Large Scale Central

Needing inline multi-pin connector

So I have an Aristo Mikado I am working on updating. the version I got sadly only had these two, two pin connectors running from the engine to the tender. With the updates I am going I am going to need a minimum of 8 pins put having a hard time finding a small inline connector. While I could try and mount the female end of a connector to the tender body I haven’t seen a good spot to do that either, so I am wondering if anyone has any connectors they have used in past? I been digging through digi-key but haven’t found anything yet.

Molex PicoBlade might work. I assume you’re driving the motor though this, though, so current is a concern. This is similar to what’s on the Hudson, and I doubled up lines for power.

https://www.molex.com/molex/products/family?key=picoblade&channel=products&chanName=family&pageTitle=Introduction&parentKey=wire_to_wire_connectors

Digit-Key carries these.

The JST connectors offer the largest selection. They com in 2 to 10 pin connectors. Here are some JST 2.54 mm. Their biggest downfall is they are hard to disconnect.

They come in 1.o mm to 3.0 mm(I think) pin spacing. A lot of people use the JST 2.5 SM connectors for higher current. JST 2.5 SM .

The JST 2pin connectors JST 2-pin like those used for R/C battery connections are popular. These are available with red, white or black housings.

I buy the ones that I can crimp myself which allows me choice of wire color and some choice of wire size. Sometimes I use different connectors for different things.

Power and lighting connectors don’t have to be the same. I think size and ease of use will always be a trade off.

Tom

My curiosity has got the best of me. What are all the connections that would require eight pins between the loco and tender?

So right now the lines needed are as follows:

Motor +

Motor -

Smoke Unit +

Smoke Unit -

+5V supply

Headlight return

Marker return

Firebox return

Possible return for cab light but could tie to head light.

Joseph, It sounds like you might be running R/C. Am I correct?

John,

Correct I will be using RailPro and battery installed in the tender.

K4 Pacific wiring:

The wiring is so convoluted, I rewired to this: (track power DCC, but only save 2 wires for battery

  1. green, one side of chuff switch (no change) (goes to ground on chuff)
  2. blue, other side of chuff switch (no change) (goes to chuff trigger input)
  3. black, ground for headlight (no change to wires)
  4. yellow, hot for headlight (no change to wires)
  5. red, power to smoke unit (no change to connector)
  6. black, gound for smoke unit (no change to connector)
  7. red, left loco pickup
  8. black, right loco pickup
  9. motor +
  10. motor -
  11. classification lights +
  12. classification lights -

8 wires aren’t a lot when you fire stuff up… notice no cab light either…

Greg

From my experience using two 4-wire connectors would be better than one 8-wire connector. The larger the connector would more difficult to connect and disconnect. That many wires on one side would also be stiff and help derail the tender or catch on the draw bar.

If you use an LED for the headlight you can use a CL2 LED driver and bridge rectifier to power the headlight from the motor. The headlight would stay on in both directions, except when stopped. I have a picture of the tiny circuit board I made for my Pacific. But unfortunately I can no longer post pictures here.

You might be able to do the same thing with the classification lights.

If you are running battery power, using the smoke unit is not a good idea as it will shorten your run time. Unless it is a very big battery.

Paul Norton said:

If you are running battery power, using the smoke unit is not a good idea as it will shorten your run time. Unless it is a very big battery.

I’m running my locos on battery power and my Forney does have a smoke unit. It was suggested to me to put a switch inline for the smoke unit so that if I’m not actively using it, I can turn it off. I’ve done just that and when it’s on I have noticed a steep decline in run time.

LGB forneys come with a 5 volt smoke unit. If you have 18 volt battery, change it to 18 volt smoke unit for longer battery operation. See seuthe line of smoke units for other voltages/current draw.

Dan Pierce said:

LGB forneys come with a 5 volt smoke unit. If you have 18 volt battery, change it to 18 volt smoke unit for longer battery operation. See seuthe line of smoke units for other voltages/current draw.

I’m using a voltage regulator on mine. At the moment it’s shoved into the front of the boiler, but I have plans to move it so I can get at it…

Watts is watts… while the voltage regulator wastes some power… a 1 watt heater uses the same “amount” of battery whether you have a 5v unit regulated down or an 18 volt one from the battery.

Basic law of energy, physics… that is also Watts = volts times amps… run a higher voltage, you use less amps for the SAME watts…

Bottom line, these units can draw about 2.5 watts (1/2 amp at 5 volts), and that is significant compared to the motor powering the loco itself…

(I use track power so I don’t worry ha ha)

I agree with Paul about considering the number of contacts and the force for a “high pin count” connector. In my example of the K4 above, that is the stock connector.

Greg

Greg Elmassian said:

(I use track power so I don’t worry ha ha)

Greg

This is why you used to get “dinged” in the rep system. No need for that statement at all. For me, it kills the credibility of your post.

https://www.youtube.com/watch?v=7WZ33w3B8Hw

Ok this thread has gone off the rails while I was stuck at work today. Anyway, I am thinking that going with two 4 pin connectors or an 8 pin connector that Eric suggested but will need to see what kind of power it can handle. Can’t help but feel like it may be crowded with two connectors but not many better options.

Sorry Jon, it’s too quiet here… we need some excitement… (https://www.largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-cool.gif)

You got it Joseph, the downside of multiple connectors is crowding the space between loco and tender, more wires to get in the way, and also you can mix up the connectors if you use the same ones.

I like using wires of heavier gauge when routing power between the tender and loco, I prefer the electronics in the tender, and whatever you use, you have to at least run the motor wires between… if you use a smoke unit, another pair of heavy wires…

Everything has a pro and a con…

Greg

Greg makes a valid assertion with regards to Watts = Watts.

A 20V smoke unit will pull less amperage as compared to a 5V unit; 5V @ 0.3A=1.5W, 20V @ 0.088=1.584W and or 0.212A difference or nearly 1/4 Amp. The math tells the tale… Seems all but trivial IMO at these numbers.

Smoke Unit Test Voltage Cold Smoking Current Dry Current Notes
volts Resistance
ohms Current
amp amp amp
LGB 5 volt 5 6.9 0.724 0.3 0.27 moderate smoke
LGB 24 volt 24 91 0.264 0.10 0.09 heavy smoke
LGB 24 volt 20 91 0.220 0.088 0.087 moderate smoke
Seuthe #7 16 44 0.363 0.141 0.129 heavy smoke
Aristo Rogers 16 27 0.59 0.26 0.25 light smoke
Aristo Rogers 20 27 0.74 0.30 0.27 moderate smoke
Aristo FA 20 14.2 1.4 0.34 0.36 moderate smoke
Aristo RS-3
(old version) 20 8.7 2.3 0.45 0.45 moderate smoke
Aristo RS-3
(2nd version) 5 4.8 1.04 0.49 0.49 light smoke
Bachmann Shay 16 72.5 0.22 0.23 0.23 heavy smoke
Bachmann
Big Hauler 12 88 0.136 0.13 0.13 moderate smoke
Bachmann
Big Hauler 16 88 0.182 0.18 0.17 heavy smoke
Aristo Long Steel Caboose 20 23 0.87 0.26 0.26 light smoke

Michael

If a cable can be connected backwards then I wire it so if it is plugged in backwards the power and motor pins remain the same.

SO, for a 4 pin connector I do MTTM Motor, Track, Track, Motor. If 8 pins then I add Sound and Light SLMTTMLS.