Archived: the OG noob question thread! 😀

How-Tos & Esk8 mechanics Esk8 Mechanics
7313

anyone else getting this?:

“Due to extreme load, this is temporarily being shown to everyone as a logged out user would see it.”

1 Like
7314

Efficiency in short. If you are running a 10S 3P build you have 30cells in the pack already, if you are arranging them in a 30S configuration you are looking at 126V when everything is fully charged. Say we go with 20S instead and 2P then 40 cells so still same as a 10S 4P in terms of number of cells but running at higher voltage means less loss in all components the current flows through and less need for additional heat dissipation. We are already at relatively high amp levels (for bigger riders on hills, personally I don’t think I’ve broke 30A on the battery side) so using more voltage to drop the amperage makes sense to me.

All that heat you mentioned is just power lost to the air.

Edit I drew 25A last night :smiley:

2 Likes
7315

Ofcourse. That makes much more sense. I knew there was a clear reason that I wasn’t seeing. Thank you

1 Like
7316

No problem there is the downside that getting into the near 100V level is getting somewhat dangerous in terms of electrical shock. Great Scott Youtuber did a comparison of having his hands on two metal plates and bumping up the voltage with AC or DC and I believe upwards of 50V started to become painful (not to mention potential current through the heart could cause a heart attack), but so long as people are safe when doing assembly this isn’t something I’d be majorly concerned about in normal usage (also anti-sparks will be necessary I believe as voltage goes up the sparks get worse from the inrush current to fill the capacitors but just guessing and something most use anyway).

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7317

I don’t think you get less range with less P groups. Range is based off wh. Higher voltage will require less amps= less heat and small wire.

1 Like
7318

Good to know.

Edit:
Source/link?

7319

Wh is calculated by battery capacity (# of p groups times cell capacity) times voltage though.

I.e. Parallel groups are directly proportional to range leaving all other variables the same

7320

Yes but if you have a a 10s6p vs a 12s5p its the same wh but one has more in parallel

7321

You changed voltages. I told you not to in my explanation :triumph:

2 Likes
7322

the motor will turn faster with higher voltage, so geared to the same top speed, it takes less motor current for the same wheel torque, increasing efficiency

1 Like
7323

“It takes more cells in series to achieve these higher voltages, which in our limited space, means that we have less room for parrallel groups, which often means decreased range.”

But this is what my original comment was directed toward.

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7324

Dammit now you’re changing gearing!

It was a simple apples to oranges comparison.

Now it’s a Mediterranean apple grown in the off-season to Himalayan oranges grown at high altitude comparison.

2 Likes
7325

with the same gearing, increasing the voltage doesn’t change the efficiency in the motor for the same acceleration

7326

I can see your point then.

I read your first statement very plainly :slightly_smiling_face:

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7327

Right to clarify it doesn’t necessarily mean the motor is running at higher efficiency but given X watts driving a motor it is more efficient to deliver that power at higher voltage and lower amperage than at higher amperage and lower voltage… this is why we have high tension high voltage lines delivering power between neighborhoods and step down the voltage to deliver into the home.

7328

@wafflejock you’re forgetting that the esc steps down the voltage to whatever is required to deliver a given motor current at a particular rpm

1 Like
7329

Well no (I recognize that) I’m just saying all the power flowing up to the point of the ESC controlling the current to the coils in the motor is going to be more efficiently delivered, less loss as heat in wires/resistors/components along the way.

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7330

yes, less heat in the battery cables with higher voltage, but that’s not where most of the heat is generated and higher voltage on its own won’t change the efficiency in the motor for the same acceleration, you have to increase the voltage and increase the gear reduction to significantly improve the efficiency with higher battery voltage.

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7331

Won’t motors just be the next bottleneck? An esc that can deliver 200v is going to melt all the motors we use given the load demand is great enough.

Is the plan to then just run massive motors?

7332

I thought amps is what melts motors.

1 Like