I added 4 nimh cells in series and 4 in parallel to the standard TF hub battery that I have paralleled to a 8ah SLA.
The total voltage at full charge is around 47.6v and the TF won't start. So I disconnect the 4 extra nimhs and rev it a few times and reconnect the 4 nimhs to get a volt reading around 47.1v on a drainbrain. Now the TF starts up.
On full charge the amps go up to 37 and the watts go to 1600. During the first few miles, amps stay around 1500 and then level off to around 1300 as the battery wears down. There is improved acceleration and hill climbing speed making the bike much more fun to ride. Without the extra 4 nimhs, the max amps was 33 and max watts was 1150. Also, Regen now goes on at around 24mph rather than 20mph. It would be nice to boost the volts up to 72v.
I think that can be done by isolating the internal hub controller's logic power line and feeding 36v into it. Then feed 72v into the mosfets. Don't know how hard that would be. That would also require replacing the 55v mosfets with 100v ones and upgrading the 50v capacitor.
The total voltage at full charge is around 47.6v and the TF won't start. So I disconnect the 4 extra nimhs and rev it a few times and reconnect the 4 nimhs to get a volt reading around 47.1v on a drainbrain. Now the TF starts up.
On full charge the amps go up to 37 and the watts go to 1600. During the first few miles, amps stay around 1500 and then level off to around 1300 as the battery wears down. There is improved acceleration and hill climbing speed making the bike much more fun to ride. Without the extra 4 nimhs, the max amps was 33 and max watts was 1150. Also, Regen now goes on at around 24mph rather than 20mph. It would be nice to boost the volts up to 72v.
I think that can be done by isolating the internal hub controller's logic power line and feeding 36v into it. Then feed 72v into the mosfets. Don't know how hard that would be. That would also require replacing the 55v mosfets with 100v ones and upgrading the 50v capacitor.