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Charging: USB and AC differences

USB sockets should be protected from short-circuits, so don't sweat it connecting a modified lead to a PC etc., especially if it's USB2 compliant...

Wikipedia explains better than I can:

"In Battery Charging Specification,[31] new powering modes are added to the USB specification. A host or hub Charging Downstream Port can supply a maximum of 1.5 A when communicating at low-bandwidth or full-bandwidth, a maximum of 900 mA when communicating at high-bandwidth, and as much current as the connector will safely handle when no communication is taking place; USB 2.0 standard-A connectors are rated at 1500 mA by default. A Dedicated Charging Port can supply a maximum of 1.8 A of current at 5.25 V. A portable device can draw up to 1.8 A from a Dedicated Charging Port. The Dedicated Charging Port shorts the D+ and D- pins with a resistance of at most 200Ω. The short disables data transfer, but allows devices to detect the Dedicated Charging Port and allows very simple, high current chargers to be manufactured. The increased current (faster, 9 W charging) will occur once both the host/hub and devices support the new charging specification."
 
After going through 4 car chargers, thanks to you guys in this thread, I solved this problem by:

1) Taking the Micro USB plug off the same charger shown by JABTAS in this thread on pg. 1. It was easy to take apart as the plug clips together. Using a soldering iron to take off the existing connections was a bit tricky as a couple of them were bridged by a tiny resistor.
2) Attaching the Micro USB plug to a USB power cable. Again taking care not to over heat the Micro USB plug terminals and knock off the small bridging resistor. This had to be done because of the USB charging / AC charging issue highlighted in this thread. The Micro USB plug off the FX charger shown by JABTAS is configured to make the HTC Desire charge in AC mode.
3) Buying a Schosche Revive 2 off AMAZON.CO.UK. Its got two sockets rated at 1A and 2.1A. It doesn't work with a "normal" usb > micro usb cable due to the USB vs. AC Charging issue. The HTC Desire drains the battery even if plugged into the 2.1A socket as it charges in USB mode.

However, add the Schosche Revive 2 and the custom cable together and voila! AC Charging mode in my car. I've yet to go on a long journey, but it seems to top up fine. My phone battery went from 75% to 79% in a 10 minute journey with Co-Pilot running when plugged into the 1A socket.

Frankly I shake my head in disbelief at the above process! OF the chargers I tried,

1) The charger I had at home was rated at 625ma and couldn't provide enough power to recharge the HTC Desire with Co-Pilot running.
2) So I ordered an Original HTC car charger but that didn't fit the cigarette socket in my Honda Civic 2002 properly so had to be returned. An issue other Civic drivers have had.
3) JABTAS charger (see pg. 1 of this thread) almost worked but got seriously hot. The HTC Desire wouldn't drain the battery, but wouldn't really charge either.
4) A "HTC DESIRE COMPATIBLE CAR CHARGER" brought off Amazon was rated at 500ma so I didn't even bother trying and just returned it.
 
And this is why Apple always uses custom cables :D -> so everyone would have the same experience. Of course, you'll pay through your nose for these official cables which is the downside :p.

But yeah, I noticed how slowly it would charge when hooked up to my PC. When moving files across and doing some other stuff, the battery can easily drop 20% over the space of just half an hour if you're not careful even when USB charging. It's a bit disappointing because the back panel feels so fragile otherwise I'd just keep a second charged battery in the car.
 
So I stumbled upon this thread on a search.. I have a powerjolt 2.1 amp charger and it charges in usb mode with my stock evo cable and an after market usb sync/charge cable. I just bought a "charge only" cable from amazon, so my question is will a charge only cable resolve this issue since it has not data capabilities?
 
A cable without a data connection has no way of shorting the data and power connections together, so it's unlikely to get the Desire to charge at 1A.
 
1
CE IN CAR CHARGER FOR HTC DESIRE G7 MICRO USB G6 G5

I recently got this from ebay and it charges AC. It does say 5V 600ma on it.
 
Hallo new user found forum thread via google. I'd like to give you the definitive answer for this.

Firstly, there are two switch-mode adapters out and most are not the one you want.

1. If it does less than 1A it is highly likely it is built around the battery charge chipset. This gives out 12v and lowers it as current diminishes (battery takes less current as it's voltage increases, LI-ION are 4.2v). These adapters may be called "variable voltage" but I've had a few which just say 5v when they are not. Plugging this into your HTC will show it as charging (either AC or USB depending on your cable) but it will not charge because the HTC's are protected against over voltage in. I've tested this with the Hero and Diamond. Another way to distinguish is it will NOT have a TO-220 FET on it.

