You can’t use a 60 volt battery on a 48 volt m620. The 1800 watt m620 has a custom controller to suit 60 volts.
Can you order you bike with the 52 volt m620, if so I would go with that. Also do you know if you are getting the Canbus or UART version of the m620?
It’s the Frey Beast - comes specced with 60 volt 1800 watt motor. Peddle hard enough and you‘ll be rewarded with 60 klm top speeds running 20 psi pressures in the Maxxis’.
To be honest though I've never gone out with fully charged battery solely for a top speed run, With different tyres and/or...
i wouldn’t.
Both of my e-bikes were derestricted by prior to purchasing by the manufacturer/dealer.
25 klm/hr is far too slow, but I can understand those less experienced riders need to be speed limited.
Use some common sense when riding and don’t attract attention to yourself (just like when...