Charging

I've just started playing with my Bangle.js and so far I can't seem to get it to charge. It arrived with about 50% battery and within 2 days on idle it got to 0% and turned off, which is a faster discharge than I expected. It's not turned back on at all since.

A green light flashed when I initially connected the charger but now nothing happens. I didn't see the tiny label about orienting the charger so I tried it both ways round initially.

Is there a trick to it? Can I do a soft/hard reset? I don't mind opening it up if I need to.

Also the demo GPS app never seemed to acquire satellites or get a time. Is this a known bug?

Thr 2019.12.26

Hi @AlexOwen, May not be of much help as these are all new questions for this fantastic product, has the 'Getting Started' page been reviewed?

'Is there a trick to it?'

https://www.espruino.com/Bangle.js+Getting+Started

'You must connect the cable the right way around: With Bangle.js facing away from you (so you're looking at the shiny back) and the CE Rohs text the right way up, the USB cable should exit from the left side of the watch.'

'mine had been left 'screen off' and went completely dead' instantly came to life using the above step

EDIT 1: Tested with WebIDE to E.getBattery() which returned a value of '0'
then, my screen went blank. (most likely as BLE draws 0.5mA and without substantial charge) Now, my screen in totally blank and dis-connecting and re-connecting the power cable isn't producing the same power on result. It appears mine is in the same condition as yours. I'll keep plugged in and report back in an hour.

EDIT 3: One hour of charging from a USB2 laptop port, now returns a value of '59'
https://banglejs.com/reference#l_E_getBattery
Incidentally for Windows10, I wasn't able to immediately connect using the WebIDE. I had to un-pair, open Settings >> Bluetooth >> Add a Device and select the first 'Bluetooth' option to pair, then open a new instance of the WebIDE before I could re-connect.

EDIT 4: Hour 2 and a value of '75'
EDIT 5: Hour 2:55 and a value of '100'

Has the 'Powering off if completely broken' section been tried?

EDIT 2: Ten minutes after above edit, Held in Btn1 and Btn2 for six seconds, even though screen is completely dark. 'Rebooting' then rendered briefly, and charging is back under way.

'and within 2 days on idle it got to 0% and turned off, which is a faster discharge than I expected'

Was GPS/Compass in use?

https://www.espruino.com/Bangle.js

'350mAh'

Should GPS have been left on, or any Javascript code running, expected uptime would be much less.

ex: at 50% battery life roughtly 175mAh of up time, might be achievable. Should Javascript be continuously executing, a 7mA draw would only allow for 25hrs duration.

The tenth bullet item has me a bit befuddled

'350mAh battery, 1 week standby time'
'Idle, accelerometer on - 0.7mA'
'This means that when idle (in the normal power-on state) you can expect around 20 days of battery life'

As there are 24 * 7 or 168 hours in a week, a 0.7mA draw would yield a 240 hour uptime. So maybe a 'week' was as close to a conservative guess (over time degradation) as one might expect, perhaps?
350 / 0.7 = 500    500 / 24 = 20.8 days   matches comment beneath heading 'Power Consumption'

Thanks for all the suggestions. I think I've tried them all already.

I've tried all the button combos on the getting started page, and nothing.

After I noticed the tag that says about correct orientation of the charger I made sure it was always the right way round.

I'll try leaving it plugged in again and see if it eventually comes back to life. Maybe it needs more time to get to a state where it can turn on at all. There's just no indication it's doing anything (no charging light etc.), but I'm also not sure there's supposed to be a charging light/animation?

I'd guess the battery died so quickly because something was running still. I think I left it on the clock (screen off) which I assumed was the idle state, but thinking about it that is probably still executing JS. That part I'm not worried about, it was more for context in case it helped.

Hi @AlexOwen,

It's not turned back on at all since.

Try resetting without loading any code

Also the demo GPS app never seemed to acquire satellites or get a time. Is this a known bug?

