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When I first fitted my K28 with radio control, the limited space in the cab lead me to use a clip with four NiMH AAA cells. This seemed to work OK initially; but, when I gave it its first real run at ECLSTS, the R/C quit after about 25 minutes. I'm not sure whether the batteries got too hot from being right next to the boiler or whether the small cells just didn't have the capacity. I decided that I would move the batteries to the tender and use larger capacity cells. Below, is an account of how I did it.
First, I made up a four-cell pack of sub-C cells which I had bought from Digi-Key. They have a 3000 mah capacity and they have soldering tabs for connecting the cells. I realize that 3000 mah is a huge capacity for the task at hand; but I should be able to steam all day without ever recharging. Getting into the space behind the water reservoir in the tender appears to be a major chore, so I elected to put my battery pack in the doghouse. The doghouse is held in place be four very small hex head bolts and is easy to remove.
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The tender deck extends over the water reservoir, so it was a simple matter to drill a hole in the doghouse floor for the wires to pass through. I taped the four batteries together and taped a square of 1/16” thick styrene to the bottom so that the soldering tabs could not chafe through and short against the brass tender. Before reinstalling the doghouse, I put tape over the tops of the batteries to further forestall any short circuits.
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I drilled a hole high in the forward bulkhead and put in a coaxial battery connector from Radio Shack. I also put in a fuse since an unhappy experience with one of my sparkie models clearly pointed out the need. I also further protected the wires from chafing by putting on heat shrink tubing.
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All-in-all, it was an easy installation and provides me with batteries of ample capacity located well away from the boiler.
Llyn
First, I made up a four-cell pack of sub-C cells which I had bought from Digi-Key. They have a 3000 mah capacity and they have soldering tabs for connecting the cells. I realize that 3000 mah is a huge capacity for the task at hand; but I should be able to steam all day without ever recharging. Getting into the space behind the water reservoir in the tender appears to be a major chore, so I elected to put my battery pack in the doghouse. The doghouse is held in place be four very small hex head bolts and is easy to remove.
The tender deck extends over the water reservoir, so it was a simple matter to drill a hole in the doghouse floor for the wires to pass through. I taped the four batteries together and taped a square of 1/16” thick styrene to the bottom so that the soldering tabs could not chafe through and short against the brass tender. Before reinstalling the doghouse, I put tape over the tops of the batteries to further forestall any short circuits.
I drilled a hole high in the forward bulkhead and put in a coaxial battery connector from Radio Shack. I also put in a fuse since an unhappy experience with one of my sparkie models clearly pointed out the need. I also further protected the wires from chafing by putting on heat shrink tubing.
All-in-all, it was an easy installation and provides me with batteries of ample capacity located well away from the boiler.
Llyn
