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Discussion Starter · #1 ·
I have 4 Aristo -9's that I use on track power inside our home on the inside portion of our Tehachapi Loop Railroad. Last fall I placed a steel tube through our foundation wall and started laying track outside. I do not want to clean track outside and built a battery car.

I placed a 14.4 v NiMHA battery pack feeding an Aristo te receiver in a stack car to power the engines. There appears to be a problem between the TE receiver and the -9's. The receiver will only power one engine at a time and only at low speeds. This was making me crazy as I switched everything around and still the problem. I then plugged the stack car battery pack into 2 of my sd-45s and they ran perfectly. I then ran my sons new gp-40 and another sd-45 which both ran well.

I talked to Aristo and they had not heard of this. Has anyone else had this problem and better yet how to fix the problem would be really great?

Thanks,

Tehachapi Dave
 

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If I remember correctly, the SD-45 wiring from end to end was a solid connection and engines could be lashed together. Problem with a battery car was the first engine had to carry too many amps on the etched circiut board, esp for 4 engines.

I believe this was changed on the Dash-9 and the MU connectors are not tied to each other form one end to the other.

However, since you are trying to run 4 dash nines from a single battery, you should install more robust wiring in the engines as the circuit board etcheswill not handle all that current especially in the first engine.

Best way to handle 4 engines with a battery car and not to have to rewire is to place the battery car in the middle of the 4 engines, not at the end. This way, only 1 engine has double the current flow through the etched circuit boards.
 

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How odd.





I wonder if there are thermal cutouts cutting out when 1 loco is trying to pass the current for 3 more through it. They put those so you don't burn up wires when you derail and the front truck gets wheels shorted to the opposite rail.


I've never looked inside a dash 9. I do have a tendancy to pull the guts out and wire equipment the way I want it.
 

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On aristo locos when you run more that one engine on Battery power, you must re wire all but the lead loco so the poly fuses dont trip, this is another good reason i run track power, no issues like this...
Nick
 

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The 14.4 volt battery can be a problem. First the TE needs 12 or more volts to operate and you drop 3 volts going thru the TE so now you have 11.4 volts to power a loco designed to run on 18 to 24 volts. I don't believe the SD45 has the poly fuses so two lashed together may work. I know two GP40's will need a bypass, from expierence. Dash9's do have poly fuses and also need bypass wiring.........Jim
 

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Posted By Tehachapi Dave on 01/14/2009 10:55 PM


I placed a 14.4 v NiMHA battery pack feeding an Aristo te receiver in a stack car to power the engines. There appears to be a problem between the TE receiver and the -9's. The receiver will only power one engine at a time and only at low speeds.



What size are the cells in the battery pack and what mah (milliamp/hour) rating does it have? If it will only power one Dash 9 at low speeds, it sounds like it can not provide enough current (amps).

As others have posted, the TE has to have greater than 12 volts to function properly. Our club members have always used 18 volts or better to power either their Aristo-Craft or USA Trains locomotives.

For our large six-axle locomotives (Dash 9, SD-70, etc.) we use two lithium-ion battery packs wiring in parallel in our Evans battery cars. The lithium-ion pack is rated for 21.5 volts, but only for 2 amps of current. To provide 4 amps of current the packs are wiring in parallel.


http://ovgrs.editme.com/files/EvansPC/PowerCar.jpg
On all the Aristo-Craft diesels I have opened, the MU plugs were always linked to each other through the circuit boards. This allows a number of MUed locomotives to share power. If the locomotives were track powered and one hit some dirty track, the other others would provide power through the MU plugs. MUed SD-45s could share power from a trailing battery car, but the unit closest to the battery car would have the current for all the locomotives passing through it.

As mentioned, all A-C diesels made after the SD-45 had polyfuses added to protect the circuit boards from shorts or overloads. If you MU Dash 9s, the one closest to battery car should shut down. There was a lot of information about this on all the large scale forums when the Dash 9s were first sold. I remember Marty posting as he runs his large locomotives hauling long trains using the TE and a battery car.

The solution is to solder jumpers between the MU plugs of each locomotive. The locomotive closest to the battery car will draw only the power it needs. The rest of the required power passes through the jumpers and MU plugs to the other locomotives.

Before you add jumpers however, you must have a battery pack capable of supplying sufficient voltage and amperage to power all the locomotives in an MUed consist.
 

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Remember this is a dash9 issue as the originator stated that 2 SD-45's were running OK.

We needed to ask if only 2 dash9's were tried and what were the results. 4 dash9's could be a battery current issue as Pau lNorton suggested, but 2 dash9's and 2 SD-45' should respond the same way.

Also, i believe that 14 volts being low is not a TE issue as HO and N scale run TE's at the lower voltage setting of the TE's, but those 4 motor aristo diesels do need over 20 volts to obtain good prototype speeds.
 

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Sounds to me like Jim has it right.
 

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When polyfuses "open" they are usually an effective open circuit, not passing any current. This does not sound like the problem, if they were open in the -9, there would be no motion.

(Now, a silly idea, is one -9 running and the other not? one is powered, and the polyfuses are open on the other? I don't think so, but check)

I considered that the -9 drew enough current to lower the voltage into the TE to make it erratic, but I discarded that idea because TWO sd-45's ran (should be even more current), and it's doubtful that someone with the obvious battery experience would not notice defective batteries or low charge (two other possible sources of low voltage).

