5 replies to this topic

[John...]

The original charger is a great way to top up the battery quickly. A couple of hours at most seems to bring it up to nearly 100%. It can deliver 5V at 2amps.

But how about other methods? I bought a backup 2.5amp charger from Maplin. In theory this should be just as good, but it's charging time is much longer.  Charging via a normal USB lead almost seems to discharge the N700.

Is this normal?

[FatherD]

John..., on Mar 23 2011, 22:16, said:

The original charger is a great way to top up the battery quickly. A couple of hours at most seems to bring it up to nearly 100%. It can deliver 5V at 2amps.

But how about other methods? I bought a backup 2.5amp charger from Maplin. In theory this should be just as good, but it's charging time is much longer.  Charging via a normal USB lead almost seems to discharge the N700.

Is this normal?

Yes I think this us typical - your PC's USB will deliver only 500ma, so will charge very slowly ... if you are running intensive tasks at the same time it may even discharge!
Quite why a 2.5a charger should take longer I don't know!

All the best.

[LoJaylo]

I'm very interested in this question.

I want to use the Viewpad 7 100% in car, so I'm trying to find a way to quick charge, as the original wall charger.
I've tried some 5V/2A chargers with an standard USB data cable, but it charges slow. Then, I saw that original USB plug charger had 10 pins.

Then, I cut the original charger cable -which has only two wires, and I solded the original 10pin plug to an standard USB cable (of course, only red&black wires). I plugged in a 5V/2A car charger and, ...it works!!! The tablet full charges from zero in two hours.

But, I need an angled 10pin USB plug, because the original is too large for my car integration.
I've analyzed original 10pin outputs, I've solded another 10p USB, I compared outputs with original one, but, ...it charges slow.
I have no idea what I've done wrong.

Anyone has any idea?

[UKChris]

I've been taking a look at the mains power supply to the Viewsonic Viewpad7 as mine has stopped "fast charging" for some as yet unknown reason. I haven't solved my problem, but I have found out thet the plug on the mains adapter is a Mini USB EMU 10 pin plug which is a standard mini USB on one side (pins 1 - 5) and the other side uses pins 6 and 10 to provide a second 5v supply. If you look at the power supply (I had to use a magnifying glass) it shows the pinouts as:-


Pin1 +5v (standard mini USB)

Pin5 -5v (standard mini USB)

Pin6 +5v (same end as pin1)

Pin10 -5v


I'm guessing that the device has two charging circuits making use of the separate supplies to charge faster.


Hope this is some help.

[Claudioggs]

Probably is the same issue than Garmin GPS chargers.
The Garmin GPS chergers have a 17.3 K resistor connected internally between pin X and ground inside the connector.
The device may detect if an original charger (2A)  or a standard USB data cable is connected.
http://pinouts.ru/GP...er_pinout.shtml

Probably this tablet charger use a similar trick to detect 2A or 0.5A chargers.

Cheers

UKChris, on 06 October 2011 - 11:31 AM, said:

I've been taking a look at the mains power supply to the Viewsonic Viewpad7 as mine has stopped "fast charging" for some as yet unknown reason. I haven't solved my problem, but I have found out thet the plug on the mains adapter is a Mini USB EMU 10 pin plug which is a standard mini USB on one side (pins 1 - 5) and the other side uses pins 6 and 10 to provide a second 5v supply. If you look at the power supply (I had to use a magnifying glass) it shows the pinouts as:-


Pin1 +5v (standard mini USB)

Pin5 -5v (standard mini USB)

Pin6 +5v (same end as pin1)

Pin10 -5v


I'm guessing that the device has two charging circuits making use of the separate supplies to charge faster.


Hope this is some help.

[Mjolinor]

The USB plug has 6 pins out of the 10 used. 4 are used as normal, +, 0 D+ D-, of the other two one is used to switch the USB into Host mode so it will run a USB stick or external keyboard and the other is to enable the fast charging.

This pin does not take the high current it just drives a transistor switch to enable the standard pins to take a high current.

If it has stopped working on yours and your charger is OK then you need to have it looked at because the plug connecting to the motherboard is very weak and if one has come off the others will follow then it won't charge or connect to a PC at all.

Edited by Mjolinor, 26 December 2011 - 08:49 AM.