I really like the Buddy L because of it’s “prairie” wheel configuration. Unfortunately, it was a real pig in the performance department. Using track power, it performed much worse than my early Big Hauler. It couldn’t make it 1/4 way around the track without stalling.
I started by gutting the original wiring. The Buddy L is wired rather oddly that one leg of the motor is sent to the tender then back to the motor. Stock, the engine won’t run without the tender connected. The engine has two small circuit boards, one of which is a chuff sensor. The Buddy L tender shell is not as roomy as the Bachmann tender. The Buddy L tender shell is much stronger, but a lot of the structure just gets in the way. I removed two heavy “ribs” from the top of the tender for a battery compartment.
I installed plugs on the wiring between the chassis and shell for ease of seperation. To keep costs down, I’m just using computer plugs I already have. No sound, but I can add it later.
I also rigged up some charging posts from odds and ends on hand. The brass posts are motherboard standoffs from a computer.
Here is the underside with everything wired up to the DPDT switch.
I used a flat 14.8v Li-ion pack to save space.
Performance is much improved with the conversion. Especially slow speed performance. However, the Buddy L still performs poorly on grades. But I have a duty in mind that will allow the Buddy L to avoid the steep grades of the Sunny View Line. Should that fail, the Buddy L will lose it’s tender to an Annie 
Ralph
Now I know what sound looks like 