Finishing up my coyote last mile build, and planning my freebie mbs deck build, my two previous builds are 10s and single motor drives.
I’m wondering what is the difference in the series options, it’s kinda hard to weed through all the info when using the search, I know that the parallel group size determines the battery amps and the range, what exactly is different between a 10s, 12s, 14s etc.
14s and up need special ESCs to not get fried, difficulty in making them increases with voltage as it exceeds the breakdown voltage of the components
Typically a high voltage system will need less current which means less heat and greater efficiency, but it’s harder on the motor and ESC to have that high of a rotational velocity (ERPM limits and bearings) so you accept the wear or get a lower kv motor (which will generate more heat)
12s is a sweet spot for components because it’s a safe voltage (for the ESC and the battery maker) plus it has lots of multiples which makes it easier to make the batteries, but if you need SPEED then step up the voltage
Thanks guys, I’ll read the battery beginner thread. I do know that the higher voltages are only specific escs, I’m thinking of using uboxes but possibly makerx or just cheapo flipskys.
The reply about voltage relative to top speed is really answering what I need to know, I’m more after the punch for dips and hills on the trail then speed, I really just need to determine if I will be happy with 10s6-8p or will I wish I went to 12s. On my street boards I like to go what I consider fast (25-30mph) but this will be my first off road build so I’m pretty much in the dark.
As far as I know, the same amount of torque gives you the same amount of heat with the same motor size.
For example, I used 2 5065:
270 kv @ 6s
140 kv @ 12s
Both ran well on 12/36 @ 83mm,
Both ran awfully hot on 18/36 @ 83mm
I think, voltage setup should be chosen depending on the popularity (there is a lot of 10s chargers, but not 9s), being time-proved (such as 2x S. I mean 6s, 10s, 12s, but not 11), and giving you a reasonable headroom for components used. Difference between 12 and 10 s efficiencies is negligible.
Suit your kv to the voltage, gearing to the desired perfomance, motor sizing to the heat generated and you will be all good with setup
So if I have 8S6P and 16S3P packs, and I limit ERPMs to the same speed and I limit motor amps to give me same torque, will 16S pack give me more range because it’s more efficient? Stress on the motor should be the same I think.
So what I’m asking, for low power long range build, is it worth it to consider going for higher voltage?
One advantage of a higher S count is easier fast charging, 16S1P is way easier to juice up quickly because you can do it at 1 amp, whereas 1S16P you need fat charging wires, a massive charging port and a big BMS to charge at the same 16 amp rate.
In theory the way you want to pick the build is to have the highest gear ratio, motor kv, then voltage. We have the most options in 190kv motors but 220kv is ever so slightly better if you can get them, the highest ERPM is from a VESC6 or a derivative is 100k ERPM so either 18s 190kv or 16s 220kv
Personally, i have yet to meet someone who went 10s and liked it. Aside from keeping weight down, it’s inferior. and 12s is just as “safe”
There are reasons for 10s but it really is the Pepsi to Cola. Usually the reasons for 10s are cost or weight/size restrictions. So if you have the room, and don’t mind the weight. I recommend doing 12s.
Assuming u use the same motor and gearing higher voltage will be less efficient in the esc unless you’re riding at the higher speed otherwise the esc has to do more chopping. If u have room to get a bigger gear ratio on the wheel and use the higher kv motor then, just like always, more gearing equates to less current needed and be more efficient, but you could do a bigger gear ratio and higher kv with the lower voltage to begin with. The motor only runs on amps so not less heat in the motor with more voltage. The real benefit would be putting a bigger gear on and less strain/current needed in the motor but we’re often limited to what gear will fit.
The watthours and range should be about the same regardless of how many cells in series.
Even the strain on the cells will be about the same either way and more in series is less strain on each cell but more in parallel is more cells to deal with the strain.