# accucraft BB



## John Allman (Jan 2, 2008)

I am debating puting battery power in a big boy. The wiring seems pretty straight forward from the diagram, but I have a few questions.

1) has anybody done it and if so, what is the easy way to get into the tender?

2) the engine is going to need 24 volts. Period. I would like to be able to use the already installed phoenix 2k2 system. So I would like a system that is compatible with that.

3) I know rcs can handle the load. Is there another system so I can compare?

Now that I have poured the gas and lit the match, I want to say thanks for the recommendations.

john


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## K27_463 (Jan 2, 2008)

I have done 2 of them. The loco does NOT require 24 volts, the gearing is such that it runs fast. It has plenty of power. The cylindrical shape of the tender at the bottom limits speaker size, but very good results can be obtained wiith the correct parts. Lots of room for 5000 mah or more of battery pack. The tender dissassembles in the usual Accucraft manner . The load you speak of is not unreasonable nor unusually high, it has 2 motors that are very efficient compared to the usual model motor. I used Airwire in both cases. Works fine with Phoenix. The wiring is indeed straightforward, however the color codes on the diagram and the actual loco are not consistent, and the color changes on the wires depending on which side of the various connectors you are looking at. The internal board mods needed in the tender are pretty conventional . 
jonathan


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## Del Tapparo (Jan 4, 2008)

John - You said you need 24V. That is usually not a problem. But what is the maximum continuous current draw you need to run this locomotive pulling a long train on your maximum grade? That is what will determine the electrical specs you need for a controller. Most of us don't have a clue what that number is. Perhaps some idea from looking at the ammeter on the track power supply before conversion? Anyone know the current draw of a Big Boy? With lack of info, the best choice is probably, the bigger the better (more amps). 

Edit: I neglected to mention stall current, which will be much higher than running current. The controller should be designed to handle overload conditions.


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## John Allman (Jan 2, 2008)

You need 24v because the locomotive is slow. Even with full voltage it is slower than you think. It would be very slow at 14volts. I am not concerned about the load. It wont really every reach full slip, because I dont have enough cars! I guess I will try and take the tender apart (still not sure how best to do that so that I can trace the wiring) and see what I can fit in. The sound is very good and I wont need a new speaker.


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