flippy said:there is very good reasons to go in higher voltages. first: much less amps. that means less peukert effect rubbish, thinner cables. less voltage loss and so on.
I'm well familiar with Peukert's law. Usually has a meaningful effect above 100kHz. Let me know the actual energy loss in % if it was ever observed and measured. I'm sure there is difference, just like adding a capacitor on your 12V car battery to save some fuel, but just how much? Is it worth all the trouble?
FIY, drop in the battery will be proportional to voltage, if capacity in Wh remains the same.
So basically the only reason - slow motor? I know many are buying a factory-made ebike and then trying to make it go faster, but the vast majority of projects here involve fresh builds. I understand it is bit hard sometimes to find a motor with correct speed constant, also discussing it in chinglish with average sales guy who don't understand your questions, but it is well worth it.flippy said:personally the main problem is that most scooters and stuff is made to run 40km/h and if the battery is full prehaps 45 for a few minutes slowly dipping into the high 30's when getting empty. that does not ride well or sell very well. it's also dangrous in the city being slower then cars. people will make dangerous overtakings just to get past you.
many people want more speed and keep that speed even if the pack discharges. so keeping 50km/h at all times requires basically a 72V battery or 20S instead of 16S.
replacing the original motor for a new one from QS is a expensive ordeal and usually means a lot of crap getting the rear brake to fit properly. adding the cost of a new motor, controller and battery makes it very cost prohibitive and most people will simply walk away from this. being able to reuse the existing motor makes a huge difference. but you do need the higher voltage to get the speed people expect across the entire voltage range.
For example I, if communication is difficult, usually order "24V" motor and then feed it 48V. Problem solved. Also some motors can be connected from Y to ∆.
Anyway, I am not pushing this 48V thing just to make you buy my BMS. This has been discussed many times already and is bit hard to understand, why are we still having this issue.
I have to confess my first ebike was also 20S. Just because I checked some threads here and checked what people are doing and later discovered I need more voltage. Later I learned my mistake and always planned ahead to stick with 48V.