Equipment advice: Battery lifetime testing

[tszaboo]

Great, please come back here and let us know what you discover - good and bad.
I'd also like more than 5V capability to cover my various projects (in particular 2S LiFePO4 and maybe 4S LiIon).
I've been considering the ITech IT6411 which is similar to the Keithley 2281S.

OK, so I visited them and spent like 20 minutes talking to the guys, and checking out the equipment.
It seems to be quite OK for the price, like it has the same capture window for the UART as the power measurement, so you can just send log messages on UART, synchronize the power measurement with it, or capture GPIO. It is a powerful unit, even without the battery capabilities. I think we will buy one to test, because honestly, the price is really good. I mean we pay something like 350 EUR for the TTI power supplies, for about 100 EUR extra, you get UART, ADC and a very easy to use software. OF course the power supply has more voltage and current, but I dont think it matters if your device is a battery powered microcontroller project. And then see how it goes from there, probably I have to convince the software guys that this is useful, use it.

I have the Otti and the weakness are
1. Sample rate
2. The annual charge for the premium "features"  (Battery profiling; Battery simulation; Scripting & Automation; Importing debug logs. ) (Euro 400/year + VAT)

Which is why I have pledged for Joulescope as I will never subscribe to a set of product features on an annual basis.

But apart from that the Otti is good even without the premium license but spec wise Joulescope is better. And I like the re-replaceable front panels. I just hope for USB-C connector vs the old type A. (Not USB-C PD but just normal "usb" power delivery just via the USB-C connector. I like them better than USB-A/B/Micro.

Well, the guy explained that the sampling method they use (probably delta sigma) integrates the current, so if you have some short events, like short RF transmission, while you dont see the actual hight, it will still calculate the mAh used properly.

Yes, the Julescope looks nice on paper, but it is not a final product, and it is something that you need with a power supply.
Well, it is still far from Keysight, who told me that I should buy a N6705C, with some plug in modules for 8000. Or Rhode and Swartz, who said, buy all this:

5000 only for the probe.

[nctnico]

I think the point about integrating short spikes is a good one. A filter will just suppress short spikes giving a false reading.

[mliberty]

Yes, the Julescope looks nice on paper, but it is not a final product, and it is something that you need with a power supply.

Not sure I get this point.  That's like saying multimeters, oscilloscopes and logic analyzers are not final products.  Joulescope is a measurement instrument that doesn't mess around -- it's easy-to-use and affordable with the performance you need.

[tszaboo]

Yes, the Julescope looks nice on paper, but it is not a final product, and it is something that you need with a power supply.

Not sure I get this point.  That's like saying multimeters, oscilloscopes and logic analyzers are not final products.  Joulescope is a measurement instrument that doesn't mess around -- it's easy-to-use and affordable with the performance you need.

Can you send me a Digikey link to buy it?

[mliberty]

Can you send me a Digikey link to buy it?

Digikey, no.  But if you or your company wants to buy a Joulescope beta unit at the full retail price, we have 1 left.  Send me a direct message.  Jetperch does provide an invoice and payment is by credit card.  We have already sold some to companies who could not wait for the Kickstarter or July general availability.  Ships within 2 business days upon receipt of payment using your choice of service from UPS, FedEx or USPS. 

Otherwise, we will have Joulescope preorders immediately following the Kickstarter for delivery in July, and we will have normal purchases in July.  EU distribution still TBD (plan to have something by July), but you can always order for shipment from the USA.

[EEEnthusiast]

Folks,

There is a similar product already out on the market. ZS-2102-A from ZSCircuits. (Disclaimer : I'm the designer for this product)

This USB powered unit has -1A to 1A range with better than 100nA resolution. (With averaging, the resolution is close to 1nA)
With an accuracy of better than 1% +/- 1uA across the full range of -1A to 1A, the step response time is well within 2uS. So this can respond to fast transient currents common in WiFi devices.
The current sampling rate is 1Msps, wheres the voltage sampling rate is 50Sps.
It has a burden resistor of only 0.1 Ohm and there is no range switching.

It sends data real-time to the PC over a USB bus and can capture profiles for more than 20 mins. (Actually tested for 1 hour)

More info at www.anglercircuits.com

[cgroen]

NANDBlog,
did you get any further with this (like buying some equipment  ) ?
I'm also looking at the 2281S, it fits my budget nicely and I can't seem to find something similar (battery simulation) out there.
Also ordering a Joulescope in a couple of days

[tszaboo]

NANDBlog,
did you get any further with this (like buying some equipment  ) ?
I'm also looking at the 2281S, it fits my budget nicely and I can't seem to find something similar (battery simulation) out there.
Also ordering a Joulescope in a couple of days

Yeah, I had the 2281S for a demo for a week. So alone it cannot create the model, you need an SMU for that. I wasnt satisfied with it, because in battery simulator mode, the current resolution is really low.
In power supply mode, it has many ranges and it shows 3uA load perfectly, but in battery simulator, it is locked in the highest range (6A) and your resulution is 10uA.

