Develop Bugs

High current car charger

Anybody come across a car charger that is high current like the HTC wall charger?

Most car chargers are classified as "rapid".

Anything designed to charge an iPad (2.1A versus the typical 1A) will give you plenty of juice. I use the Scosche reVIVE II with Pandora, Bluetooth, and GPS Navigation all on and still have enough power to positively charge my battery.
Fair warning, though, this will cause the phone to get real hot (I've had the overheating warning lights flash twice so far), so make sure you have plenty of ventilation around the phone, keep it out of the sun, etc etc.

Any charger that is at least 1 amp. will do. The phone 'pulls' a max of around 0.85 amps. No need for more then 1 amp.
If it has a replaceable cable, it must be the heaviest gauge, shortest cable, that you can use. I have seen long cheap thin cables that drop over a volt, and the Thunderbolt charges really slowly.
The charger or cable have to state that they for rapid charging. To rapid charge, you need to have the USB D- and D+ lines shorted. If that are not shorted, the Thunderbolt limits the charge current to around 0.35 amps. thinking it is connected to a PC. If they are shorted, letting the Thunderbolt know it can be rapid charged, you get up there around 0.85. You can easily modify the charger for high rate if it is good for at least an amp.
And in the end is heat. Heat and lots of it. It will damage the battery. So put it out of the sun and in cool air like near a vent.

Motorola Rapid Charger on Amazon is the best. I bought two.
http://www.amazon.com/Motorola-Vehi...Q9CA/ref=sr_1_1?ie=UTF8&qid=1309959388&sr=8-1
Review off Amazon
Genuine Motorola charger in retail packaging. 4.75-5.25V 950mA output, works w/ most micro-USB phones like Incredible, etc., June 11, 2010
By
David Pearlman "sound fanatic" (Arlington, MA) - See all my reviews
(TOP 500 REVIEWER) (VINE VOICE) (REAL NAME)
Amazon Verified Purchase(What's this?)
There are so many sketchy sellers selling phone chargers out there, that it can be a bit scary. The problem is that if the charger is poorly made, the output of the charger can be out of spec and can, in some cases, fry the phone you connect to it.
For that reason, when it comes to phone chargers, you should stick to name brands. (They are all made in China, but the name brand ones are usually subject to stricter QA).
When I found this charger on Amazon, SOLD BY AMAZON, I jumped on it. It's a MICRO USB car charger, made for Motorola and sold under the Motorola name, in retail packaging. The rated output is 4.75-5.25V and 950mA.
This charger should work fine with most any phone that uses the MICRO USB connector. The key number to pay attention to is the second one, the rated amperage. This is the MAXIMUM amount of current that the phone can request from the charger. A typical USB port on a PC provides as little as 100mA, and few provide more than 500mA. So this charger should charge your phone faster than when it's connected to a PC. A few phones out now can use up to 1000mA. But that just means they CAN use that amount. If 950mA is provided, they'll still charge, just a bit more slowly.
Note that the amperage (second number) merely tells you how much the charger CAN supply, if requested. The phone itself is responsible for asking for the current. That is to say, if this charger can provide 950mA, but your phone can only use 300mA--no problem. Your phone asks for 300mA and the charger provides all of what is requested. If, on the other hand, your phone can use 1000mA, this charger will provide all it can, which is 950mA--a wee bit less than the max asked for. That's also not a problem; it just means your phone will charge a little bit (not much in this case) more slowly. The rated voltage for this charger is presented in a range of 4.75-5.25V. The "ideal" voltage for a USB charger of any type if 5V. And most chargers for home use are rated right at 5V. But car chargers work in a noisier environment and thus you have the range. This is where a cheapo charger can really do damage, as some of them are poorly regulated and can provide voltages that are WAY out of spec. Again, when you can get a name brand charger from a seller you can trust (Amazon) for such a reasonable price, it's very foolish to consider the cheapo no-names.
This is an excellent quality name brand travel micro USB charger at a price that beats the no-name junk from third party sellers. What's not to like?
BE SURE TO ORDER IT FROM AMAZON AND NOT ONE OF THE THIRD PARTY SELLERS, as some of those have been known to make mistakes with respect to what they ship relative to the listing. I can confirm that Amazon is shipping the P513 /89143N charger, as pictured.
Click to expand...
Click to collapse

ddgarcia05 said:
Motorola Rapid Charger on Amazon is the best. I bought two.
http://www.amazon.com/Motorola-Vehi...Q9CA/ref=sr_1_1?ie=UTF8&qid=1309959388&sr=8-1
Review off Amazon
Click to expand...
Click to collapse
I've been contemplating buying this one, but I'd like to ask you if it charges your battery with navigation+music going? I have a usb charger in my truck, and with both of those going it just manages to keep my battery level where its at, sometimes losing a % or two.

