What batteries can be connected to the M5 Core2?

kosa

What batteries can be connected to the M5 Core2?
For example, is it possible to connect a 10,000mA battery(LiPo 3.7V)?

I tried to connect it. It works, but the M5 Core2 heats up so much that I can't touch it.

What is the battery capacity that the M5 Core2 supports?

felmue

first of all the M5Core2 should not heat up that much if at all. Whether the battery capacity is 500mAh or 10000mAh doesn't really change things except for how long the M5Core2 can run from it or how long it takes to charge the battery through the M5Core2.

how exactly did you connect the 10000mAh battery?
is the battery included with M5Core2 still connected?
what exactly is heating up, the whole M5Core2, the charger IC or the ESP32 chip itself?

I don't think there is a technical limit regarding battery capacity, but if you want to charge the battery through the M5Core2 then I guess a practical limit would be the time it takes to charge a large capacity battery. The AXP192, responsible for charging, by default is set to 100mA charging current which means it takes about 100 hours to fully charge a 10000mAh battery. The charging current can be increased, but you'd have to look that up.

Thanks
Felix

can be set to to a maximum of about 1300mA which means a charging time close to about 8 hours.

kosa

Hi @felmue .
Thanks for the reply.

I am relieved to hear that the battery capacity is not relevant as I recognized.
As for the connection method, the standard bottom battery of the M5Core2 is not connected.
It is connected to the small battery connector on the back side.

The entire M5Core2 seems to be heating up. The LCD is also hot. The IMU board of the Core2 connected to the back side is also heating up.

I understand about the charging time.I am not considering charging with the M5 Core2.
It is not realistic to charge the battery for 100 hours.

M5.Axp.SetCHGCurrent(AXP192::kCHG_1320mA);

With this function, we have set the current to 1320mA.

felmue

Hello @kosa

hmm, does it get hot while charging the battery, running from battery or in both cases.

I've setup my M5Core2 to output the maximum charging current (1320 mA) and attached a fairly empty battery. The current started at the maximum but dropped down to 900 mA after about 10 minutes and continues dropping. So far the M5Core2 only is getting hand warm.

Have you measured the actual current going into the battery over time? Are you sure your wiring is correct and the battery is not faulty?

Thanks
Felix

kosa

Hello @felmue

Thanks for the reply.

I found the cause. It was broken.
When I connected the battery to the new M5Stack Core2, there was no heat generated.
It seems that the two M5Stack Core2 we tried were not working properly.

I apologize for the inconvenience.

felmue

Hello @kosa

No need to apologize. I am glad to hear you found the cause. Thank you for reporting back.

Thanks
Felix

ggerrronimo

I'd recommend using batteries with a lower capacity. The M5 Core2 is designed to support batteries with a capacity of around 3000-4000mA, so sticking within that range should help prevent overheating issues. Additionally, if you're looking for alternative battery options, you might consider lifepo4 cylindrical cells. These are known for their stability and safety, making them a popular choice for various devices.