Actual project: 2012 SR conversion
Goal : get more power and acceleration
.. not top speed!
limitation: low 66V Battery voltage = limiting battery max power
You probably saw my post with teh desire to add a size 6 or a 75-7 motor to my Zero... believe it or not! i'll do both !!
It is really complicated to replace all the MBB, BMS and DC-DC to reconfigure the battery voltage to 28s ( 102V nom) so i'll keep it to 66V!!
NOw with that fact, i need to dig somewhere else to get more power on my 2012 S !!
Solution? better motor and higher current !!
Here is my idea:
Right now with teh Stock size 4 during i'm accelerating, at about 75mph i see 30.2kW max on my cycle Analyst before it drop while continuing to 86mph. I see about 452A max on calibrated cycle analyst display during the peak of power. The controller is exploited to 105% for the current and only 64% for the voltage. BUt as you know i dont want to raise voltage for the reasons above. So for a 420A controller getting 452A would probably mean getting 690A max on the size 6 and probably 45kW.
The ZF9 battery can take that easy from what i saw. The contactor and high current wiring should be ok with gauge 1/0. Apparently the stock 425A fuse is ok with a Size 6...
Maybe one day i will just rebuild the battery to 28s and add my own BMS and will get rid of the MBB.. but from now i wanna ride my bike this summer not in 2 years of battery work lol !!!
The S is 40kW wich mean would mean 400A and pretty close to the max 420A power the stock size 4 can do. so the 2013-14 S is exploiting the Size 4 to about 100%.
Liquid cooling the 75-7 might be a great project for race application!
On my side the size 6 with 660A and 66V would give me 44kW, so it would be a little above the 2013-14 S power of 40kW!!!. Now if raising max current to 660A that could give an appreciable boost of power on the 2012 and givbe 44kW wich is a little more than the 2013-14 S of 40kW
I can confirme that the 75-7 motor DOES FIT in the 2012 S frame. I made a foam dummy 75-7 based on the measurement i did on a 2013 S. I'll just have to add holes to fit it to the frame or add an adaptor bracket to match the different shape.
I ordered from Harlan the 25T, the 28T and the 30T so i'll be able to play with various config for finetuning the powerband.
WIth these calculations i can say that my 2012 SR should be between the 2013S and 2014SR in term of power with the controller set to 660A.
I also remember that many people that converted their 2012 to size 6 said that the size 6 heatsink is not required...
My actual ZF9 battery internal resistance is about 8 miliohm. This mean that at 660A it should dissipate 3.4kW. let say that accelrration last for max 10 sec this is equivalent to 34kJ of energy wich is i guess probably ok if dissipated during 95% of the discharge time.. let say 1h ride from 100 to 0$ soc.... so 170W continuously average.
Fo rthe motor, the 75-7 motor should be able to manage the heat pretty well for 44kW.. otherwise i'll add forced airflow on the case fins
I expect to be able to buy the Size 6 from Harlan with in about 3-4 weeks.
That will be awsome!
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Topic: 2012.5 SR vs 2013 S (Read 1827 times)