You are absolutely correct about the difference between Joules and A·h, but what I am pointing out here is that they have omitted the time-scale entirely. They are not talking about continuous draw here, they explicitly mention the operation of transmitting 10 bytes, which should always be reported in terms of energy, not current/power.
So are they trying to report average current, or energy? Well, a typical wireless chip consumes several mA during rx/tx, not 0.026mA. This means they either have invented a wireless chip that is three orders of magnitude more energy efficient compared to industry standards, or they are talking about average current over time (for example, an NRF24L01 consumes up to 14mA during rx/tx: http://www.nordicsemi.com/eng/Products/2.4GHz-RF/nRF24L01).
I think we can safely assume therefore that they are talking about average current draw. Coming back to my original point, what is missing from their numbers are duty cycle and data rate. In other words, how often does the chip wake up to transmit a packet, and how many packets/hour can I pump through their network?
Given that BLE is just a standard 2.4MHz packet radio, which should draw a comparable amount of current to what they are using, it seems obvious the main difference is traffic rate and duty cycle, which they don't report.
I'll take it on the chin, but just say that in my experience in my previous job, I firmware-tested and provisioned 3G modems for low-power usage in remote telemetry units. Not an EE myself, I worked closely with them, and when they were looking for replacement modems from various vendors to replace an end-of-life model, the primary (relevant) stat listed and discussed was mA rather than joules - it seemed normal to me that mA was acceptable to mention for the task.
Sorry for the delayed comment - HN speed-post limitation.
Anyway, batteries come in standard voltage ratings - 1.5, 3, 9, 12, 24, and a host more. You select a battery that has the same rating as your electrical tool's requirements, so the voltage is already known, and the charge is delivered within the tolerance range of that voltage rating. And whether you're working in amp-hours or joules, you still need to know the voltage rating of your power source, so you will have this information at hand - it's utter nonsense to think that the only rating you need to know would be joules, or that the voltage for a given model of battery would be mysteriously unknown (and even if it were, trivially solvable with a multimeter, unlike amp-hour or joule).
You are not partially wrong. You are 100% wrong. Learn to accept feedback now or you will learn later when the stakes are higher.
Or, seen from a customer's perspective: If this company is as stubborn and misguided about this, how much more of reality are they unwilling to allow in? Why shouldn't I go with a vendor who faces reality?
AmpHours are not the same thing as reporting milliAmps. And neither one is power consumption. And neither one is useful for estimating power consumption. And don't bother looking for counter examples. That would be like showing me someone who said, "I drove three volts to work this morning."
As far as your second paragraph, it demonstrates an extremely sparse knowledge of electronic engineering. Yes, you kind of have some things kind of right, but not enough to communicate or make important decisions. I would highly advise you to take on a seasoned electrical engineer stat.
For example, you say "it's utter nonsense to think that the only rating you need to know would be Joules," but do you realize by only giving current you're doing the same or worse?
This is all neverminding the entire dimensions of time and the long-term implications of those two things junior electrical engineers always screw up: heat and vibration.
How can I possibly appease you, if you refuse to read my words properly - that is, even when the relevant italicised phrase is prefixed with exactly the criticism you're making? There's also a couple of other spots where you've twisted my words to better target your ire.
Why on earth should I 'learn to accept feedback' of this shoddy quality?
I too agree that 0.026mA is completely meaningless to me.
> In theory, there is no difference between theory and practice. In practice, there is.
I've read this a few times and I'm still at a loss as to what you're trying to say.
> reporting power consumption in mA is used in industry, so it's useful to report.
The example you gave is of a different industry. This device is a digital communications module, and so I'd expect information to be provided in a form which is useful for digital electronics desginers to use. The data provided by the Helium people is not sufficient to understand the power use of the radio. I agree that reporting current draw during transmission is useful, but it is only one of a number of figures required to allow an accurate assessment of the radio's capabilities and power consumption. The electronics industry has standardised on multi-page datasheets to provide key information on device functionality. There's a reason for this. Ultimately the information given about the device is not sufficient to allow a design engineer to make an accurate assessment of its capabilities.
Yes, I am not a digital device engineer. I did, however, sit next to them and provision their designs for customers (also tested various bits of firmware for same). The 3G specialist low-power modems we used were rated by mA. Replacement modems we looked at were primarily rated by mA. Yes, there are datasheets, but the convention was to talk in current draw, not total power. Not to mention the original complaint was "they reported A, not j", not "they reported A, not a datasheet".
I look forward to hearing you explain how 3G modems are 'different' to digital communications, just because they're transmitting over a paddock rather than a tenement.
I've read this a few times and I'm still at a loss as to what you're trying to say.
Well, basically it's saying that you using terms like "completely" is wrong. There are plenty of places in the real world where things don't follow the script laid down by "shoulds".
Note that lead-acid batteries are rated in amp-hours AND a voltage. With those two pieces of information together, one can compute their power capacity. Your boss only had people show A·h in the tool, b/c most people working with lead-acid batteries know the voltage of their batteries. The voltage of the Helium device under question is unknown.
The fact that people are downvoting EEs below makes me weep for the future.
Note that your boss was also overly pedantic. One can clearly see Ah is valid on the wikipedia page [0]. It follows the same form as Nm or N·m being valid for Newton-meters [1].
[0] http://en.wikipedia.org/wiki/Ampere-hour [1] http://en.wikipedia.org/wiki/Newton_metre
Nah, not really. When your battery is rated in "amp-hours" and you're being extremely tight with your radio, turning it on and off as necessary, it's fine to measure it in mA - the time unit is 'silent'. Radio was on for 10 seconds? Take 10x0.026 off the amp-hour stored in the battery. My last workplace dealt in agricultural telemetry based off solar-panel charged lead-acid batteries, rated in amp-hours. Amp-hours are similar to units of energy, but are subtly different - really they are actually measuring storage of electrical charge, which is not the same thing: http://en.wikipedia.org/wiki/Ampere-hour
They even had to put unicode support into the software configuration tool, because the boss was very clear that the proper unit for amp-hour is A·h, not Ah.