I have a self made Isolation Board which consists of 2 Relay Switches and provides a kind switching function to cut off the power supplied to a Sensor Device on the other side of this Board.
The sensor device is battery operated and in common scenarios will take the power from the Raspberry Pi 2 via the Isolation Board.
Current Specifications in general for Raspberry Pi-2 and the world standard for USB-2.0 is rated approximately
~500mA. This creates a problem since the Sensor is battery operated and the ratings on it are
This means when the battery of the sensor is completely drained out and if I would like to get the Raspberry Pi to start charging it for me-
- The sensor would try to get more current from the USB port of the Pi (
>500mA). This creates an electrical malfunction and the Raspberry Pi HANGS. Hence I cannot do anything with the Pi.
Possible Solutions already tried:
I am already using a Standard
2APower Adapter of a very decent company to fulfill the main power supply needs hence Checking the Power Adapter option is not in question
I have also tried doing the
usb_max_current = 1int the
config.txtfile for increasing the current at USB. This too fails and the problem still persists. The Schematic of the Pi splits the current evenly to all the 4 ports and hence getting a single port with
1Acurrent is not possible and it would also not comply to the USB standards
Are there any other ways to tackle this situation? The only possible way is limiting the current from the Sensor board to close it to
~450mA but that could be the last resort for this problem.
Can I use adapters that have higher current ratings? e.g.
3 or 4 A current ratings and even if I do use them will they help to overcome this problem?
the Sensor battery is high current hungry Lithium Polymer (LiPo) battery and they will draw massive currents when the sensor is completely discharged.
another current hungry device are the Relays which are on the Isolation Board but somehow how they aren't the real devil here.