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Correct battery voltage

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#21 ·
Before changing to battery, the Dash 9 would easily pull 50 coal hoppers on level track.
Randy,

You certainly raised a lot of issues and questions.

What voltage / amps / watts did you have when running from track power?

There's another consideration - how many watts your batteries can deliver continuously - sort of like 'cold cranking amps' for a car battery. You haven't mentioned what capacity the batteries have in amp-hours.

I can't understand why it wouldn't spin the wheels. That's a sign the batteries didn't have enough power (volts X amps). (They weren't fully charged, or there was something in the circuit preventing the power from getting to the motors, or something else.)
 
#22 ·
This is the on-board set-up I installed in My Red 70Mac. Two panel meters in Volts and AMP, green and red. They are bright enough to be easily seen in bright sun-light while walking along with the loco, even at ground level. The switches allow me to read Voltages applied to the trucks directly or the single voltage in any battery set. The Amps of course read power the trucks consume.



This is a pre-installation check with the loco bench run, showing the meters reading a non-load at the time.



And the loco on the bench during installation and testing.




I have only found it necessary to build one loco for this purpose, and as a reference, I can then apply any results to other locos.

Dirk
 
#23 ·
Hey Dirk, tell me you are getting 300 foot range from your locolinc!!

ha ha!

Seriously, you changed out the analog meter later?

Do you have a stall test amp reading on that loco (full slip against a backstop)?

I have an ampmeter on my layout... got up to 9.7 amps with a long passenger and all lighted cars... about 5 amps was the car lighting!

Greg
 
#24 ·
If the Loco was shutting down and trying to restart with a LiIon battery it's a good bet you were pulling too many amps, the question would be where? Alot of the LiIon batteries I have have a 4 amp draw cut out. My friend just installed a 14.8 LiIon battery in an aristo SD45 and he was getting 3.7 volt draw at stall with a single loco. So, with all that weight on a steep grade? Yeah, the battery may be cutting out on you to save itself. BUT, it is still possible that you have a bad motor making the loco work that much harder. If I was a betting man i'd say it was the battery.

Terry
 
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#25 ·
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#26 ·
mmm Ya' say locol.. inc eh... wwelll umm A,.. I don't think it goe's too fer at all, mate'! too bad too.. too bad too oh well nugh that!
Without fussing with my loco antenna - on another loco, I get in the neighbor hood of 200 feet at this point,, I have however reached out to about 225 feet during aircraft per-flights, on the ground, and with the TRxM. ant collapsed... So should have some more room for trains once I it get it all sorted out!! then up with the ant. some, as needed...

Analog got me going and ran my first runs with meters, voltage meter was not here yet!

Sorry, - NO I have never run it up to full stall and spinning wheels....
Can some time soon tho! good added info!

Did you need passenger cars to run against a backstop..?? curious! You could run the car lights and loco at separate times to get clear readings for each piece. loco so much, car lights so much..

I have seen it read about 7.1 - 7.2 amp - pulling 70 cars on above a 2.5 % ( up to 2.8% for a bit ) grade, the highest readings while running. In the same place on the same layout, it was at a peak of 6.0 amps with 50 cars behind her, when I also discovered that the problem was poooooR track work.. other wise it does not run this high on most of the test layout runs I have done.

I am looking forward to running tests here with the completion of some track!! Then I can focus on a major test program, covering many aspects of loco and car loads!!.

Dirk - DMS Ry.
 
#27 ·
Yeah, some of the stories about huge amp draws come from a pioneer in this hobby George Schreyer. He really wanted to know what was going on, so he measured "locked rotor stall speed", where you actually stop the motor from turning and see how much current it will draw, to get a worst case.

In the old days, early decoder designs did not have much tolerance for over current, so if you had a 4 amp decoder, it might blow it's output transistors at 4.5 amps... George found that USAT motors can, with the motor locked, draw up to something like 17 amps (as I remember).

Now, you say this will never happen, but what happens is that it actually can draw that current for a brief instant. This explained some failures where people were reading average current that "looked" safe. It also explains excessive arcing and wheel pitting on track power.

It's interesting stuff.

More useful nowadays with modern decoders is full wheel slip... that is basically the worst case your decoder will have... be sure to remove those traction tires though!

Regards, Greg
 
#28 ·
Well I have already ''spun''.. My traction tires - ALL 12 of 'em... And did not blow a fuse, 'course My loco was 'being drug backwards'' at the time, the wheels stopped and after a bit,.. started moving again,.. about the time I reached down to shut it all OFF...all on a loco linc board to btw, which did not suffer... still using it, but maybe not much longer ...:~}

Running 7.5 amp fuses will not allow me to get any higher ...

Dirk
 
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