So, what is the difference? Well, you need to consider how small differences in internal wiring can make large differences in radio interference. The -9 has the famous Aristo noise generator circuitry, i.e. on on board PWM power supply for the lights. SD-45's are also famous for causing problems. Small differences in internal wiring can make big differences in interference, since often the wire length acts as an "Antenna" for transmitting internal RF noise.

I would try, if possible, disconnecting everything inside the -9's except the motors... you need to make sure the smoke unit is off (easy), and you need to disconnect INPUT power to the on-board power supply for the lights (tough)... turning off the lights at the OUTPUT of this switching power supply is probably not sufficient to sort this out.

So, that's my guess on what is wrong. It might not be the answer, but it is the step I would take if the locos were in my shop.

Regards, Greg
 

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I run my E-8 From a TE set up with 16.8 v 3.8 Ah packs and get about 3 hours of run time but thats just one loco. 4 locos? That's 16 motors. I doubt you would ever get the TE to run that much juice. I'm surprised the thing didn't start smokin'.

-Brian
 

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Posted By Tehachapi Dave on 01/14/2009 10:55 PM





I talked to Aristo and they had not heard of this. Has anyone else had this problem and better yet how to fix the problem would be really great?

Thanks,

Tehachapi Dave



I had this exact same problem with my Dash 9's. You need to bypass the polyfuses. You will also have the same problem with the GP40's. Aristo is well aware of this problem and would not respond to Marty Cozad's question on the A-C forum when he asked about the GP40's prior to production. Aristo is concerned about fried circuit boards during derailments, when track powered.
 

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Yep, and the GP40 has more polyfuses in it than any other loco!

Brian, he tried 2 SD-45's and the system works fine. 2 dash-9's don't. He's only trying to run 2 locos at a time. The current load should be almost identical between the 45 set up and the -9 setup. The TE will handle up to 10 amps. I know that even 4 locos will be under 10 amps.

I still find it hard to believe it's the polyfuses, since they pretty much "trip" to completely off. Maybe I am misunderstanding Dave's statement:
"The receiver will only power one engine at a time and only at low speeds."

Dave, does this mean that:
1. you can NEVER run 2 -9's
2. one -9 will work, but only at low speeds.
3. (here's the important one), does the system shut down at higher speeds with one -9, or is it impossible to go faster with a -9.

If the system shuts down when you try going faster with one -9, then you do indeed need to go on a polyfuse hunt.

I was interpreting your statement that the -9 would only go slowly, like there was a lack of current/power.

Regards, Greg
 

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Discussion Starter · #15 ·
I would like to thank everybody for suggestions to my problem. I have been a viewer for a number of years but just joined. I was stuck in Chicago yesterday and did not get home to early this AM i.e. 2:20 hence my late reply. I believe I did not explain the problem fully and as I was in a hotel room and I had the battery pack voltage wrong.
The battery pack is 16.8 V as I have previously experienced the voltage drop problem. As some day I hope to fill our ½ acre back yard modeling the Tehachapi loop and other prominent locations between the loop and Bakersfield a bought 4.2 Amp Hr battery so as to have, what I thought would be plenty of running time. I figured that the 16.8 V battery would allow the TE to work correctly and as we are modeling a mountain mainline where the trains are rarely moving move then 25 miles an hour why spent the money for additional voltage.
As for running the -9’s I was only trying to run 2 at one time. I have four and tried many different combinations of the 4 different engine coupled as pairs. As I could not even get two to run together I never got to 3 of 4. I use two TE’s on the inside portion of the railroad which is basically a double track mainline operation. The railroad runs around the perimeter of our basement so as to allow eight foot or betters radius and we typically run 30 -35 car trains with two -9’s on the front and two on the back pushing. Works great until a derailment but that is another discussion.
The suggestion that polyfuses is the problem sounds correct as when operating at slow speeds one of the two engines would shut down. I’m a bit confused as I’m a mechanical engineer and not an electrical engineer, why to the engines run fine on track power and not on battery? Are the polyfuses only on the battery side of the input power circuit and if that is correct what are they protecting?
As you guys have been great so far how do you fix the polyfuse problem?
Thanks,
Dave
 

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Remove them!

With this explanation, the polyfuses sound like the culprit. They are little circuit breakers, and will self reset after the overload is removed, and they have cooled down.

When on track power, each loco pulls it's power from it's own wheels, through (usually) a 3 amp polyfuse (or one on each of the 2 wires)... no problem, the circuit breakers are matched to the load.

When using the "battery connectors" in an Aristo loco, the wires usually have the polyfuses in line.

When running from battery, the wiring is such that the load from BOTH locos can go through a polyfuse that is only rated for ONE loco, and you get a "trip".

You need to jumper the polyfuses that are in the internal "power buss" that goes between the 2 external connectors..

Regards, Greg
 

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Troublemaker!

Hey, keep your fingers crossed, hopefully tomorrow is the day your bell circuit comes alive! Got the circuit figured out Nick.

Greg
 

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Dave, a simple fix for the polyfuses is to run jumper wires from one end of the Loco to the other end. Attach the wires between the battery plug and the PCB on one end of the Loco and the battery plug on the opposite end. Make sure you don't cross the wires by doing a simple continuity check. Plug in the lead Loco, if it travels in the same direction as the trailing Loco, you got it right.
 

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I thought this was RC battery forum, why would track power folks care????

Dave e-mail me ,,[email protected]
And I KNOW Aristo knows about this for a fact..
 
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