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Comment by SOLAR_FIELDS | Hacker News Reader

For those interested in energy profiling tools that have applications for developing battery powered hardware products I can highly recommend Nordic Semiconductor’s PPK II. For a reasonable price you get a hardware tool and software kit that can profile your actual energy usage quite well. It has punched well above its weight on providing power profiles against tools an order of magnitude higher in price. If you are designing a hardware product that runs on battery a tool like this is a necessity.

I know above sounds like an advertisement but it isn’t. I’m not affiliated with NS at all. It’s just a great tool and I’m happy to recommend it as there are very few cost effective options in this space.

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That tool is for someone who needs to maximize battery life for a small device.

For higher powered DC loads, there are Hall effect sensors. These usually come as plastic-enclosed devices with a hole in them, through which you route one of the high-current wires. They need some DC power, usually 5V or so, and you get a voltage out proportional to the current. They sense the magnetic field from the wire, without requiring a direct connection, which is good when you're measuring high current, high voltage, or both. Some have a split ring so you can install the sensor around an existing wire without cutting it.

For AC, there are current transformers, which install the same way, and put out a small current in a fixed ratio to the current in the wire being sensed.

The hand-held version is a clamp-around AC/DC current meter, a common tool.

These are all standard, modestly priced items.

I used Hall effect sensors for a project and found they needed a fair bit of calibration. Shunt resistors also did the job with fewer problems but this was a 16p2s module.

> I used Hall effect sensors for a project and found they needed a fair bit of calibration.

From AliExpress?

Hall sensors have a lot of issues. If you can handle the power dissipation in the resistor, a shunt plus a fancy zero-drift difference amplifier is almost always going to be superior.

Hall sensors win for very high currents, high bandwidths, and when isolation or noninvasive measurement is required.

Technically, yes. That's how most meters work. But now you have high current, high voltage, and isolation issues in your sensing device. So you need more testing and approvals.

> Nordic Semiconductor’s PPK II

This looks great, from their page:

"can measure and optionally supply currents all the way from sub-uA and as high as 1A"

Do you have recommendations, for a similar device, that can supply more than 1A?

It depends on what you need. But you should start by looking at Keithley's SourceMeter "source measure units" and competing instruments from Keysight and Rohde & Schwartz. There are even specific instruments in this vein that can emulate battery charge/discharge models out of the box. These are typically called "battery simulators" or "battery emulators".

https://www.tek.com/en/products/keithley/dc-power-supplies/2... https://www.keysight.com/us/en/product/E36731A/battery-emula...

Sorry, I have only developed low current devices and can only speak to applications around those.

The folks developing the Sensor Watch also used the Power Profiler Kit II to test its power consumption. Seems to be a really good device.

https://www.nordicsemi.com/Products/Development-hardware/Pow...

How hard is it for an electronics layman to use this hardware? I want to buy one in order to help out but when it comes to circuits I'm a pretty much a beginner.

Good to know, do you develop battery powered hardware?

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