I mounted 2 Makita 18V tool battery to the bike with at simple AL bracket and the Eplus's water bottle lugs. I used the mounting connectors from a 2 Makita tools. The Makitas were wired in series to give 36v (nominal) and then wired in parallel to the NiMH 36v (nominal) in the front hub. I also included a 300amp switch, just in case I needed to separate the Li Ion battery from the NiMH and the rest of the E plus. BTW, the second battery connector behind the seat is wired directly to the battery connector that attaches to the front hub battery. For test purposes, std. spade connectors work fine to connect the Li Ion to the E plus's connector.

I only had time for a brief ride, but I was happy with the preliminary results. The PWR setting measure only the watts provided by the NiMH battery and it was 100 to 150 watts less than the same conditions without the Li Ion battery assisting. So the Li Ion Makita battery is sharing the load.

These Makita batts are very old and very used. I do test later with fresh ones.