Build in GPS only works outside, and may take a while to find satellites.

Thanks for the help, I've also tried that combo several times too. Nothing displays on the screen so I can't do the second part of it.

After ~2 hours of charging it's just started flashing the green LED on the back (HR monitor?) randomly but there's still no display/beeps/vibration. I'm going to leave it for a while longer and see what happens.

WRT to the GPS, that makes sense, I was inside when I tried it. I was probably expecting too much of it.

Fri 2019.12.17

ref #3 post 'but I'm also not sure there's supposed to be a charging light/animation?'

No. Just discovered there is no charging indication. The screen stays completely dark.

'Nothing displays on the screen so I can't do the second part of it'
'but there's still no display/beeps/vibration'

FYI - Nothing was displayed and no vibration on mine either, (see my EDIT 1 inside #2 post) but I had just viewed the splash screen before, so I just formed a mental picture while counting 'One-one thousand, two-one thousand, . . . ' and as I released both buttons, the word 'Rebooting' in tiny ?2?pt font briefly flashed. I left it plugged in for a good twenty minutes more, and then it just started right up.

'After ~2 hours of charging it's just started flashing the green LED on the back'

This is a good sign. As you are just leaving it plugged in for a bit more is the best option at this point. In a pseudo panic state, I did the above routine at least five times before any duration longer than a few seconds of up time were observed. Patience.

https://www.espruino.com/Bangle.js+Technical

502527 Lithium ion battery

Found this article on how to bring a Li-Ion back to life. They are a bit more finiky than the old NiCd or NiMH rechargeables.

https://batteryuniversity.com/learn/article/low_voltage_cut_off

Even though your device indicated it had some amount of charge, and only a few days elapsed, it might be that the low threshold was reached, temporarily rendering the battery in a non-starting state.

What type of device is being used on the charging side? Is there another cable involved? Could either be suspect? Are the pins next to the magnets shinny? Try depressing and releasing them. Maybe a spring is stuck. Any crud on the back side of the watch?

The USB cable is perfectly intact, the pogo pins are free and there's nothing on the pads at all.

The LED is still just flashing irregularly and very fast, but nothing else is happening. I tried all the different combos again and it's just as lifeless.

I've tried charging it directly from my laptop and now it's been sitting on a high power USB mains plug for a few hours. I know the plug is fine because I use it for my phone.

This is normally where I'd re-flash the firmware, but I don't think it's simple (or possible?) to flash them without the OTA part working. I know it's a beta version, so I'm not expecting it to be 100% right away. Hopefully someone will have a winning idea soon.

As there is an indication of activity with the flashing LED, then by now there should be sufficient charge to attempt the following. I had to do this five times before the screen came to life.

What exactly happens while viewing the screen, when (top - between N and E) BTN1 and BTN2 are held in for a full six seconds, and then releasing just the BTN2 middle button, keeping BTN1 held in for another six seconds before finally releasing that?

I've tried it about 10 times (on charge and not) and still nothing.

I've noticed the LED only flashes (fast and regularly) when it's on charge, and when I start pressing any buttons the flashing becomes very erratic. When I disconnect the charger it turns off completely.

The screen never turns on whether it's charging or not. No errors, no messages, no animations. As it's OLED it could be off or just no data/image I guess.

Fri 2019.12.27

Alex, just had a crazy thought. Has any attempt been made to see if the WebIDE actually sees the Bangle, even with the display off?

Not sure which PC OS you have, I only have experience with Windows10, and have had to un-pair and re-pair at times. Just wondering if we may be able to reboot the device OTA. Are you able to press the WebIDE Amber 'Connect' button and does the WebIDE see the Bangle?

Yes, what Robin wrote: check if it's "visible" for your laptop. And try NRF Connect on a phone. IIRC if there is no Espruino JS code, the screen doesn't turn on, and the buttons don't do anything. But you can connect to it with the Web ide / app loader.

