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Battery motor question

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Bikenut:
I have been interesested in some time in building an emotorcycle. If the rolling chassis is 200 pounds, with 26 inch high tires, what should I look for in a motor battery configuration for top speed of 60 mph, and a range of 60 miles?

Bikemad:

--- Quote from: Bikenut on February 23, 2019, 07:31:35 PM --- I was thinking the electric hub, but am struggling to get the battery side for that. If I use a standard 16 inch rim, gives me 24 inch tire, the hub is 10 kW

--- End quote ---


--- Quote from: Bikenut on February 23, 2019, 07:34:43 PM ---Should have said the enertrac hub it says it needs 96 volts by 95 amps for 60 mph

--- End quote ---

Hi Bikenut andto the forum.

If that motor requires 95 Amps @ 96V (9.12kW) to maintain 60 mph, you would need a 96V battery of at least 95Ah capacity (preferably 120Ah to enable a 80% maximum discharge for a longer battery life), and it must be able to supply a continuous current of at least 95 Amps to achieve a range of 60 miles @ 60 mph.

26 early Nissan Leaf battery modules (2 sets of 13 modules in series, both connected in Parallel) would produce a 98.8V pack with a capacity of ~128 Ah.

Unfortunately, this would produce a very large and heavy battery which might be very difficult to squeeze into a motorcycle frame:



A single row of 26 modules would be 884mm long (~35") 222mm wide (~9") and 300mm tall (~12"), and the weight of 26 modules, each weighing 3.7kg/8.16lbs, would be 96.2kg/212.16lbs, and that's without any casing, connectors, bolts, brackets, wiring and BMS etc..

Alan
 

Bikenut:
thanks For the welcome and the information Alan. You’re right, 35 inches is too big, no matter how you look at it. The weight I could likely live with. Have you any suggestions for a motor if the hub isn’t practical? I don’t want to go below a range of 50 miles, the top speed is a must. I have a complete rolling chassis, so the hub motor is an option only. The engine area Would easily accommodate 12 inches wide 23 inches high, and 13 inches front to. Ack. That would leave 12 inches wide by 12 inches high for a motor. Controllers etc. Can be fit elsewhere

Bikenut:
so could a triple  bank of 38120HP 8000 mAh-3.2V 120A headway batteries, in series and paralell work? Am I wrong to see a total of 115 volts, and 288 amps.

Bikemad:

--- Quote from: Bikenut on February 25, 2019, 01:50:38 PM ---so could a triple  bank of 38120HP 8000 mAh-3.2V 120A headway batteries, in series and parallel work? Am I wrong to see a total of 115 volts, and 288 amps.

--- End quote ---

36 groups of 3 parallelled 8Ah cells connected in series would give 115.2V but only 24Ah capacity.

Connecting cells in parallel increases the overall capacity, but not the voltage, whereas connecting cells in series increases the voltage but not the capacity.

36 groups of 12 parallelled 8Ah cells connected in series (36S12P) would be needed to create a 115.2v 96Ah battery pack, but trying to fit 432 of those cells into the frame might be a bit ambitious too.

According to the Battery Shape Configurator, the most 38120 cells you could fit (2 cells wide) into your available space would be ~262 cells:



This space would only be sufficient for a 48Ah pack of up to 137.6V (36S6P), a 64Ah pack of up to 115.2V (32S8P), or a 80Ah pack of up to 83.2V (26S10P).

Alternatively, building your own pack using 3Ah 3.7V 18650 LiIon cells would allow a much larger capacity within the available space:



If the battery was 4 cells wide, you could fit 2480 cells into the same space, which would be enough for a 114.7V battery with 240Ah capacity! (31S80P)

Alan
 

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