Ok , so I’ve had my jam for a good 18 months now and only used the tec battery once , it’s obvious to me that I’m not going to need it.
What’s it worth good people ?
You might be better off keeping it for when you sell the bike. I have a Focus and don't use the TEC pack often, but I'm glad I bought it when I got the bike. When I need the TEC pack, I sure as hell need it. I would not buy a used Focus without one. So you may get your money back that way. Take into account that the battery capacity declines with use. So even if you plan to keep the Focus for many years, you may find that eventually you may need the TEC pack more and more just to do your regular routes.
If you decide to sell it, from what I have seen,they appear to be rarer than hen's teeth, so don't sell it too cheap. To try and establish a price, try buying one!