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PiSupply / PiJuice

Resources for PiJuice HAT for Raspberry Pi - use your Pi Anywhere
https://uk.pi-supply.com/collections/pijuice/products/pijuice-portable-power-raspberry-pi
GNU General Public License v3.0
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Battery charge current is too low #899

Open plafond75 opened 2 years ago

plafond75 commented 2 years ago

Hi,

I have a RPi3 B+ on which is mounted a Pijuice module. I wired a 12.000mAh PiSupply battery on J2. The battery profile applied on pijuice_cli is the 12.000Ah one.

While my RPi is shutdown, I'm charging the battery through the PiJuice micro-usb. I tried charging it with both a QuickCharge USB plug and a lab PSU; in both cases, only ~750mA go to the battery (amp meter between the battery and the pijuice module) Both charging sources are able to deliver up to 3A but they only give ~0.8A.

Why is the battery not charging at ~2 or 2.5A since it's capable of ?

Is there any settings on the pijuice module I should change ?

Thanks in advance ! :)

tvoverbeek commented 2 years ago

What is the battery temperature indicated in the CLI? If the temperature is over 49 deg charging is reduced, while over 65 deg it stops completely. Normal charging current in the profile is 2.5A

plafond75 commented 2 years ago

Temperature is at 27°C (battery is not close to RPi) Now that RPi is running, the USB power source indicates 900 mA and the battery gets 400 mA. GPIO power input oscillates between 0.9 and 1.5A

Battery current (from the I2C API) gives -2368, which seems pretty weird...

tvoverbeek commented 2 years ago

Battery current (from the I2C API) is reported in mA. Negative means current into the battery (i.e. charging), positive is delivered by the battery (i.e. discharging). So a charge current of 2.368 A looks OK for a 12000 mAh battery

plafond75 commented 2 years ago

Theoretically, yes, 2.3A would be perfect; however, even if it's what's shown as a return of the GetBatteryCurrent() method, it's not what i observe with an Amp meter... (~ -400 mA) It kind of feels like the charging current is only "virtually" changed... The module "thinks" it's charging the battery at a ~2.5A rate, but in reality it only gives ~0.5A to the battery... Could this happen ?

NB : When i'm in discharging mode (no power source connected) : The Amp meter says 600mA (which seems acceptable for an Idle RPi3B+) but the GetBatteryCurrent() method returns 3210mA

NB2 : When i change the battery_profile to the default BP7X (but keeping the 12.000mAh battery wired), i get results that are closer to what physically happen:

tvoverbeek commented 2 years ago

Read up on the charging profile of a LiPo. See e.g the datasheet of the PiJuice charging control IC (https://github.com/PiSupply/PiJuice/blob/master/Hardware/Datasheets/BQ24160RGET.pdf) section 9.3.1.1

plafond75 commented 2 years ago

I am aware that the charging current is going to vary depending on the charge level of the battery, but in regulation mode, the charging current is stuck to ~800mA, it will never reach the 2.5A, even if the power source is capable of. Have you already tried the pijuice module with a 12.000mAh battery and measured a high charging current ?