kr0n1c said:
I've been contemplating buying this one, but I'd like to ask you if it charges your battery with navigation+music going? I have a usb charger in my truck, and with both of those going it just manages to keep my battery level where its at, sometimes losing a % or two.
Click to expand...
Click to collapse
From what I've read in the past here on XDA and on the reviews for the charger (on amazon) you shouldn't have a problem. The second review for the charger on amazon states that the reviewer was looking for a charger which actually charged his phone will using GPS and that he found it. It's a very well built charger and cheap. It's made my Motorola and sold by Amazon so buy with confidence.

kr0n1c said:
I've been contemplating buying this one, but I'd like to ask you if it charges your battery with navigation+music going? I have a usb charger in my truck, and with both of those going it just manages to keep my battery level where its at, sometimes losing a % or two.
Click to expand...
Click to collapse
It does indeed charge. I've had it since my original Droid and was concerned when I updated to the TB but it will charge the TB no matter what you're doing (I've had Nav running while on a phone call with BT and searching the internet and it still showed it was charging). Just be prepared for your phone to get HOT!! Great charger.

worwig said:
Any charger that is at least 1 amp. will do. The phone 'pulls' a max of around 0.85 amps. No need for more then 1 amp.
Click to expand...
Click to collapse
Actually, the phone will pull more than 850 mA. You're probably basing that on using a battery monitor, which only shows the flow of current into/out of the battery. I've seen 800 mA into the battery at the same time I have display, GPS and a phone call going, which is definitely more than an additional 50 mA. It wouldn't surprise me if the phone can take advantage of something more than 1A, since I see a battery drain of more than 200 mA with all of that going when not on the charger.

kr0n1c said:
I've been contemplating buying this one, but I'd like to ask you if it charges your battery with navigation+music going? I have a usb charger in my truck, and with both of those going it just manages to keep my battery level where its at, sometimes losing a % or two.
Click to expand...
Click to collapse
I have that Motorola charger and am a heavy GPS user. It charges the battery as if it were plugged into the wall. You'll be very satisfied.

mike.s said:
Actually, the phone will pull more than 850 mA. You're probably basing that on using a battery monitor, which only shows the flow of current into/out of the battery. I've seen 800 mA into the battery at the same time I have display, GPS and a phone call going, which is definitely more than an additional 50 mA. It wouldn't surprise me if the phone can take advantage of something more than 1A, since I see a battery drain of more than 200 mA with all of that going when not on the charger.
Click to expand...
Click to collapse
No, that was measured at the 5 volt power supply, based upon a lab power supply. I did a lot of experimenting when I developed the charger and phone mount for my motorcycle. And to get the 850ma from the power supply, I used a very short, maybe 8 inch, USB cable, and a charge voltage close to 5.3 volts. With 5 volts at the power supply, it would only pull about 650ma from the power supply. That was due to the voltage drop in the USB cable. With the 5.3 volts at the power supply, I was getting close to an actual 5 volts at the Thunderbolt. I never measured the current at the battery, but I could see it being a bit more then the 850ma in, if there were a switch mode supply in there.
Though I like the Battery Monitor widget as a rough guide, I never tested to see if the battery current and the battery monitor are accurate.

Does anyone know if the included HTC ac adapter and cable will charge faster than using your pc with the included USB cable?

happimeal said:
Does anyone know if the included HTC ac adapter and cable will charge faster than using your pc with the included USB cable?
Click to expand...
Click to collapse
Absolutely.
A PC USB port is limited to under 500ma. The Thunderbolt appears to to limit PC USB draw to about 350ma. I haven't measured the actual current in the HTC charger, but it is a high current charger, and charges my Thunderbolt very quickly. Battery Monitor widget shows high battery charge rates. I suspect it is getting near the max rate up near 1 amp.

worwig said:
Absolutely.
A PC USB port is limited to under 500ma. The Thunderbolt appears to to limit PC USB draw to about 350ma. I haven't measured the actual current in the HTC charger, but it is a high current charger, and charges my Thunderbolt very quickly. Battery Monitor widget shows high battery charge rates. I suspect it is getting near the max rate up near 1 amp.
Click to expand...
Click to collapse
HTC charger states 5V/1A on the charger itself.