2. If it does 1A to 2A it is certainly a proper 5v switch mode and will work ok. I've seen a few 1A ones but mostly they are 1.5A+. The HP PDA's all have these so one of those genuine adapters are guaranteed to work as are the IPAD chargers on ebay. Another way to distinguish is it WILL have a TO-220 FET on it as no 8-pin chip can do over 750mA directly.

With the correct adapter, shorting the data pins should make no difference as USBv2 can supply 1.5A. Using a multimeter is useless as the amps will change (will be max when battery is at 0%). However the HTC's do a quick check upon plug-in and if the switch mode is not fast enough to go from it's idle state then it will limit charge for USBv1 compatibility. If it didn't do this USBv1 hardware would detect the device as a short and cut power. For this reason shorting the data pins is highly recommended!

Finally, if you use a 3-in-1, 2-in-1 adapter you may find it forces Charging USB mode. The official one does and another I have does as well. This wont matter if your switching supply is fast enough. I'm not sure why they do this yet.

TO-220 FET: Recognizing The Case Of Transistors

Best HTC charger (2A) but you need to swap connector: APPLE IPAD IN CAR 2A CHARGER ADAPTER LEAD 3G WIFI WHITE on eBay (end time 07-Dec-10 03:52:22 GMT)

Regards, Andrew (charging his HTC with Co-pilot, music, screen on - motorcycle and car!)
 
I've just got this car USB charger online, to charge my HTC desire in car while Navigation is on.

attachment.php


The charger is rated 700mA output. The original charger that came with the phone is rated 1A. So is this safe to assume that this charger will charge the phone properly (not as fast as the original charger) thus keeping the battery from draining?

Is there any other issues using this kind of chargers in car while navigation is up and running? I have noted that phone heats up a bit while we use Navigation.
 

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ifb-online said:
I don't think 700ma is enough to maintain the battery level while navigating.
Ian
Click to expand...

Thanks Ian. I figured it out while testing it today evening while driving back home, I had navigation on for the whole 20 minutes drive, and the charger was connected. The battery level went down from 43% to 42%. Battery discharging at a very very slow pace. :(
 
I bought an HTC Desire just over a month ago, and after discovering that the genuine HTC CC C200 in-car charger doesn't fit properly in the cigarette lighter socket in my car (Saab 9-3, 2002) I started looking for alternatives. I'm glad I found this thread as it's so informative and helpful! :)

So, in the spirit of giving something back I'd like to share my findings...

For my HTC Desire I now have 2 (or probably 3) in-car chargers which provide an output sufficient to increase the charge level of the battery whilst constantly using the Desire's pre-installed Google Maps Navigation app. I purchased all of the chargers recently from Amazon.co.uk (prices correct at time of writing, including delivery):

- Fonerange micro-USB in-car charger,
 

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On reading this thread I had a wee nosey Myself and just as it happens I was going somewhere today where I needed 'navigation'. I have the official HTC charger and was surprised to find that it didn't fit the ciggy socket when I received it, thankfully My motor has two 12v ciggy lighty type sockets and it fits into those.

Anyways, left house with 83%, drove for about an hour using 'navigation' and finished with phone fully charged :)

What is the story with the HTC charger not fitting normal ciggy sockets? My last two motors had a solitary ciggarette lighter, just lucky this new rustbucket has charging sockets
 
Devices that plug into a car cigarette lighter socket appear to come in 2 designs with regard to the tip - one has a wider, more rounded tip (like the genuine HTC CC C200), and others have a narrower tip (like all 3 mentioned in my previous post).

Then there's the car cigarette lighter socket itself, which also appears to come in 2 designs - wide and narrow. I don't believe there's any easy way to tell which is fitted in your car until you try to plug in a wide-tipped device and then discover that it doesn't fit properly! This is exactly what happened to me when I tried the HTC CC C200 charger in my Saab.

As well as my Saab, I know some models of Honda and Alfa Romeo cars are also fitted with with the narrower socket. Basically it's just down to luck, depending on which type of socket your car manufacturer fitted to your particular model of car.

Si
 
Ok, now I'm confused.

I had the Belkin USB car adapter but, as others, could only get 'usb' charging out of it, so with GPS on I would get slow discharge of the phone.

Just bought the official HTC car charger (cc c200). With the curly cable that comes with it I indeed get 'ac' charging. However that cable is uselessly short (and curly) for my needs. With the normal data cable that I've attached to my car + the HTC charger I can only get 'usb' charging.

The Belkin + curly cable also only does usb charging.

I'm stuck. I thought the HTC charger would have the necessary pins shorted to give ac charging and the cable would make no difference.

