3 of the 8 were stuck and the springs had no temper. I replaced those so I could run the unit. Runs faster in reverse than forwards to. I did go thru and lubricate everything. Motors run good when powered one at a time. Some power drop is the lights as well. I need to see which board powers the beacon and see if its powered from track voltage or a constant fixed source as I would want to retain that board if I gut the sound out of the unit. Mike
For information purposes, the throttle is a MRC power command 9500 with the twin meters. Running short hood lead, a full 12 volts(full throttle) was needed for a reasonable speed, sound was on, and amps ranged from 2 to 2.5. Running long hood lead, I could back the voltage down to around 8-9 volts and amps fell to 1.7 to 1.8 and approach 2 when in the tight curves and climbing a little bit as one end of my layout isnt level at the moment. From experience with my fathers Lionel that had wore out studs that the reduction gears rode on, it would run like a champ in reverse and crawl in forward from the wear. So I suspect wear in the thrust bearings on one or both trucks from lots of forward running. I can reverse the trucks and run them till they do the same thing again, then swap in the NOS pair of power trucks I have. What does a typical USA GP9 pull amp wise when running with a light load or just light engine? You all have to keep in mind I am not the atypical large scale operator that wants sound, in fact most of the time I run with sound switch set to OFF. I find it annoying on small layouts where the sound never fades away like on a large railway, it becomes a potential source of sensory overload with my autism, so its either set very low, which is where the infinate volume control is nice on the stock board. There is a switch on the bottom of the unit that kills power to the sound, leaving just the directional lighting and beacon circuit powered up. I still am staying with my original plan for now, to retain the Lionel sound since it is rarely used, then bypass and remove the track track pickups and MU the unit to the trailing dummy unit that will carry the battery and RC of some sort. Since I have time to consider different systems and I am not tied to Revo with any other train, I am looking at other options like RCS ect. The main requirement is Linear power to keep the Lionel lighting and sound boards happy. Revo can do this with an extra filter board. I will turn the trucks around tomorrow and see if short hood lead works better or if there is a voltage drop in that direction over reverse. The only visable change is the lights in the cab for the headlight/number boards goes out in reverse, both front and rear class lights stay on as does the beacon. But with the partialy melted plunger tubes and collapsed brush springs, I suspect wear in the motors causing some binding in foward right now. Since the powered unit will lead 99% of the time, I should be able to get some more life out of the motor blocks if I switch them around. Ebay is ones friend when keeping old units like these going, much like the net is usefull for the real older EMD’s! Mike
update, reversing the trucks has no effect on running qualites, still runs better in reverse over fowards. Looks like the voltage loss is in the factory electronics. Looks like I maybe just removing the old stuff other than the beacon light circuit and putting the battery and Revo or whatever in the powered unit. Mike
Yep, as posted in the other slowly dissolving forum, I believe that I have a theory:
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swapping the trucks made no difference in running. This would indicate that the problem is in the direction of the body of the loco, not the trucks.
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looking for what is different between forwards and reverse makes me consider lighting, it runs more poorly forwards (short hood) and that might be when more lamps are on, they are incandescents.
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for the theory to hold water, you would also have to be running a marginal power supply, and indeed you are, the MRC9500 is not suited for G scale voltages nor G scale current (except small LGB).
Greg
So, that’s my current theory that seems to address your issues, symptoms, and commonly accepted laws of physics. (http://www.largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-cool.gif)
Power supply is fine Greg, it runs his LGB/Aster K28 with dual motors and Phoneix sound in it for hours on end and barely gets warm. The problem is pictured below, didnt see the burnt damage as the wire loom ran right above the board. I gutted the electronics from the unit, lost my roof beacon in the process. So I swiped the stand alone beacon board from the trailing dummy unit and installed it in the lead unit. Engine runs much better, Runs the same in both directions, still draws around 2 amps pulling the dummy engine and 4 box cars. Probably about right for the older motors and there being 4 of them. I bet a pair of USA GP9s, which would be 4 motors draws nearly that. Mike