You can use the Palm car charger for $3.75+tax, free shipping. it is 5V/1A, same rating as the HTC wall charger.
Go here for 25% off
http://www.wireless.att.com/cell-ph...otion/accessories.jsp?source=EC0A0011600jtl10
Add product here, must add to cart to see 25% discount.
http://www.wireless.att.com/cell-ph...027&q_sku=sku4720234&q_manufacturer=&q_model=
Also, if so inclined, you can lop the top off of the charger so that you can use any usb cable (ipod, iphone, anything)

dpham00 said:
HTC charger states 5V/1A on the charger itself.
Click to expand...
Click to collapse
That doesn't mean much. That is the MAX the charger can output. The amount that the Thunderbolt will pull varies. If it thinks it is plugged into a USB, it will be less then 500ma. even if the charger is capable of 10 amps.

worwig said:
That doesn't mean much. That is the MAX the charger can output. The amount that the Thunderbolt will pull varies. If it thinks it is plugged into a USB, it will be less then 500ma. even if the charger is capable of 10 amps.
Click to expand...
Click to collapse
i have used the Palm car charger, checking with bmw, it shows around 850ma, same as on my htc charger.

worwig said:
Any charger that is at least 1 amp. will do. The phone 'pulls' a max of around 0.85 amps. No need for more then 1 amp.
If it has a replaceable cable, it must be the heaviest gauge, shortest cable, that you can use. I have seen long cheap thin cables that drop over a volt, and the Thunderbolt charges really slowly.
The charger or cable have to state that they for rapid charging. To rapid charge, you need to have the USB D- and D+ lines shorted. If that are not shorted, the Thunderbolt limits the charge current to around 0.35 amps. thinking it is connected to a PC. If they are shorted, letting the Thunderbolt know it can be rapid charged, you get up there around 0.85. You can easily modify the charger for high rate if it is good for at least an amp.
And in the end is heat. Heat and lots of it. It will damage the battery. So put it out of the sun and in cool air like near a vent.
Click to expand...
Click to collapse
um, i am aware that any charger that will do 1A will do. that was my question, what car charger will do 1A. Alot of times, they dont have that info listed on pages that are selling them.
and the whole thing about the D- and D+ shorted together, i do not believe. the HTC cable that came with the phone does rapid charging and i use it for data all the time too. if they D- and D+ was shorted, i would not be able to use it for data transfer. not unless the HTC charger shorts them internally inside the charger.

leoingle said:
unless the HTC charger shorts them internally inside the charger.
Click to expand...
Click to collapse
Bingo!!

leoingle said:
um, i am aware that any charger that will do 1A will do. that was my question, what car charger will do 1A. Alot of times, they dont have that info listed on pages that are selling them.
and the whole thing about the D- and D+ shorted together, i do not believe. the HTC cable that came with the phone does rapid charging and i use it for data all the time too. if they D- and D+ was shorted, i would not be able to use it for data transfer. not unless the HTC charger shorts them internally inside the charger.
Click to expand...
Click to collapse
Yes, it is hard to find the current info online or even on the package sometimes.
Yes, it is shorted in the charger. I have seen it done in the cable and the cable can't be used for data of course. Not sure why anyone would do that, but they do.

Automobile Quick Charging Solution

What is the best solution for quick charging the Galaxy Nexus in an automobile?

I have started to use 12-220 volt converter so I can use wall chargers.

