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Charging: USB and AC differences

Surprised you didn't get any response to this - very interesting.

What is that touch screen test app you were using?

Ian

It is Multitouch Visualizer, by Luke Harrison, in the Android Market. It's meant to demonstrate the limitations of the design in identifying the location of both fingers when doing multi-touch but it's quite good I think as a simple tester.

I've thrown that charger away! In any case it was only doing "USB charge" instead of "AC charge" and I suspect it is a low-quality piece of dangerous crud.

Goodness knows how precisely a charger can stuff up a screen like that.

doug
 
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So, summed up:
- If a generic micro-usb charger is used its got to be 1A.
- If the HTC Official charger is used it will work fine.
- If a USB adaptor is used with the HTC data cable, then at some point the data lines must be linked to charge.
- If a USB adaptor is used with a generic/power micro-usb cable, then it should work fine.

So realistically, the choices are:
Official Charger:HTC: Accessory store: Pocket PC Power Adaptors + Batteries: HTC Desire Car Charger with USB/micUSB Cable CC C200 (1A/5V): Description

Generic 1A Charger off ebay:
Car Charger for HTC Desire on eBay (end time 13-Jul-10 00:57:47 BST)

USB Adaptor:
Micro DC to USB Adaptor Home Car Maplin


Im tempted to get the official charger tbh.
Although this has caught my eye:
HTC: Accessory store: Pocket PC Vehicle Kits: HTC Desire Car Upgrade Kit CU S420: Description
However it doesnt say if it functions like the N1's version of it, where i cant use BT to transfer music/calls to my cars stereo as it uses its on BT for its version of a handsfree....
 
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What is different in this charger than any other 1A cigarette charger? I have one 1A cigarette charger and still when running the GPS the battery is discharging instead of charging.... Is this charger somehow different from any other 1A charger?


Heres the thing, armed with a number of cigarette USB adapters i have been having trouble with charging of the phone and using it as a sat nav. It seems that wether you are using the unit as a sat nav on charge or battery it gets hots this can only be down to the fact that the processor is working hard updating the images of the map the GPS is also working and the battery draw is heavy. All these things in a small unit will cause heat build up

I tried a number of different adapters along with a new lead that i had bought and the results were pathetic. So i went back to basics comparing charging time with the original lead and charger and the new lead. The original HTC lead seemed to charge fairly quickly but the new lead did not (it was cheap). The same results were obtained with another usb 240 volt adapter.

So using the original lead i found a car charger that seemed to just charge the battery whilst listening to music but discharged when using the sat nav. In the mean time i purchased a retractable lead which has charging only capability, this worked better as the part that plugs into the charger is smaller and doesn't catch on the gear lever when in 5th gear. I plugged this into the desktop charger and the charging results were quicker than normal.

I took this lead and the best charger and finished the charging cycle in the car whilst the wife played DJ. The unit charged quickly, after charging had finished the adapted cooled down indicating that the power output had decreased in accordance. The next part of the journey, albeit it short was with the sat nav going and the music playing and it seemed to be without problem, keeping the battery fully charged

So it was in the lead, some further reading on WIKI Universal Serial Bus - Wikipedia, the free encyclopedia seems to confirm the differences with charging rates of devices

You do need an adapter that can supply 1000ma and to be on the safe side make sure it is a switch mode adapter so that over charging does not occur.

I have yet to do further testing but early results are indicating success
 
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I just bought a cheap USB charger marked "1200mA". Of course it only accomplished "Charging (USB)". :rolleyes:

Assuming the charger is actually capable of delivering 1A (sustained), I've hacked together a short USB-USB cable where I've shorted out the 2&3 wires. This works just fine, the phone now reports "Charging (AC)" and actually does charge while simultaneously streaming from Last.fm and running Google Navigation with the screen on full blast. :cool:

Code:
car      phone
1------------1
2----,-------2
3----'-------3
4------------4
But then I thought, I wonder if this is in any way damaging to the phone, and that maybe I should leave the phone-end of the data wires unconnected? :thinking:

Code:
car      phone
1------------1
2----,     --2
3----'     --3
4------------4
I could open up the cable and experiment, but I'm hoping somebody here will know. So ... Any advice on this?
 
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But then I thought, I wonder if this is in any way damaging to the phone, and that maybe I should leave the phone-end of the data wires unconnected? :thinking:

Code:
car      phone
1------------1
2----,     --2
3----'     --3
4------------4

As I understand it, with that cable the phone will think that's a PC connection and limit itself to drawing 500mA. i.e. it's the phone which detects the short, and uses it as a (dumb) signal that the charger is capable of higher currents.
 