Also, by the looks of it, the ESR is simulated, so it takes a current measurement, and adjusts the voltage accordingly. Which is slow, hovewer probably an OK model if you have high currents for a long time.
I think their target market is phones and other equipment with rechargeable battery. Definitely not my use case, I have devices with 10 year battery life.

The salesman suggested buying a 2461 SMU, which has 1MSPS, the required range for current measurement, and spending a bunch of time writing scripts. But then again, that is already an expensive equipment.

At this point, I think "two boxes" would solve the problem a lot easier than 1 box. I am talking about a power supply with sense lines and a current measurement device (probably multimeter). If it can compensate for the burden voltage, then it should be fine, and the statistics on multimeters should be enough.

For sure, the Julescope would be interesting when it is available. Also, I guess mAh reading could be added. Otherwise I will ghetto-rig something together.

[mliberty]

Quote from: NANDBlog on Today at 01:47:01 am

For sure, the Julescope would be interesting when it is available.

Joulescope is available, in stock and shipping now!  You can purchase one at https://shop.joulescope.com/.  We have already shipped to all of our Kickstarter backers and preorder customers.  We are shipping orders placed on the shop as of today.

Disclaimer: I am the creator of Joulescope

[cgroen]

Yeah, I had the 2281S for a demo for a week. So alone it cannot create the model, you need an SMU for that. I wasnt satisfied with it, because in battery simulator mode, the current resolution is really low.
In power supply mode, it has many ranges and it shows 3uA load perfectly, but in battery simulator, it is locked in the highest range (6A) and your resulution is 10uA.

Also, by the looks of it, the ESR is simulated, so it takes a current measurement, and adjusts the voltage accordingly. Which is slow, hovewer probably an OK model if you have high currents for a long time.
I think their target market is phones and other equipment with rechargeable battery. Definitely not my use case, I have devices with 10 year battery life.

The salesman suggested buying a 2461 SMU, which has 1MSPS, the required range for current measurement, and spending a bunch of time writing scripts. But then again, that is already an expensive equipment.

At this point, I think "two boxes" would solve the problem a lot easier than 1 box. I am talking about a power supply with sense lines and a current measurement device (probably multimeter). If it can compensate for the burden voltage, then it should be fine, and the statistics on multimeters should be enough.

For sure, the Julescope would be interesting when it is available. Also, I guess mAh reading could be added. Otherwise I will ghetto-rig something together.

Thanks NANDBlog,
As far as I can tell, there are a number of csv files of "known" batteries for the 2281S, I hope I can cope with that and/or find someone with a 2450 that can get the data from a specific battery.
I need something to act as a battery for some of the stuff I do, normally it is with LiIon (1S) around 2000 to 3000 mA/H and current drawn is usually around 20 mA when active and down to maybe 50 uA when sleeping.

Joulescope is available, in stock and shipping now!  You can purchase one at https://shop.joulescope.com/.  We have already shipped to all of our Kickstarter backers and preorder customers.  We are shipping orders placed on the shop as of today.
Disclaimer: I am the creator of Joulescope

I actually placed my order for a Joulescope today, so looking forward to getting my hands on it

[tszaboo]

Thanks NANDBlog,
As far as I can tell, there are a number of csv files of "known" batteries for the 2281S, I hope I can cope with that and/or find someone with a 2450 that can get the data from a specific battery.
I need something to act as a battery for some of the stuff I do, normally it is with LiIon (1S) around 2000 to 3000 mA/H and current drawn is usually around 20 mA when active and down to maybe 50 uA when sleeping.

That might work, because the sales rep said that it still accumulates the data for low currents, just doesnt show it.
Basically you have a CSV for a battery, for every % of SOC they measure an ESR, and votlage, and that's it. I would need to have at least a 3rd dimension, temperature. The voltage and the ESR of a battery changes a lot with temperature, and a 3.6V battery could be 2.4V at -40, with 3x the ESR. And my average current is below 10uA, so it showed 0 on the screen. Not very useful.
But probably it is fine for consumer stuff with pouch cells, AAs or 18650s. Those dont last that long on their own anyway.

[Kean]

I put off buying anything (apart from the Joulescope) for now.  Nothing beats testing with real batteries, but it does take time.