In a feat of over-engineering, [Everett Bradford] hacked his power bank to add power monitor via an OLED display to show live current, voltage, temperature, and capacity information. The idea came when he learned about the INA219 chip. The INA219 is a current shunt and power monitor IC with an I²C or SMBUS compatible interface. The device is able to monitor both shunt voltage drop and bus supply voltage, with programmable conversion times and filtering. A programmable calibration value, combined with an internal multiplier, enables direct readouts of current in amperes. An additional multiplying register calculates power in watts.
With impressive miniaturization skills, [Everett] dissembles the Xiaomi Mi power bank and manages to add a custom power monitoring module and an OLED display. Not only that, he replaced the 4 LEDs that were the battery level indicators and actually consume more amps than his board plus the display. While active, the board consumes about 8mA. In sleep mode, it consumes less than 30µA.
The 32×64 OLED display and the custom-made circuit was assembled and tightly fitted into the original case. The power bank now gives readings of the battery charge level in a small graph, numeric current input/output, voltage and temperature. The seamless integration of the display into the power bank makes it look like something that could perfectly have come from a store. This is not your typical DIY power bank nor a gigantic 64 cells power bank. It is a precise and careful modification of an existing product, adding value, functionality, and dare I say it, style: an awesome hack!
We can see [Everett] process in the following video:
That’s nicely done.
Nice hack, but too many informations isn’t good either in simply devices like powerbanks.
I wonder how well those tiny shunt wires can handle the 2A rated output of the battery. Beautiful job though.
They only measure voltage drop across the shunt resistor- very small current…
In the video he said the shunt resistor is still on the original PCB.
Looks stock, like as though it has always had said display!
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Imho there should be more power banks with info displays like this, should have a hold and tap mode selection for the power button to support various modes:
# – Auto off – for those keep-it-green SJWs,
# – Always on – Ignore load current and supply anyway and shut down on “charger” removal for quick transport,
# – UPS mode – Like “always on” but continues to supply even after loss of “charger” power.
Also should be capable of supplying a minimum of 3A
Only 3? The USB coffee machine I’m making needs at least 30….
USB controlled, or USB powered?
It’s going to be a long wait for coffee on 150W.
You just set it to start 45 mins before your alarm in the morning, and presto, 5 oz of lukewarm coffee to chug as soon as you wake!
I wish a board like that could be bought. Superb!
I left a comment on his Youtube page asking him to share the board on OSHPARK.
sweet stuff :)
Displaying power seams like a job better suited to an e ink display.
NM, I just watched the video and it is only powered up when the device is active and extremely dynamic. I was thinking that it would be good to see the information updated once a minute when powered and also to be able to see the previous state of use when inactive, basically not as much dynamic information.
Nice job.
Anybody know of a reasonable (cheap, small-quantity) source for the solder-strippable “magnet” wire he makes liberal use of there?
All magnet wire I’ve used is solder strippable. You just need to flux the end of the wire first.
I have a good stock of litz wire that (wonderfully) strips with just solder – no flux needed. But out of the dozen or so different spools of magnet wire I’ve bought (different brands, different suppliers, different quoted insulation types) I have not found one that works as cleanly as that litz stuff. Even the polyurethane/polyimide stuff that’s *supposed* to be low-temp melting (155C) doesn’t work near as well. Digikey doesn’t offer anything that looks suitable, and their cheapest is >C$80 per spool anyway. Mouser has nothing.
So, where are people getting this stuff?
A very well executed mod. Quite a bit of skill involved. This would be a very good addition to a power bank. I wonder how long until we see them coming out installed with this?
We can all hope!