15W PD limit?

[AndyN]

The quick start guide for the PineTab2 mentions only charging at 5v and 3 amps. I.e. not using a charger beyond 15W. 

Since I thought PD was supposed to negotiate the safe limits between the devices.

A couple of possibilities come to mind:
1. The testing just hasn’t been completed to certify that higher voltages are okay
2. The BMS/PD is programmable and Pine has no way to know what OS distributions have done to it.
3. There are inherent limitations in the circuitry that preclude the use of higher wattages. 

Basically if someone with knowledge of the charging circuitry weigh in that would be great. 

Thanks

[chzbacon]

Out of curiosity I hooked the PT2 up to my Anker 65w PD charger and connected it to a killawatt meter. I'm drawing .5 amps at roughly 8 watts. I haven't tested with a 15 watt 3 amp charger yet but that's next on the todo list. Just thought I would drop my findings here.

From what Segfault mentioned in the discord is that it's configured to draw 5V 1.5A with some chargers being able to do 5V 3A. 

The quick start guide for the PineTab2 mentions only charging at 5v and 3 amps. I.e. not using a charger beyond 15W. 

Since I thought PD was supposed to negotiate the safe limits between the devices.

A couple of possibilities come to mind:
1. The testing just hasn’t been completed to certify that higher voltages are okay
2. The BMS/PD is programmable and Pine has no way to know what OS distributions have done to it.
3. There are inherent limitations in the circuitry that preclude the use of higher wattages. 

Basically if someone with knowledge of the charging circuitry weigh in that would be great. 

Thanks

---

Did another quick test using a Lenovo tablet charger rated for 10 watts @ 2 amps and I'm drawing .6 amps and 9.9 watts on the killawatt meter.

[frtodd]

The quick start guide for the PineTab2 mentions only charging at 5v and 3 amps. I.e. not using a charger beyond 15W. 

I took note of that, too. What it actually says:

The PineTab2 should be charged using a 15W (5V 3A) USB-PD power adapter. Charging at a higher voltage may result in damage to your device.

My interpretation:

You need 15 WATTS minimum to properly charge the device. That's reasonable. That's the power capacity of the charger.

Charging at higher VOLTAGE will damage it: 5V (the USB standard) is what's required.

I plugged it into my laptop dock with 85W PD: it works great. I left it on an Anker charging station overnight: that seemed fine, too. Some of the more puny device chargers you may have lying around may not produce enough power, though they will still be operating at the USB standard of 5V. Upping the voltage with some other random charger, though, would not be helpful.

[AndyN]

The quick start guide for the PineTab2 mentions only charging at 5v and 3 amps. I.e. not using a charger beyond 15W. 

I took note of that, too. What it actually says:

The PineTab2 should be charged using a 15W (5V 3A) USB-PD power adapter. Charging at a higher voltage may result in damage to your device.

My interpretation:

You need 15 WATTS minimum to properly charge the device. That's reasonable. That's the power capacity of the charger.

Charging at higher VOLTAGE will damage it: 5V (the USB standard) is what's required.

I plugged it into my laptop dock with 85W PD: it works great. I left it on an Anker charging station overnight: that seemed fine, too. Some of the more puny device chargers you may have lying around may not produce enough power, though they will still be operating at the USB standard of 5V. Upping the voltage with some other random charger, though, would not be helpful.

Re-reading that statement as you posted is a little clearer. In my understanding the charger should restrict the voltage to what’s supported. Your 85W charger would support 20v, but would be choosing not too.

I’m guessing the wording might be accounting for some poorly implemented chargers that might dump higher voltages by default. Make sure you trust your charger if it’s more than 15W basically.

 I had a look at the schematic and if I’ve understood correctly, the capacitors across the usb port are only spec’d to 10v which if implemented on the board means higher voltages will not be supported.

I charged off a regular USB charger and it stayed around 1.4 amps at 5v.it did charge, slowly.