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@KlayenDK Whatever you do, don't plug that modified cable (with shorted-pins 2+3) into a laptop/PC, that could well and truly knacker your computer!!! That is why it would be best to modify the Car charger module, rather than the cable. Less chance of a cock-up in months to come when you desperately need a USB cable ;-)
 
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I have the Maplin 1A charger with the centre pins joined so it shows AC Charging on the Desire. I thought all would be well, how wrong I was...

I plugged the Desire into the car charger with it showing 98% charge (AC charging), turned bluetooth and GPS on and arrived 2 1/2 hours later with it showing 9% charge :(.

Hmmm. I'm thinking "first disappointment with Desire" thread. However I thought I'd do a quick test first...

So I plugged the Desire into the HTC mains charger, turned on bluetooth and GPS, connected the headset, set a route in CoPilot and left it on the window ledge to get a satellite fix. It started with 52% battery and 1 1/2 hours later shows 88% :) (it is bloody hot though).

Conclusion; even though your usb charger may be showing AC Charging it might not be providing anywhere near 1A (and maybe only little more than 500mA).

I'm off to buy a genuine HTC car charger and if it don't power bluetooth and GPS its going back :)

As an aside does anyone know of an app the displays the charging current?
 
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it's the phone which detects the short
@KlayenDK Whatever you do, don't plug that modified cable (with shorted-pins 2+3) into a laptop/PC
Don't worry mate, that's not happening. One, it's ridiculously short; two, it's clearly marked.
But what you to are saying is that the cable should be modified the other way around, then?
Code:
car      phone
1------------1
2--       ,--2
3--       '--3
4------------4
As an aside does anyone know of an app the displays the charging current?
Not as such, but for instance JuicePlotter will show (a) a rising graph, where you can sort of judge from the steepness, and (b) a widget with charge time remaining, which should be half as much (if even that) on AC than on USB.
 
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I have the Maplin 1A charger with the centre pins joined so it shows AC Charging on the Desire. I thought all would be well, how wrong I was...

I plugged the Desire into the car charger with it showing 98% charge (AC charging), turned bluetooth and GPS on and arrived 2 1/2 hours later with it showing 9% charge :(.

OK first question, how hot was the Phone? There appears to be some form of thermal cut-out that stops the phone charging when the phone reaches a certain temperature. I would imagine that was the reason the Phone was discharging rather than charging. Could this be the reason?
 
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Whatever you do, don't plug that modified cable (with shorted-pins 2+3) into a laptop/PC
But what you to are saying is that the cable should be modified the other way around, then?
Code:
car      phone
1------------1
2--       ,--2
3--       '--3
4------------4
it doesn't matter where the short on pins 2+3 occurs, they just need to be shorted out.
Well my thought was that, using this last variant, I would not risk frying a pc... ? I just want to make a cable that's as safe as possible (as well as document here what that is).
 
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Not as such, but for instance JuicePlotter will show (a) a rising graph, where you can sort of judge from the steepness, and (b) a widget with charge time remaining, which should be half as much (if even that) on AC than on USB.
Cheers, I'll give it a go.

OK first question, how hot was the Phone? There appears to be some form of thermal cut-out that stops the phone charging when the phone reaches a certain temperature. I would imagine that was the reason the Phone was discharging rather than charging. Could this be the reason?

The phone was actually hot while mains charging. I didn't check the actual temp but I tend to think it was 'normal' given it was running bluetooth and GPS at the time. I'll give it another go once I've installed JuicePlotter.

It runs cool in the car as it sits by the centre vent which I have directed at it (much to the annoyance of any passengers :))
 
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The interesting thing is, that the supplied charger say output 600 - 750ma
58f3410f.jpg


I just did a 35min journey, Google Navigation + GPS + Auto screen brightness
According to the battery graph produced by Battery Snap, the charge state rose from 64% to 69% in that 35mins
HTC
I brought possibly the same cradle kit, as that lead looks like the same sticker as mine.
FLASH SUPERSTORE PREMIUM SUBLIME CAR HOLDER/KIT: Amazon.co.uk: Electronics & Photo

Anyway after reading this, i plugged the desire into the car and loaded up NDrive. I didnt drive anywhere but i left it in the car for 30mins with the screen on and ndrive open, BT on and connected to headset.
30mins - battery charged 7%

It said AC charging.

I was using a little CIg lighter to USB socket thing, which said 1000mA on it (USB charging), although using a cheapo usb cable and the HTC one, the battery de charged when using google nav. I do wonder if the cheap cable was USB 1.0 though.
 
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