DrkAngel
1 GW
Stay tuned for my 44 Magnum!
The Lipo packs I recycle, are nicely built in 3S, 11.1v, "bricks".
It has been bothersome adding 1S, to build 7S 25.9V and 10S 37V packs.
Fortunately, a 12S 44.4V pack charges nicely to 50.4V.
The 48V controllers, I've been eying, have low voltage cutoffs of 41V & 42V ...
42V / 12S = 3.5V, which is my personally recommended, optimal DOD (Depth Of Discharge)!
Test pack will use 2160mah cells, in a 12S 10P configuration. (.96kWh)
44.4V - 21.6ah
Which can be easily paired with Twin Sister Pack for 1.92kWh pack.
44.4V - 43.2ah
Yeah ... I stocked up on cells!
My initial use will be on my 24V EZips ...
Running a 24V motor at 44V might seem like a good way to burn up it up?
There are many stories of these motors being burnt up, running at 36V.
Some have gone to extravagant measures of, cooling, ventilation etc.
Well ... I do not propose this option as an uninformed or lightly considered manner.
I have run multiple bikes at 37V, for thousands of miles, with no problems.
My key to motor 'survival" is not additional cooling, it is prevention of heat production!
Full throttle draw at a dead stop is 30+ Amp, full throttle at top speed is 10- Amps.
Full throttle at 5mph might produce 80% waste heat and 20% usable power.
DC motors seem to have an efficiency range, this range moves - dependent on throttle position.
Throttle, "effectively", regulates the voltage to the motor, the "efficiency range" of the motor seems to be in the 50-80+% of top speed, nearing 80%+ efficiency & 20%- wasted heat.
With the EZip 24V:
Throttle % : Equiv. V : Max mph : Best Pwr
....25...........6V.......... 5....... 3-4 mph
....50...........12V.........10.......5-8 mph
....75...........18V.........15...... 7-12 mph
...100...........24V.........20......10-16 mph
With the EZip 44.4V:
Throttle % : Equiv. V : Max mph : Best Pwr
....14...........6V..........5.........3-4 mph
....27..........12V.........10.........5-8 mph
....40......... 18V..........15........7-12 mph
....45......... 24V..........20 .......10-16 mph
....67..........30V......... 25........13-19 mph
....81......... 36V..........30........15-24 mph
....90 .........40V..........35........18-30 mph
...100......... 44.4V.......39 **......20-35 mph
As long as the throttle is regulated and the motor kept in the efficiency groove, heat should be manageable.
24V full throttle at 5mph (80% wasted heat)
Should prove much more damaging than -
44.4V full throttle at 30 mph (20% wasted heat)
44.4V full throttle, @ 30mph, produces less than 1/2 the heat as 24V full throttle @ 5mph!
Moderate initial throttle, combined with pedal-assist, keeps my motors in the pink, (moderate temperature).
Personally, I have difficulty understanding eBikers that pump more and more amps into their motors.
2x the amps might produce 50% more low speed torque, but it also produces 300% of the damaging heat.
With only a slight, if any, increase in top speed.
But that might just be my frugal spirit being offended by the speed, sorry, power demons!
** "Max Mph" does not reflect wind resistance! Still ... 44.4V should produce 30++ mph!
37V provides 27mph, with pedal assist, past 30mph.
EZIP ENGINEERING 101
The Lipo packs I recycle, are nicely built in 3S, 11.1v, "bricks".
It has been bothersome adding 1S, to build 7S 25.9V and 10S 37V packs.
Fortunately, a 12S 44.4V pack charges nicely to 50.4V.
The 48V controllers, I've been eying, have low voltage cutoffs of 41V & 42V ...
42V / 12S = 3.5V, which is my personally recommended, optimal DOD (Depth Of Discharge)!
Test pack will use 2160mah cells, in a 12S 10P configuration. (.96kWh)
44.4V - 21.6ah
Which can be easily paired with Twin Sister Pack for 1.92kWh pack.
44.4V - 43.2ah
Yeah ... I stocked up on cells!
My initial use will be on my 24V EZips ...
Running a 24V motor at 44V might seem like a good way to burn up it up?
There are many stories of these motors being burnt up, running at 36V.
Some have gone to extravagant measures of, cooling, ventilation etc.
Well ... I do not propose this option as an uninformed or lightly considered manner.
I have run multiple bikes at 37V, for thousands of miles, with no problems.
My key to motor 'survival" is not additional cooling, it is prevention of heat production!
Full throttle draw at a dead stop is 30+ Amp, full throttle at top speed is 10- Amps.
Full throttle at 5mph might produce 80% waste heat and 20% usable power.
DC motors seem to have an efficiency range, this range moves - dependent on throttle position.
Throttle, "effectively", regulates the voltage to the motor, the "efficiency range" of the motor seems to be in the 50-80+% of top speed, nearing 80%+ efficiency & 20%- wasted heat.
With the EZip 24V:
Throttle % : Equiv. V : Max mph : Best Pwr
....25...........6V.......... 5....... 3-4 mph
....50...........12V.........10.......5-8 mph
....75...........18V.........15...... 7-12 mph
...100...........24V.........20......10-16 mph
With the EZip 44.4V:
Throttle % : Equiv. V : Max mph : Best Pwr
....14...........6V..........5.........3-4 mph
....27..........12V.........10.........5-8 mph
....40......... 18V..........15........7-12 mph
....45......... 24V..........20 .......10-16 mph
....67..........30V......... 25........13-19 mph
....81......... 36V..........30........15-24 mph
....90 .........40V..........35........18-30 mph
...100......... 44.4V.......39 **......20-35 mph
As long as the throttle is regulated and the motor kept in the efficiency groove, heat should be manageable.
24V full throttle at 5mph (80% wasted heat)
Should prove much more damaging than -
44.4V full throttle at 30 mph (20% wasted heat)
44.4V full throttle, @ 30mph, produces less than 1/2 the heat as 24V full throttle @ 5mph!
Moderate initial throttle, combined with pedal-assist, keeps my motors in the pink, (moderate temperature).
Personally, I have difficulty understanding eBikers that pump more and more amps into their motors.
2x the amps might produce 50% more low speed torque, but it also produces 300% of the damaging heat.
With only a slight, if any, increase in top speed.
But that might just be my frugal spirit being offended by the speed, sorry, power demons!
** "Max Mph" does not reflect wind resistance! Still ... 44.4V should produce 30++ mph!
37V provides 27mph, with pedal assist, past 30mph.