# Q - Vesc settings

Hello,

It’s been too long, i’d love it if someone could explain how to calculate vesc settings.

I’ve got a 10s3P battery with Samsung 18650 25R cells.
( 3.6V - 2.5Ah - 20A Cont. dischage - 50A Burst)

Single 190Kv motor - 14 poles
83mm wheels, 15x36T pulleys

FocBox Vesc.

How does one calculate the current, rpm, temp and voltage limits settings ?

1 Like

As the cells can output 20A current, you divide that number by the number of cells in paralell. Since you have a 10s3p where “p” stands for paralell, you can have 20 x 3 = 60A current.

An 18650 cell should be able to discharge down to 3.0 volts. Since it is 10 cells in series, that makes 3.0 x 10 = 30 volts. So cutoff start at 30.00 volts and cutoff end at 28.00 volts

4 Likes

Thanks mate, kinda dumb, but I’ve just now found that the bloc tool explains it all on hover haha

Worth mentioning. If you have the cutoff at 30 volts, you will need to stop riding as soon as the cutoff starts, since going below 30 volts could be harmful to the cells. Maybe having the start at 31 volts would be better. I have it at 30 but I stop riding as soon as the cutoff begins.

2 Likes

Hmm, Strange…
The bldc tool says that for Li-ion cells you should use 3V cutoff start and 2.8V cutoff end.
Is this incorrect ?

10s battery = 3v x 10 = 30v hard cutoff

2.8v is too low. The amount of energy in the cell between 3.0v and 2.8v isnt enough to matter to you(, but it will to the bms/cell).

5 Likes

Aight !

1 Like

maybe these graphs can help you tailor your voltage cutoff settings, as the 25r tends to sag a little early.

2 Likes

Try using Ackmaniac 3.103 firmware and tool and setting

If you use your cells’ full rated current output you will reduce their lifetime significantly and it will only boost your top speed by a tiny bit. That’s why I suggested 30A, or 10A per P-pack, which is plenty for most street skateboards

1 Like

I’m using a Mac. Ackmaniac 3.xxx isn’t available on Mac (or at least I couldn’t find one).

I’m trying to setup FOC mode, but It keeps on failing to detect hall sensors.
faults cmd provides me with:

Fault : FAULT_CODE_UNDER_VOLTAGE
Current : 14.6
Current filtered : 14.9
Voltage : 7.12
Duty : 0.12
RPM : 14.9
Tacho : 0
Cycles running : 584
TIM duty : 2050
TIM val samp : 5
TIM current samp : 16798
TIM top : 16800
Comm step : 0
Temperature : 27.38

Can you measure the voltage of your battery? A voltage that low is never good

Came to also second don’t go below 30V for 10s. Cutoff start at 3.1V and end at 3.0V. Stop riding after cutoff end asap to preserve battery longevity.

Also, whilst in parallel, you multiple the current output of a single cell with how many are in parallel, not divide

bldc tool real time data says 34.7V in.

at the bottom of the below post is v3.103_ACKMANIAC for mac (check it quickly before @b264 chastises me for using fruit powered device)

2 Likes

Sensors can be nice, but they add a huge failure point.

I recommend not using them.