:? DAMN TOM MY BRAIN IS GOING TO EXPLODE.
Ok here goes nothing.... I am fine with my packs being 200 volts/300 volts with lower amps. Lets say i am designing a fancy frame for kickstarter / indiegogo because as i believe if its electric it should have a hard sci fi futuristic look to it. Help my brain one more time if you will lol. Lets cut the highway distance to 25 miles with a little more kick from higher voltage to lower battery weight and go with the idea that if someone wanted to ride this bike for short faster trips on the highway they would flip the switch to the high voltage pack and for around towning switch to a smaller 100 volt 2600 watt pack. My main hurdle here is that i am trying to stay away from making the bike look like a refrigerator on two wheels and i am shying away from the typical styling people follow to make electric bikes look just like gas bikes. It just doesnt feel right to me. My add is raging right now so if you could give me a rough estimate for the two packs that would be awesome. Most likely ill just have them made by someone else for the first prototype build to get it up and running. Thanks for your time i appreciate it[2quote=litespeed post_id=1398959 time=1532825226 user_id=16967]
All a big guess on what you actually might do and since your not for sure here goes,
My figures should be pretty good in a hypothetical draft!
Id tell you to stick with 24s which is 88 volts nominal and 100 volts hot off the charger. Since your looking at a 20kw motor we need to see your max amp draw. At 20kw at 85% efficiency divided by your nominal voltage of 88 gives you an amp draw of 20,000 x 1.15 = 23000 / 88 = 261 amps. That motor says peak can hit 50kw which would be over 650 amps and would most probably be a lot more considering voltage sag....yowsers!
Assuming you go with the 150 Watts per mile for 50 miles that would be 7.5kw pack. 7500 divided by the 88 volts nominal of a 24s pack means you would need about 85 amps. I say we just round up to 90 amps which would mean if you went 30Q ( 3 amps cells!) you would need 30p. 30p rated at 15 amps per cell (about 5c. C rating is how many times the capacity max discharge is. In this example 5 x 3 amp = 15!) would give you a peak of only 450 amps. You could go with a VTC6 cells which claims it’s a 30 amp cell but more like 20 amps. It has a bit more capacity at 3.12 amps and would boost your peak draw to 600 amps. If you did a higher capacity cell like a GA or Tesla cell you could get about 3.5 amps but have a lower c ratings of 2 to 3 c which would drop max amp draw to Around 300 amps. You could go higher voltage to lower the amp draw but you then get into dangerous high DC voltages which could equal death or blown off/black fingers! First time around I’d stick with the lower 24s or less voltages until you know what your up against. This would be your lightest route. So you understand how many cells you would need At 24s (88 volts nominal.24 x 3.7 volts nominal for a lithium battery and 4.2 volts fully charged up 24 x 4.2 = 100.8 volts.) and 30p (30 Cell’s paralleled) that would give you a total of 720 cells!
You could go to a higher output cell such as a 25R, VTC4, or 5 that are 20 amp+ discharge but offer less capacity meaning more cells and a heavier pack. Going with the 90 amp pack you need you would need 36p of the 25R or VTC5 which would peak around 720 amps. You would need 42p of the VTC4 but this pack would peak in the 1200 amp range which would be just short of amazing but heavy.
So to sum it all up including rough weights,
30Q 24s30p 720 Cell’s peak discharge 450 amps weight about 80 lbs about $2700 in just cells
VTC6 24s30p 720 Cell’s peak discharge 600 amps weight about 80 lbs about $3400 in just cells
25R 24s36p 864 Cell’s peak discharge of 720 amps weight about 95 lbs about $2400 in just cells
VTC5 24s36p 864 Cell’s peak discharge of 720 amps weight about 95 lbs about $2900 in just cells
VTC4 24s42p 1008 Cell’s peak discharge over 1200 amps weight about 112 lbs about $2600 in just cells
Sky is the limit and Hopefully this will get you started.
Tom
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wow great replies guys. I could quote reply alot of you to thank you and refine my needs but ill just try and add more details in this post so you have a better idea of what i am working towards.