Sigh.
 
@milliontown: that would suggest that with the official HTC charger, the data pins in the charger itself are not shorted, but the data lines in the uselessly short curly cable are shorted instead. (Obviously no normal data cable can have the data pins shorted as it wouldn't then be able to transfer data.)

IMO that's rather naff and annoying - it means you can get AC charging from the HTC charger only if you use the curly cable that comes with it. Crap design on HTC's part if you ask me!
 
If the data pins were shorted in the curly cable, surely you'd expect ac charging when using it with the Belkin charger..?

I'm beginning to think there's another factor at play.

I'll get out my multitester at some point and have a prod.
 
milliontown said:
If the data pins were shorted in the curly cable, surely you'd expect ac charging when using it with the Belkin charger..?

I'm beginning to think there's another factor at play.

I'll get out my multitester at some point and have a prod.
Click to expand...

I have the CC200 and I agree that it is the cable that is shorted. In fact I think it only actually has 2 wires that is how they manage to get 1amp down such a slim cable.
Not realising this I plugged it into my car stereo USB port to use a a data cable. Not only did I get no data but it said "charging AC". I unplugged it ASAP because I was not sure what this would do to my stereo.
 
milliontown said:
If the data pins were shorted in the curly cable, surely you'd expect ac charging when using it with the Belkin charger..?

I'm beginning to think there's another factor at play.

I'll get out my multitester at some point and have a prod.
Click to expand...


surprised you only get USB with the curly cable and the Belkin? read posts before where people have hacked cables and got AC charging. Perhaps the Belkin cannot supply 1amp and the phone has a secondary mechanism for choosing the charging type.
If there are no data wires the pins may only be shorted at the micro end so you will need a pretty fine multitester probe to test it.

You options seem to be a
a)cigarette lighter extension lead. 3M CAR CIGAR LIGHTER EXTENSION LEAD CABLE SOCKET 12V on eBay (end time 09-Apr-11 23:47:45 BST)

b)get a longer cable cut into it and short the wires but since the power cables will only be standard size they may not like supplying 1amp

I would go for a
 
USB puts out ~500mA (usually 5V) and AC chargers varies between 600A to 1.2A and 4.8V to 5.2V, USB charging is slower. I have a dual USB car charger, it says 1.2A but no voltage mentioned.
 
Here's the official response from HTC to my question about why I can't use the longer, standard cable:

Thank you for contacting HTC regarding your HTC car charger I understand that you are currently experiencing difficulties with the cable properties and charging the device. We are not able to advise on modifying the device as this would invalidate the manufacturers warranty.


Well yeah, thanks for that.

What's more, the problem report number they gave me for replying via their website brings me back me someone else's complaint!
 
milliontown said:
Here's the official response from HTC to my question about why I can't use the longer, standard cable:

Thank you for contacting HTC regarding your HTC car charger I understand that you are currently experiencing difficulties with the cable properties and charging the device. We are not able to advise on modifying the device as this would invalidate the manufacturers warranty.


Well yeah, thanks for that.

What's more, the problem report number they gave me for replying via their website brings me back me someone else's complaint!
Click to expand...

What a ridiculous answer! What the person means is that they don't know and can't be bothered to find out
If they don't want you to use a different cable with the charger then it should come with a permanently attached lead instead of using a standard USB port.
 
Jason71 said:
surprised you only get USB with the curly cable and the Belkin? read posts before where people have hacked cables and got AC charging. Perhaps the Belkin cannot supply 1amp and the phone has a secondary mechanism for choosing the charging type.
Click to expand...

Yes, I'm surprised too, and I was thinking the same - perhaps the phone not only detects whether the data pins are shorted but also the level of current supplied.

From my previous tests with extension cables and carefully placed bits of tin foil shorting the data pins within the USB connectors, my HTC Desire would happily charge at the AC level even though the Santok charger I was using did not yet have its data pins shorted internally.

Though it was a bit of a hassle to open up the Santok charger and solder the data pins together ('cos if it were made properly that would be done already during manufacture!), I decided this was the best option since I would then have a high output charger with a standard USB socket, capable of powering anything via any USB cable I choose - as mentioned, curly cables are generally annoyingly short! :mad:
 
An update:
spent an hour or so messing about with a multitester gradually getting nowhere. I did observe the data pins in the HTC charger appear to be shorted.
Out of desparation tried a new cable altogether (the HTC one that comes with the phone) with the CC C200 and hey presto! AC charging. Tried another Nokia cable and the same. So...it appears there's something very weird about my long cable installed in the car.

I've installed a usb socket extension cable to use with one of these other cables and all is well.

Phew.
 
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