n2mb said:
Tommm said:
alarum_78 said:
Hello,
Looking to grab the newest CYC X1 Pro and run the BAC855 at 3000W. I am new to this game but I am not sure if its the best route for me to run a 52v or 72v setup?
I am under the impression higher voltage is ?? better??
Thanks in advance for any insight.
This is an easy question since the bac855 will never reach 2000w on 52v. Even if it did more rpm/less torque will always be better on your drivetrain. So if you want 3000w (and you do), go 72v.
Btw there is a topic for this motor, no need for new threads.
https://endless-sphere.com/forums/viewtopic.php?f=28&t=95704&start=675
Actually, I do hit 3100 watts peak with the 855 at 52V. But, it only spins the motor at 7000 rpm, so I'm switching to 72V to hit 10,000 rpm. That will allow me to stay in one gear with good chain alignment on the street at any speed I would need.
Ok, the bac controllers are power limited, on lower volts they will get you more battery amps, I wasn't sure of that, anyway, you won't get more power from it, yes the motor will spin faster, but getting a new battery is the single most expensive thing you can do to fix your issue.
The torque curve won't change at all, an 52v battery running at 3000w will be undiscernible from a 72v one at 3000w if the gearing difference is accounted for, you won't be able to keep it in a gear longer.
If both systems top out at 3000w, and:
If you are in a gear with a 20mph top speed with 52v battery
It is true that gear will give 30mph top speed with 72v battery
But if you switch to a gear with 30mph top speed on 52v battery, the acceleration, top speed, everything will be the same as if you were running on a 72v battery that also maxes out at 3000w.
If chain alignment is your issue it is a whole different discussion, or if you want to use a bigger rear cog that is a separate issue, but swapping batteries to fix something that can be done for $10, doesn't make sense.
To fix chain alignment: Put a small cog (smallest or one before the smallest one) behind the big cog of your cassette, it will bring all your gears outwards by 1 gear and spacer width. If you are willing to sacrifice more gears, you can buy a "single speed conversion kit" on ebay, they will provide you with ample amount of spacers you can use to get rid of 3-4 cogs even, and shuffle the big cogs in the middle.
To be able to use higher teeth cont rear gears at lower speeds:
You can get a bigger motor cog (12t)
Smaller front motor cog (219h 63t or 53t vs 72t)
Get a bigger bike chainring 36-38 should fit on anything, sometimes up to 44t.