I have bought a few of the low profile car usb chargers but they were never recognized as an AC charge. Come to find out, it was the USB cable. I bought a usb charging cable from Amazon last week and it goes in the USB charger and the phone does not think it is a USB charge. I have not timed it but it is recognized the same as the wall charger.
http://www.amazon.com/gp/product/B003VYBCAY

ellisz said:
I have bought a few of the low profile car usb chargers but they were never recognized as an AC charge. Come to find out, it was the USB cable. I bought a usb charging cable from Amazon last week and it goes in the USB charger and the phone does not think it is a USB charge. I have not timed it but it is recognized the same as the wall charger.
http://www.amazon.com/gp/product/B003VYBCAY
Click to expand...
Click to collapse
+1 .. this solution has been working great for me, as well.

I've been getting 2.1A car chargers (look for ones for the iPad), most of the ones I had prior to this were 700mA or so and they can't keep up with my 1A phones. Be careful of dual port chargers advertising 2A, they may only be 1A each and may be "optimistic" about that rating. And don't worry about getting one rated for too much current, the Galaxy Nexus won't pull more than an amp no matter what the charger rating.

Some really good solutions here and thank you all for the help.
I'd really hate to use an inventer in my car just to maintain a clean install, so that really isnt an option for me.
Was really hoping to be able to use a off the shelf car charger with the correct pins to trick the GNexus into thinking that it was charging from a USB port, but the above solution should work well with using a socket USB charger.

I've never run into a car adapter that looks like a USB port, including the VZW charger with a spare port or the cheap 2.1A chargers I got from Amazon. My guess is that a charger not built correctly and leaving the data pins open only supports ~500mA anyway. Even if that's not the case I have a moral objection toward buying a cable to fix a design flaw in another cheap product - but that's just me

Grant H said:
Some really good solutions here and thank you all for the help.
I'd really hate to use an inventer in my car just to maintain a clean install, so that really isnt an option for me.
Was really hoping to be able to use a off the shelf car charger with the correct pins to trick the GNexus into thinking that it was charging from a USB port, but the above solution should work well with using a socket USB charger.
Click to expand...
Click to collapse
I've got a charger similar to http://www.ebay.com.au/itm/USB-Car-...ccessories&hash=item4ab18358f4#ht_1638wt_1392
All I had to do was undo the screws at the top, put a bit of solder between the middle usb pins, and my phone recognises it as a AC source rather than USB.

There has got to be a standard car charger on the market with the middle usb pins already soldiered!
I found this on Amazon which advertises itself as a rapid charging device.
http://www.amazon.com/gp/product/B000S5Q9CA

Grant H said:
What is the best solution for quick charging the Galaxy Nexus in an automobile?
Click to expand...
Click to collapse
Make sure the charger has the IC (rapid) chip. I use this one:
http://www.amazon.com/Motorola-Vehicle-Adapter-micro-USB-Charger/dp/B000S5Q9CA

I've heard that Motorola one mentioned a lot as a good one.
The nice thing about having the low-profile usb plug is (a) it is low profile, (b) I can use it to charge other devices. The charge-only cable is only about $4, so I had no issues buying it to work with this to charge as an AC charge over a USB charge.

Grant H said:
There has got to be a standard car charger on the market with the middle usb pins already soldiered!
I found this on Amazon which advertises itself as a rapid charging device.
http://www.amazon.com/gp/product/B000S5Q9CA
Click to expand...
Click to collapse
I have this one and it charges just like it does from the home outlet and its says "AC" charging. I bought another 8 for family and friends and they all love it.

I think I've figured out the disconnect, I've run into chargers that appear as a USB host which limits the charging to 500mA on previous phones I've had.
You guys are concerned about USB vs. AC charging mode. Of the chargers I've got, this one lists as AC while the rest as USB. However, the fact that the other chargers all work just fine keeping up with GPS+streaming music indicates that the USB vs. AC really has no bearing on the charge current delivered. I'd stay away from charge-only cables just because they'll get mixed in with your standard USB cables and you'll knock yourself out wondering why they don't work. On the other hand, if you really want AC in your battery info order the one I linked.

