Battery discharged


(Scott R) #1

Recently I experienced a full discharge on my battery where it rapidly dropped to 0.14v. And said in another post I would document the behaviour.
At the time of discharge the Arduboy was connected to usb and shortly after uploading a sketch the bottom half of the screen garbled and then the Arduboy switched off.
I immediately thought I had corrupted the bootloader to find the Arduboy booted and run fine when connected to an ISP programmer, at this stage I grabbed my multimeter to find the battery depleted and refusing to charge.

  • The Arduboys charge led will not switch on unless the Arduboy is turned on but the unit itself will not power on.

  • Jumping the Battery + terminal to Vcc will allow the unit to boot from usb power

  • connecting a second Lipo in parallel also allowed the unit to power on and charge whilst this allowed some charge to enter the battery it wasn’t any significant level.

  • the battery will not take a charge from another Lipo charger I have but will increase to 0.34v on a lithium Ion charger but this rapidly depleted.

I’m yet to hack up a NiCd/NiMH charger to try get it up to 3v but it’s been few days so it’s probably too late.

Under normal circumstances it’s advised to contact @bateske via the contact us page. However my Arduboy is a bit of a warrior from 2017 and has already had the mcu replaced.

I’m not 100% certain what caused the battery to drop but I’m guessing it’s possibly something to do with leaving a mpu6050 connected via i2c for a long period but thought this would be fine due to the battery protection circuit.

For now the old warrior lives on to fight another day with a salvaged micro drone battery.


(Holmes) #2

It lives! You gonna make a new backing for it?


(Scott R) #3

Hopefully I’ll have something sorted for it I’ve grown quite attached to this unit and it was my first one.


#4

Same here, call it first :heart: :blush:


(Pharap) #5

Name it Ichiro.


(Kevin) #6

Depends on where you hooked up the chip power supply to? Was it connected directly to VBAT because then it was powered even when the device was off.

The battery has had an internal failure which has lead to a short circuit. Continuing to try and charge it will likely cause a fire hazard so I wouldn’t really try that. Or if you do (which you shouldn’t) make sure to do it outside with fire protection equipment.


(Scott R) #7

Connected to VCC,GND,SCL,SDA test pads the board also had its own power led that went on and off with the Arduboy.


(Kevin) #8

I think its unrelated to anything, the battery just failed. It’s probably due to the fact you touched it a lot, honestly. They are fragile.


(Scott R) #9

What is it that’s stopping units from switching on with a dead or no battery when usb powered is it the lack of current on the charge circuit?


#10

The MCU(let’s just call it that for now) had a built-in voltage limit of 3.3V.
A voltage lower than that can power it, but it won’t power on.
The charger block work by detecting battery’s voltage, then pump out a slightly higher voltage.
If the voltage do not reach 3.3V MCU can’t be switched on.
That is also why hooking up a capacitor son’t work – there is no voltage from it.

salvaged micro drone battery

Mine ran on a salvaged … Bluetooth keyboard battery.
I also had a salvaged micro drone battery with 20ma more than yours.
Or I can get myself a 2200mah, 3.7V big slab drone battery. (full-week power-on!)
But a 500mah salvaged bluetooth speaker battery sounds more reasonable.
You can also use thin wires to break out the battery to the outside of Arduboy. That is what I did.


#11

That’s what the power switch also (supposed to) does. Is there a bad track / solder joint somewhere?

From what I’ve learned is that conductive particels (copper) get loose from one of the electrodes and causes the internal resistance to lower. When removing the charger.The battery will rappidly discharge internally. Time to recycle it.


#12

As everyone has said internal battery failure has led to a short. Possibly due to some kind of dendrite growth puncturing the insulating separator and shorting the two electrodes with some relatively low resistance current path. I’d safely recycle it and not bother trying to charge it anymore for risk of catastrophic failure.


(Scott) #13

Incorrect. The ATmega32U4 processor is specified down to 2.7V.
From the datasheet:

Table 29-1. DC Characteristic, TA = -40°C to 85°C, VCC = 2.7V to 5.5V

The chip has brown out detection circuitry, which can be set to limit the minimum voltage that the chip will operate at. This voltage is determined by programmable fuses. For the Arduboy, the fuses are set for a brown out detection level of 2.6V.


(Scott R) #14

I have continuity between the switch and vcc and it also works with a good battery connected. It’s just when you remove the battery (or it’s dead) that it doesn’t boot from USB.


#15

Pretty sure this is normal behavior. The 5V USB only goes to the usb supply pins on the micro and not its main Vcc supply pins and thus usb alone cannot power the arduboy (which is why the arduboy must be turned on and plugged into usb to upload a new game).


(Kevin) #16

Oh, if the battery was installed with this mod, you were injecting 5v to the battery when it was plugged in.


(Scott R) #17

the i2c install or the jumping to vcc?

when jumping to vcc the battery was already dead and the arduboy will not boot from usb only power without a working battery.


#18

most likely because the charger chip doesn’t see the battery/the bad battery and doesn’t try to charge it as a safety precaution.

When you look at the schematic you can see that the Battery + terminal is connected to the switch and the other end to Vcc. So when it closes it connects the + terminal to Vcc. If it doesn’t work with the switch on but it does work connecting + to Vcc manually. There must be something wrong. Have tried measuring the resistance between theBattery + and Vcc ?


(Kevin) #19

The battery is dead yo. As mentioned before I think physical contact killed it.


(Scott R) #20

Let me clarify since replacing the battery the unit works as expected.

The bit where I’m confused is why it doesn’t boot when connected to USB without a battery even though there’s voltage present at the terminal when switched on.