Does anyone know the USB phone charging voltage level thresholds?

Thread Starter

Rich:-)

Joined Oct 14, 2016
44
I'm guessing their aren't any hard and fast standards as phones seem to behave differently but are there any standards they work to for the charger voltage?

Background
I run an Android phone as a sat nav on my motorcycle and have done this with many phones.
The PSU is usually a generic car charger that I re-package to make waterproof. My latest version though is a sealed 5v 2.5 amp PSU (from ebay), which worked fine with a previous phone but not with my latest.

I've done some testing between my 2 current phones and two chargers and have different results for each.
Charger A is labelled as output 5v 1.0 amp (mains charger) and has an open voltage of 5.1 volts.
Charger B is labelled as output 5.3v 2.0 amp (mains charger) and has an open voltage of 5.28 volts.

Phone 1 is a Nokia 7 Plus that is USB-C and has fast charging 18W
Phone 2 is a Blackview BV6900 is USB-C and has fast charging rated at 9v 2A / 18W

Charge current was monitored using an app on each phone.

Phone 1 on charger A charged at 1250 mA., and on charger B managed 1450 mA.
Phone 2 on charger A charged at 150 mA., and on charger B managed 1650 mA.

On my motorcycle's PSU Phone 2 only manages 150mA but it needs to be at least 600 mA for it to keep pace when in use.
So my plan is the make a new PSU from a DC-DC buck converter and to tune the voltage until I get an acceptable charge rate (to around 5.3 volts I think).
I don't want to kill this phone though hence I'm wondering if there are safe voltages that are higher than 5v?
 
Last edited:

Yaakov

Joined Jan 27, 2019
3,464
USB C has some rigorous standards for negotiating voltage and current. Is the Motorcycle charger a USB C charger or a fixed 5V power supply?
 

Thread Starter

Rich:-)

Joined Oct 14, 2016
44
Fixed 5v power supply.... and it seems like it is trying to establish a charge rate as it cycles between several charge currents - 45ma to 150ma.
 
Last edited:

Yaakov

Joined Jan 27, 2019
3,464

Thread Starter

Rich:-)

Joined Oct 14, 2016
44
Just thinking about this... do the USB Type C chargers use the data wires in the cable?
If so that would be difficult as my cable run on the bike doesn't include them.
 

Yaakov

Joined Jan 27, 2019
3,464
Just thinking about this... do the USB Type C chargers use the data wires in the cable?
If so that would be difficult as my cable run on the bike doesn't include them.
Yes, and in fact if you wanted even the simple higher current with USB 1.x+ you have to short the data lines to tell the phone its a DCP (Dedicated Charging Port) so it can be clued to draw full current.
 

Thread Starter

Rich:-)

Joined Oct 14, 2016
44
Yeh, that make sense..
I could just get a long cable (3-5 meters) so I can still run it to rear of the bike where all the electrics are.
 

Thread Starter

Rich:-)

Joined Oct 14, 2016
44
I didn't have USB charging issues with my last phones as they were all Sony Z's which have a two pin magnetic connection on the side, fast charging and a simple & fast connection... but I killed them accidentally so decided a rugged bike phone was the way forward.
Anyway.. I think I'm sorted now thanks.
 

Yaakov

Joined Jan 27, 2019
3,464
I didn't have USB charging issues with my last phones as they were all Sony Z's which have a two pin magnetic connection on the side, fast charging and an fast & water tight connection... but I killed them accidentally so decided a rugged bike phone was the way forward.
Anyway.. I think I'm sorted now thanks.
Let us know how it works out, maybe some photos...
 

Thread Starter

Rich:-)

Joined Oct 14, 2016
44
That's the phone in the upper position.
Sometimes I have a Garmin Montana there instead so the phone would then be down on the bars.
It's nice to have two Sat Nav's when touring.
The connector seen at bottom left is the switched 5v DC feed (to be removed), and there is also a 12v DC switch on another connector for the Garmin.
Then there's the 12V power outlet on the dash but I don't use that as it's not waterproof when in use. Good for running the mini tyre compressor though.
IMG_20210417_192234 small.jpg
 

Reloadron

Joined Jan 15, 2015
6,058
I use a Garmin Drive Smart 65 on my bike as well as in the truck. I can use my phone but much prefer the larger screen in the Garmin. My 12 volt - 5 volt USB type adapter is a 2.0 Amp max and that is more than enough. Both the Garmin and Samsung 7 cell have no problems running off that single adapter. Originally I was using the cigarette lighter socket but eventually just hard wired a socket. Both the Phone and Garmin determine their own rates of charge with the 5.0 volt USB input. The Garmin also has it's own lighter to USB Mini connector which I don't bother using. I use one of these for phone and my Garmin. This is hard wired into the bike.

Ron
 

Thread Starter

Rich:-)

Joined Oct 14, 2016
44
Hi Ron

Yes.. I'm going to do similar. I already have one of the wired power socket things doing nothing so that will be installed.
Also I did look into still making up a box an putting a QC 3.0 2.0 usb fast charging module in it but it was actually cheaper just to buy a pre-made car charger and use that with the wired socket.
So I have one of these on it's way to me.
Capture.JPG

Also from looking at the mains charger that came with my Blackview BV6900 it appears the phone is QC2.0/3.0 compatible.

BV.jpg

When I plugged that into the phone the app reported a 2.8 amp charging rate.. but as nice as it is to have that I prefer to charge slower.
The BV6900 has a 5580mAh battery so I don't suppose 2.8 amp charge rate is stressing it too much.. but still... 1.5 amps is plenty.
 
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