The wisper is advertised as a real alternative to Bosch mid drive, well I,mm sorry but it simply is not. There is no way a hub motor can compete with a cd unit on limited current on any type of steep climb.
I tried about 6 different ebikes before settling on a yam cd drive, which I felt was best hill climber with Bosch a close second . The only hub drive I tried was fine on moderate climbs but well down on other two mentioned on anything challenging. Seems to me there is a lot of BS pedalled, suggesting its a fitness problem or something else.. In reality its simple. Hub drives cant compete on hills with crank drives on 250w ( or thereabouts)
Buyers spending the cash they do on ebikes should not have to discover this for themselves, especially post purchase.
If you want to climb hills buy a mtb style mid drive, I think yam best but that could be a personal thing.
There is no way I,d describe myself as fit. 58 years old, replacement knee, 105 kg..
No idea of gradient I,ve climbed but had height gain of 3500ft , over 2 hrs using 98% of battery. Is there a hub drive built could compete with that on 400wh battery. I do not think so. Forum should be informing all of this.