Looking at a graph created by djozz in this tread, your emitter should need around 3.5 volts at 2.5 amps. Match's chart here indicates a little less than 3.3volts would be needed, but I think he said he was not confident in his voltage readings. If you can afford it, it may be a good idea to get the 4.35v cell (and capable charger). Would be nice to have regardless. In the meantime, have you copper braided your driver spring?
