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Discussion Starter #1
Hello all,
I recently installed a 4 amp Tsunami 2 sound decoder in my Bachmann 2-6-6-2T Mallet. The model uses a 14.8v Lithium-Ion battery and an Airwire 6 Amp receiver. All that works fine and the model runs great...until it hits a grade. The engine stalls and the locomotive lights all flash, indicating a motor overload. The model has 2 fairly large motors in it, but I figured a 4 amp decoder could handle that. Apparently it can't. I'm wondering if anyone has any ideas as to how I can solve this issue. I really like the Tsunami 2 and want to find a way to make it work with the engine.

Thank You in advance,
Trevor
 

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Wonder if your battery is providing enough volts? If you don't get a solution from this Forum, suggest you contact Soundtraxx' Support Dept: [email protected] They're very responsive. I asked them a question this morning about the CV programming to keep the loco's headlight on in reverse direction......the Tsunami2 guides didn't cover it and they responded with the procedure.

By the way, I can't program any of the Tsunami2 decoders I recently bought using my Massoth Central Station and Dimax Navigator, even after I bought and tried using their PTB-100 Programming Track Booster. So sent Soundtraxx Support Dept an email today asking for help. This is odd since I can change the CVs on the Bachmann large scale locos with the factory installed sound systems, which are also made by Soundtraxx. So something is wierd with the Tsunami2 decoders.
 

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Discussion Starter #3
Yeah I was thinking about upping the volts. Given that the Tsunami 2 can handle up to 21 volts and the AirWire Converter 6 amp can handle 22, I'd say 18 volts would be safe. I am going to supply the engine 18 volts from an external power supply and see what that does and report back.

The current fix right now is that I actually removed one of the motors and now the front engine set rolls free. One motor does not overload the Tsunami, but now the thing does not pull all that well. Hopefully more volts will remedy the problem.

Trevor
 

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The Tsunami2 TSU-4400's specifications should handle your two motors that probably don't draw more than below:
Motor Stall Current - 4A Maximum;
DCC Track Voltage - 7.5V - 26V.
Tom
 

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Can you test the current draw of each motor individually? The 2-6-6-2 uses a Mabuchi motor, and I've seen those go bad, with one drawing a lot more current than the other. Typically that manifests itself in one motor running slower than the other as well, but you're not going to see that if the loco is always running on the rails. Failing that, check with Soundtraxx with your overload issues. You should be able to drive 2 Bachmann motors without trouble. I vaguely recall a conversation with Soundtraxx about that rating where they suggested it was somewhat conservative. I used to own a 2-6-6-2; its average current draw (based on battery life) was between 3/4 and 1 amp depending on whether I was doing a lot of switching or not.

One thing to consider: The old Tsunami decoders were rated at 1 amp. There was a company who was modifying them for O scale, giving them a 3-amp rating. Their change? Wrapping a heat sink around the decoder. That was it. The current overload trigger on them apparently wasn't something that was actually measuring the current coming through the board, since the "modified" boards were good for three times the current. I haven't a clue if the Tsunami2s are the same way, but given the possibility of a bit of headroom in the rating, I would suspect something similar to be the case.

Later,

K
 

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Discussion Starter #6
My temporary solution was actually to remove one of the motors and run the engine with only 1 motor. It does run without overloading now, but the pulling power is somewhat pathetic now. So maybe I can measure the draw from one motor at a time. I will try to give Soundtraxx a call and ask about the heat sink. The decoder definitely gets hot when it overloads, so maybe that'll mediate the problem.

Trevor
 

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When looking at specs, Zimo gives us the raated average current max and they also give the surge current which can last 10 seconds or more. So the 6 amp decoder will sustain a 10 amp surge. Not all manufacturers give this type of data. Zimo also does this with voltage specs.
 

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The Tsunami2 TSU-4400's specifications should handle your two motors that probably don't draw more than below:
Motor Stall Current - 4A Maximum;
DCC Track Voltage - 7.5V - 26V.
Tom
Tom,
As I pointed out in another thread, no other Large Scale DCC manufacturer uses stall current as their main current spec.
A stall current of 4 amps means that the continuous current spec is around 1.5 amps or so. Strangely enough, I could not find an actual continuous current spec for the Tsunami 2.
When you compare decoders from different manufacturers, keep that in mind.
 
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