First commute on e-mtb

[roubaixtuesday]

Minor clarification, a watt-second is equivalent to 1 joule. One watt-hour (the total energy expended delivering a power of 1 watt for 1 hour), is 3,600 joules.

Agree, sorry that my original wasn't clear on that.

 

[albion]

And Amps x volts is NOT the instantaneous power the battery produces, in watts (W), it being the total energy expressed as watt hours. (wh)

 

[Dadam]

And Amps x volts is NOT the instantaneous power the battery produces, in watts (W), it being the total energy expressed as watt hours. (wh)

Sorry but that part was correct. Electrical power is current (amps) x voltage (volts) expressed in watts. It IS an instantaneous measurement. You need a time component to get an total energy. A watt-hour is 1 volt x 1 amp-hour.

 

[roubaixtuesday]

And Amps x volts is NOT the instantaneous power the battery produces, in watts (W), it being the total energy expressed as watt hours. (wh)

I don't quite understand your sentence, but for the avoidance of doubt:

Amps, Watts, and Volts are all different units used to describe different aspects of electricity:

• Amps(Amperes) measure the flow of electrical current (charge) through a circuit.
• Watts measures the rate of energy consumption or generation, also known as power.
• Voltsmeasure the force or potential difference that drives the flow of electrons through a circuit.

These three units are related through the formula: Power (Watts) = Voltage (Volts) x Current (Amps)
From https://www.anker.com/blogs/others/basics-of-watts-to-amps

 

[albion]

You said "Amps x volts is the instantaneous power the battery produces, in watts (W)".


Wrong. I guess if you did fully understand you would not have erred.

 

[roubaixtuesday]

You said "Amps x volts is the instantaneous power the battery produces, in watts (W)".


Wrong. I guess if you did fully understand you would not have erred.

The emboldened is correct - see the link I provided which says the same thing, to quote directly

Power (Watts) = Voltage (Volts) x Current (Amps)

 

[Slick]

I'm glad I brought it up now.

 

[albion]

That is the web for you. It amplifies errors.
In the old days we had proof readers.

 

[roubaixtuesday]

That is the web for you. It amplifies errors.
In the old days we had proof readers.

Every single reputable source will give you the same, as has everyone here.

I would be *very* interested in a source which disagrees that Watts= Amps*Volts.

I look forward to you providing one!

 

[Dadam]

You said "Amps x volts is the instantaneous power the battery produces, in watts (W)".


Wrong. I guess if you did fully understand you would not have erred.

Yours was the error I'm afraid.

The WATT is the SI unit of power, the JOULE is the SI unit of energy. However watt-hour (Wh) is a commonly used unit of energy capacity for a battery. 1 Watt-hour is 3,600 joules

 

[albion]

Rofl.

 

[mustang1]

One thing I noticed about my battery is after a full charge (10 bars), it very quickly shows 9 bars. This morning for example, after only 10 minutes at max power, it showed 9 bars.

My guess is battery degradation (2 year old battery, 1700km on bike, battery is charged "carefully" (meaning, up to 100% on the day before I want to use the bike and never gone below 30%). I was hoped the battery did degrade that much after only 2 years and that little mileage but it's ok I suppose, still more than meets all my needs.

 

[roubaixtuesday]

Rofl.

Well, that irrefutable logic combined with the authoritative references certainly has me convinced!

 

[albion]

You said "Amps x volts is the instantaneous power the battery produces, in watts (W)".
Wrong. I guess if you did fully understand you would not have erred.

Anyone want to expand on this. It might be best if all replies get deleted after the "wh = Amps multiplied by Volts" posting. It simply lost the plot afterwards.

Raw power is often expressed in Amps like you get with a car battery crank power. However we were never multiplying by crank power, were we?

 

[roubaixtuesday]

Raw power is often expressed in Amps like you get with a car battery crank power. However we were never multiplying by crank power, were we?

I think it would probably help clarity if you provided an equation, ideally with a reference, rather than text alone as it can be very ambiguous.

I've no experience of "crank power" but could imagine it's a very loose description of "oomph" rather than "power" in the engineering sense.

For example "Crank Power (watts) = Battery current (amps) * [anything else you feel is included"

In the case of an ebike, I stand by "Instantaneous Power (watts) = Current (Amps) * Voltage (Volts)" as per the references provided.