I keep it in my car... i think I've heard on other threads that USB charging doesn't keep up with GPS (for Directions). Any verify?
Sent from my Galaxy Nexus using XDA App

TheKaz said:
I keep it in my car... i think I've heard on other threads that USB charging doesn't keep up with GPS (for Directions). Any verify?
Sent from my Galaxy Nexus using XDA App
Click to expand...
Click to collapse
What's much more important is the rating on the power source. The GN can pull up to 1000mA, if your charger is only rated for 800mA (like many car chargers) it doesn't matter if it's in AC mode.

jdbower said:
What's much more important is the rating on the power source. The GN can pull up to 1000mA, if your charger is only rated for 800mA (like many car chargers) it doesn't matter if it's in AC mode.
Click to expand...
Click to collapse
makes sense.. the one I use has dual usb (1.0 and 2.1)

You went and gave me a project for the weekend, and once again science prevails over anecdotal evidence. I took each of my 5 chargers and hooked them up to a 12V power supply that measures current. I then recorded whether the charger reported AC or USB, for the ones with USB I modified a right-angle adapter to short out the data pins, and I measured the current. The contenders:
Verizon Wireless Dual Charger
XTG Dual Port Charger
Griffen Powerjolt Dual USB Charger
Griffen Portjolt Micro
CostMad Dual USB Charger
The VZW model was USB out the external port as I had tested before, however AC out the built-in cable which I hadn't bothered to test. It pulled 0.25A @12V via the USB port and 0.59A via the cable. Hmmm... A hole develops in my previous observation. While I had used this on a long car trip with no issues, it was via the built-in cable.
The XTG was new, I hadn't used it before as it's in the car I rarely drive. It reported USB and 0.22A. With the adapter to make it report AC it pulled 0.48A.
The pattern was set. I had expected the Griffen adapters to be built more appropriately but the dual charger reported 0.22A without the adapter and 0.42A with. I had used this without losing charge in the past so this was surprising to me, but it's possible I just wasn't drawing as much current because the screen was dimmer or something.
The compact Griffen adapter (which is great for a laptop bag, BTW) pulled 0.21A and 0.47A respectively.
The cheap CostMad adapter was the only one that performed well out of the box, both reporting AC and pulled 0.57A.
In theory, a perfect adapter should pull 0.42A. Anything more is waste, anything less means it's not keeping up. I have doubts about the Griffen 2x allowing for a full amp, but the VZW and CostMad chargers are pretty lossy. What's even worse is that I'm pretty sure the VZW charger is rated for 800mA (but I can't find an actual spec on it) which would mean that it pulled the most power for the least current. Not that this really matters unless you've got an electric car.
Sorry for misleading you earlier, I should have checked the other port of the known-good VZW charger and probably doublechecked the numbers on my other "known good" charger. Still hating cables that work for charging but not for data, I ended up modifying each of the chargers to short the middle pins (except for the VZW one). If I didn't have the soldering iron for this, I probably would have gone for some of these instead.

Grant H said:
There has got to be a standard car charger on the market with the middle usb pins already soldiered!
I found this on Amazon which advertises itself as a rapid charging device.
http://www.amazon.com/gp/product/B000S5Q9CA
Click to expand...
Click to collapse
CyberPunk7t9 said:
Make sure the charger has the IC (rapid) chip. I use this one:
http://www.amazon.com/Motorola-Vehicle-Adapter-micro-USB-Charger/dp/B000S5Q9CA
Click to expand...
Click to collapse
I'm using the same one and it works perfect. Charges even when GPS navigation is running.
Make sure you select Amazon as the seller though. I heard there are a lot of fake ones.

Grant H said:
There has got to be a standard car charger on the market with the middle usb pins already soldiered!
I found this on Amazon which advertises itself as a rapid charging device.
http://www.amazon.com/gp/product/B000S5Q9CA
Click to expand...
Click to collapse
+1 to those recommending this one. I have this exact model and it does indeed charge at the "AC" rate, about twice as fast as the "USB" rate.

TheKaz said:
I keep it in my car... i think I've heard on other threads that USB charging doesn't keep up with GPS (for Directions). Any verify?
Sent from my Galaxy Nexus using XDA App
Click to expand...
Click to collapse
The Motorola one will charge even when using GPS. I have a friend I bought one for that uses his GPS all day and loves the Motorola charger.

I'm Having Charging Issues - Are All Micro USB Cables Created Equally?

