14S VESC ?

General topics and discussions about the VESC and its development.
joe90
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Re: 14S VESC ?

Postby joe90 » 14 Jun 2016, 17:11

No problems with magic smoke, I am just hitting programmed limits

My absolute max current is 150A
Max phase current is 90A

Max measurable current is 160A with 0.001ohms shunts. it's the max current the DRV is able to read.
So to have protection you need to be under that.

I was not willing to go higher than 150A because before the esc enter protection it need a little time and sometime it shut dowm and the reading is 153A
but those are spikes while my phase current is set to 100A

You have to play with phase current to keep absolute max current under 150A
everything is fine for me like this.
Last edited by joe90 on 15 Jun 2016, 13:03, edited 2 times in total.
Michel Cote
Twin v4.7 + SK3 6374 149KV
Bicycle
2500W peak/unit on 12S

Hummie
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Re: 14S VESC ?

Postby Hummie » 15 Jun 2016, 00:56

The battery current won't go higher than the phase current though right?

Hummie
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Re: 14S VESC ?

Postby Hummie » 19 Jun 2016, 04:42

Will the current be pushed through faster with higher voltage and allow for quicker amps and better acceleration

rew
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Re: 14S VESC ?

Postby rew » 21 Jun 2016, 08:34

Right. The battery current will be at most the phase current (plus what the control electronics uses).

No, a "slow acceleration" due to low voltage would only happen if the inductance is really, really high. In practice it is at least orders of magnitude lower than what would be necessary to cause a noticeable effect on acceleration. (and a BLDC motor wouldn't even be able to function with that kind of inductance).

Hummie
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Re: 14S VESC ?

Postby Hummie » 06 Aug 2016, 19:24


rew
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Re: 14S VESC ?

Postby rew » 07 Aug 2016, 08:26


Hummie
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Re: 14S VESC ?

Postby Hummie » 09 Mar 2017, 06:58

Been running at 45 battery amps and 200 motor amps happily. Is there a risk doing this? I'd heard there was some loss of over current protection or something. Running a single hub motor with 12s foc.
My other confusing question before..is it less efficient to run with a high voltage battery that gives a top speed way beyond what I'd ride, compared to riding with a lower voltage?

Have to say on 200motor amps I have much less cogging and can take off from practically a standstill and much greater torque an acceleration from a standstill. It's much better!

rew
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Re: 14S VESC ?

Postby rew » 09 Mar 2017, 08:44

The VESC cannot measure a current of 200A. This would make it hard for the VESC to run a motor at 200A.

At the current sense resistor: 200A * 1mOhm = 200mV.
At the DRV current sense amplifier: 200mV * 10 = 2V.

Offset that to 1.65V: 1.65+2V = 3.65V which is more than 3.3V so cannot be measured.
And with the current going the other way: 1.65 - 2V = -0.35V which is less than 0V so cannot be measured.

artteth
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Re: 14S VESC ?

Postby artteth » 09 Mar 2017, 10:26

but if use 0.5miliohm shunt?

Hummie
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Re: 14S VESC ?

Postby Hummie » 10 Mar 2017, 08:11

I'll bring it down to 165 which is seemingly the limit then I guess but if it truly can't measure the current why haven't I blown up? maybe the 200 amp currrent is smoothed out to a lower current by the time it makes it to the sensors? the 200 is the best performance I've had and without getting the motor amps up high such as this the power output of the vesc is decreased at lower duty cycle. With a pulley setup maybe it's not as significant.


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