13s 15p or 20s 10p all things being equal.

[x.l.r.8]

I'm new to this so please bare with me and my silly questions. I'm back playing with what's my best solution, controller is an adjustable 48-84v 50Amp 500-1000w item so it's pretty conservative. Motor is the 72v item that will probably be fine. At present I have a luna 48v charger and a 48v 20ah that does general duty extending the range on my current scooter and powering my urban. So I'm looking at building a pack that fits in the space of 2 20Ahr SLA's for adaptability more than anything and my choices are (using 200 Samsung 22p cells) a 20Hr 72v pack giving me 1440 watts or a 30Ahr 48v pack also giving me 1440 watts. 45km/hr is plenty fast enough for my daily commute and taking a trip to the shops. I'm in Toronto so not exactly mountainous, and 45km/he is twice the speed of the local traffic. I want acceleration more than top speed, crawling up to 50km is not my idea of fun, I'd rather get to 40 quickly. I know these are modest goals but I'm unsure what's going to be better if there is even a difference. Will more Amps give less sag and better average power, or having 72 volts to call on mean it's working much less? If there's no difference I'll probably go with the 48v pack and buy the advanced charger and leave all 3 bikes at 48v

 

[crazymanc]

You need voltage headroom over the motors back EMF to keep providing power at higher rpms. So if acceleration is really what you are after then voltage is what's required to get you there.

That's the simple answer.

 

[dogman dan]

It kind of is just that simple.

This is why,

Your controller is a fixed max amps. you say 50 amps? Not sure that is right, 50 amps x 48v is around 2500w, not 1000. But in any case, if 50 x 48v is around 2500w, then 50 x 72v is about 1000w more.

1000w more, means it will take off faster, provided its not actually saturating the motor. I don't know when that occurs for your motor, but chances are you can run 72v without getting too far into that. Watching your motor temp can help with finding out, if it gets real hot in 5 min, likely its saturating the motor. If it takes 30 min of hard running to get real hot, you are near its max. If your motor never gets overhot, you are running well under that saturation point. ( all assuming you are not overheating the motor by overloading it)

Find out, with a watt meter, what your controller really puts out. My personal experience is that for city riding, 2000w provides plenty of acceleration, even for heavier vehicles that weigh 100-150 pounds without a rider. 3000w is even nicer, but not if it leads to a hot motor all the time.

At the moment, on my heavy longtail cruiser bike, I run 60v and 25 amps, about 1700w. Its all I need to keep up with traffic on a 35 mph street. I could run a lot more, but then I just hammer my battery harder, run out of juice faster, and the motor gets hotter.

 

[x.l.r.8]

So I'm dependent on a controller that at best powered a 72v brushless motor, my values are quoted from the box so I'm sure in a way they add up for PR purposes. Thank you for your responses.