PeteCress
1 kW
Here's a clip from http://toolhacker.com/2010/01/bosch-dewalt-makita-milwaukee-ryobi-ridgid-hilti-battery-specs/
What's got my little non-engineering mind going is the apparently-identical storage capacities and maximum delivery rates of the two batteries: both about 2.3 ampere hours and 30 * 2.3 = 69 amps.
Yet the 28v contains fewer cells... Seems logical from a voltage standpoint: stack more, get more volts, stack fewer get less volts... but it seems like the 28v pack would have to contain bigger cells to get the same amount of stored energy into fewer cells.
Am I making sense so far?
If so, is it fair to say that somehow the voltage determines how fast a motor can spin the wheel, but not the amount of energy that can be applied to the road?
If that's true, would it be correct to extrapolate that if, for instance, somebody didn't care to go more than 10 mph under battery power the lower-voltage battery could deliver just as much energy to the wheel as the higher-voltage battery?
Where I'm going with this is that the 28v batteries cost less than half of what the 36v batteries cost - and if they can deliver the same performance when climbing a hill at less than 10 mph and the user doesn't plan on using them on the flats, maybe they're the more rational choice economically.
??
Code:
DeWalt
Line: 36V (Nirvana)
Model: DC9360
Chemistry: LiFePO4, nanophosphate
Voltage: 36
Max cell discharge rate: 30C
Capacity: ~2.3 Ah 10S
Line: 28V (Nirvana)
Model: DC9280
Chemistry: LiFePO4, nanophosphate
Voltage: 28
Max cell discharge rate: 30C
Capacity: ~2.3 Ah 8S
Yet the 28v contains fewer cells... Seems logical from a voltage standpoint: stack more, get more volts, stack fewer get less volts... but it seems like the 28v pack would have to contain bigger cells to get the same amount of stored energy into fewer cells.
Am I making sense so far?
If so, is it fair to say that somehow the voltage determines how fast a motor can spin the wheel, but not the amount of energy that can be applied to the road?
If that's true, would it be correct to extrapolate that if, for instance, somebody didn't care to go more than 10 mph under battery power the lower-voltage battery could deliver just as much energy to the wheel as the higher-voltage battery?
Where I'm going with this is that the 28v batteries cost less than half of what the 36v batteries cost - and if they can deliver the same performance when climbing a hill at less than 10 mph and the user doesn't plan on using them on the flats, maybe they're the more rational choice economically.
??