I bought an OEM Samsung wall charger that charges at 1 Ampere. I started to charge my Zerolemon battery with it yesterday at about 6pm and here it is today and it is only at about 80% charge rate. Something is not right. I contacted the seller and they told me that the charger is from Samsung and it charges at 1 Ampere. It is either the charger is a knock off or my Micro-usb cable that connects into the wall charger is not the right kind.
Are there different variations of micro-usb cables that will work better? Some that allow more current to flow over them than others? My cable says that it is 28awg/2C. I remember when I had a playstation 3 I had problems with syncing the device with my playstation 3 with the USB cables I had bought. After tons of research it was the USB cables that were the issue. They didn't allow enough current to work properly with the PS3. I'm starting to wonder if I'm having the same issue with the Samsung Wall Charger. Is the 28awg wire gauge too thin?

---->[email protected]<---- said:
I bought an OEM Samsung wall charger that charges at 1 Ampere. I started to charge my Zerolemon battery with it yesterday at about 6pm and here it is today and it is only at about 80% charge rate. Something is not right. I contacted the seller and they told me that the charger is from Samsung and it charges at 1 Ampere. It is either the charger is a knock off or my Micro-usb cable that connects into the wall charger is not the right kind.
Are there different variations of micro-usb cables that will work better? Some that allow more current to flow over them than others? My cable says that it is 28awg/2C. I remember when I had a playstation 3 I had problems with syncing the device with my playstation 3 with the USB cables I had bought. After tons of research it was the USB cables that were the issue. They didn't allow enough current to work properly with the PS3. I'm starting to wonder if I'm having the same issue with the Samsung Wall Charger. Is the 28awg wire gauge too thin?
Click to expand...
Click to collapse
- charger is rated 1amp but usually puts out less depending on the quality and efficiency of it. You won't get the fastest charge with a 1amp psu. Get yourself a cheap 2amp and have plenty of headroom.
- also, if voltage in your wall outlet is low (rare) that would affect psu output.
- yes super thin usb cables can be part of the cause.
- of course, if the cable is meant for PC charging, it will be wired in such a way, to not exceed 450ma (or so) whereas a usb cable or charger that is meant and wired for fast charge, will provide...for me...1150ma (Search/Research my past posts for more detailed info)
- also, most kernels, slow down the charge rate as the batter gets closer to 100% charge.
- a bad battery or custom kernel with bad code, could both affect charging speed.

Slow QI charging

Ordered a QI charger off Amazon (the same Lerway Chinese brand one everyone seems to get) and it's charging incredibly slow. Not sure if the app I'm using to record the charge rate is incorrect or I'm not reading it correctly but it says it's charging at only +200mA max sometimes as slow as <50mA.
Anyone else experience this?

skusa93 said:
Ordered a QI charger off Amazon (the same Lerway Chinese brand one everyone seems to get) and it's charging incredibly slow. Not sure if the app I'm using to record the charge rate is incorrect or I'm not reading it correctly but it says it's charging at only +200mA max sometimes as slow as <50mA.
Anyone else experience this?
Click to expand...
Click to collapse
What kind of power source you use to power the charger and what kind of cable do you use?
If you connect the charger to computer USB port it will not provide enough power for the charger. Same with cheap cables, like the ones mostly included with the generic QI chargers. You need a premium USB cable.
Also if you have a thick case on your phone it will diminish the charging current received by a coil in your phone.
Firstly check how much power and what current your charger gets, so instead of plugging the QI charger, plug your phone and check what amperage you get (I use Current Widget). If it's less then 1600mA (maximum amperage that N5 will allow from direct charging through cable) your charger is underpowered and you need to change socket charger to 2A one. If you're using 2A socket charger and still get under 1600mA then your micro USB cable isn't good enough.
Properly and fully powered Qi charger should charge your bare phone (without a case) at about 700-800mA.

Znamir81 said:
What kind of power source you use to power the charger and what kind of cable do you use?
If you connect the charger to computer USB port it will not provide enough power for the charger. Same with cheap cables, like the ones mostly included with the generic QI chargers. You need a premium USB cable.
Also if you have a thick case on your phone it will diminish the charging current received by a coil in your phone.
Firstly check how much power and what current your charger gets, so instead of plugging the QI charger, plug your phone and check what amperage you get (I use Current Widget). If it's less then 1600mA (maximum amperage that N5 will allow from direct charging through cable) your charger is underpowered and you need to change socket charger to 2A one. If you're using 2A socket charger and still get under 1600mA then your micro USB cable isn't good enough.
Properly and fully powered Qi charger should charge your bare phone (without a case) at about 700-800mA.
Click to expand...
Click to collapse
Thanks for the info I thought I was going crazy.
No case so that isn't an issue.
I have the phone connected direct to a 3A charger currently and am only getting 995mA charge rate with the screen on and it looks like full 1.5A with the screen off. Maybe a defective QI charger?