Do you have a USB power meter a bench power supply, or a DMM and some USB cable to check the carging current? Mine charges at a fairly constant ~230mA. What do you see? I think the manual say don't connect the charger backwards, don't know whether it has reverse polarity protection. It should be as simple as a schottky diode...

WRT GPS: well, gps lock feels slower compared to my phone, but phones cheat: they "remember" the last GPS location, can guess your location based on mobile cell information, wifi...

'whether it has reverse polarity protection. It should be as simple as a schottky diode...'

I would hope the designers of that watch (not associated in anyway to Espruino development) would have had enough sense to add that 0.01 part to protect the unit, when they came up with their magnetic convoluted 'either direction' charging adapter. That design fubar is just asking for trouble.

Sat 2019.12.28

'I've noticed the LED only flashes (fast and regularly) when it's on charge'

@AlexOwen, while attempting to render the 'Settings' menu, I noticed some parallel observations with what might be going on with your device.

forum thread BTN2 doesn't enable Settings Menu

Had the 'Heart Rate' monitor app been loaded, making use of the detector LEDs on the watch back?

As I needed to re-charge my device, I paid particular attention to the back of the watch, as your indication is that the LEDs flash. In my particular situation, the LEDs never flashed, but then again, I never loaded the 'Heart Rate' app nor I have I been successful at loading other apps.

However, as the LED has enough intensity to illuminate, the battery must be in the process of charging.

While attempting to learn how to render the 'Settings' menu, I was able to duplicate at least a half dozen times, the same no viewable display situation as in your case. The only recovery means, was to use the suggestion as outlined in #4 post. Mentally count, as the display never illuminated for me either, until a successful 'reboot' sequence occurs.

While I am unable to speak for other PC OS's, for Windows10 the 'apps' web page and the WebIDE have the ability to communicate as indicated in #11 post, despite not being able to see detail on the display. Any luck perfoming that task on your end?

Hi @AlexOwen,

There's definitely reverse voltage protection.

Sorry to hear you're having trouble with it. The heart rate monitor flashes at boot time (before much else happens) to show that the device is booting, but it should just flash once.

Repeated flashing of the light could be because it's trying to boot but it's not getting enough power to get past the initial boot procedure, so it's resetting (probably when the LCD screen backlight is turned on) and just repeating the same thing over and over.

Have you tried a different USB charger? It may be that whatever charger you're using isn't supplying enough power to get it over that initial hurdle.

Otherwise I guess it could be a problem with the charge cable. If you have a power supply you could actually attempt to supply power to the two pins on the back of the watch yourself.

If it's not that then I guess you'd need to open up the watch and add power to the battery manually - that may be something that you'd want to send it back here for though.

Is anyone else having this issue? If it's a problem then I may have to modify the bootloader to check battery charge and then refuse to boot until it's as some 'safe' level.

Tue 2020.01.07

I wish @AlexOwen had reported back with any info, and hopefully success.

Not having exactly that issue, . . . but,

'I may have to modify the bootloader to check battery charge and then refuse to boot until it's as some 'safe' level.'

I don't have sufficient direct practical experience with Li-Ion yet. I've read enough to know that I should be prepared! From the recovery link in #6 post, along with the simple fact I was faced with a dark display, to which having that knowledge and the wisdom to show patience with rechargables that can effectively render themselves non-starting. I lucked out with patience, rather than fiddling more.

IMO it would be smart to not allow booting for at least a fifteen minute charge time, when the device can't boot. Would it be possible to show (is display even visible when not booted?) a graphic indicating a charge is necessary prior to Espruino boot? My Amazon Kindle Fire HD stays in a red battery icon mode until at least 15% battery charge duration has occured. Can't turn on/boot until that, which takes about fifteen minutes.

Add as a back burner task. . . .

The bootloader has very little space left inside it (it's 4k smaller than it's supposed to be and it has to handle the LCD too) so it's hard to do anything too serious. Just checking battery charge may be a step too far.

