Right, a little update....
I modified the rear pannier on my wife's bike by cutting out what was in the way and welding in an additional piece of steel to support the raised base I made for the battery. This lifts the battery about 25mm above the pannier frame thus allowing me to fit a pannier bag setup such as
this for example underneath the battery, ....with a little bit of modification to the bag of course. It does however solve the problem I had and looks reasonably neat.
I took the bike to one of my usual forest trails yesterday and have to say I am very pleasantly surprised at the power. As far as my wife's bike is concerned, it needs no alterations to gearing as it is capable of ascending anything we tested it on. I removed the speed limit and tested the bike on the stand just to see what it could theoretically reach in each of the seven gears. First at maximum was 12.2 mph and seventh reached 24.4. I tested it myself despite the bike being too small for me on a bit of a hill that I would normally have to get off on and walk up. It's nothing too severe but tiring to me at least. I tried the bike out in each of the four modes and started off in third gear on level ground at the base of the hill while providing plenty of input myself. I was standing up much of the way and noticed that on sport and particularly turbo modes the front of the bike was light and the rear wheel was spinning at times. To my mind there's no shortage of power, and what surprised me most was that eco mode provided much more assistance than I was expecting. It in itself is very usable too.
I did not however as yet carry out the bearing mod. I noted how loose they were on the shaft and this concerned me regarding the ingress of dirt and grit onto the motor. Yesterday following a couple of hours worth of cycling on the rough, gravel forest paths, the motor acquired a decent covering of dust over it such that I suspect that in an environment such as this, the bearings while prolonging the life of the motor in one way might shorten it in another. I don't know for certain but it is something I am thinking about whether rightly or wrongly.
The battery level (Samsung 48v 14.4 AH) meanwhile on both the screen and the battery itself did not change one bit at all. A smaller one would have done very well had one been available at a good price but I've no regrets there really.
I believe the TSDZ2B will be sufficiently powerful for my own bike if I alter the gearing. I too have seven gears on the rear. I will have to determine if the gears can be changed, if seven of a different ratio would suffice or if I would need to change to a greater number of gears. The question there is what is actually on my bike at the minute, can I even change to a bigger cassette, freewheel hub etc and if it fits, can I actually select the gears due to chain line. I must add at this point that the seven on my wife's bike change with no issue and no excessive noise. The motor itself is very quiet indeed but it is of course brand new so that may change with use.
The subject of gearing is virgin territory to me and I know precious little about what would work and what doesn't. I'll have a go though and see once I get around to gathering up the bits and pieces now to convert mine too. However, I wanted to update anyone interested and especially all those who kindly chipped in with their time and knowledge. I now have one ebike conversion which has turned out very well indeed with an owner who is over the moon with it. Job done, ...or at least it will be once I have tidied up the cables to my satisfaction.
Thanks very much to all who helped.
AJ