Nope. Everything is normal. You just need a better cable that will manage to transfer 2A of current.
QI charger needs 2A input to give 1A output on a coil. Giving about 70-80% efficiency rate, your phone would be getting about 700-800mA.
Since your charger gets only about 1A input it gives about 500mA output. Therefore giving that efficiency rate, your phone should be getting about 350-400mA tops. It is possible that your charger has lower efficiency rate (some have about 50-60%), so the values that you're getting are pretty normal unless you use a premium micro usb cable, preferably with thicker, like AWG24 or lower (the lower value the better) power wires.

Might want to try these cables, a lot of people have had great luck with using them on Qi chargers. Don't know which length you would need, they have 3 and 6 foot cables. For the price, I'm ordering 6 6ft cables.
http://www.monoprice.com/Product?c_id=103&cp_id=10303&cs_id=1030307&p_id=9762&seq=1&format=2

Car Tablet Install Not Charging Consistently.

As the title I'm having problems charging. A lot of the time the battery is discharging and requires being charged inside, where it does charge consistent and fast!
I the car I have a 10amp 5v dc/dc converter providing the power, I have the thick cable OTG from amazon, along with Amazon basic USB cable extensions, and a 4 port hub.
I've used different chargers, even dual chargers with a USB hub that had independent power, I changed the OTG cable, Heck I even changed TABLETS! From a Wi-Fi to an LTE. The only common thread is the backup camera and Timur's kernel.
Considering it charges perfectly plugged into a wall I assume it's not the kernel.
I've seen at least one other with this issue, Any ideas? I've been playing with this for months and as mentioned have changed every aspect of the install except the camera.

fr4nk1yn said:
As the title I'm having problems charging. A lot of the time the battery is discharging and requires being charged inside, where it does charge consistent and fast! I the car I have a 10amp 5v dc/dc converter providing the power, ...
Click to expand...
Click to collapse
These car chargers supply perfect 5.0V while your original Asus AC charger delivers 5.2V (have a look at its specs). Believe it or not, 0.2V makes the difference, and at 5.0V your tablet will not charge reliably. I actually use a regulated PSU set higher, at 5.3V, to compensate for voltage drop on poor USB cables.
Look for 5.2V/2A car charger and use max 1m quality USB cable, no hubs.

Thanks. The charger is indeed 5.2v. Odd. What charger are you using?
This is the one I have: https://www.amazon.com/Converter-Re...1513386282&sr=8-8&keywords=dc+to+dc+converter and it puts out 5.1v
I found it was only getting 8v-10.5v and wired it directly to the car's wiring, I was using spades previously to connct to the Aux power connector, Getting full 14.2v made no difference to the tablet's charging.
Next I removed the tablet and plugged it into a 5v/2amp wall charger using the old OTG and the old 3 foot USB extension cable. It charges consistently between 580 - 740mA. Meanwhile it went dead installed in the dash, again.

fr4nk1yn said:
This is the one I have: https://www.amazon.com/Converter-Re...1513386282&sr=8-8&keywords=dc+to+dc+converter and it puts out 5.1v.... Meanwhile it went dead installed in the dash, again.
Click to expand...
Click to collapse
To diagnose this problem you will have to acquire a simple, cheap USB meter and connect it as close as possible to N7. Note on the attachment my N7, 15cm USB cable and a tester measuring 5.18V. Please post your voltage reading.

I bought a 3amp adjustable DC to DC converter.
Set the voltage to 5.3v initially, then measured at the end of my 1 meter USB extension cable. It was still 5.3 so I dropped it back to 5.2v.
Plugged the tablet in, and it's immediately discharging at 563mAh. No apparent change after some use.

Thanks @k23m for the help. This thing just deteriorated. Something pulling a huge amount of power too. Sucked a fully charged battery to 0 in a day of of running errands. And it was sluggish beyond belief. I thought the ROM might be corrupt.
So I did the battery removal mod. It's working great on the bench so it's being wired up tomorrow. Thanks again.