Charging dangers!

Nova Series
#1

I am writing to warn others not to do what I (apparently) have done with my Nova Pro. Noticing that my MacBook Pro USB-C cable would work as a charging cable for Nova, I plugged it in to charge the tablet. Unfortunately, I forgot it was still plugged into the adaptor of the computer, which puts out a lot more power than a normal cellphone or tablet charger. Now the Nova seems to be dead, so I assume I killed it with a power source that was too strong. I wrote to Book help and am waiting for a reply.

Just for your information - watch which chargers you use when USB-C is your cable. I might be wrong about my tablet, but it has been frozen for 12 hours now…

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#2

Hi Scott, thank you for your kind remind! Yes, Boox users are suggested to use the original USB cable and the 5V 2.4A charger to charge the Boox device.

#3

Update: I wrote to the help desk at Onyx and received an answer within hours. They suggested I plug in the correct charger and wait a few hours. Sure enough, the tablet revived! I guess it had an overcharge protection circuit? Anyway, thanks Boox, for excellent service.

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#4

Is there any chance that a future update will fix this issue so that we can charge the nova using a normal USB-C PD cable and charger, or is this a hardware issue that would require buying a new tablet? This is a somewhat frustrating deficiency given that the sales literature touts the USB-C connection without mentioning the restrictions.

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#5

Please note that this is a hardware issue and it could not be solved by firmware update. We will forward the request to make the restriction publicly to our relative colleagues. Apologize for any inconvenience that may cause.

#6

So, what if I lost the original charger and am having the same issue? Now what? I’m dead because you don’t sell chargers? 30 days and I can’t boot the device because I plugged into another USB-C adapter and don’t have my original.

#7

As for the 5V 2.4A adapter, you could kindly order one from Booxshop, Amazon or Ebay.

#8

Hi Scott,

Thanks god I think you helped me to understand why my Nova Pro has frozen.
I think I mixed my fuji gfx100 camera’s usb-c with my Boox usb-c.
So you mean it is enough to over charge the reader?

In the past, for exemple i always used same cable for kindle and fuji camera.
But this time with nova, It is not possible anymore, am I right?

I will have my answer tomorrow when I will receive my new cable.

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#9

Hi Claire,

10 days to one month to receive a charger from Boox when this issue happen, it’s a sad.

#10

Hi.
In my case, I used the charger for my Apple laptop computer, which is a LOT stronger than the Nova charger. But even so, the Nova recovered fine after I charged it with the Boox official charger. I’m very careful now!

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#11

Even the quickchargers from my Samsung Tab S3 or Huawei Mate 10 Pro are compliant. So I think a wide range of standard USB © chargers are working fine.

#12

Per our colleagues, the ETA will be longer for those accessory order since we choose the 4PX as a courier instead of the DHL, UPS and similar courier which would deliver within 5-10 working days but more expensive, and that would be more convenient for both customers and Booxshop. Hope you could understand that. If you request a faster way, please kindly contact the Booxshop to upgrade the delivery service.

#13

Which charger can I use for the nova pro?

P.S When I uploaded the pics they were the right side up don’t know why they turned.

#15

Please kindly use the second adapter, 5V 2.4A.

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#16

Hi @claire …I have just bought my first NOVA PRO. Could you answer me this question? It is safe to use a 5V - 1.55A charger to charge the device? Could this generate problems in the future because I do not use the recommended 5V - 2.4A? thanks.

#17

Hi everyone,

You can safely charge any device with your macbook USB-C charger, except if the device for some reason doesn’t turn off charging.

USB-C chargers work by default by putting out 5V. The device can then request to switch to higher voltage to be able to supply higher power by increasing the voltage to 19V to decrease the current through the thin wires. If your device is not a laptop, it will not request this high-voltage mode, and everything will work just like any other charger.

The amperage of the charger doesn’t matter as far as it is >= as officially recommended (not even if they are lower, see below). Chargers are voltage source and not a current source. They have a maximum current they can put out, but they can go lower without any problems. Using a 100A charger instead of a 2.4A one wouldn’t mean that the 100A will flow through the device. The same amount will flow as with the 2.4A one. Just like if you have a tap with a huge pipe connected to a thin pipe will not result in more water flowing out than if the tap is of the same width as the pipe thin pipe.

Most of the USB charger ICs also have a mechanism built in that can reduce the charging power if there is not enough current provided by the charger. It does this by monitoring the voltage drop and adjusting the charge current to be lower. Lower charge current is actually preferable: it will result in less heat in your battery, which, as a result, will last longer. The downside is that charging might take a long time.

The above-mentioned mechanism also kicks in when you connect your tablet to your PC: the USB port has a current limit of 500mA. If the device would try to pull more out of it, the port would be just turned off for safety reasons. So your device is completely fine with 500mA of current.

They only thing that really matters is that the charger should put out a stable 5V.

In some cases, it might happen that either digital communication or some pullup/pulldown resistors on the USB lines are used to identify the charger. In this case, the device might refuse to charge itself in some chargers.

The only danger of using a laptop USB-C adapter is that it might be a cheap aftermarket one, and I’m not sure all of them are respecting the specifications, and they might put out 19V by default. With the OEM charger of any manufacturer, you are safe (I used it myself multiple times on all kinds of devices).

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#18

Sorry for the late reply here. Please use the 5V2.4A adapter to charge the device instead of the 5V1.55A to ensure a better battery performance and protect the device.

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