Around late 2019, I bought an Urbanbiker Viena new off Amazon for my daily work commute (around 15km/day at that time, now it’s a bit lower at about 10km/day).
After about 4000km, my (first) battery started failing, with symptoms similar to How to make a 10 year old electric bike battery work better? :
Even after a full-night charge, the bike’s display would display a full charge, but as soon as (or just a few hundred meters after) I start pedaling/demanding power, the battery display would drop to nearly-empty, then suddenly stop (sometimes displaying a flashing "maintenance" icon).
I contacted Urbanbiker support, and after some remote troubleshooting, I sent the battery and the display (but not the controller) for diagnosis. They couldn’t find any fault, but they sent me a new display nonetheless along with the same battery.
Changing the display did nothing, and the battery eventually died for good. Support then told me I would have to replace it, but at 700€+ new, I opted for a second-hand one that the seller described as lightly-used (they had their e-bike stolen, and hence sold their spare battery).
However, that second battery is now displaying the same behaviour, after only 500km of use by myself.
The batteries are marked as 48V 17.5Ah, and the provided charger is marked as 54.6V 2.0A out (I can provide pictures).
FWIW, lazy as I am, I often use the maximum assistance mode, although the place I live (in France) is pretty much 100% flat. Urbanbiker support told me that’s what causes my batteries to degrade… but somehow I’m not convinced.
Is that normal that those batteries fail that fast? What can I do to repair them and especially prevent this behaviour from happening again?
I’m on the verge of selling this bike as I’m unsatisfied with other issues (assist is not "snappy" enough from a stop, though acceleration is then good; and unassisted pedaling feels overly sluggish), but I’m willing to give it a last try.
EDIT: I've eventually ordered a refurbished Moustache e-bike from https://upway.fr/ as a replacement and will sell the Urbanbiker Viena to recoup the cost.