A problem with the high capacity low output model is that it makes using them as power measuring devices difficult.
Can you add a low capacity high output one?

Hmm... makes sense. I didn't notice because I use a power monitor building mod. In keeping with the physics, I think what I can consider is just giving you an accumulator that uses a single battery. What does it use right now, 5 batteries? So I'll make another accumulator, same power output, but 1/5 the energy. I THINK that should make it quite fast. This will take some time because I'll need to create a new graphic, but yes this seems like a very reasonable request.