However, it's possible that I could just make the bootloader put the watch to sleep unless BTN1 is pressed (since that's the button that's used to turn the device on).

Again, this may not be needed. I haven't had any dead units here, so really it depends whether any of the beta units suffer issues.

Sorry for the lack of reply, I've been really busy and away.

I've just got home and tried two other USB adapters (2.1A and 2.5A) and neither has done anything different. It's still just sitting there flashing the LED constantly.

I could send it back if you want to have a look at it? I think I've reached the limit of what I can do without taking it apart, which I'd rather not do if you want to see the malfunction.

Yes, sure. Since you're in the UK it should be trivial (and it'll also be good for me to figure out what's wrong) - I'll email you the address to use in a second.

Sun 2020.01.12

@Gordon, would you please expound on the difference between standby and idle please. ref #2 post

'350mAh battery, 1 week standby time'
'Idle, accelerometer on - 0.7mA'
'This means that when idle (in the normal power-on state) you can expect around 20 days of battery life'

As there are 24 * 7 or 168 hours in a week, a 0.7mA draw would yield a 240 hour uptime.
350 / 0.7 = 500 500 / 24 = 20.8 days

At idle is 10 days, capacity calculation is 20 days, but standby only a week? Puzzling. . . .

Where are those two things written?

I believe I'm probably just underestimating the battery life so people don't complain if it doesn't reach the advertised though.

Mon 2020.01.13

'Where are those two things written?'

As those 1000+ emails have caused some mental anguish, ;-) the link is in the #2 post, just above my comment.

link reposted here:

https://www.espruino.com/Bangle.js

Both found under 'Features' tenth bullet and 'Power Consumption' first bullet and comment beneath that grouping.

And an update on my actual usage

100% CPU usage running JavaScript - 7mA
LCD on - 40mA

On a brand new only charged once Beta Bangle, I ran a Javascript battery monitor endless loop, updating the display every five seconds until battery death. Ran for eleven hours!

Calc: 350 / (7 + 40) = 7.44 hr

So maybe the display is slightly better than advertised? Super conservative est ~30ma
or an actual pixel on percentage needs to be taken into account? Didn't think LCDs worked that way though.

Calc: 350 / (7 + 30) = 9.46 hr
Calc: 350 / (7 + 25) = 10.92 hr
or
Est: 11 * (7 + 40) = 517 mAhr

Which seems unlikely ~30% improvement over listed?

It will be interesting to see how LiIon holds out over time, after daily charging cycles. I expect it to drop off after 50-100 as the articles inform us.

Bangle LiIon     https://www.espruino.com/Bangle.js+Technical

'underestimating the battery life so people don't complain if it doesn't reach the advertised though'

Understood, and by my first inital test, makes sense so I wouldn't change the content. More concerned about standby and idle concept difference.

Ok, thanks.

So 350mAh battery, 1 week standby time in the features is definitely just an underestimate, but is meant to be taking into account that you'll probably have some stuff running on your watch that may use more power.

But in general the figures I give are definitely on the conservative side, and it wouldn't surprise me if there were also minor differences between watches - the watch I do power measurement on is one of the first ones I bought to take apart and develop with, so is from a completely different batch to the KS watches and could potentially have different resistors or even display backlight. I always felt that 40mA was pretty extreme for the display

Just an update, this turned out to be a manufacturing defect with the watch. Gordon replaced it (very quickly) and the new one seems to be doing great.

[update-all is well. I have some charge. I guess the constant green light is an indicator of charging.]

How do you tell if the watch is charging? My screen is dark, with an empty battery sign in the corner. A constant green light is coming out of the back. Should it be flashing as above, or is all well?

As long as you have the battery widget installed the watch should buzz when power is applied, and it'll display a little charging icon next to the battery symbol.

The green light on the back of the watch shouldn't be on normally unless you installed something like the heart rate widget.