About six or seven years I ago, I bought my Takahashi TG-SP II in the hope to use it as my life long partner, since it's very compact and portable with high quality. Over those years, I even tried to motorized the DEC and to add autoguiding function to it.
Later when I have a calling from God, I found that I couldn't keep all these luxuries. Then, I sold my stuff progressively and the TG-SP II was no exception. That was my last tracking mount in my equipment cabinet. Basically, everything that could be sold for around $100 USD has been sold. I kept only my Ranger (with ugly looking lens), a couple of eyepieces, barlows, and a 410 head and a simple tripod to keep myself in the hobby.
It turns out really unexpected that I got my hand into a legendary GOTO Mark-X. On selling my TG-SP II, the buyer offered to sell me a mount which left unused due to a failed tracking motor. Later, I realized that it was a GOTO Mark-X and so I accepted his offer as partial trade at a very low cost.
This mount is very hard to find since the manufacturer discontinued it many years ago. It was the mount of choice for portability and accuracy by then. It has a DEC body for the full version and it's capacity and accuracy are far higher than that of the TG-SP II. I took the plunge to get it, for the baseline is that, I could do hand tracking or even re-sell it.
After so many adventures, I made the following:
Lithium-ion 18650 battery used with the hand controller, can provide 20 hr of continuous usage. For the loading, one side with manual slow motion control and Vixen style dovetail, another side with ball head. I consider it done except maybe adding a polarscope illuminator.
Thank God that when I decided to give up for Him but then He gave me something even better, and this project even trained myself up on drilling, metal work, and electronic techniques.