Norns battery life

2 questions:

  1. what’s the expected typical battery run time of a factory norns? i.e. approx. how long should a norns run on battery before I need to recharge it?

  2. can I replace the battery with an off-the-shelf new one with longer run time / more capacity?

Mine (a brand new one, bought a while back) has never seemed to have ever lasted more than 30 minutes or, and I’d like it to. I typically use it with WIFI on, and a grid connected, but nothing else out of the ordinary happening. Just the usual scripts.

  1. battery life is extremely variable, because power draw is incredibly variable. the wifi nub draws a lot of current, and grids can draw even more depending on how many LEDs are lit. what’s more— the CPU itself massively impacts battery life depending on how hard it’s working: some engines are very heavy. you can observe all of this by hitting K2 on the HOME screen, where you’ll see the power draw (in mA, negative is draining battery, positive is charging), something like -520mA.

  2. this battery is identical to what we use: and you can also contact if you think your battery is defective. this is the biggest battery that will fit. i spent months working this out, and wasn’t interested in making the physical design bigger just to accommodate a bigger battery.

generally i’d suggest powering the norns externally, especially if you have a bunch of USB devices plugged in. the raspberry pi is a pretty high powered computer compared to the tech that is inside many other instruments that use batteries. if you need reliable operation on the go i’d very much suggest using a battery powerpack plugged in to the norns power port. but of course it’s ok to use the built-in battery as-is, if you’re conscious of the realities of how much power your current setup (script and external devices) are using.


thanks for the detailed response - all understood.

I doubt my particular battery is defective, but I’ll do some more tests and make contact if needed.

FYI, I’m in Australia, and these batteries seem to be hard to come by. I’ve not yet found any local stock (after 5 mins of googling), and digikey and other big retailers won’t deliver these batteries here at present (coronavirus?).

Came here with the same thoughts. I’m sometimes shocked how quickly I can burn the battery and started wondering if it was failing. Perhaps we could benchmark with the awake script and nothing in the usb ports. I’ve been running awake and keeping an eye on the battery drain, it was draining quite dramatically but once I removed the wifi dongle it drains at about 2% per minute. With a draw of ~331mA .

Hm, that would put the battery capacity well below the factory spec of 2k mAh, no?

(Unfortunately not an unforeseeable outcome of use. My norns battery is getting weak too I think)

I’ve not really been concerned, as I mostly use norns powered, I think it’s the only thing I have with an inbuilt battery actually. Also my testing is pretty unscientific. Would it be worth making some sort of benchmark/test script? I’m also in Australia and I suspect those supply issues haven’t yet been resolved.

there are two possibilities:

  1. the battery is failing, which is not entirely unlikely but also testable by letting the battery actually run to zero and see if the unit turns off. and if it doesn’t…

  2. there’s something going on with the battery driver. this was reported some months ago and my attempts to figure out the reporting didn’t result in a fix (whereupon i got distracted by other issues of course). i believe the reported max capacity (to linux) is incorrect. this all happens within the /sys/class/power_supply internals.

needless to say, if your battery is failing email for a replacement, and if not, hopefully i’ll get a fix for the reporting (any help from linux wizards very much welcome!)

(side note for non-norns, here’s a cli method for get battery percentage)

echo `cat /sys/class/power_supply/BAT0/energy_now`/`cat /sys/class/power_supply/BAT0/energy_full` | bc -l
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Pretty sure that needs to be back-ticks, not single-quotes:

echo `cat /sys/class/power_supply/BAT0/energy_now`/`cat /sys/class/power_supply/BAT0/energy_full` | bc -l
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thanks!! fixed my pastefail

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Hey @tehn & @dan_derks ,

I ordered a new battery for my Norns last week because I thought it was failing (Norns won’t turn off when at 0% and says LOW BATTERY). I installed the new battery yesterday and before charging it, I let the Norns run a script until the battery ran down to 0% again. The Norns did not shut itself down. Also when put to sleep at 0% and powered back on, it loads up and continues to report LOW BATTERY. I charged the battery to full overnight and let it run down again and same behavior today as described above.

Does this mean something is going on with the battery driver as mentioned? Is this harmful to the Norns to leave it running at the 0% state? I guess it should eventually shut itself down?

At any rate, I wanted to report here for troubleshooting/ upcoming fixes since I just put in a fresh battery. Here are the two batteries for comparison (Looks like the original might have a date stamp of 2018?). My Norns has a green PCB if that helps, too. Thanks yall :raised_hands:

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the batteries look good. does the new battery charge?

the 0% report is a known bug in the driver— i think what’s happening is the capacity is miscalibrated and there’s much more charge available… which is why it doesn’t just die at 0%. will prioritize looking into this.

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Yes the new battery charges to 100% with no issue as did the old one. I’ve not done any real comparison of battery time differences but the new one seems to hold charge longer with a wifi nub and a script running.

sounds good - thank you & much appreciated !

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Is it bad for the internal Norns battery to be plugged in 24-7? I’m wondering what the best practice is. Unplug after use? Some circuit that protects over charging?


ooh, good question. bump!

FYI the charging IC is this:

it’s pretty smart so i suspect it’s fine to leave it plugged in, but i have not done a deep dive.


Please let us know if you have any information about this. I’m getting my new norns back and was also wondering if I could keep it in charge all the time or not. Thanks!

I’m curious as well about this 24/7 connected cable point, I personally tried both, now I tend to not leave it connected all the time, but I’m not a lucky case I guess, as I had a couple battery issues through the time, I’m not saying the problem is the charger cable anyway :slight_smile: but I don’t have an answer to share.

Atm moment my battery seems dead, so I’m able to use Norns only with the cable connected, otherwise Norns doesn’t work.

I’m wondering if it’s normal that the percentage detection goes crazy like that …

I have to buy an other battery alone, or it could also be a detection chip issue, as it’s happened to me the first time?

email and we’ll get you fixed up


Hi Sidiblue - did you get a response on this question?

@studio_snippets No more than what is mentioned in this thread

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