Qoitech Otii

[mikeselectricstuff]

I've looked at this problem a few times over the years.
My conclusion is that the easiest way to do it is to use a voltage regulator with a consistent, known quiescent current, and measure the input current. This addresses the issue of voltage drop across a sensing resistor.
To deal with the wide range, about 3 sensing R's in series, with bypass diodes to limit the voltage across them to about 1V.
Measure the voltage across all 3 simultaneously, and select the one that's in range.

I've also looked at the "charge bucket" approach with capacitors, but leakage and nonlinearities make this a non-starter

In practice it is often possible to avoid the need for special testgear by manually forcing various modes, measuring the current in each, then looking at the time spent in each mode in normal operation.
Batteries are not precision devices, so you don't need to measure avarage draw accurately - 10% is easly good enough
 

[jeremy]

Yes, I agree that 10% is probably ok for most applications. Sadly though, a lot of these instruments do give people a false sense of security about how precise batteries are, and of course nobody is going to correct them if it sells less meters...

I recently read a R&S white paper on measuring radio module current and estimating battery life. It was basically just: if you buy our $50k instrument, it will tell you that your device sending a tiny packet once per week can last 19 years on a rechargeable lipo_{(assuming no self-discharge)}

[Apollyon25_]

At one of my work places, we have two Otii Arc's, and I've found them extremely versatile for measuring the current consumption of our IoT remote trigger device.

We've used it to qualify our coin cell battery (Primary Li), optimise our FW for sleep mode currents and wake periods, as well as characterise the various operating modes we'd see while awake.

I've used it to fix a quirk with our implementation of an ST Microelectronics battery charger IC, used with a larger Li-ion battery pack, and have used it as a general PSU and volt/current meter a few times. I've used its GPIO and ADC/Sense channels just as a readily useable scope/logic analyser...

I've used it to qualify our changes to our app, between various versions of the Tizen OS on the various generations of the Samsung watch, and it's been used to direct how our app behaves to obtain the best battery life without limiting our product features too much.

Sure, the scripting is a premium feature, and you pay for this with a subscription model. This isn't too different to many software licencing arrangements, and I can understand some people's reluctance to support such a sales model.

I've found their support exemplary! They've helped debug my setups, my scripts, and they've updated FW and app for me specifically to address any issues I've come up against. They take UI improvement suggestions on-board, and even updated me when a few of these were implemented.

I looked at a bunch of Keysight gear to do much the same (battery emulation) and I needed three bits of kit and none of them were cheap.

It works for me.

[EEEnthusiast]

You might want to consider the ZS-2102-A from ZSCircuits. It does what the Otii Arc can do and much more. It has a higher bandwidth with a pulse response time of < 2uS. It samples at 1Msps and has a dynamic range of -1A to 1A. With 1uA accuracy and less than 100nA resolution for average measurements. It can measure negative currents as well which is useful in some IOT devices which may use solar cells or buck boost converters which can feed currents back to the battery. And the software is free.

[julianhigginson]

I saw this today, and was really interested in it at first glance, but soured a bit on further reading.
I figured someone on here would have has some opinions already.. ;-)

The sampling rate is a bit lower than I'd prefer, but the breakdown between basic features and subscription features is the dealbreaker.  It's a shame, because with battery profiling/simulation capability outside the subscription model, it'd be pretty much perfect for a lot of things I've worked on in the past and will work on in future.

I see the point of needing an ongoing income source for keeping computer software (which is a major component of this instrument by the looks of it) up to date and working and growing...  it just seems that this isn't making the tradeoff quite right. Especially for a small company with just one product that we have no guarantee will even be around in another year.

[julianhigginson]

that zscircuits option looks interesting.

[EEEnthusiast]

I forgot to mention that I am the designer for the ZS-2102-A. My apologies.

[jii]

Sorry for replying to an older thread,
but does anyone have experience on the battery simulation / profiling on the Otii?
How accurate it is and is it useful when testing equipment on "low battery"?

BTW, We are right now using nRF Power Profiler as a measurement device.
Low cost, although max. measuring current is 70mA and the voltage range is small. But should be enough for many MCUs out there.

[horeich]

Hello,

sorry for reviving this old thread but I'm in need for an Otii alternative.

I currently have an Otii and albeit it is ok for some use cases, some things bug me all the time:
* only 4.5V, Minimum 9V would be great
* The desktop software is super slow after longer usage (think it eats up all your RAM)
* Desktop UI is only usable in full-screen mode when using two screens
* Worst: They've just started a subscription model for their lab devices' basic software. If I want to use the bug free version 3 to use myOtii, I have to enter a subscription. They prentend to still support 2.X but I think everyone knows what that means. Also, Otii just went up from $399 to $799. I think the startup time is over and investors wanna get their money back.

My question:
Is there an alternative which supports >= 9V output voltage and also power profiles in a wide current range between >0uA and 3A? I read about the 66319D; is it able to profile current?

Thank you

[oewean]

Hi,
Check out the Joulescope: https://www.joulescope.com/
Really nice product with open source software, and no monthly subscriptions.

PS! I'm a little biased as an Joulescope distributor :-)

[horeich]

Thank you for the suggestion. Looks interesting indeed.

But it does not seem to be available atm? Do you have any info about future availability?

[oewean]

We have it in stock, can ship worldwide, just get in touch.

Also if it goes as planned new stock will be available at manufacturer within the month of October.

 

[luma]

* Worst: They've just started a subscription model for their lab devices' basic software. If I want to use the bug free version 3 to use myOtii, I have to enter a subscription. They prentend to still support 2.X but I think everyone knows what that means. Also, Otii just went up from $399 to $799. I think the startup time is over and investors wanna get their money back.

And this right here is why everyone was saying not to buy into this system.  Any company holding your device hostage by way of subscribe-for-features is doing so to keep their hand in your pocket, and eventually they’re going to want more.

Subscription models for hardware features are a cancer on this industry.

[horeich]

I think there has been a huge backlash due to their subscription model. But they won't change it, just rename the Otii Arc to Otii Arc Pro to include the subscrption. 

I mean, the Otii Ace is an interesting product (hardware-wise), but if you stop paying money it'll be worth nothing. It's ridiculous.