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General Category => General Discussion => Topic started by: Mattbastard on August 26, 2017, 11:53:02 AM

Title: What kind of amp draw do you see
Post by: Mattbastard on August 26, 2017, 11:53:02 AM: on the highway, for instance. I suppose this is for anyone who has the metering to see current draw at any given time.

Just curious, for pack-sizing my build. Thanks.
Title: Re: What kind of amp draw do you see
Post by: togo on August 26, 2017, 10:33:37 PM: Depends on volts too : - )

I think I've seen momentary draws as high as 45kw though the zero app. That would be 387A at 116v. I think the sevcon size 6 gen 4.5 supplied with the 2017 models can do 2X that. Look at the specs pages at zeromotorcycles.com fit the amps and volts of production vehicles for comparison.
Title: Re: What kind of amp draw do you see
Post by: Mattbastard on August 27, 2017, 01:29:09 AM: True, I suppose I should have clarified that. I've heard the rule of thumb is 100W/mile. Back that math out tells me about 2A with a 48V system, which I can't believe.

Regarding the Zero specs, aren't those all max capacities?
Title: Re: What kind of amp draw do you see
Post by: BrianTRice@gmail.com on August 27, 2017, 06:25:42 AM: 100Wh/mi is a rough number you can use for napkin calculations.

At 102V (nominal and most common Zero battery voltage) and 60mph:

100 W-hr/mi * 60 mi/hr = 6000W.

6000W / 102V = 60A.

6000W / 116V = 51A, though.

The reality is that the current, voltage, and RPMs are the direct measurements, and you should see those in the logs, and everything else is calculated from that (including speed by configuring parameters to inform of gear ratios and wheel size).
Title: Re: What kind of amp draw do you see
Post by: togo on August 29, 2017, 05:50:15 AM: Quote from: Mattbastard on August 27, 2017, 01:29:09 AM
True, I suppose I should have clarified that. I've heard the rule of thumb is 100W/mile. Back that math out tells me about 2A with a 48V system, which I can't believe.

Regarding the Zero specs, aren't those all max capacities?

100 watt-hours, not watts, per mile, riding unfaired pretty slowly on a highway. Brian says 60 MPH, I was thinking 55 MPH, his current sensor is better than mine.

Watts is instantaneous power, watt-hours is energy storage or use.

Watts, about 6 kilowatts to proceed at 60 mph, 4 kilowatts is considered the minimum to do it if you are streamlined.

Yes of course the Zero specs are max.
Title: Re: What kind of amp draw do you see
Post by: Mattbastard on August 29, 2017, 10:32:44 AM: Wow, bit of a rabbit hole, lotsa math too. Thanks everyone.
Title: Re: What kind of amp draw do you see
Post by: togo on August 29, 2017, 10:23:12 PM: The main thing is don't confuse watt hours with watts, and don't think amps us a useful measure without volts.

P=IV is the key equation
Power (watts) = current (amps) times voltage